From f318903c0bf42448b4c884732df2bbb0ef7a2284 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 27 Mar 2020 16:58:52 +0100 Subject: bpf: Add netns cookie and enable it for bpf cgroup hooks In Cilium we're mainly using BPF cgroup hooks today in order to implement kube-proxy free Kubernetes service translation for ClusterIP, NodePort (*), ExternalIP, and LoadBalancer as well as HostPort mapping [0] for all traffic between Cilium managed nodes. While this works in its current shape and avoids packet-level NAT for inter Cilium managed node traffic, there is one major limitation we're facing today, that is, lack of netns awareness. In Kubernetes, the concept of Pods (which hold one or multiple containers) has been built around network namespaces, so while we can use the global scope of attaching to root BPF cgroup hooks also to our advantage (e.g. for exposing NodePort ports on loopback addresses), we also have the need to differentiate between initial network namespaces and non-initial one. For example, ExternalIP services mandate that non-local service IPs are not to be translated from the host (initial) network namespace as one example. Right now, we have an ugly work-around in place where non-local service IPs for ExternalIP services are not xlated from connect() and friends BPF hooks but instead via less efficient packet-level NAT on the veth tc ingress hook for Pod traffic. On top of determining whether we're in initial or non-initial network namespace we also have a need for a socket-cookie like mechanism for network namespaces scope. Socket cookies have the nice property that they can be combined as part of the key structure e.g. for BPF LRU maps without having to worry that the cookie could be recycled. We are planning to use this for our sessionAffinity implementation for services. Therefore, add a new bpf_get_netns_cookie() helper which would resolve both use cases at once: bpf_get_netns_cookie(NULL) would provide the cookie for the initial network namespace while passing the context instead of NULL would provide the cookie from the application's network namespace. We're using a hole, so no size increase; the assignment happens only once. Therefore this allows for a comparison on initial namespace as well as regular cookie usage as we have today with socket cookies. We could later on enable this helper for other program types as well as we would see need. (*) Both externalTrafficPolicy={Local|Cluster} types [0] https://github.com/cilium/cilium/blob/master/bpf/bpf_sock.c Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/c47d2346982693a9cf9da0e12690453aded4c788.1585323121.git.daniel@iogearbox.net --- include/linux/bpf.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/bpf.h b/include/linux/bpf.h index bdb981c204fa..78046c570596 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -233,6 +233,7 @@ enum bpf_arg_type { ARG_CONST_SIZE_OR_ZERO, /* number of bytes accessed from memory or 0 */ ARG_PTR_TO_CTX, /* pointer to context */ + ARG_PTR_TO_CTX_OR_NULL, /* pointer to context or NULL */ ARG_ANYTHING, /* any (initialized) argument is ok */ ARG_PTR_TO_SPIN_LOCK, /* pointer to bpf_spin_lock */ ARG_PTR_TO_SOCK_COMMON, /* pointer to sock_common */ -- cgit v1.2.3 From 0f09abd105da6c37713d2b253730a86cb45e127a Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 27 Mar 2020 16:58:54 +0100 Subject: bpf: Enable bpf cgroup hooks to retrieve cgroup v2 and ancestor id Enable the bpf_get_current_cgroup_id() helper for connect(), sendmsg(), recvmsg() and bind-related hooks in order to retrieve the cgroup v2 context which can then be used as part of the key for BPF map lookups, for example. Given these hooks operate in process context 'current' is always valid and pointing to the app that is performing mentioned syscalls if it's subject to a v2 cgroup. Also with same motivation of commit 7723628101aa ("bpf: Introduce bpf_skb_ancestor_cgroup_id helper") enable retrieval of ancestor from current so the cgroup id can be used for policy lookups which can then forbid connect() / bind(), for example. Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/d2a7ef42530ad299e3cbb245e6c12374b72145ef.1585323121.git.daniel@iogearbox.net --- include/linux/bpf.h | 1 + include/uapi/linux/bpf.h | 21 ++++++++++++++++++++- kernel/bpf/core.c | 1 + kernel/bpf/helpers.c | 18 ++++++++++++++++++ net/core/filter.c | 12 ++++++++++++ tools/include/uapi/linux/bpf.h | 21 ++++++++++++++++++++- 6 files changed, 72 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 78046c570596..372708eeaecd 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1501,6 +1501,7 @@ extern const struct bpf_func_proto bpf_get_stack_proto; extern const struct bpf_func_proto bpf_sock_map_update_proto; extern const struct bpf_func_proto bpf_sock_hash_update_proto; extern const struct bpf_func_proto bpf_get_current_cgroup_id_proto; +extern const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto; extern const struct bpf_func_proto bpf_msg_redirect_hash_proto; extern const struct bpf_func_proto bpf_msg_redirect_map_proto; extern const struct bpf_func_proto bpf_sk_redirect_hash_proto; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index bd81c4555206..222ba11966e3 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2963,6 +2963,24 @@ union bpf_attr { * instead of sockets. * Return * A 8-byte long opaque number. + * + * u64 bpf_get_current_ancestor_cgroup_id(int ancestor_level) + * Description + * Return id of cgroup v2 that is ancestor of the cgroup associated + * with the current task at the *ancestor_level*. The root cgroup + * is at *ancestor_level* zero and each step down the hierarchy + * increments the level. If *ancestor_level* == level of cgroup + * associated with the current task, then return value will be the + * same as that of **bpf_get_current_cgroup_id**\ (). + * + * The helper is useful to implement policies based on cgroups + * that are upper in hierarchy than immediate cgroup associated + * with the current task. + * + * The format of returned id and helper limitations are same as in + * **bpf_get_current_cgroup_id**\ (). + * Return + * The id is returned or 0 in case the id could not be retrieved. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3087,7 +3105,8 @@ union bpf_attr { FN(read_branch_records), \ FN(get_ns_current_pid_tgid), \ FN(xdp_output), \ - FN(get_netns_cookie), + FN(get_netns_cookie), \ + FN(get_current_ancestor_cgroup_id), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 914f3463aa41..916f5132a984 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2156,6 +2156,7 @@ const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; const struct bpf_func_proto bpf_get_current_comm_proto __weak; const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; +const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; const struct bpf_func_proto bpf_get_local_storage_proto __weak; const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 01878db15eaf..bafc53ddd350 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -340,6 +340,24 @@ const struct bpf_func_proto bpf_get_current_cgroup_id_proto = { .ret_type = RET_INTEGER, }; +BPF_CALL_1(bpf_get_current_ancestor_cgroup_id, int, ancestor_level) +{ + struct cgroup *cgrp = task_dfl_cgroup(current); + struct cgroup *ancestor; + + ancestor = cgroup_ancestor(cgrp, ancestor_level); + if (!ancestor) + return 0; + return cgroup_id(ancestor); +} + +const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto = { + .func = bpf_get_current_ancestor_cgroup_id, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_ANYTHING, +}; + #ifdef CONFIG_CGROUP_BPF DECLARE_PER_CPU(struct bpf_cgroup_storage*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]); diff --git a/net/core/filter.c b/net/core/filter.c index 3083c7746ee0..5cec3ac9e3dd 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -6018,6 +6018,12 @@ sock_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_get_netns_cookie_sock_proto; case BPF_FUNC_perf_event_output: return &bpf_event_output_data_proto; +#ifdef CONFIG_CGROUPS + case BPF_FUNC_get_current_cgroup_id: + return &bpf_get_current_cgroup_id_proto; + case BPF_FUNC_get_current_ancestor_cgroup_id: + return &bpf_get_current_ancestor_cgroup_id_proto; +#endif #ifdef CONFIG_CGROUP_NET_CLASSID case BPF_FUNC_get_cgroup_classid: return &bpf_get_cgroup_classid_curr_proto; @@ -6052,6 +6058,12 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_get_local_storage_proto; case BPF_FUNC_perf_event_output: return &bpf_event_output_data_proto; +#ifdef CONFIG_CGROUPS + case BPF_FUNC_get_current_cgroup_id: + return &bpf_get_current_cgroup_id_proto; + case BPF_FUNC_get_current_ancestor_cgroup_id: + return &bpf_get_current_ancestor_cgroup_id_proto; +#endif #ifdef CONFIG_CGROUP_NET_CLASSID case BPF_FUNC_get_cgroup_classid: return &bpf_get_cgroup_classid_curr_proto; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index bd81c4555206..222ba11966e3 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2963,6 +2963,24 @@ union bpf_attr { * instead of sockets. * Return * A 8-byte long opaque number. + * + * u64 bpf_get_current_ancestor_cgroup_id(int ancestor_level) + * Description + * Return id of cgroup v2 that is ancestor of the cgroup associated + * with the current task at the *ancestor_level*. The root cgroup + * is at *ancestor_level* zero and each step down the hierarchy + * increments the level. If *ancestor_level* == level of cgroup + * associated with the current task, then return value will be the + * same as that of **bpf_get_current_cgroup_id**\ (). + * + * The helper is useful to implement policies based on cgroups + * that are upper in hierarchy than immediate cgroup associated + * with the current task. + * + * The format of returned id and helper limitations are same as in + * **bpf_get_current_cgroup_id**\ (). + * Return + * The id is returned or 0 in case the id could not be retrieved. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3087,7 +3105,8 @@ union bpf_attr { FN(read_branch_records), \ FN(get_ns_current_pid_tgid), \ FN(xdp_output), \ - FN(get_netns_cookie), + FN(get_netns_cookie), \ + FN(get_current_ancestor_cgroup_id), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call -- cgit v1.2.3 From 92234c8f15c8d96ad7e52afdc5994cba6be68eb9 Mon Sep 17 00:00:00 2001 From: Toke Høiland-Jørgensen Date: Wed, 25 Mar 2020 18:23:26 +0100 Subject: xdp: Support specifying expected existing program when attaching XDP MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit While it is currently possible for userspace to specify that an existing XDP program should not be replaced when attaching to an interface, there is no mechanism to safely replace a specific XDP program with another. This patch adds a new netlink attribute, IFLA_XDP_EXPECTED_FD, which can be set along with IFLA_XDP_FD. If set, the kernel will check that the program currently loaded on the interface matches the expected one, and fail the operation if it does not. This corresponds to a 'cmpxchg' memory operation. Setting the new attribute with a negative value means that no program is expected to be attached, which corresponds to setting the UPDATE_IF_NOEXIST flag. A new companion flag, XDP_FLAGS_REPLACE, is also added to explicitly request checking of the EXPECTED_FD attribute. This is needed for userspace to discover whether the kernel supports the new attribute. Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Alexei Starovoitov Reviewed-by: Jakub Kicinski Link: https://lore.kernel.org/bpf/158515700640.92963.3551295145441017022.stgit@toke.dk --- include/linux/netdevice.h | 2 +- include/uapi/linux/if_link.h | 4 +++- net/core/dev.c | 26 +++++++++++++++++++++----- net/core/rtnetlink.c | 14 ++++++++++++++ 4 files changed, 39 insertions(+), 7 deletions(-) (limited to 'include/linux') diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 654808bfad83..b503d468f0df 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3768,7 +3768,7 @@ struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev, typedef int (*bpf_op_t)(struct net_device *dev, struct netdev_bpf *bpf); int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, - int fd, u32 flags); + int fd, int expected_fd, u32 flags); u32 __dev_xdp_query(struct net_device *dev, bpf_op_t xdp_op, enum bpf_netdev_command cmd); int xdp_umem_query(struct net_device *dev, u16 queue_id); diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h index 61e0801c82df..c2f768c8d65b 100644 --- a/include/uapi/linux/if_link.h +++ b/include/uapi/linux/if_link.h @@ -972,11 +972,12 @@ enum { #define XDP_FLAGS_SKB_MODE (1U << 1) #define XDP_FLAGS_DRV_MODE (1U << 2) #define XDP_FLAGS_HW_MODE (1U << 3) +#define XDP_FLAGS_REPLACE (1U << 4) #define XDP_FLAGS_MODES (XDP_FLAGS_SKB_MODE | \ XDP_FLAGS_DRV_MODE | \ XDP_FLAGS_HW_MODE) #define XDP_FLAGS_MASK (XDP_FLAGS_UPDATE_IF_NOEXIST | \ - XDP_FLAGS_MODES) + XDP_FLAGS_MODES | XDP_FLAGS_REPLACE) /* These are stored into IFLA_XDP_ATTACHED on dump. */ enum { @@ -996,6 +997,7 @@ enum { IFLA_XDP_DRV_PROG_ID, IFLA_XDP_SKB_PROG_ID, IFLA_XDP_HW_PROG_ID, + IFLA_XDP_EXPECTED_FD, __IFLA_XDP_MAX, }; diff --git a/net/core/dev.c b/net/core/dev.c index d84541c24446..651a3c28d33a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -8655,15 +8655,17 @@ static void dev_xdp_uninstall(struct net_device *dev) * @dev: device * @extack: netlink extended ack * @fd: new program fd or negative value to clear + * @expected_fd: old program fd that userspace expects to replace or clear * @flags: xdp-related flags * * Set or clear a bpf program for a device */ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, - int fd, u32 flags) + int fd, int expected_fd, u32 flags) { const struct net_device_ops *ops = dev->netdev_ops; enum bpf_netdev_command query; + u32 prog_id, expected_id = 0; struct bpf_prog *prog = NULL; bpf_op_t bpf_op, bpf_chk; bool offload; @@ -8684,15 +8686,29 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, if (bpf_op == bpf_chk) bpf_chk = generic_xdp_install; - if (fd >= 0) { - u32 prog_id; + prog_id = __dev_xdp_query(dev, bpf_op, query); + if (flags & XDP_FLAGS_REPLACE) { + if (expected_fd >= 0) { + prog = bpf_prog_get_type_dev(expected_fd, + BPF_PROG_TYPE_XDP, + bpf_op == ops->ndo_bpf); + if (IS_ERR(prog)) + return PTR_ERR(prog); + expected_id = prog->aux->id; + bpf_prog_put(prog); + } + if (prog_id != expected_id) { + NL_SET_ERR_MSG(extack, "Active program does not match expected"); + return -EEXIST; + } + } + if (fd >= 0) { if (!offload && __dev_xdp_query(dev, bpf_chk, XDP_QUERY_PROG)) { NL_SET_ERR_MSG(extack, "native and generic XDP can't be active at the same time"); return -EEXIST; } - prog_id = __dev_xdp_query(dev, bpf_op, query); if ((flags & XDP_FLAGS_UPDATE_IF_NOEXIST) && prog_id) { NL_SET_ERR_MSG(extack, "XDP program already attached"); return -EBUSY; @@ -8715,7 +8731,7 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, return 0; } } else { - if (!__dev_xdp_query(dev, bpf_op, query)) + if (!prog_id) return 0; } diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 14e6ea21c378..709ebbf8ab5b 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1872,7 +1872,9 @@ static const struct nla_policy ifla_port_policy[IFLA_PORT_MAX+1] = { }; static const struct nla_policy ifla_xdp_policy[IFLA_XDP_MAX + 1] = { + [IFLA_XDP_UNSPEC] = { .strict_start_type = IFLA_XDP_EXPECTED_FD }, [IFLA_XDP_FD] = { .type = NLA_S32 }, + [IFLA_XDP_EXPECTED_FD] = { .type = NLA_S32 }, [IFLA_XDP_ATTACHED] = { .type = NLA_U8 }, [IFLA_XDP_FLAGS] = { .type = NLA_U32 }, [IFLA_XDP_PROG_ID] = { .type = NLA_U32 }, @@ -2799,8 +2801,20 @@ static int do_setlink(const struct sk_buff *skb, } if (xdp[IFLA_XDP_FD]) { + int expected_fd = -1; + + if (xdp_flags & XDP_FLAGS_REPLACE) { + if (!xdp[IFLA_XDP_EXPECTED_FD]) { + err = -EINVAL; + goto errout; + } + expected_fd = + nla_get_s32(xdp[IFLA_XDP_EXPECTED_FD]); + } + err = dev_change_xdp_fd(dev, extack, nla_get_s32(xdp[IFLA_XDP_FD]), + expected_fd, xdp_flags); if (err) goto errout; -- cgit v1.2.3 From fc611f47f2188ade2b48ff6902d5cce8baac0c58 Mon Sep 17 00:00:00 2001 From: KP Singh Date: Sun, 29 Mar 2020 01:43:49 +0100 Subject: bpf: Introduce BPF_PROG_TYPE_LSM Introduce types and configs for bpf programs that can be attached to LSM hooks. The programs can be enabled by the config option CONFIG_BPF_LSM. Signed-off-by: KP Singh Signed-off-by: Daniel Borkmann Reviewed-by: Brendan Jackman Reviewed-by: Florent Revest Reviewed-by: Thomas Garnier Acked-by: Yonghong Song Acked-by: Andrii Nakryiko Acked-by: James Morris Link: https://lore.kernel.org/bpf/20200329004356.27286-2-kpsingh@chromium.org --- MAINTAINERS | 1 + include/linux/bpf.h | 3 +++ include/linux/bpf_types.h | 4 ++++ include/uapi/linux/bpf.h | 2 ++ init/Kconfig | 12 ++++++++++++ kernel/bpf/Makefile | 1 + kernel/bpf/bpf_lsm.c | 17 +++++++++++++++++ kernel/trace/bpf_trace.c | 12 ++++++------ tools/include/uapi/linux/bpf.h | 2 ++ tools/lib/bpf/libbpf_probes.c | 1 + 10 files changed, 49 insertions(+), 6 deletions(-) create mode 100644 kernel/bpf/bpf_lsm.c (limited to 'include/linux') diff --git a/MAINTAINERS b/MAINTAINERS index 5dbee41045bc..3197fe9256b2 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3147,6 +3147,7 @@ R: Martin KaFai Lau R: Song Liu R: Yonghong Song R: Andrii Nakryiko +R: KP Singh L: netdev@vger.kernel.org L: bpf@vger.kernel.org T: git git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 372708eeaecd..3bde59a8453b 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1515,6 +1515,9 @@ extern const struct bpf_func_proto bpf_tcp_sock_proto; extern const struct bpf_func_proto bpf_jiffies64_proto; extern const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto; +const struct bpf_func_proto *bpf_tracing_func_proto( + enum bpf_func_id func_id, const struct bpf_prog *prog); + /* Shared helpers among cBPF and eBPF. */ void bpf_user_rnd_init_once(void); u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index c81d4ece79a4..ba0c2d56f8a3 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -70,6 +70,10 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_STRUCT_OPS, bpf_struct_ops, void *, void *) BPF_PROG_TYPE(BPF_PROG_TYPE_EXT, bpf_extension, void *, void *) +#ifdef CONFIG_BPF_LSM +BPF_PROG_TYPE(BPF_PROG_TYPE_LSM, lsm, + void *, void *) +#endif /* CONFIG_BPF_LSM */ #endif BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 222ba11966e3..f1fbc36f58d3 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -181,6 +181,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_TRACING, BPF_PROG_TYPE_STRUCT_OPS, BPF_PROG_TYPE_EXT, + BPF_PROG_TYPE_LSM, }; enum bpf_attach_type { @@ -211,6 +212,7 @@ enum bpf_attach_type { BPF_TRACE_FENTRY, BPF_TRACE_FEXIT, BPF_MODIFY_RETURN, + BPF_LSM_MAC, __MAX_BPF_ATTACH_TYPE }; diff --git a/init/Kconfig b/init/Kconfig index 20a6ac33761c..deae572d1927 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1616,6 +1616,18 @@ config KALLSYMS_BASE_RELATIVE # end of the "standard kernel features (expert users)" menu # syscall, maps, verifier + +config BPF_LSM + bool "LSM Instrumentation with BPF" + depends on BPF_SYSCALL + depends on SECURITY + depends on BPF_JIT + help + Enables instrumentation of the security hooks with eBPF programs for + implementing dynamic MAC and Audit Policies. + + If you are unsure how to answer this question, answer N. + config BPF_SYSCALL bool "Enable bpf() system call" select BPF diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 046ce5d98033..f2d7be596966 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -29,4 +29,5 @@ obj-$(CONFIG_DEBUG_INFO_BTF) += sysfs_btf.o endif ifeq ($(CONFIG_BPF_JIT),y) obj-$(CONFIG_BPF_SYSCALL) += bpf_struct_ops.o +obj-${CONFIG_BPF_LSM} += bpf_lsm.o endif diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c new file mode 100644 index 000000000000..82875039ca90 --- /dev/null +++ b/kernel/bpf/bpf_lsm.c @@ -0,0 +1,17 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2020 Google LLC. + */ + +#include +#include +#include + +const struct bpf_prog_ops lsm_prog_ops = { +}; + +const struct bpf_verifier_ops lsm_verifier_ops = { + .get_func_proto = bpf_tracing_func_proto, + .is_valid_access = btf_ctx_access, +}; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index e619eedb5919..37ffceab608f 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -779,8 +779,8 @@ static const struct bpf_func_proto bpf_send_signal_thread_proto = { .arg1_type = ARG_ANYTHING, }; -static const struct bpf_func_proto * -tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +const struct bpf_func_proto * +bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_map_lookup_elem: @@ -865,7 +865,7 @@ kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_override_return_proto; #endif default: - return tracing_func_proto(func_id, prog); + return bpf_tracing_func_proto(func_id, prog); } } @@ -975,7 +975,7 @@ tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_get_stack: return &bpf_get_stack_proto_tp; default: - return tracing_func_proto(func_id, prog); + return bpf_tracing_func_proto(func_id, prog); } } @@ -1082,7 +1082,7 @@ pe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_read_branch_records: return &bpf_read_branch_records_proto; default: - return tracing_func_proto(func_id, prog); + return bpf_tracing_func_proto(func_id, prog); } } @@ -1210,7 +1210,7 @@ raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_get_stack: return &bpf_get_stack_proto_raw_tp; default: - return tracing_func_proto(func_id, prog); + return bpf_tracing_func_proto(func_id, prog); } } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 222ba11966e3..f1fbc36f58d3 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -181,6 +181,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_TRACING, BPF_PROG_TYPE_STRUCT_OPS, BPF_PROG_TYPE_EXT, + BPF_PROG_TYPE_LSM, }; enum bpf_attach_type { @@ -211,6 +212,7 @@ enum bpf_attach_type { BPF_TRACE_FENTRY, BPF_TRACE_FEXIT, BPF_MODIFY_RETURN, + BPF_LSM_MAC, __MAX_BPF_ATTACH_TYPE }; diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c index b782ebef6ac9..2c92059c0c90 100644 --- a/tools/lib/bpf/libbpf_probes.c +++ b/tools/lib/bpf/libbpf_probes.c @@ -108,6 +108,7 @@ probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns, case BPF_PROG_TYPE_TRACING: case BPF_PROG_TYPE_STRUCT_OPS: case BPF_PROG_TYPE_EXT: + case BPF_PROG_TYPE_LSM: default: break; } -- cgit v1.2.3 From 98e828a0650f348be85728c69875260cf78069e6 Mon Sep 17 00:00:00 2001 From: KP Singh Date: Sun, 29 Mar 2020 01:43:50 +0100 Subject: security: Refactor declaration of LSM hooks The information about the different types of LSM hooks is scattered in two locations i.e. union security_list_options and struct security_hook_heads. Rather than duplicating this information even further for BPF_PROG_TYPE_LSM, define all the hooks with the LSM_HOOK macro in lsm_hook_defs.h which is then used to generate all the data structures required by the LSM framework. The LSM hooks are defined as: LSM_HOOK(, , , args...) with acccessible in security.c as: LSM_RET_DEFAULT() Signed-off-by: KP Singh Signed-off-by: Daniel Borkmann Reviewed-by: Brendan Jackman Reviewed-by: Florent Revest Reviewed-by: Kees Cook Reviewed-by: Casey Schaufler Acked-by: James Morris Link: https://lore.kernel.org/bpf/20200329004356.27286-3-kpsingh@chromium.org --- include/linux/lsm_hook_defs.h | 381 +++++++++++++++++++++++++ include/linux/lsm_hooks.h | 628 +----------------------------------------- security/security.c | 41 ++- 3 files changed, 423 insertions(+), 627 deletions(-) create mode 100644 include/linux/lsm_hook_defs.h (limited to 'include/linux') diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h new file mode 100644 index 000000000000..9cd4455528e5 --- /dev/null +++ b/include/linux/lsm_hook_defs.h @@ -0,0 +1,381 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Linux Security Module Hook declarations. + * + * Copyright (C) 2001 WireX Communications, Inc + * Copyright (C) 2001 Greg Kroah-Hartman + * Copyright (C) 2001 Networks Associates Technology, Inc + * Copyright (C) 2001 James Morris + * Copyright (C) 2001 Silicon Graphics, Inc. (Trust Technology Group) + * Copyright (C) 2015 Intel Corporation. + * Copyright (C) 2015 Casey Schaufler + * Copyright (C) 2016 Mellanox Techonologies + * Copyright (C) 2020 Google LLC. + */ + +/* + * The macro LSM_HOOK is used to define the data structures required by the + * the LSM framework using the pattern: + * + * LSM_HOOK(, , , args...) + * + * struct security_hook_heads { + * #define LSM_HOOK(RET, DEFAULT, NAME, ...) struct hlist_head NAME; + * #include + * #undef LSM_HOOK + * }; + */ +LSM_HOOK(int, 0, binder_set_context_mgr, struct task_struct *mgr) +LSM_HOOK(int, 0, binder_transaction, struct task_struct *from, + struct task_struct *to) +LSM_HOOK(int, 0, binder_transfer_binder, struct task_struct *from, + struct task_struct *to) +LSM_HOOK(int, 0, binder_transfer_file, struct task_struct *from, + struct task_struct *to, struct file *file) +LSM_HOOK(int, 0, ptrace_access_check, struct task_struct *child, + unsigned int mode) +LSM_HOOK(int, 0, ptrace_traceme, struct task_struct *parent) +LSM_HOOK(int, 0, capget, struct task_struct *target, kernel_cap_t *effective, + kernel_cap_t *inheritable, kernel_cap_t *permitted) +LSM_HOOK(int, 0, capset, struct cred *new, const struct cred *old, + const kernel_cap_t *effective, const kernel_cap_t *inheritable, + const kernel_cap_t *permitted) +LSM_HOOK(int, 0, capable, const struct cred *cred, struct user_namespace *ns, + int cap, unsigned int opts) +LSM_HOOK(int, 0, quotactl, int cmds, int type, int id, struct super_block *sb) +LSM_HOOK(int, 0, quota_on, struct dentry *dentry) +LSM_HOOK(int, 0, syslog, int type) +LSM_HOOK(int, 0, settime, const struct timespec64 *ts, + const struct timezone *tz) +LSM_HOOK(int, 0, vm_enough_memory, struct mm_struct *mm, long pages) +LSM_HOOK(int, 0, bprm_set_creds, struct linux_binprm *bprm) +LSM_HOOK(int, 0, bprm_check_security, struct linux_binprm *bprm) +LSM_HOOK(void, LSM_RET_VOID, bprm_committing_creds, struct linux_binprm *bprm) +LSM_HOOK(void, LSM_RET_VOID, bprm_committed_creds, struct linux_binprm *bprm) +LSM_HOOK(int, 0, fs_context_dup, struct fs_context *fc, + struct fs_context *src_sc) +LSM_HOOK(int, 0, fs_context_parse_param, struct fs_context *fc, + struct fs_parameter *param) +LSM_HOOK(int, 0, sb_alloc_security, struct super_block *sb) +LSM_HOOK(void, LSM_RET_VOID, sb_free_security, struct super_block *sb) +LSM_HOOK(void, LSM_RET_VOID, sb_free_mnt_opts, void *mnt_opts) +LSM_HOOK(int, 0, sb_eat_lsm_opts, char *orig, void **mnt_opts) +LSM_HOOK(int, 0, sb_remount, struct super_block *sb, void *mnt_opts) +LSM_HOOK(int, 0, sb_kern_mount, struct super_block *sb) +LSM_HOOK(int, 0, sb_show_options, struct seq_file *m, struct super_block *sb) +LSM_HOOK(int, 0, sb_statfs, struct dentry *dentry) +LSM_HOOK(int, 0, sb_mount, const char *dev_name, const struct path *path, + const char *type, unsigned long flags, void *data) +LSM_HOOK(int, 0, sb_umount, struct vfsmount *mnt, int flags) +LSM_HOOK(int, 0, sb_pivotroot, const struct path *old_path, + const struct path *new_path) +LSM_HOOK(int, 0, sb_set_mnt_opts, struct super_block *sb, void *mnt_opts, + unsigned long kern_flags, unsigned long *set_kern_flags) +LSM_HOOK(int, 0, sb_clone_mnt_opts, const struct super_block *oldsb, + struct super_block *newsb, unsigned long kern_flags, + unsigned long *set_kern_flags) +LSM_HOOK(int, 0, sb_add_mnt_opt, const char *option, const char *val, + int len, void **mnt_opts) +LSM_HOOK(int, 0, move_mount, const struct path *from_path, + const struct path *to_path) +LSM_HOOK(int, 0, dentry_init_security, struct dentry *dentry, + int mode, const struct qstr *name, void **ctx, u32 *ctxlen) +LSM_HOOK(int, 0, dentry_create_files_as, struct dentry *dentry, int mode, + struct qstr *name, const struct cred *old, struct cred *new) + +#ifdef CONFIG_SECURITY_PATH +LSM_HOOK(int, 0, path_unlink, const struct path *dir, struct dentry *dentry) +LSM_HOOK(int, 0, path_mkdir, const struct path *dir, struct dentry *dentry, + umode_t mode) +LSM_HOOK(int, 0, path_rmdir, const struct path *dir, struct dentry *dentry) +LSM_HOOK(int, 0, path_mknod, const struct path *dir, struct dentry *dentry, + umode_t mode, unsigned int dev) +LSM_HOOK(int, 0, path_truncate, const struct path *path) +LSM_HOOK(int, 0, path_symlink, const struct path *dir, struct dentry *dentry, + const char *old_name) +LSM_HOOK(int, 0, path_link, struct dentry *old_dentry, + const struct path *new_dir, struct dentry *new_dentry) +LSM_HOOK(int, 0, path_rename, const struct path *old_dir, + struct dentry *old_dentry, const struct path *new_dir, + struct dentry *new_dentry) +LSM_HOOK(int, 0, path_chmod, const struct path *path, umode_t mode) +LSM_HOOK(int, 0, path_chown, const struct path *path, kuid_t uid, kgid_t gid) +LSM_HOOK(int, 0, path_chroot, const struct path *path) +#endif /* CONFIG_SECURITY_PATH */ + +/* Needed for inode based security check */ +LSM_HOOK(int, 0, path_notify, const struct path *path, u64 mask, + unsigned int obj_type) +LSM_HOOK(int, 0, inode_alloc_security, struct inode *inode) +LSM_HOOK(void, LSM_RET_VOID, inode_free_security, struct inode *inode) +LSM_HOOK(int, 0, inode_init_security, struct inode *inode, + struct inode *dir, const struct qstr *qstr, const char **name, + void **value, size_t *len) +LSM_HOOK(int, 0, inode_create, struct inode *dir, struct dentry *dentry, + umode_t mode) +LSM_HOOK(int, 0, inode_link, struct dentry *old_dentry, struct inode *dir, + struct dentry *new_dentry) +LSM_HOOK(int, 0, inode_unlink, struct inode *dir, struct dentry *dentry) +LSM_HOOK(int, 0, inode_symlink, struct inode *dir, struct dentry *dentry, + const char *old_name) +LSM_HOOK(int, 0, inode_mkdir, struct inode *dir, struct dentry *dentry, + umode_t mode) +LSM_HOOK(int, 0, inode_rmdir, struct inode *dir, struct dentry *dentry) +LSM_HOOK(int, 0, inode_mknod, struct inode *dir, struct dentry *dentry, + umode_t mode, dev_t dev) +LSM_HOOK(int, 0, inode_rename, struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry) +LSM_HOOK(int, 0, inode_readlink, struct dentry *dentry) +LSM_HOOK(int, 0, inode_follow_link, struct dentry *dentry, struct inode *inode, + bool rcu) +LSM_HOOK(int, 0, inode_permission, struct inode *inode, int mask) +LSM_HOOK(int, 0, inode_setattr, struct dentry *dentry, struct iattr *attr) +LSM_HOOK(int, 0, inode_getattr, const struct path *path) +LSM_HOOK(int, 0, inode_setxattr, struct dentry *dentry, const char *name, + const void *value, size_t size, int flags) +LSM_HOOK(void, LSM_RET_VOID, inode_post_setxattr, struct dentry *dentry, + const char *name, const void *value, size_t size, int flags) +LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name) +LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry) +LSM_HOOK(int, 0, inode_removexattr, struct dentry *dentry, const char *name) +LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry) +LSM_HOOK(int, 0, inode_killpriv, struct dentry *dentry) +LSM_HOOK(int, -EOPNOTSUPP, inode_getsecurity, struct inode *inode, + const char *name, void **buffer, bool alloc) +LSM_HOOK(int, -EOPNOTSUPP, inode_setsecurity, struct inode *inode, + const char *name, const void *value, size_t size, int flags) +LSM_HOOK(int, 0, inode_listsecurity, struct inode *inode, char *buffer, + size_t buffer_size) +LSM_HOOK(void, LSM_RET_VOID, inode_getsecid, struct inode *inode, u32 *secid) +LSM_HOOK(int, 0, inode_copy_up, struct dentry *src, struct cred **new) +LSM_HOOK(int, 0, inode_copy_up_xattr, const char *name) +LSM_HOOK(int, 0, kernfs_init_security, struct kernfs_node *kn_dir, + struct kernfs_node *kn) +LSM_HOOK(int, 0, file_permission, struct file *file, int mask) +LSM_HOOK(int, 0, file_alloc_security, struct file *file) +LSM_HOOK(void, LSM_RET_VOID, file_free_security, struct file *file) +LSM_HOOK(int, 0, file_ioctl, struct file *file, unsigned int cmd, + unsigned long arg) +LSM_HOOK(int, 0, mmap_addr, unsigned long addr) +LSM_HOOK(int, 0, mmap_file, struct file *file, unsigned long reqprot, + unsigned long prot, unsigned long flags) +LSM_HOOK(int, 0, file_mprotect, struct vm_area_struct *vma, + unsigned long reqprot, unsigned long prot) +LSM_HOOK(int, 0, file_lock, struct file *file, unsigned int cmd) +LSM_HOOK(int, 0, file_fcntl, struct file *file, unsigned int cmd, + unsigned long arg) +LSM_HOOK(void, LSM_RET_VOID, file_set_fowner, struct file *file) +LSM_HOOK(int, 0, file_send_sigiotask, struct task_struct *tsk, + struct fown_struct *fown, int sig) +LSM_HOOK(int, 0, file_receive, struct file *file) +LSM_HOOK(int, 0, file_open, struct file *file) +LSM_HOOK(int, 0, task_alloc, struct task_struct *task, + unsigned long clone_flags) +LSM_HOOK(void, LSM_RET_VOID, task_free, struct task_struct *task) +LSM_HOOK(int, 0, cred_alloc_blank, struct cred *cred, gfp_t gfp) +LSM_HOOK(void, LSM_RET_VOID, cred_free, struct cred *cred) +LSM_HOOK(int, 0, cred_prepare, struct cred *new, const struct cred *old, + gfp_t gfp) +LSM_HOOK(void, LSM_RET_VOID, cred_transfer, struct cred *new, + const struct cred *old) +LSM_HOOK(void, LSM_RET_VOID, cred_getsecid, const struct cred *c, u32 *secid) +LSM_HOOK(int, 0, kernel_act_as, struct cred *new, u32 secid) +LSM_HOOK(int, 0, kernel_create_files_as, struct cred *new, struct inode *inode) +LSM_HOOK(int, 0, kernel_module_request, char *kmod_name) +LSM_HOOK(int, 0, kernel_load_data, enum kernel_load_data_id id) +LSM_HOOK(int, 0, kernel_read_file, struct file *file, + enum kernel_read_file_id id) +LSM_HOOK(int, 0, kernel_post_read_file, struct file *file, char *buf, + loff_t size, enum kernel_read_file_id id) +LSM_HOOK(int, 0, task_fix_setuid, struct cred *new, const struct cred *old, + int flags) +LSM_HOOK(int, 0, task_setpgid, struct task_struct *p, pid_t pgid) +LSM_HOOK(int, 0, task_getpgid, struct task_struct *p) +LSM_HOOK(int, 0, task_getsid, struct task_struct *p) +LSM_HOOK(void, LSM_RET_VOID, task_getsecid, struct task_struct *p, u32 *secid) +LSM_HOOK(int, 0, task_setnice, struct task_struct *p, int nice) +LSM_HOOK(int, 0, task_setioprio, struct task_struct *p, int ioprio) +LSM_HOOK(int, 0, task_getioprio, struct task_struct *p) +LSM_HOOK(int, 0, task_prlimit, const struct cred *cred, + const struct cred *tcred, unsigned int flags) +LSM_HOOK(int, 0, task_setrlimit, struct task_struct *p, unsigned int resource, + struct rlimit *new_rlim) +LSM_HOOK(int, 0, task_setscheduler, struct task_struct *p) +LSM_HOOK(int, 0, task_getscheduler, struct task_struct *p) +LSM_HOOK(int, 0, task_movememory, struct task_struct *p) +LSM_HOOK(int, 0, task_kill, struct task_struct *p, struct kernel_siginfo *info, + int sig, const struct cred *cred) +LSM_HOOK(int, -ENOSYS, task_prctl, int option, unsigned long arg2, + unsigned long arg3, unsigned long arg4, unsigned long arg5) +LSM_HOOK(void, LSM_RET_VOID, task_to_inode, struct task_struct *p, + struct inode *inode) +LSM_HOOK(int, 0, ipc_permission, struct kern_ipc_perm *ipcp, short flag) +LSM_HOOK(void, LSM_RET_VOID, ipc_getsecid, struct kern_ipc_perm *ipcp, + u32 *secid) +LSM_HOOK(int, 0, msg_msg_alloc_security, struct msg_msg *msg) +LSM_HOOK(void, LSM_RET_VOID, msg_msg_free_security, struct msg_msg *msg) +LSM_HOOK(int, 0, msg_queue_alloc_security, struct kern_ipc_perm *perm) +LSM_HOOK(void, LSM_RET_VOID, msg_queue_free_security, + struct kern_ipc_perm *perm) +LSM_HOOK(int, 0, msg_queue_associate, struct kern_ipc_perm *perm, int msqflg) +LSM_HOOK(int, 0, msg_queue_msgctl, struct kern_ipc_perm *perm, int cmd) +LSM_HOOK(int, 0, msg_queue_msgsnd, struct kern_ipc_perm *perm, + struct msg_msg *msg, int msqflg) +LSM_HOOK(int, 0, msg_queue_msgrcv, struct kern_ipc_perm *perm, + struct msg_msg *msg, struct task_struct *target, long type, int mode) +LSM_HOOK(int, 0, shm_alloc_security, struct kern_ipc_perm *perm) +LSM_HOOK(void, LSM_RET_VOID, shm_free_security, struct kern_ipc_perm *perm) +LSM_HOOK(int, 0, shm_associate, struct kern_ipc_perm *perm, int shmflg) +LSM_HOOK(int, 0, shm_shmctl, struct kern_ipc_perm *perm, int cmd) +LSM_HOOK(int, 0, shm_shmat, struct kern_ipc_perm *perm, char __user *shmaddr, + int shmflg) +LSM_HOOK(int, 0, sem_alloc_security, struct kern_ipc_perm *perm) +LSM_HOOK(void, LSM_RET_VOID, sem_free_security, struct kern_ipc_perm *perm) +LSM_HOOK(int, 0, sem_associate, struct kern_ipc_perm *perm, int semflg) +LSM_HOOK(int, 0, sem_semctl, struct kern_ipc_perm *perm, int cmd) +LSM_HOOK(int, 0, sem_semop, struct kern_ipc_perm *perm, struct sembuf *sops, + unsigned nsops, int alter) +LSM_HOOK(int, 0, netlink_send, struct sock *sk, struct sk_buff *skb) +LSM_HOOK(void, LSM_RET_VOID, d_instantiate, struct dentry *dentry, + struct inode *inode) +LSM_HOOK(int, -EINVAL, getprocattr, struct task_struct *p, char *name, + char **value) +LSM_HOOK(int, -EINVAL, setprocattr, const char *name, void *value, size_t size) +LSM_HOOK(int, 0, ismaclabel, const char *name) +LSM_HOOK(int, 0, secid_to_secctx, u32 secid, char **secdata, + u32 *seclen) +LSM_HOOK(int, 0, secctx_to_secid, const char *secdata, u32 seclen, u32 *secid) +LSM_HOOK(void, LSM_RET_VOID, release_secctx, char *secdata, u32 seclen) +LSM_HOOK(void, LSM_RET_VOID, inode_invalidate_secctx, struct inode *inode) +LSM_HOOK(int, 0, inode_notifysecctx, struct inode *inode, void *ctx, u32 ctxlen) +LSM_HOOK(int, 0, inode_setsecctx, struct dentry *dentry, void *ctx, u32 ctxlen) +LSM_HOOK(int, 0, inode_getsecctx, struct inode *inode, void **ctx, + u32 *ctxlen) + +#ifdef CONFIG_SECURITY_NETWORK +LSM_HOOK(int, 0, unix_stream_connect, struct sock *sock, struct sock *other, + struct sock *newsk) +LSM_HOOK(int, 0, unix_may_send, struct socket *sock, struct socket *other) +LSM_HOOK(int, 0, socket_create, int family, int type, int protocol, int kern) +LSM_HOOK(int, 0, socket_post_create, struct socket *sock, int family, int type, + int protocol, int kern) +LSM_HOOK(int, 0, socket_socketpair, struct socket *socka, struct socket *sockb) +LSM_HOOK(int, 0, socket_bind, struct socket *sock, struct sockaddr *address, + int addrlen) +LSM_HOOK(int, 0, socket_connect, struct socket *sock, struct sockaddr *address, + int addrlen) +LSM_HOOK(int, 0, socket_listen, struct socket *sock, int backlog) +LSM_HOOK(int, 0, socket_accept, struct socket *sock, struct socket *newsock) +LSM_HOOK(int, 0, socket_sendmsg, struct socket *sock, struct msghdr *msg, + int size) +LSM_HOOK(int, 0, socket_recvmsg, struct socket *sock, struct msghdr *msg, + int size, int flags) +LSM_HOOK(int, 0, socket_getsockname, struct socket *sock) +LSM_HOOK(int, 0, socket_getpeername, struct socket *sock) +LSM_HOOK(int, 0, socket_getsockopt, struct socket *sock, int level, int optname) +LSM_HOOK(int, 0, socket_setsockopt, struct socket *sock, int level, int optname) +LSM_HOOK(int, 0, socket_shutdown, struct socket *sock, int how) +LSM_HOOK(int, 0, socket_sock_rcv_skb, struct sock *sk, struct sk_buff *skb) +LSM_HOOK(int, 0, socket_getpeersec_stream, struct socket *sock, + char __user *optval, int __user *optlen, unsigned len) +LSM_HOOK(int, 0, socket_getpeersec_dgram, struct socket *sock, + struct sk_buff *skb, u32 *secid) +LSM_HOOK(int, 0, sk_alloc_security, struct sock *sk, int family, gfp_t priority) +LSM_HOOK(void, LSM_RET_VOID, sk_free_security, struct sock *sk) +LSM_HOOK(void, LSM_RET_VOID, sk_clone_security, const struct sock *sk, + struct sock *newsk) +LSM_HOOK(void, LSM_RET_VOID, sk_getsecid, struct sock *sk, u32 *secid) +LSM_HOOK(void, LSM_RET_VOID, sock_graft, struct sock *sk, struct socket *parent) +LSM_HOOK(int, 0, inet_conn_request, struct sock *sk, struct sk_buff *skb, + struct request_sock *req) +LSM_HOOK(void, LSM_RET_VOID, inet_csk_clone, struct sock *newsk, + const struct request_sock *req) +LSM_HOOK(void, LSM_RET_VOID, inet_conn_established, struct sock *sk, + struct sk_buff *skb) +LSM_HOOK(int, 0, secmark_relabel_packet, u32 secid) +LSM_HOOK(void, LSM_RET_VOID, secmark_refcount_inc, void) +LSM_HOOK(void, LSM_RET_VOID, secmark_refcount_dec, void) +LSM_HOOK(void, LSM_RET_VOID, req_classify_flow, const struct request_sock *req, + struct flowi *fl) +LSM_HOOK(int, 0, tun_dev_alloc_security, void **security) +LSM_HOOK(void, LSM_RET_VOID, tun_dev_free_security, void *security) +LSM_HOOK(int, 0, tun_dev_create, void) +LSM_HOOK(int, 0, tun_dev_attach_queue, void *security) +LSM_HOOK(int, 0, tun_dev_attach, struct sock *sk, void *security) +LSM_HOOK(int, 0, tun_dev_open, void *security) +LSM_HOOK(int, 0, sctp_assoc_request, struct sctp_endpoint *ep, + struct sk_buff *skb) +LSM_HOOK(int, 0, sctp_bind_connect, struct sock *sk, int optname, + struct sockaddr *address, int addrlen) +LSM_HOOK(void, LSM_RET_VOID, sctp_sk_clone, struct sctp_endpoint *ep, + struct sock *sk, struct sock *newsk) +#endif /* CONFIG_SECURITY_NETWORK */ + +#ifdef CONFIG_SECURITY_INFINIBAND +LSM_HOOK(int, 0, ib_pkey_access, void *sec, u64 subnet_prefix, u16 pkey) +LSM_HOOK(int, 0, ib_endport_manage_subnet, void *sec, const char *dev_name, + u8 port_num) +LSM_HOOK(int, 0, ib_alloc_security, void **sec) +LSM_HOOK(void, LSM_RET_VOID, ib_free_security, void *sec) +#endif /* CONFIG_SECURITY_INFINIBAND */ + +#ifdef CONFIG_SECURITY_NETWORK_XFRM +LSM_HOOK(int, 0, xfrm_policy_alloc_security, struct xfrm_sec_ctx **ctxp, + struct xfrm_user_sec_ctx *sec_ctx, gfp_t gfp) +LSM_HOOK(int, 0, xfrm_policy_clone_security, struct xfrm_sec_ctx *old_ctx, + struct xfrm_sec_ctx **new_ctx) +LSM_HOOK(void, LSM_RET_VOID, xfrm_policy_free_security, + struct xfrm_sec_ctx *ctx) +LSM_HOOK(int, 0, xfrm_policy_delete_security, struct xfrm_sec_ctx *ctx) +LSM_HOOK(int, 0, xfrm_state_alloc, struct xfrm_state *x, + struct xfrm_user_sec_ctx *sec_ctx) +LSM_HOOK(int, 0, xfrm_state_alloc_acquire, struct xfrm_state *x, + struct xfrm_sec_ctx *polsec, u32 secid) +LSM_HOOK(void, LSM_RET_VOID, xfrm_state_free_security, struct xfrm_state *x) +LSM_HOOK(int, 0, xfrm_state_delete_security, struct xfrm_state *x) +LSM_HOOK(int, 0, xfrm_policy_lookup, struct xfrm_sec_ctx *ctx, u32 fl_secid, + u8 dir) +LSM_HOOK(int, 1, xfrm_state_pol_flow_match, struct xfrm_state *x, + struct xfrm_policy *xp, const struct flowi *fl) +LSM_HOOK(int, 0, xfrm_decode_session, struct sk_buff *skb, u32 *secid, + int ckall) +#endif /* CONFIG_SECURITY_NETWORK_XFRM */ + +/* key management security hooks */ +#ifdef CONFIG_KEYS +LSM_HOOK(int, 0, key_alloc, struct key *key, const struct cred *cred, + unsigned long flags) +LSM_HOOK(void, LSM_RET_VOID, key_free, struct key *key) +LSM_HOOK(int, 0, key_permission, key_ref_t key_ref, const struct cred *cred, + unsigned perm) +LSM_HOOK(int, 0, key_getsecurity, struct key *key, char **_buffer) +#endif /* CONFIG_KEYS */ + +#ifdef CONFIG_AUDIT +LSM_HOOK(int, 0, audit_rule_init, u32 field, u32 op, char *rulestr, + void **lsmrule) +LSM_HOOK(int, 0, audit_rule_known, struct audit_krule *krule) +LSM_HOOK(int, 0, audit_rule_match, u32 secid, u32 field, u32 op, void *lsmrule) +LSM_HOOK(void, LSM_RET_VOID, audit_rule_free, void *lsmrule) +#endif /* CONFIG_AUDIT */ + +#ifdef CONFIG_BPF_SYSCALL +LSM_HOOK(int, 0, bpf, int cmd, union bpf_attr *attr, unsigned int size) +LSM_HOOK(int, 0, bpf_map, struct bpf_map *map, fmode_t fmode) +LSM_HOOK(int, 0, bpf_prog, struct bpf_prog *prog) +LSM_HOOK(int, 0, bpf_map_alloc_security, struct bpf_map *map) +LSM_HOOK(void, LSM_RET_VOID, bpf_map_free_security, struct bpf_map *map) +LSM_HOOK(int, 0, bpf_prog_alloc_security, struct bpf_prog_aux *aux) +LSM_HOOK(void, LSM_RET_VOID, bpf_prog_free_security, struct bpf_prog_aux *aux) +#endif /* CONFIG_BPF_SYSCALL */ + +LSM_HOOK(int, 0, locked_down, enum lockdown_reason what) + +#ifdef CONFIG_PERF_EVENTS +LSM_HOOK(int, 0, perf_event_open, struct perf_event_attr *attr, int type) +LSM_HOOK(int, 0, perf_event_alloc, struct perf_event *event) +LSM_HOOK(void, LSM_RET_VOID, perf_event_free, struct perf_event *event) +LSM_HOOK(int, 0, perf_event_read, struct perf_event *event) +LSM_HOOK(int, 0, perf_event_write, struct perf_event *event) +#endif /* CONFIG_PERF_EVENTS */ diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 20d8cf194fb7..c09623b32489 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -1456,625 +1456,15 @@ * @what: kernel feature being accessed */ union security_list_options { - int (*binder_set_context_mgr)(struct task_struct *mgr); - int (*binder_transaction)(struct task_struct *from, - struct task_struct *to); - int (*binder_transfer_binder)(struct task_struct *from, - struct task_struct *to); - int (*binder_transfer_file)(struct task_struct *from, - struct task_struct *to, - struct file *file); - - int (*ptrace_access_check)(struct task_struct *child, - unsigned int mode); - int (*ptrace_traceme)(struct task_struct *parent); - int (*capget)(struct task_struct *target, kernel_cap_t *effective, - kernel_cap_t *inheritable, kernel_cap_t *permitted); - int (*capset)(struct cred *new, const struct cred *old, - const kernel_cap_t *effective, - const kernel_cap_t *inheritable, - const kernel_cap_t *permitted); - int (*capable)(const struct cred *cred, - struct user_namespace *ns, - int cap, - unsigned int opts); - int (*quotactl)(int cmds, int type, int id, struct super_block *sb); - int (*quota_on)(struct dentry *dentry); - int (*syslog)(int type); - int (*settime)(const struct timespec64 *ts, const struct timezone *tz); - int (*vm_enough_memory)(struct mm_struct *mm, long pages); - - int (*bprm_set_creds)(struct linux_binprm *bprm); - int (*bprm_check_security)(struct linux_binprm *bprm); - void (*bprm_committing_creds)(struct linux_binprm *bprm); - void (*bprm_committed_creds)(struct linux_binprm *bprm); - - int (*fs_context_dup)(struct fs_context *fc, struct fs_context *src_sc); - int (*fs_context_parse_param)(struct fs_context *fc, struct fs_parameter *param); - - int (*sb_alloc_security)(struct super_block *sb); - void (*sb_free_security)(struct super_block *sb); - void (*sb_free_mnt_opts)(void *mnt_opts); - int (*sb_eat_lsm_opts)(char *orig, void **mnt_opts); - int (*sb_remount)(struct super_block *sb, void *mnt_opts); - int (*sb_kern_mount)(struct super_block *sb); - int (*sb_show_options)(struct seq_file *m, struct super_block *sb); - int (*sb_statfs)(struct dentry *dentry); - int (*sb_mount)(const char *dev_name, const struct path *path, - const char *type, unsigned long flags, void *data); - int (*sb_umount)(struct vfsmount *mnt, int flags); - int (*sb_pivotroot)(const struct path *old_path, const struct path *new_path); - int (*sb_set_mnt_opts)(struct super_block *sb, - void *mnt_opts, - unsigned long kern_flags, - unsigned long *set_kern_flags); - int (*sb_clone_mnt_opts)(const struct super_block *oldsb, - struct super_block *newsb, - unsigned long kern_flags, - unsigned long *set_kern_flags); - int (*sb_add_mnt_opt)(const char *option, const char *val, int len, - void **mnt_opts); - int (*move_mount)(const struct path *from_path, const struct path *to_path); - int (*dentry_init_security)(struct dentry *dentry, int mode, - const struct qstr *name, void **ctx, - u32 *ctxlen); - int (*dentry_create_files_as)(struct dentry *dentry, int mode, - struct qstr *name, - const struct cred *old, - struct cred *new); - - -#ifdef CONFIG_SECURITY_PATH - int (*path_unlink)(const struct path *dir, struct dentry *dentry); - int (*path_mkdir)(const struct path *dir, struct dentry *dentry, - umode_t mode); - int (*path_rmdir)(const struct path *dir, struct dentry *dentry); - int (*path_mknod)(const struct path *dir, struct dentry *dentry, - umode_t mode, unsigned int dev); - int (*path_truncate)(const struct path *path); - int (*path_symlink)(const struct path *dir, struct dentry *dentry, - const char *old_name); - int (*path_link)(struct dentry *old_dentry, const struct path *new_dir, - struct dentry *new_dentry); - int (*path_rename)(const struct path *old_dir, struct dentry *old_dentry, - const struct path *new_dir, - struct dentry *new_dentry); - int (*path_chmod)(const struct path *path, umode_t mode); - int (*path_chown)(const struct path *path, kuid_t uid, kgid_t gid); - int (*path_chroot)(const struct path *path); -#endif - /* Needed for inode based security check */ - int (*path_notify)(const struct path *path, u64 mask, - unsigned int obj_type); - int (*inode_alloc_security)(struct inode *inode); - void (*inode_free_security)(struct inode *inode); - int (*inode_init_security)(struct inode *inode, struct inode *dir, - const struct qstr *qstr, - const char **name, void **value, - size_t *len); - int (*inode_create)(struct inode *dir, struct dentry *dentry, - umode_t mode); - int (*inode_link)(struct dentry *old_dentry, struct inode *dir, - struct dentry *new_dentry); - int (*inode_unlink)(struct inode *dir, struct dentry *dentry); - int (*inode_symlink)(struct inode *dir, struct dentry *dentry, - const char *old_name); - int (*inode_mkdir)(struct inode *dir, struct dentry *dentry, - umode_t mode); - int (*inode_rmdir)(struct inode *dir, struct dentry *dentry); - int (*inode_mknod)(struct inode *dir, struct dentry *dentry, - umode_t mode, dev_t dev); - int (*inode_rename)(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, - struct dentry *new_dentry); - int (*inode_readlink)(struct dentry *dentry); - int (*inode_follow_link)(struct dentry *dentry, struct inode *inode, - bool rcu); - int (*inode_permission)(struct inode *inode, int mask); - int (*inode_setattr)(struct dentry *dentry, struct iattr *attr); - int (*inode_getattr)(const struct path *path); - int (*inode_setxattr)(struct dentry *dentry, const char *name, - const void *value, size_t size, int flags); - void (*inode_post_setxattr)(struct dentry *dentry, const char *name, - const void *value, size_t size, - int flags); - int (*inode_getxattr)(struct dentry *dentry, const char *name); - int (*inode_listxattr)(struct dentry *dentry); - int (*inode_removexattr)(struct dentry *dentry, const char *name); - int (*inode_need_killpriv)(struct dentry *dentry); - int (*inode_killpriv)(struct dentry *dentry); - int (*inode_getsecurity)(struct inode *inode, const char *name, - void **buffer, bool alloc); - int (*inode_setsecurity)(struct inode *inode, const char *name, - const void *value, size_t size, - int flags); - int (*inode_listsecurity)(struct inode *inode, char *buffer, - size_t buffer_size); - void (*inode_getsecid)(struct inode *inode, u32 *secid); - int (*inode_copy_up)(struct dentry *src, struct cred **new); - int (*inode_copy_up_xattr)(const char *name); - - int (*kernfs_init_security)(struct kernfs_node *kn_dir, - struct kernfs_node *kn); - - int (*file_permission)(struct file *file, int mask); - int (*file_alloc_security)(struct file *file); - void (*file_free_security)(struct file *file); - int (*file_ioctl)(struct file *file, unsigned int cmd, - unsigned long arg); - int (*mmap_addr)(unsigned long addr); - int (*mmap_file)(struct file *file, unsigned long reqprot, - unsigned long prot, unsigned long flags); - int (*file_mprotect)(struct vm_area_struct *vma, unsigned long reqprot, - unsigned long prot); - int (*file_lock)(struct file *file, unsigned int cmd); - int (*file_fcntl)(struct file *file, unsigned int cmd, - unsigned long arg); - void (*file_set_fowner)(struct file *file); - int (*file_send_sigiotask)(struct task_struct *tsk, - struct fown_struct *fown, int sig); - int (*file_receive)(struct file *file); - int (*file_open)(struct file *file); - - int (*task_alloc)(struct task_struct *task, unsigned long clone_flags); - void (*task_free)(struct task_struct *task); - int (*cred_alloc_blank)(struct cred *cred, gfp_t gfp); - void (*cred_free)(struct cred *cred); - int (*cred_prepare)(struct cred *new, const struct cred *old, - gfp_t gfp); - void (*cred_transfer)(struct cred *new, const struct cred *old); - void (*cred_getsecid)(const struct cred *c, u32 *secid); - int (*kernel_act_as)(struct cred *new, u32 secid); - int (*kernel_create_files_as)(struct cred *new, struct inode *inode); - int (*kernel_module_request)(char *kmod_name); - int (*kernel_load_data)(enum kernel_load_data_id id); - int (*kernel_read_file)(struct file *file, enum kernel_read_file_id id); - int (*kernel_post_read_file)(struct file *file, char *buf, loff_t size, - enum kernel_read_file_id id); - int (*task_fix_setuid)(struct cred *new, const struct cred *old, - int flags); - int (*task_setpgid)(struct task_struct *p, pid_t pgid); - int (*task_getpgid)(struct task_struct *p); - int (*task_getsid)(struct task_struct *p); - void (*task_getsecid)(struct task_struct *p, u32 *secid); - int (*task_setnice)(struct task_struct *p, int nice); - int (*task_setioprio)(struct task_struct *p, int ioprio); - int (*task_getioprio)(struct task_struct *p); - int (*task_prlimit)(const struct cred *cred, const struct cred *tcred, - unsigned int flags); - int (*task_setrlimit)(struct task_struct *p, unsigned int resource, - struct rlimit *new_rlim); - int (*task_setscheduler)(struct task_struct *p); - int (*task_getscheduler)(struct task_struct *p); - int (*task_movememory)(struct task_struct *p); - int (*task_kill)(struct task_struct *p, struct kernel_siginfo *info, - int sig, const struct cred *cred); - int (*task_prctl)(int option, unsigned long arg2, unsigned long arg3, - unsigned long arg4, unsigned long arg5); - void (*task_to_inode)(struct task_struct *p, struct inode *inode); - - int (*ipc_permission)(struct kern_ipc_perm *ipcp, short flag); - void (*ipc_getsecid)(struct kern_ipc_perm *ipcp, u32 *secid); - - int (*msg_msg_alloc_security)(struct msg_msg *msg); - void (*msg_msg_free_security)(struct msg_msg *msg); - - int (*msg_queue_alloc_security)(struct kern_ipc_perm *perm); - void (*msg_queue_free_security)(struct kern_ipc_perm *perm); - int (*msg_queue_associate)(struct kern_ipc_perm *perm, int msqflg); - int (*msg_queue_msgctl)(struct kern_ipc_perm *perm, int cmd); - int (*msg_queue_msgsnd)(struct kern_ipc_perm *perm, struct msg_msg *msg, - int msqflg); - int (*msg_queue_msgrcv)(struct kern_ipc_perm *perm, struct msg_msg *msg, - struct task_struct *target, long type, - int mode); - - int (*shm_alloc_security)(struct kern_ipc_perm *perm); - void (*shm_free_security)(struct kern_ipc_perm *perm); - int (*shm_associate)(struct kern_ipc_perm *perm, int shmflg); - int (*shm_shmctl)(struct kern_ipc_perm *perm, int cmd); - int (*shm_shmat)(struct kern_ipc_perm *perm, char __user *shmaddr, - int shmflg); - - int (*sem_alloc_security)(struct kern_ipc_perm *perm); - void (*sem_free_security)(struct kern_ipc_perm *perm); - int (*sem_associate)(struct kern_ipc_perm *perm, int semflg); - int (*sem_semctl)(struct kern_ipc_perm *perm, int cmd); - int (*sem_semop)(struct kern_ipc_perm *perm, struct sembuf *sops, - unsigned nsops, int alter); - - int (*netlink_send)(struct sock *sk, struct sk_buff *skb); - - void (*d_instantiate)(struct dentry *dentry, struct inode *inode); - - int (*getprocattr)(struct task_struct *p, char *name, char **value); - int (*setprocattr)(const char *name, void *value, size_t size); - int (*ismaclabel)(const char *name); - int (*secid_to_secctx)(u32 secid, char **secdata, u32 *seclen); - int (*secctx_to_secid)(const char *secdata, u32 seclen, u32 *secid); - void (*release_secctx)(char *secdata, u32 seclen); - - void (*inode_invalidate_secctx)(struct inode *inode); - int (*inode_notifysecctx)(struct inode *inode, void *ctx, u32 ctxlen); - int (*inode_setsecctx)(struct dentry *dentry, void *ctx, u32 ctxlen); - int (*inode_getsecctx)(struct inode *inode, void **ctx, u32 *ctxlen); - -#ifdef CONFIG_SECURITY_NETWORK - int (*unix_stream_connect)(struct sock *sock, struct sock *other, - struct sock *newsk); - int (*unix_may_send)(struct socket *sock, struct socket *other); - - int (*socket_create)(int family, int type, int protocol, int kern); - int (*socket_post_create)(struct socket *sock, int family, int type, - int protocol, int kern); - int (*socket_socketpair)(struct socket *socka, struct socket *sockb); - int (*socket_bind)(struct socket *sock, struct sockaddr *address, - int addrlen); - int (*socket_connect)(struct socket *sock, struct sockaddr *address, - int addrlen); - int (*socket_listen)(struct socket *sock, int backlog); - int (*socket_accept)(struct socket *sock, struct socket *newsock); - int (*socket_sendmsg)(struct socket *sock, struct msghdr *msg, - int size); - int (*socket_recvmsg)(struct socket *sock, struct msghdr *msg, - int size, int flags); - int (*socket_getsockname)(struct socket *sock); - int (*socket_getpeername)(struct socket *sock); - int (*socket_getsockopt)(struct socket *sock, int level, int optname); - int (*socket_setsockopt)(struct socket *sock, int level, int optname); - int (*socket_shutdown)(struct socket *sock, int how); - int (*socket_sock_rcv_skb)(struct sock *sk, struct sk_buff *skb); - int (*socket_getpeersec_stream)(struct socket *sock, - char __user *optval, - int __user *optlen, unsigned len); - int (*socket_getpeersec_dgram)(struct socket *sock, - struct sk_buff *skb, u32 *secid); - int (*sk_alloc_security)(struct sock *sk, int family, gfp_t priority); - void (*sk_free_security)(struct sock *sk); - void (*sk_clone_security)(const struct sock *sk, struct sock *newsk); - void (*sk_getsecid)(struct sock *sk, u32 *secid); - void (*sock_graft)(struct sock *sk, struct socket *parent); - int (*inet_conn_request)(struct sock *sk, struct sk_buff *skb, - struct request_sock *req); - void (*inet_csk_clone)(struct sock *newsk, - const struct request_sock *req); - void (*inet_conn_established)(struct sock *sk, struct sk_buff *skb); - int (*secmark_relabel_packet)(u32 secid); - void (*secmark_refcount_inc)(void); - void (*secmark_refcount_dec)(void); - void (*req_classify_flow)(const struct request_sock *req, - struct flowi *fl); - int (*tun_dev_alloc_security)(void **security); - void (*tun_dev_free_security)(void *security); - int (*tun_dev_create)(void); - int (*tun_dev_attach_queue)(void *security); - int (*tun_dev_attach)(struct sock *sk, void *security); - int (*tun_dev_open)(void *security); - int (*sctp_assoc_request)(struct sctp_endpoint *ep, - struct sk_buff *skb); - int (*sctp_bind_connect)(struct sock *sk, int optname, - struct sockaddr *address, int addrlen); - void (*sctp_sk_clone)(struct sctp_endpoint *ep, struct sock *sk, - struct sock *newsk); -#endif /* CONFIG_SECURITY_NETWORK */ - -#ifdef CONFIG_SECURITY_INFINIBAND - int (*ib_pkey_access)(void *sec, u64 subnet_prefix, u16 pkey); - int (*ib_endport_manage_subnet)(void *sec, const char *dev_name, - u8 port_num); - int (*ib_alloc_security)(void **sec); - void (*ib_free_security)(void *sec); -#endif /* CONFIG_SECURITY_INFINIBAND */ - -#ifdef CONFIG_SECURITY_NETWORK_XFRM - int (*xfrm_policy_alloc_security)(struct xfrm_sec_ctx **ctxp, - struct xfrm_user_sec_ctx *sec_ctx, - gfp_t gfp); - int (*xfrm_policy_clone_security)(struct xfrm_sec_ctx *old_ctx, - struct xfrm_sec_ctx **new_ctx); - void (*xfrm_policy_free_security)(struct xfrm_sec_ctx *ctx); - int (*xfrm_policy_delete_security)(struct xfrm_sec_ctx *ctx); - int (*xfrm_state_alloc)(struct xfrm_state *x, - struct xfrm_user_sec_ctx *sec_ctx); - int (*xfrm_state_alloc_acquire)(struct xfrm_state *x, - struct xfrm_sec_ctx *polsec, - u32 secid); - void (*xfrm_state_free_security)(struct xfrm_state *x); - int (*xfrm_state_delete_security)(struct xfrm_state *x); - int (*xfrm_policy_lookup)(struct xfrm_sec_ctx *ctx, u32 fl_secid, - u8 dir); - int (*xfrm_state_pol_flow_match)(struct xfrm_state *x, - struct xfrm_policy *xp, - const struct flowi *fl); - int (*xfrm_decode_session)(struct sk_buff *skb, u32 *secid, int ckall); -#endif /* CONFIG_SECURITY_NETWORK_XFRM */ - - /* key management security hooks */ -#ifdef CONFIG_KEYS - int (*key_alloc)(struct key *key, const struct cred *cred, - unsigned long flags); - void (*key_free)(struct key *key); - int (*key_permission)(key_ref_t key_ref, const struct cred *cred, - unsigned perm); - int (*key_getsecurity)(struct key *key, char **_buffer); -#endif /* CONFIG_KEYS */ - -#ifdef CONFIG_AUDIT - int (*audit_rule_init)(u32 field, u32 op, char *rulestr, - void **lsmrule); - int (*audit_rule_known)(struct audit_krule *krule); - int (*audit_rule_match)(u32 secid, u32 field, u32 op, void *lsmrule); - void (*audit_rule_free)(void *lsmrule); -#endif /* CONFIG_AUDIT */ - -#ifdef CONFIG_BPF_SYSCALL - int (*bpf)(int cmd, union bpf_attr *attr, - unsigned int size); - int (*bpf_map)(struct bpf_map *map, fmode_t fmode); - int (*bpf_prog)(struct bpf_prog *prog); - int (*bpf_map_alloc_security)(struct bpf_map *map); - void (*bpf_map_free_security)(struct bpf_map *map); - int (*bpf_prog_alloc_security)(struct bpf_prog_aux *aux); - void (*bpf_prog_free_security)(struct bpf_prog_aux *aux); -#endif /* CONFIG_BPF_SYSCALL */ - int (*locked_down)(enum lockdown_reason what); -#ifdef CONFIG_PERF_EVENTS - int (*perf_event_open)(struct perf_event_attr *attr, int type); - int (*perf_event_alloc)(struct perf_event *event); - void (*perf_event_free)(struct perf_event *event); - int (*perf_event_read)(struct perf_event *event); - int (*perf_event_write)(struct perf_event *event); - -#endif + #define LSM_HOOK(RET, DEFAULT, NAME, ...) RET (*NAME)(__VA_ARGS__); + #include "lsm_hook_defs.h" + #undef LSM_HOOK }; struct security_hook_heads { - struct hlist_head binder_set_context_mgr; - struct hlist_head binder_transaction; - struct hlist_head binder_transfer_binder; - struct hlist_head binder_transfer_file; - struct hlist_head ptrace_access_check; - struct hlist_head ptrace_traceme; - struct hlist_head capget; - struct hlist_head capset; - struct hlist_head capable; - struct hlist_head quotactl; - struct hlist_head quota_on; - struct hlist_head syslog; - struct hlist_head settime; - struct hlist_head vm_enough_memory; - struct hlist_head bprm_set_creds; - struct hlist_head bprm_check_security; - struct hlist_head bprm_committing_creds; - struct hlist_head bprm_committed_creds; - struct hlist_head fs_context_dup; - struct hlist_head fs_context_parse_param; - struct hlist_head sb_alloc_security; - struct hlist_head sb_free_security; - struct hlist_head sb_free_mnt_opts; - struct hlist_head sb_eat_lsm_opts; - struct hlist_head sb_remount; - struct hlist_head sb_kern_mount; - struct hlist_head sb_show_options; - struct hlist_head sb_statfs; - struct hlist_head sb_mount; - struct hlist_head sb_umount; - struct hlist_head sb_pivotroot; - struct hlist_head sb_set_mnt_opts; - struct hlist_head sb_clone_mnt_opts; - struct hlist_head sb_add_mnt_opt; - struct hlist_head move_mount; - struct hlist_head dentry_init_security; - struct hlist_head dentry_create_files_as; -#ifdef CONFIG_SECURITY_PATH - struct hlist_head path_unlink; - struct hlist_head path_mkdir; - struct hlist_head path_rmdir; - struct hlist_head path_mknod; - struct hlist_head path_truncate; - struct hlist_head path_symlink; - struct hlist_head path_link; - struct hlist_head path_rename; - struct hlist_head path_chmod; - struct hlist_head path_chown; - struct hlist_head path_chroot; -#endif - /* Needed for inode based modules as well */ - struct hlist_head path_notify; - struct hlist_head inode_alloc_security; - struct hlist_head inode_free_security; - struct hlist_head inode_init_security; - struct hlist_head inode_create; - struct hlist_head inode_link; - struct hlist_head inode_unlink; - struct hlist_head inode_symlink; - struct hlist_head inode_mkdir; - struct hlist_head inode_rmdir; - struct hlist_head inode_mknod; - struct hlist_head inode_rename; - struct hlist_head inode_readlink; - struct hlist_head inode_follow_link; - struct hlist_head inode_permission; - struct hlist_head inode_setattr; - struct hlist_head inode_getattr; - struct hlist_head inode_setxattr; - struct hlist_head inode_post_setxattr; - struct hlist_head inode_getxattr; - struct hlist_head inode_listxattr; - struct hlist_head inode_removexattr; - struct hlist_head inode_need_killpriv; - struct hlist_head inode_killpriv; - struct hlist_head inode_getsecurity; - struct hlist_head inode_setsecurity; - struct hlist_head inode_listsecurity; - struct hlist_head inode_getsecid; - struct hlist_head inode_copy_up; - struct hlist_head inode_copy_up_xattr; - struct hlist_head kernfs_init_security; - struct hlist_head file_permission; - struct hlist_head file_alloc_security; - struct hlist_head file_free_security; - struct hlist_head file_ioctl; - struct hlist_head mmap_addr; - struct hlist_head mmap_file; - struct hlist_head file_mprotect; - struct hlist_head file_lock; - struct hlist_head file_fcntl; - struct hlist_head file_set_fowner; - struct hlist_head file_send_sigiotask; - struct hlist_head file_receive; - struct hlist_head file_open; - struct hlist_head task_alloc; - struct hlist_head task_free; - struct hlist_head cred_alloc_blank; - struct hlist_head cred_free; - struct hlist_head cred_prepare; - struct hlist_head cred_transfer; - struct hlist_head cred_getsecid; - struct hlist_head kernel_act_as; - struct hlist_head kernel_create_files_as; - struct hlist_head kernel_load_data; - struct hlist_head kernel_read_file; - struct hlist_head kernel_post_read_file; - struct hlist_head kernel_module_request; - struct hlist_head task_fix_setuid; - struct hlist_head task_setpgid; - struct hlist_head task_getpgid; - struct hlist_head task_getsid; - struct hlist_head task_getsecid; - struct hlist_head task_setnice; - struct hlist_head task_setioprio; - struct hlist_head task_getioprio; - struct hlist_head task_prlimit; - struct hlist_head task_setrlimit; - struct hlist_head task_setscheduler; - struct hlist_head task_getscheduler; - struct hlist_head task_movememory; - struct hlist_head task_kill; - struct hlist_head task_prctl; - struct hlist_head task_to_inode; - struct hlist_head ipc_permission; - struct hlist_head ipc_getsecid; - struct hlist_head msg_msg_alloc_security; - struct hlist_head msg_msg_free_security; - struct hlist_head msg_queue_alloc_security; - struct hlist_head msg_queue_free_security; - struct hlist_head msg_queue_associate; - struct hlist_head msg_queue_msgctl; - struct hlist_head msg_queue_msgsnd; - struct hlist_head msg_queue_msgrcv; - struct hlist_head shm_alloc_security; - struct hlist_head shm_free_security; - struct hlist_head shm_associate; - struct hlist_head shm_shmctl; - struct hlist_head shm_shmat; - struct hlist_head sem_alloc_security; - struct hlist_head sem_free_security; - struct hlist_head sem_associate; - struct hlist_head sem_semctl; - struct hlist_head sem_semop; - struct hlist_head netlink_send; - struct hlist_head d_instantiate; - struct hlist_head getprocattr; - struct hlist_head setprocattr; - struct hlist_head ismaclabel; - struct hlist_head secid_to_secctx; - struct hlist_head secctx_to_secid; - struct hlist_head release_secctx; - struct hlist_head inode_invalidate_secctx; - struct hlist_head inode_notifysecctx; - struct hlist_head inode_setsecctx; - struct hlist_head inode_getsecctx; -#ifdef CONFIG_SECURITY_NETWORK - struct hlist_head unix_stream_connect; - struct hlist_head unix_may_send; - struct hlist_head socket_create; - struct hlist_head socket_post_create; - struct hlist_head socket_socketpair; - struct hlist_head socket_bind; - struct hlist_head socket_connect; - struct hlist_head socket_listen; - struct hlist_head socket_accept; - struct hlist_head socket_sendmsg; - struct hlist_head socket_recvmsg; - struct hlist_head socket_getsockname; - struct hlist_head socket_getpeername; - struct hlist_head socket_getsockopt; - struct hlist_head socket_setsockopt; - struct hlist_head socket_shutdown; - struct hlist_head socket_sock_rcv_skb; - struct hlist_head socket_getpeersec_stream; - struct hlist_head socket_getpeersec_dgram; - struct hlist_head sk_alloc_security; - struct hlist_head sk_free_security; - struct hlist_head sk_clone_security; - struct hlist_head sk_getsecid; - struct hlist_head sock_graft; - struct hlist_head inet_conn_request; - struct hlist_head inet_csk_clone; - struct hlist_head inet_conn_established; - struct hlist_head secmark_relabel_packet; - struct hlist_head secmark_refcount_inc; - struct hlist_head secmark_refcount_dec; - struct hlist_head req_classify_flow; - struct hlist_head tun_dev_alloc_security; - struct hlist_head tun_dev_free_security; - struct hlist_head tun_dev_create; - struct hlist_head tun_dev_attach_queue; - struct hlist_head tun_dev_attach; - struct hlist_head tun_dev_open; - struct hlist_head sctp_assoc_request; - struct hlist_head sctp_bind_connect; - struct hlist_head sctp_sk_clone; -#endif /* CONFIG_SECURITY_NETWORK */ -#ifdef CONFIG_SECURITY_INFINIBAND - struct hlist_head ib_pkey_access; - struct hlist_head ib_endport_manage_subnet; - struct hlist_head ib_alloc_security; - struct hlist_head ib_free_security; -#endif /* CONFIG_SECURITY_INFINIBAND */ -#ifdef CONFIG_SECURITY_NETWORK_XFRM - struct hlist_head xfrm_policy_alloc_security; - struct hlist_head xfrm_policy_clone_security; - struct hlist_head xfrm_policy_free_security; - struct hlist_head xfrm_policy_delete_security; - struct hlist_head xfrm_state_alloc; - struct hlist_head xfrm_state_alloc_acquire; - struct hlist_head xfrm_state_free_security; - struct hlist_head xfrm_state_delete_security; - struct hlist_head xfrm_policy_lookup; - struct hlist_head xfrm_state_pol_flow_match; - struct hlist_head xfrm_decode_session; -#endif /* CONFIG_SECURITY_NETWORK_XFRM */ -#ifdef CONFIG_KEYS - struct hlist_head key_alloc; - struct hlist_head key_free; - struct hlist_head key_permission; - struct hlist_head key_getsecurity; -#endif /* CONFIG_KEYS */ -#ifdef CONFIG_AUDIT - struct hlist_head audit_rule_init; - struct hlist_head audit_rule_known; - struct hlist_head audit_rule_match; - struct hlist_head audit_rule_free; -#endif /* CONFIG_AUDIT */ -#ifdef CONFIG_BPF_SYSCALL - struct hlist_head bpf; - struct hlist_head bpf_map; - struct hlist_head bpf_prog; - struct hlist_head bpf_map_alloc_security; - struct hlist_head bpf_map_free_security; - struct hlist_head bpf_prog_alloc_security; - struct hlist_head bpf_prog_free_security; -#endif /* CONFIG_BPF_SYSCALL */ - struct hlist_head locked_down; -#ifdef CONFIG_PERF_EVENTS - struct hlist_head perf_event_open; - struct hlist_head perf_event_alloc; - struct hlist_head perf_event_free; - struct hlist_head perf_event_read; - struct hlist_head perf_event_write; -#endif + #define LSM_HOOK(RET, DEFAULT, NAME, ...) struct hlist_head NAME; + #include "lsm_hook_defs.h" + #undef LSM_HOOK } __randomize_layout; /* @@ -2100,6 +1490,12 @@ struct lsm_blob_sizes { int lbs_task; }; +/* + * LSM_RET_VOID is used as the default value in LSM_HOOK definitions for void + * LSM hooks (in include/linux/lsm_hook_defs.h). + */ +#define LSM_RET_VOID ((void) 0) + /* * Initializing a security_hook_list structure takes * up a lot of space in a source file. This macro takes diff --git a/security/security.c b/security/security.c index 565bc9b67276..7fed24b9d57e 100644 --- a/security/security.c +++ b/security/security.c @@ -668,6 +668,25 @@ static void __init lsm_early_task(struct task_struct *task) panic("%s: Early task alloc failed.\n", __func__); } +/* + * The default value of the LSM hook is defined in linux/lsm_hook_defs.h and + * can be accessed with: + * + * LSM_RET_DEFAULT() + * + * The macros below define static constants for the default value of each + * LSM hook. + */ +#define LSM_RET_DEFAULT(NAME) (NAME##_default) +#define DECLARE_LSM_RET_DEFAULT_void(DEFAULT, NAME) +#define DECLARE_LSM_RET_DEFAULT_int(DEFAULT, NAME) \ + static const int LSM_RET_DEFAULT(NAME) = (DEFAULT); +#define LSM_HOOK(RET, DEFAULT, NAME, ...) \ + DECLARE_LSM_RET_DEFAULT_##RET(DEFAULT, NAME) + +#include +#undef LSM_HOOK + /* * Hook list operation macros. * @@ -1338,16 +1357,16 @@ int security_inode_getsecurity(struct inode *inode, const char *name, void **buf int rc; if (unlikely(IS_PRIVATE(inode))) - return -EOPNOTSUPP; + return LSM_RET_DEFAULT(inode_getsecurity); /* * Only one module will provide an attribute with a given name. */ hlist_for_each_entry(hp, &security_hook_heads.inode_getsecurity, list) { rc = hp->hook.inode_getsecurity(inode, name, buffer, alloc); - if (rc != -EOPNOTSUPP) + if (rc != LSM_RET_DEFAULT(inode_getsecurity)) return rc; } - return -EOPNOTSUPP; + return LSM_RET_DEFAULT(inode_getsecurity); } int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags) @@ -1356,17 +1375,17 @@ int security_inode_setsecurity(struct inode *inode, const char *name, const void int rc; if (unlikely(IS_PRIVATE(inode))) - return -EOPNOTSUPP; + return LSM_RET_DEFAULT(inode_setsecurity); /* * Only one module will provide an attribute with a given name. */ hlist_for_each_entry(hp, &security_hook_heads.inode_setsecurity, list) { rc = hp->hook.inode_setsecurity(inode, name, value, size, flags); - if (rc != -EOPNOTSUPP) + if (rc != LSM_RET_DEFAULT(inode_setsecurity)) return rc; } - return -EOPNOTSUPP; + return LSM_RET_DEFAULT(inode_setsecurity); } int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size) @@ -1740,12 +1759,12 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4, unsigned long arg5) { int thisrc; - int rc = -ENOSYS; + int rc = LSM_RET_DEFAULT(task_prctl); struct security_hook_list *hp; hlist_for_each_entry(hp, &security_hook_heads.task_prctl, list) { thisrc = hp->hook.task_prctl(option, arg2, arg3, arg4, arg5); - if (thisrc != -ENOSYS) { + if (thisrc != LSM_RET_DEFAULT(task_prctl)) { rc = thisrc; if (thisrc != 0) break; @@ -1917,7 +1936,7 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name, continue; return hp->hook.getprocattr(p, name, value); } - return -EINVAL; + return LSM_RET_DEFAULT(getprocattr); } int security_setprocattr(const char *lsm, const char *name, void *value, @@ -1930,7 +1949,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value, continue; return hp->hook.setprocattr(name, value, size); } - return -EINVAL; + return LSM_RET_DEFAULT(setprocattr); } int security_netlink_send(struct sock *sk, struct sk_buff *skb) @@ -2315,7 +2334,7 @@ int security_xfrm_state_pol_flow_match(struct xfrm_state *x, const struct flowi *fl) { struct security_hook_list *hp; - int rc = 1; + int rc = LSM_RET_DEFAULT(xfrm_state_pol_flow_match); /* * Since this function is expected to return 0 or 1, the judgment -- cgit v1.2.3 From 9d3fdea789c8fab51381c2d609932fabe94c0517 Mon Sep 17 00:00:00 2001 From: KP Singh Date: Sun, 29 Mar 2020 01:43:51 +0100 Subject: bpf: lsm: Provide attachment points for BPF LSM programs When CONFIG_BPF_LSM is enabled, nop functions, bpf_lsm_, are generated for each LSM hook. These functions are initialized as LSM hooks in a subsequent patch. Signed-off-by: KP Singh Signed-off-by: Daniel Borkmann Reviewed-by: Brendan Jackman Reviewed-by: Florent Revest Reviewed-by: Kees Cook Acked-by: Yonghong Song Acked-by: James Morris Link: https://lore.kernel.org/bpf/20200329004356.27286-4-kpsingh@chromium.org --- include/linux/bpf_lsm.h | 22 ++++++++++++++++++++++ kernel/bpf/bpf_lsm.c | 14 ++++++++++++++ 2 files changed, 36 insertions(+) create mode 100644 include/linux/bpf_lsm.h (limited to 'include/linux') diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h new file mode 100644 index 000000000000..83b96895829f --- /dev/null +++ b/include/linux/bpf_lsm.h @@ -0,0 +1,22 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Copyright (C) 2020 Google LLC. + */ + +#ifndef _LINUX_BPF_LSM_H +#define _LINUX_BPF_LSM_H + +#include +#include + +#ifdef CONFIG_BPF_LSM + +#define LSM_HOOK(RET, DEFAULT, NAME, ...) \ + RET bpf_lsm_##NAME(__VA_ARGS__); +#include +#undef LSM_HOOK + +#endif /* CONFIG_BPF_LSM */ + +#endif /* _LINUX_BPF_LSM_H */ diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index 82875039ca90..3b3bbb28603e 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -7,6 +7,20 @@ #include #include #include +#include +#include + +/* For every LSM hook that allows attachment of BPF programs, declare a nop + * function where a BPF program can be attached. + */ +#define LSM_HOOK(RET, DEFAULT, NAME, ...) \ +noinline RET bpf_lsm_##NAME(__VA_ARGS__) \ +{ \ + return DEFAULT; \ +} + +#include +#undef LSM_HOOK const struct bpf_prog_ops lsm_prog_ops = { }; -- cgit v1.2.3 From 9e4e01dfd3254c7f04f24b7c6b29596bc12332f3 Mon Sep 17 00:00:00 2001 From: KP Singh Date: Sun, 29 Mar 2020 01:43:52 +0100 Subject: bpf: lsm: Implement attach, detach and execution JITed BPF programs are dynamically attached to the LSM hooks using BPF trampolines. The trampoline prologue generates code to handle conversion of the signature of the hook to the appropriate BPF context. The allocated trampoline programs are attached to the nop functions initialized as LSM hooks. BPF_PROG_TYPE_LSM programs must have a GPL compatible license and and need CAP_SYS_ADMIN (required for loading eBPF programs). Upon attachment: * A BPF fexit trampoline is used for LSM hooks with a void return type. * A BPF fmod_ret trampoline is used for LSM hooks which return an int. The attached programs can override the return value of the bpf LSM hook to indicate a MAC Policy decision. Signed-off-by: KP Singh Signed-off-by: Daniel Borkmann Reviewed-by: Brendan Jackman Reviewed-by: Florent Revest Acked-by: Andrii Nakryiko Acked-by: James Morris Link: https://lore.kernel.org/bpf/20200329004356.27286-5-kpsingh@chromium.org --- include/linux/bpf_lsm.h | 11 ++++++++++ kernel/bpf/bpf_lsm.c | 23 ++++++++++++++++++++ kernel/bpf/btf.c | 16 +++++++++++++- kernel/bpf/syscall.c | 57 +++++++++++++++++++++++++++++++++---------------- kernel/bpf/trampoline.c | 17 +++++++++++---- kernel/bpf/verifier.c | 19 +++++++++++++---- 6 files changed, 116 insertions(+), 27 deletions(-) (limited to 'include/linux') diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h index 83b96895829f..af74712af585 100644 --- a/include/linux/bpf_lsm.h +++ b/include/linux/bpf_lsm.h @@ -17,6 +17,17 @@ #include #undef LSM_HOOK +int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog, + const struct bpf_prog *prog); + +#else /* !CONFIG_BPF_LSM */ + +static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog, + const struct bpf_prog *prog) +{ + return -EOPNOTSUPP; +} + #endif /* CONFIG_BPF_LSM */ #endif /* _LINUX_BPF_LSM_H */ diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index 3b3bbb28603e..19636703b24e 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -9,6 +9,8 @@ #include #include #include +#include +#include /* For every LSM hook that allows attachment of BPF programs, declare a nop * function where a BPF program can be attached. @@ -22,6 +24,27 @@ noinline RET bpf_lsm_##NAME(__VA_ARGS__) \ #include #undef LSM_HOOK +#define BPF_LSM_SYM_PREFX "bpf_lsm_" + +int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog, + const struct bpf_prog *prog) +{ + if (!prog->gpl_compatible) { + bpf_log(vlog, + "LSM programs must have a GPL compatible license\n"); + return -EINVAL; + } + + if (strncmp(BPF_LSM_SYM_PREFX, prog->aux->attach_func_name, + sizeof(BPF_LSM_SYM_PREFX) - 1)) { + bpf_log(vlog, "attach_btf_id %u points to wrong type name %s\n", + prog->aux->attach_btf_id, prog->aux->attach_func_name); + return -EINVAL; + } + + return 0; +} + const struct bpf_prog_ops lsm_prog_ops = { }; diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 6f397c4da05e..de335cd386f0 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3710,7 +3710,21 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, } if (arg == nr_args) { - if (prog->expected_attach_type == BPF_TRACE_FEXIT) { + if (prog->expected_attach_type == BPF_TRACE_FEXIT || + prog->expected_attach_type == BPF_LSM_MAC) { + /* When LSM programs are attached to void LSM hooks + * they use FEXIT trampolines and when attached to + * int LSM hooks, they use MODIFY_RETURN trampolines. + * + * While the LSM programs are BPF_MODIFY_RETURN-like + * the check: + * + * if (ret_type != 'int') + * return -EINVAL; + * + * is _not_ done here. This is still safe as LSM hooks + * have only void and int return types. + */ if (!t) return true; t = btf_type_by_id(btf, t->type); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index b2584b25748c..a616b63f23b4 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -25,6 +25,7 @@ #include #include #include +#include #define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \ (map)->map_type == BPF_MAP_TYPE_CGROUP_ARRAY || \ @@ -1935,6 +1936,7 @@ bpf_prog_load_check_attach(enum bpf_prog_type prog_type, switch (prog_type) { case BPF_PROG_TYPE_TRACING: + case BPF_PROG_TYPE_LSM: case BPF_PROG_TYPE_STRUCT_OPS: case BPF_PROG_TYPE_EXT: break; @@ -2366,10 +2368,28 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog) struct file *link_file; int link_fd, err; - if (prog->expected_attach_type != BPF_TRACE_FENTRY && - prog->expected_attach_type != BPF_TRACE_FEXIT && - prog->expected_attach_type != BPF_MODIFY_RETURN && - prog->type != BPF_PROG_TYPE_EXT) { + switch (prog->type) { + case BPF_PROG_TYPE_TRACING: + if (prog->expected_attach_type != BPF_TRACE_FENTRY && + prog->expected_attach_type != BPF_TRACE_FEXIT && + prog->expected_attach_type != BPF_MODIFY_RETURN) { + err = -EINVAL; + goto out_put_prog; + } + break; + case BPF_PROG_TYPE_EXT: + if (prog->expected_attach_type != 0) { + err = -EINVAL; + goto out_put_prog; + } + break; + case BPF_PROG_TYPE_LSM: + if (prog->expected_attach_type != BPF_LSM_MAC) { + err = -EINVAL; + goto out_put_prog; + } + break; + default: err = -EINVAL; goto out_put_prog; } @@ -2448,16 +2468,10 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr) if (IS_ERR(prog)) return PTR_ERR(prog); - if (prog->type != BPF_PROG_TYPE_RAW_TRACEPOINT && - prog->type != BPF_PROG_TYPE_TRACING && - prog->type != BPF_PROG_TYPE_EXT && - prog->type != BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE) { - err = -EINVAL; - goto out_put_prog; - } - - if (prog->type == BPF_PROG_TYPE_TRACING || - prog->type == BPF_PROG_TYPE_EXT) { + switch (prog->type) { + case BPF_PROG_TYPE_TRACING: + case BPF_PROG_TYPE_EXT: + case BPF_PROG_TYPE_LSM: if (attr->raw_tracepoint.name) { /* The attach point for this category of programs * should be specified via btf_id during program load. @@ -2465,11 +2479,14 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr) err = -EINVAL; goto out_put_prog; } - if (prog->expected_attach_type == BPF_TRACE_RAW_TP) + if (prog->type == BPF_PROG_TYPE_TRACING && + prog->expected_attach_type == BPF_TRACE_RAW_TP) { tp_name = prog->aux->attach_func_name; - else - return bpf_tracing_prog_attach(prog); - } else { + break; + } + return bpf_tracing_prog_attach(prog); + case BPF_PROG_TYPE_RAW_TRACEPOINT: + case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE: if (strncpy_from_user(buf, u64_to_user_ptr(attr->raw_tracepoint.name), sizeof(buf) - 1) < 0) { @@ -2478,6 +2495,10 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr) } buf[sizeof(buf) - 1] = 0; tp_name = buf; + break; + default: + err = -EINVAL; + goto out_put_prog; } btp = bpf_get_raw_tracepoint(tp_name); diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index f30bca2a4d01..9be85aa4ec5f 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -6,6 +6,7 @@ #include #include #include +#include /* dummy _ops. The verifier will operate on target program's ops. */ const struct bpf_verifier_ops bpf_extension_verifier_ops = { @@ -233,15 +234,23 @@ out: return err; } -static enum bpf_tramp_prog_type bpf_attach_type_to_tramp(enum bpf_attach_type t) +static enum bpf_tramp_prog_type bpf_attach_type_to_tramp(struct bpf_prog *prog) { - switch (t) { + switch (prog->expected_attach_type) { case BPF_TRACE_FENTRY: return BPF_TRAMP_FENTRY; case BPF_MODIFY_RETURN: return BPF_TRAMP_MODIFY_RETURN; case BPF_TRACE_FEXIT: return BPF_TRAMP_FEXIT; + case BPF_LSM_MAC: + if (!prog->aux->attach_func_proto->type) + /* The function returns void, we cannot modify its + * return value. + */ + return BPF_TRAMP_FEXIT; + else + return BPF_TRAMP_MODIFY_RETURN; default: return BPF_TRAMP_REPLACE; } @@ -255,7 +264,7 @@ int bpf_trampoline_link_prog(struct bpf_prog *prog) int cnt; tr = prog->aux->trampoline; - kind = bpf_attach_type_to_tramp(prog->expected_attach_type); + kind = bpf_attach_type_to_tramp(prog); mutex_lock(&tr->mutex); if (tr->extension_prog) { /* cannot attach fentry/fexit if extension prog is attached. @@ -305,7 +314,7 @@ int bpf_trampoline_unlink_prog(struct bpf_prog *prog) int err; tr = prog->aux->trampoline; - kind = bpf_attach_type_to_tramp(prog->expected_attach_type); + kind = bpf_attach_type_to_tramp(prog); mutex_lock(&tr->mutex); if (kind == BPF_TRAMP_REPLACE) { WARN_ON_ONCE(!tr->extension_prog); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 46ba86c540e2..047b2e876399 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -20,6 +20,7 @@ #include #include #include +#include #include "disasm.h" @@ -6492,8 +6493,9 @@ static int check_return_code(struct bpf_verifier_env *env) struct tnum range = tnum_range(0, 1); int err; - /* The struct_ops func-ptr's return type could be "void" */ - if (env->prog->type == BPF_PROG_TYPE_STRUCT_OPS && + /* LSM and struct_ops func-ptr's return type could be "void" */ + if ((env->prog->type == BPF_PROG_TYPE_STRUCT_OPS || + env->prog->type == BPF_PROG_TYPE_LSM) && !prog->aux->attach_func_proto->type) return 0; @@ -9923,7 +9925,9 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) if (prog->type == BPF_PROG_TYPE_STRUCT_OPS) return check_struct_ops_btf_id(env); - if (prog->type != BPF_PROG_TYPE_TRACING && !prog_extension) + if (prog->type != BPF_PROG_TYPE_TRACING && + prog->type != BPF_PROG_TYPE_LSM && + !prog_extension) return 0; if (!btf_id) { @@ -10054,8 +10058,16 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) return -EINVAL; /* fallthrough */ case BPF_MODIFY_RETURN: + case BPF_LSM_MAC: case BPF_TRACE_FENTRY: case BPF_TRACE_FEXIT: + prog->aux->attach_func_name = tname; + if (prog->type == BPF_PROG_TYPE_LSM) { + ret = bpf_lsm_verify_prog(&env->log, prog); + if (ret < 0) + return ret; + } + if (!btf_type_is_func(t)) { verbose(env, "attach_btf_id %u is not a function\n", btf_id); @@ -10070,7 +10082,6 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) tr = bpf_trampoline_lookup(key); if (!tr) return -ENOMEM; - prog->aux->attach_func_name = tname; /* t is either vmlinux type or another program's type */ prog->aux->attach_func_proto = t; mutex_lock(&tr->mutex); -- cgit v1.2.3 From 3f50f132d8400e129fc9eb68b5020167ef80a244 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 30 Mar 2020 14:36:39 -0700 Subject: bpf: Verifier, do explicit ALU32 bounds tracking It is not possible for the current verifier to track ALU32 and JMP ops correctly. This can result in the verifier aborting with errors even though the program should be verifiable. BPF codes that hit this can work around it by changin int variables to 64-bit types, marking variables volatile, etc. But this is all very ugly so it would be better to avoid these tricks. But, the main reason to address this now is do_refine_retval_range() was assuming return values could not be negative. Once we fixed this code that was previously working will no longer work. See do_refine_retval_range() patch for details. And we don't want to suddenly cause programs that used to work to fail. The simplest example code snippet that illustrates the problem is likely this, 53: w8 = w0 // r8 <- [0, S32_MAX], // w8 <- [-S32_MIN, X] 54: w8 64-bit 2. MOV ALU64 - copy 64-bit -> 32-bit 3. op ALU32 - zext 32-bit -> 64-bit 4. op ALU64 - n/a 5. jmp ALU32 - 64-bit: var32_off | upper_32_bits(var64_off) 6. jmp ALU64 - 32-bit: (>> (<< var64_off)) Details for each case, For "MOV ALU32" BPF arch zero extends so we simply copy the bounds from 32-bit into 64-bit ensuring we truncate var_off and 64-bit bounds correctly. See zext_32_to_64. For "MOV ALU64" copy all bounds including 32-bit into new register. If the src register had 32-bit bounds the dst register will as well. For "op ALU32" zero extend 32-bit into 64-bit the same as move, see zext_32_to_64. For "op ALU64" calculate both 32-bit and 64-bit bounds no merging is done here. Except we have a special case. When RSH or ARSH is done we can't simply ignore shifting bits from 64-bit reg into the 32-bit subreg. So currently just push bounds from 64-bit into 32-bit. This will be correct in the sense that they will represent a valid state of the register. However we could lose some accuracy if an ARSH is following a jmp32 operation. We can handle this special case in a follow up series. For "jmp ALU32" mark 64-bit reg unknown and recalculate 64-bit bounds from tnum by setting var_off to ((<<(>>var_off)) | var32_off). We special case if 64-bit bounds has zero'd upper 32bits at which point we can simply copy 32-bit bounds into 64-bit register. This catches a common compiler trick where upper 32-bits are zeroed and then 32-bit ops are used followed by a 64-bit compare or 64-bit op on a pointer. See __reg_combine_64_into_32(). For "jmp ALU64" cast the bounds of the 64bit to their 32-bit counterpart. For example s32_min_value = (s32)reg->smin_value. For tnum use only the lower 32bits via, (>>(< Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/158560419880.10843.11448220440809118343.stgit@john-Precision-5820-Tower --- include/linux/bpf_verifier.h | 4 + include/linux/limits.h | 1 + include/linux/tnum.h | 12 + kernel/bpf/tnum.c | 15 + kernel/bpf/verifier.c | 1118 +++++++++++++++++++++++++++++++----------- 5 files changed, 869 insertions(+), 281 deletions(-) (limited to 'include/linux') diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 5406e6e96585..6abd5a778fcd 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -123,6 +123,10 @@ struct bpf_reg_state { s64 smax_value; /* maximum possible (s64)value */ u64 umin_value; /* minimum possible (u64)value */ u64 umax_value; /* maximum possible (u64)value */ + s32 s32_min_value; /* minimum possible (s32)value */ + s32 s32_max_value; /* maximum possible (s32)value */ + u32 u32_min_value; /* minimum possible (u32)value */ + u32 u32_max_value; /* maximum possible (u32)value */ /* parentage chain for liveness checking */ struct bpf_reg_state *parent; /* Inside the callee two registers can be both PTR_TO_STACK like diff --git a/include/linux/limits.h b/include/linux/limits.h index 76afcd24ff8c..0d3de82dd354 100644 --- a/include/linux/limits.h +++ b/include/linux/limits.h @@ -27,6 +27,7 @@ #define S16_MAX ((s16)(U16_MAX >> 1)) #define S16_MIN ((s16)(-S16_MAX - 1)) #define U32_MAX ((u32)~0U) +#define U32_MIN ((u32)0) #define S32_MAX ((s32)(U32_MAX >> 1)) #define S32_MIN ((s32)(-S32_MAX - 1)) #define U64_MAX ((u64)~0ULL) diff --git a/include/linux/tnum.h b/include/linux/tnum.h index ea627d1ab7e3..498dbcedb451 100644 --- a/include/linux/tnum.h +++ b/include/linux/tnum.h @@ -86,4 +86,16 @@ int tnum_strn(char *str, size_t size, struct tnum a); /* Format a tnum as tristate binary expansion */ int tnum_sbin(char *str, size_t size, struct tnum a); +/* Returns the 32-bit subreg */ +struct tnum tnum_subreg(struct tnum a); +/* Returns the tnum with the lower 32-bit subreg cleared */ +struct tnum tnum_clear_subreg(struct tnum a); +/* Returns the tnum with the lower 32-bit subreg set to value */ +struct tnum tnum_const_subreg(struct tnum a, u32 value); +/* Returns true if 32-bit subreg @a is a known constant*/ +static inline bool tnum_subreg_is_const(struct tnum a) +{ + return !(tnum_subreg(a)).mask; +} + #endif /* _LINUX_TNUM_H */ diff --git a/kernel/bpf/tnum.c b/kernel/bpf/tnum.c index d4f335a9a899..ceac5281bd31 100644 --- a/kernel/bpf/tnum.c +++ b/kernel/bpf/tnum.c @@ -194,3 +194,18 @@ int tnum_sbin(char *str, size_t size, struct tnum a) str[min(size - 1, (size_t)64)] = 0; return 64; } + +struct tnum tnum_subreg(struct tnum a) +{ + return tnum_cast(a, 4); +} + +struct tnum tnum_clear_subreg(struct tnum a) +{ + return tnum_lshift(tnum_rshift(a, 32), 32); +} + +struct tnum tnum_const_subreg(struct tnum a, u32 value) +{ + return tnum_or(tnum_clear_subreg(a), tnum_const(value)); +} diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index dda3b94d9661..1c60d001bb46 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -550,6 +550,22 @@ static void print_verifier_state(struct bpf_verifier_env *env, tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); verbose(env, ",var_off=%s", tn_buf); } + if (reg->s32_min_value != reg->smin_value && + reg->s32_min_value != S32_MIN) + verbose(env, ",s32_min_value=%d", + (int)(reg->s32_min_value)); + if (reg->s32_max_value != reg->smax_value && + reg->s32_max_value != S32_MAX) + verbose(env, ",s32_max_value=%d", + (int)(reg->s32_max_value)); + if (reg->u32_min_value != reg->umin_value && + reg->u32_min_value != U32_MIN) + verbose(env, ",u32_min_value=%d", + (int)(reg->u32_min_value)); + if (reg->u32_max_value != reg->umax_value && + reg->u32_max_value != U32_MAX) + verbose(env, ",u32_max_value=%d", + (int)(reg->u32_max_value)); } verbose(env, ")"); } @@ -924,6 +940,20 @@ static void __mark_reg_known(struct bpf_reg_state *reg, u64 imm) reg->smax_value = (s64)imm; reg->umin_value = imm; reg->umax_value = imm; + + reg->s32_min_value = (s32)imm; + reg->s32_max_value = (s32)imm; + reg->u32_min_value = (u32)imm; + reg->u32_max_value = (u32)imm; +} + +static void __mark_reg32_known(struct bpf_reg_state *reg, u64 imm) +{ + reg->var_off = tnum_const_subreg(reg->var_off, imm); + reg->s32_min_value = (s32)imm; + reg->s32_max_value = (s32)imm; + reg->u32_min_value = (u32)imm; + reg->u32_max_value = (u32)imm; } /* Mark the 'variable offset' part of a register as zero. This should be @@ -978,8 +1008,52 @@ static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg, tnum_equals_const(reg->var_off, 0); } -/* Attempts to improve min/max values based on var_off information */ -static void __update_reg_bounds(struct bpf_reg_state *reg) +/* Reset the min/max bounds of a register */ +static void __mark_reg_unbounded(struct bpf_reg_state *reg) +{ + reg->smin_value = S64_MIN; + reg->smax_value = S64_MAX; + reg->umin_value = 0; + reg->umax_value = U64_MAX; + + reg->s32_min_value = S32_MIN; + reg->s32_max_value = S32_MAX; + reg->u32_min_value = 0; + reg->u32_max_value = U32_MAX; +} + +static void __mark_reg64_unbounded(struct bpf_reg_state *reg) +{ + reg->smin_value = S64_MIN; + reg->smax_value = S64_MAX; + reg->umin_value = 0; + reg->umax_value = U64_MAX; +} + +static void __mark_reg32_unbounded(struct bpf_reg_state *reg) +{ + reg->s32_min_value = S32_MIN; + reg->s32_max_value = S32_MAX; + reg->u32_min_value = 0; + reg->u32_max_value = U32_MAX; +} + +static void __update_reg32_bounds(struct bpf_reg_state *reg) +{ + struct tnum var32_off = tnum_subreg(reg->var_off); + + /* min signed is max(sign bit) | min(other bits) */ + reg->s32_min_value = max_t(s32, reg->s32_min_value, + var32_off.value | (var32_off.mask & S32_MIN)); + /* max signed is min(sign bit) | max(other bits) */ + reg->s32_max_value = min_t(s32, reg->s32_max_value, + var32_off.value | (var32_off.mask & S32_MAX)); + reg->u32_min_value = max_t(u32, reg->u32_min_value, (u32)var32_off.value); + reg->u32_max_value = min(reg->u32_max_value, + (u32)(var32_off.value | var32_off.mask)); +} + +static void __update_reg64_bounds(struct bpf_reg_state *reg) { /* min signed is max(sign bit) | min(other bits) */ reg->smin_value = max_t(s64, reg->smin_value, @@ -992,8 +1066,48 @@ static void __update_reg_bounds(struct bpf_reg_state *reg) reg->var_off.value | reg->var_off.mask); } +static void __update_reg_bounds(struct bpf_reg_state *reg) +{ + __update_reg32_bounds(reg); + __update_reg64_bounds(reg); +} + /* Uses signed min/max values to inform unsigned, and vice-versa */ -static void __reg_deduce_bounds(struct bpf_reg_state *reg) +static void __reg32_deduce_bounds(struct bpf_reg_state *reg) +{ + /* Learn sign from signed bounds. + * If we cannot cross the sign boundary, then signed and unsigned bounds + * are the same, so combine. This works even in the negative case, e.g. + * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff. + */ + if (reg->s32_min_value >= 0 || reg->s32_max_value < 0) { + reg->s32_min_value = reg->u32_min_value = + max_t(u32, reg->s32_min_value, reg->u32_min_value); + reg->s32_max_value = reg->u32_max_value = + min_t(u32, reg->s32_max_value, reg->u32_max_value); + return; + } + /* Learn sign from unsigned bounds. Signed bounds cross the sign + * boundary, so we must be careful. + */ + if ((s32)reg->u32_max_value >= 0) { + /* Positive. We can't learn anything from the smin, but smax + * is positive, hence safe. + */ + reg->s32_min_value = reg->u32_min_value; + reg->s32_max_value = reg->u32_max_value = + min_t(u32, reg->s32_max_value, reg->u32_max_value); + } else if ((s32)reg->u32_min_value < 0) { + /* Negative. We can't learn anything from the smax, but smin + * is negative, hence safe. + */ + reg->s32_min_value = reg->u32_min_value = + max_t(u32, reg->s32_min_value, reg->u32_min_value); + reg->s32_max_value = reg->u32_max_value; + } +} + +static void __reg64_deduce_bounds(struct bpf_reg_state *reg) { /* Learn sign from signed bounds. * If we cannot cross the sign boundary, then signed and unsigned bounds @@ -1027,21 +1141,106 @@ static void __reg_deduce_bounds(struct bpf_reg_state *reg) } } +static void __reg_deduce_bounds(struct bpf_reg_state *reg) +{ + __reg32_deduce_bounds(reg); + __reg64_deduce_bounds(reg); +} + /* Attempts to improve var_off based on unsigned min/max information */ static void __reg_bound_offset(struct bpf_reg_state *reg) { - reg->var_off = tnum_intersect(reg->var_off, - tnum_range(reg->umin_value, - reg->umax_value)); + struct tnum var64_off = tnum_intersect(reg->var_off, + tnum_range(reg->umin_value, + reg->umax_value)); + struct tnum var32_off = tnum_intersect(tnum_subreg(reg->var_off), + tnum_range(reg->u32_min_value, + reg->u32_max_value)); + + reg->var_off = tnum_or(tnum_clear_subreg(var64_off), var32_off); } -/* Reset the min/max bounds of a register */ -static void __mark_reg_unbounded(struct bpf_reg_state *reg) +static void __reg_assign_32_into_64(struct bpf_reg_state *reg) { - reg->smin_value = S64_MIN; - reg->smax_value = S64_MAX; - reg->umin_value = 0; - reg->umax_value = U64_MAX; + reg->umin_value = reg->u32_min_value; + reg->umax_value = reg->u32_max_value; + /* Attempt to pull 32-bit signed bounds into 64-bit bounds + * but must be positive otherwise set to worse case bounds + * and refine later from tnum. + */ + if (reg->s32_min_value > 0) + reg->smin_value = reg->s32_min_value; + else + reg->smin_value = 0; + if (reg->s32_max_value > 0) + reg->smax_value = reg->s32_max_value; + else + reg->smax_value = U32_MAX; +} + +static void __reg_combine_32_into_64(struct bpf_reg_state *reg) +{ + /* special case when 64-bit register has upper 32-bit register + * zeroed. Typically happens after zext or <<32, >>32 sequence + * allowing us to use 32-bit bounds directly, + */ + if (tnum_equals_const(tnum_clear_subreg(reg->var_off), 0)) { + __reg_assign_32_into_64(reg); + } else { + /* Otherwise the best we can do is push lower 32bit known and + * unknown bits into register (var_off set from jmp logic) + * then learn as much as possible from the 64-bit tnum + * known and unknown bits. The previous smin/smax bounds are + * invalid here because of jmp32 compare so mark them unknown + * so they do not impact tnum bounds calculation. + */ + __mark_reg64_unbounded(reg); + __update_reg_bounds(reg); + } + + /* Intersecting with the old var_off might have improved our bounds + * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), + * then new var_off is (0; 0x7f...fc) which improves our umax. + */ + __reg_deduce_bounds(reg); + __reg_bound_offset(reg); + __update_reg_bounds(reg); +} + +static bool __reg64_bound_s32(s64 a) +{ + if (a > S32_MIN && a < S32_MAX) + return true; + return false; +} + +static bool __reg64_bound_u32(u64 a) +{ + if (a > U32_MIN && a < U32_MAX) + return true; + return false; +} + +static void __reg_combine_64_into_32(struct bpf_reg_state *reg) +{ + __mark_reg32_unbounded(reg); + + if (__reg64_bound_s32(reg->smin_value)) + reg->s32_min_value = (s32)reg->smin_value; + if (__reg64_bound_s32(reg->smax_value)) + reg->s32_max_value = (s32)reg->smax_value; + if (__reg64_bound_u32(reg->umin_value)) + reg->u32_min_value = (u32)reg->umin_value; + if (__reg64_bound_u32(reg->umax_value)) + reg->u32_max_value = (u32)reg->umax_value; + + /* Intersecting with the old var_off might have improved our bounds + * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), + * then new var_off is (0; 0x7f...fc) which improves our umax. + */ + __reg_deduce_bounds(reg); + __reg_bound_offset(reg); + __update_reg_bounds(reg); } /* Mark a register as having a completely unknown (scalar) value. */ @@ -2774,6 +2973,12 @@ static int check_tp_buffer_access(struct bpf_verifier_env *env, return 0; } +/* BPF architecture zero extends alu32 ops into 64-bit registesr */ +static void zext_32_to_64(struct bpf_reg_state *reg) +{ + reg->var_off = tnum_subreg(reg->var_off); + __reg_assign_32_into_64(reg); +} /* truncate register to smaller size (in bytes) * must be called with size < BPF_REG_SIZE @@ -2796,6 +3001,14 @@ static void coerce_reg_to_size(struct bpf_reg_state *reg, int size) } reg->smin_value = reg->umin_value; reg->smax_value = reg->umax_value; + + /* If size is smaller than 32bit register the 32bit register + * values are also truncated so we push 64-bit bounds into + * 32-bit bounds. Above were truncated < 32-bits already. + */ + if (size >= 4) + return; + __reg_combine_64_into_32(reg); } static bool bpf_map_is_rdonly(const struct bpf_map *map) @@ -4431,7 +4644,17 @@ static bool signed_add_overflows(s64 a, s64 b) return res < a; } -static bool signed_sub_overflows(s64 a, s64 b) +static bool signed_add32_overflows(s64 a, s64 b) +{ + /* Do the add in u32, where overflow is well-defined */ + s32 res = (s32)((u32)a + (u32)b); + + if (b < 0) + return res > a; + return res < a; +} + +static bool signed_sub_overflows(s32 a, s32 b) { /* Do the sub in u64, where overflow is well-defined */ s64 res = (s64)((u64)a - (u64)b); @@ -4441,6 +4664,16 @@ static bool signed_sub_overflows(s64 a, s64 b) return res > a; } +static bool signed_sub32_overflows(s32 a, s32 b) +{ + /* Do the sub in u64, where overflow is well-defined */ + s32 res = (s32)((u32)a - (u32)b); + + if (b < 0) + return res < a; + return res > a; +} + static bool check_reg_sane_offset(struct bpf_verifier_env *env, const struct bpf_reg_state *reg, enum bpf_reg_type type) @@ -4677,6 +4910,9 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, !check_reg_sane_offset(env, ptr_reg, ptr_reg->type)) return -EINVAL; + /* pointer types do not carry 32-bit bounds at the moment. */ + __mark_reg32_unbounded(dst_reg); + switch (opcode) { case BPF_ADD: ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0); @@ -4840,6 +5076,32 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, return 0; } +static void scalar32_min_max_add(struct bpf_reg_state *dst_reg, + struct bpf_reg_state *src_reg) +{ + s32 smin_val = src_reg->s32_min_value; + s32 smax_val = src_reg->s32_max_value; + u32 umin_val = src_reg->u32_min_value; + u32 umax_val = src_reg->u32_max_value; + + if (signed_add32_overflows(dst_reg->s32_min_value, smin_val) || + signed_add32_overflows(dst_reg->s32_max_value, smax_val)) { + dst_reg->s32_min_value = S32_MIN; + dst_reg->s32_max_value = S32_MAX; + } else { + dst_reg->s32_min_value += smin_val; + dst_reg->s32_max_value += smax_val; + } + if (dst_reg->u32_min_value + umin_val < umin_val || + dst_reg->u32_max_value + umax_val < umax_val) { + dst_reg->u32_min_value = 0; + dst_reg->u32_max_value = U32_MAX; + } else { + dst_reg->u32_min_value += umin_val; + dst_reg->u32_max_value += umax_val; + } +} + static void scalar_min_max_add(struct bpf_reg_state *dst_reg, struct bpf_reg_state *src_reg) { @@ -4864,7 +5126,34 @@ static void scalar_min_max_add(struct bpf_reg_state *dst_reg, dst_reg->umin_value += umin_val; dst_reg->umax_value += umax_val; } - dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg->var_off); +} + +static void scalar32_min_max_sub(struct bpf_reg_state *dst_reg, + struct bpf_reg_state *src_reg) +{ + s32 smin_val = src_reg->s32_min_value; + s32 smax_val = src_reg->s32_max_value; + u32 umin_val = src_reg->u32_min_value; + u32 umax_val = src_reg->u32_max_value; + + if (signed_sub32_overflows(dst_reg->s32_min_value, smax_val) || + signed_sub32_overflows(dst_reg->s32_max_value, smin_val)) { + /* Overflow possible, we know nothing */ + dst_reg->s32_min_value = S32_MIN; + dst_reg->s32_max_value = S32_MAX; + } else { + dst_reg->s32_min_value -= smax_val; + dst_reg->s32_max_value -= smin_val; + } + if (dst_reg->u32_min_value < umax_val) { + /* Overflow possible, we know nothing */ + dst_reg->u32_min_value = 0; + dst_reg->u32_max_value = U32_MAX; + } else { + /* Cannot overflow (as long as bounds are consistent) */ + dst_reg->u32_min_value -= umax_val; + dst_reg->u32_max_value -= umin_val; + } } static void scalar_min_max_sub(struct bpf_reg_state *dst_reg, @@ -4893,7 +5182,38 @@ static void scalar_min_max_sub(struct bpf_reg_state *dst_reg, dst_reg->umin_value -= umax_val; dst_reg->umax_value -= umin_val; } - dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg->var_off); +} + +static void scalar32_min_max_mul(struct bpf_reg_state *dst_reg, + struct bpf_reg_state *src_reg) +{ + s32 smin_val = src_reg->s32_min_value; + u32 umin_val = src_reg->u32_min_value; + u32 umax_val = src_reg->u32_max_value; + + if (smin_val < 0 || dst_reg->s32_min_value < 0) { + /* Ain't nobody got time to multiply that sign */ + __mark_reg32_unbounded(dst_reg); + return; + } + /* Both values are positive, so we can work with unsigned and + * copy the result to signed (unless it exceeds S32_MAX). + */ + if (umax_val > U16_MAX || dst_reg->u32_max_value > U16_MAX) { + /* Potential overflow, we know nothing */ + __mark_reg32_unbounded(dst_reg); + return; + } + dst_reg->u32_min_value *= umin_val; + dst_reg->u32_max_value *= umax_val; + if (dst_reg->u32_max_value > S32_MAX) { + /* Overflow possible, we know nothing */ + dst_reg->s32_min_value = S32_MIN; + dst_reg->s32_max_value = S32_MAX; + } else { + dst_reg->s32_min_value = dst_reg->u32_min_value; + dst_reg->s32_max_value = dst_reg->u32_max_value; + } } static void scalar_min_max_mul(struct bpf_reg_state *dst_reg, @@ -4903,11 +5223,9 @@ static void scalar_min_max_mul(struct bpf_reg_state *dst_reg, u64 umin_val = src_reg->umin_value; u64 umax_val = src_reg->umax_value; - dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg->var_off); if (smin_val < 0 || dst_reg->smin_value < 0) { /* Ain't nobody got time to multiply that sign */ - __mark_reg_unbounded(dst_reg); - __update_reg_bounds(dst_reg); + __mark_reg64_unbounded(dst_reg); return; } /* Both values are positive, so we can work with unsigned and @@ -4915,9 +5233,7 @@ static void scalar_min_max_mul(struct bpf_reg_state *dst_reg, */ if (umax_val > U32_MAX || dst_reg->umax_value > U32_MAX) { /* Potential overflow, we know nothing */ - __mark_reg_unbounded(dst_reg); - /* (except what we can learn from the var_off) */ - __update_reg_bounds(dst_reg); + __mark_reg64_unbounded(dst_reg); return; } dst_reg->umin_value *= umin_val; @@ -4932,16 +5248,59 @@ static void scalar_min_max_mul(struct bpf_reg_state *dst_reg, } } +static void scalar32_min_max_and(struct bpf_reg_state *dst_reg, + struct bpf_reg_state *src_reg) +{ + bool src_known = tnum_subreg_is_const(src_reg->var_off); + bool dst_known = tnum_subreg_is_const(dst_reg->var_off); + struct tnum var32_off = tnum_subreg(dst_reg->var_off); + s32 smin_val = src_reg->s32_min_value; + u32 umax_val = src_reg->u32_max_value; + + /* Assuming scalar64_min_max_and will be called so its safe + * to skip updating register for known 32-bit case. + */ + if (src_known && dst_known) + return; + + /* We get our minimum from the var_off, since that's inherently + * bitwise. Our maximum is the minimum of the operands' maxima. + */ + dst_reg->u32_min_value = var32_off.value; + dst_reg->u32_max_value = min(dst_reg->u32_max_value, umax_val); + if (dst_reg->s32_min_value < 0 || smin_val < 0) { + /* Lose signed bounds when ANDing negative numbers, + * ain't nobody got time for that. + */ + dst_reg->s32_min_value = S32_MIN; + dst_reg->s32_max_value = S32_MAX; + } else { + /* ANDing two positives gives a positive, so safe to + * cast result into s64. + */ + dst_reg->s32_min_value = dst_reg->u32_min_value; + dst_reg->s32_max_value = dst_reg->u32_max_value; + } + +} + static void scalar_min_max_and(struct bpf_reg_state *dst_reg, struct bpf_reg_state *src_reg) { + bool src_known = tnum_is_const(src_reg->var_off); + bool dst_known = tnum_is_const(dst_reg->var_off); s64 smin_val = src_reg->smin_value; u64 umax_val = src_reg->umax_value; + if (src_known && dst_known) { + __mark_reg_known(dst_reg, dst_reg->var_off.value & + src_reg->var_off.value); + return; + } + /* We get our minimum from the var_off, since that's inherently * bitwise. Our maximum is the minimum of the operands' maxima. */ - dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg->var_off); dst_reg->umin_value = dst_reg->var_off.value; dst_reg->umax_value = min(dst_reg->umax_value, umax_val); if (dst_reg->smin_value < 0 || smin_val < 0) { @@ -4961,16 +5320,58 @@ static void scalar_min_max_and(struct bpf_reg_state *dst_reg, __update_reg_bounds(dst_reg); } +static void scalar32_min_max_or(struct bpf_reg_state *dst_reg, + struct bpf_reg_state *src_reg) +{ + bool src_known = tnum_subreg_is_const(src_reg->var_off); + bool dst_known = tnum_subreg_is_const(dst_reg->var_off); + struct tnum var32_off = tnum_subreg(dst_reg->var_off); + s32 smin_val = src_reg->smin_value; + u32 umin_val = src_reg->umin_value; + + /* Assuming scalar64_min_max_or will be called so it is safe + * to skip updating register for known case. + */ + if (src_known && dst_known) + return; + + /* We get our maximum from the var_off, and our minimum is the + * maximum of the operands' minima + */ + dst_reg->u32_min_value = max(dst_reg->u32_min_value, umin_val); + dst_reg->u32_max_value = var32_off.value | var32_off.mask; + if (dst_reg->s32_min_value < 0 || smin_val < 0) { + /* Lose signed bounds when ORing negative numbers, + * ain't nobody got time for that. + */ + dst_reg->s32_min_value = S32_MIN; + dst_reg->s32_max_value = S32_MAX; + } else { + /* ORing two positives gives a positive, so safe to + * cast result into s64. + */ + dst_reg->s32_min_value = dst_reg->umin_value; + dst_reg->s32_max_value = dst_reg->umax_value; + } +} + static void scalar_min_max_or(struct bpf_reg_state *dst_reg, struct bpf_reg_state *src_reg) { + bool src_known = tnum_is_const(src_reg->var_off); + bool dst_known = tnum_is_const(dst_reg->var_off); s64 smin_val = src_reg->smin_value; u64 umin_val = src_reg->umin_value; + if (src_known && dst_known) { + __mark_reg_known(dst_reg, dst_reg->var_off.value | + src_reg->var_off.value); + return; + } + /* We get our maximum from the var_off, and our minimum is the * maximum of the operands' minima */ - dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg->var_off); dst_reg->umin_value = max(dst_reg->umin_value, umin_val); dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask; if (dst_reg->smin_value < 0 || smin_val < 0) { @@ -4990,17 +5391,62 @@ static void scalar_min_max_or(struct bpf_reg_state *dst_reg, __update_reg_bounds(dst_reg); } -static void scalar_min_max_lsh(struct bpf_reg_state *dst_reg, - struct bpf_reg_state *src_reg) +static void __scalar32_min_max_lsh(struct bpf_reg_state *dst_reg, + u64 umin_val, u64 umax_val) { - u64 umax_val = src_reg->umax_value; - u64 umin_val = src_reg->umin_value; - /* We lose all sign bit information (except what we can pick * up from var_off) */ - dst_reg->smin_value = S64_MIN; - dst_reg->smax_value = S64_MAX; + dst_reg->s32_min_value = S32_MIN; + dst_reg->s32_max_value = S32_MAX; + /* If we might shift our top bit out, then we know nothing */ + if (umax_val > 31 || dst_reg->u32_max_value > 1ULL << (31 - umax_val)) { + dst_reg->u32_min_value = 0; + dst_reg->u32_max_value = U32_MAX; + } else { + dst_reg->u32_min_value <<= umin_val; + dst_reg->u32_max_value <<= umax_val; + } +} + +static void scalar32_min_max_lsh(struct bpf_reg_state *dst_reg, + struct bpf_reg_state *src_reg) +{ + u32 umax_val = src_reg->u32_max_value; + u32 umin_val = src_reg->u32_min_value; + /* u32 alu operation will zext upper bits */ + struct tnum subreg = tnum_subreg(dst_reg->var_off); + + __scalar32_min_max_lsh(dst_reg, umin_val, umax_val); + dst_reg->var_off = tnum_subreg(tnum_lshift(subreg, umin_val)); + /* Not required but being careful mark reg64 bounds as unknown so + * that we are forced to pick them up from tnum and zext later and + * if some path skips this step we are still safe. + */ + __mark_reg64_unbounded(dst_reg); + __update_reg32_bounds(dst_reg); +} + +static void __scalar64_min_max_lsh(struct bpf_reg_state *dst_reg, + u64 umin_val, u64 umax_val) +{ + /* Special case <<32 because it is a common compiler pattern to sign + * extend subreg by doing <<32 s>>32. In this case if 32bit bounds are + * positive we know this shift will also be positive so we can track + * bounds correctly. Otherwise we lose all sign bit information except + * what we can pick up from var_off. Perhaps we can generalize this + * later to shifts of any length. + */ + if (umin_val == 32 && umax_val == 32 && dst_reg->s32_max_value >= 0) + dst_reg->smax_value = (s64)dst_reg->s32_max_value << 32; + else + dst_reg->smax_value = S64_MAX; + + if (umin_val == 32 && umax_val == 32 && dst_reg->s32_min_value >= 0) + dst_reg->smin_value = (s64)dst_reg->s32_min_value << 32; + else + dst_reg->smin_value = S64_MIN; + /* If we might shift our top bit out, then we know nothing */ if (dst_reg->umax_value > 1ULL << (63 - umax_val)) { dst_reg->umin_value = 0; @@ -5009,11 +5455,55 @@ static void scalar_min_max_lsh(struct bpf_reg_state *dst_reg, dst_reg->umin_value <<= umin_val; dst_reg->umax_value <<= umax_val; } +} + +static void scalar_min_max_lsh(struct bpf_reg_state *dst_reg, + struct bpf_reg_state *src_reg) +{ + u64 umax_val = src_reg->umax_value; + u64 umin_val = src_reg->umin_value; + + /* scalar64 calc uses 32bit unshifted bounds so must be called first */ + __scalar64_min_max_lsh(dst_reg, umin_val, umax_val); + __scalar32_min_max_lsh(dst_reg, umin_val, umax_val); + dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val); /* We may learn something more from the var_off */ __update_reg_bounds(dst_reg); } +static void scalar32_min_max_rsh(struct bpf_reg_state *dst_reg, + struct bpf_reg_state *src_reg) +{ + struct tnum subreg = tnum_subreg(dst_reg->var_off); + u32 umax_val = src_reg->u32_max_value; + u32 umin_val = src_reg->u32_min_value; + + /* BPF_RSH is an unsigned shift. If the value in dst_reg might + * be negative, then either: + * 1) src_reg might be zero, so the sign bit of the result is + * unknown, so we lose our signed bounds + * 2) it's known negative, thus the unsigned bounds capture the + * signed bounds + * 3) the signed bounds cross zero, so they tell us nothing + * about the result + * If the value in dst_reg is known nonnegative, then again the + * unsigned bounts capture the signed bounds. + * Thus, in all cases it suffices to blow away our signed bounds + * and rely on inferring new ones from the unsigned bounds and + * var_off of the result. + */ + dst_reg->s32_min_value = S32_MIN; + dst_reg->s32_max_value = S32_MAX; + + dst_reg->var_off = tnum_rshift(subreg, umin_val); + dst_reg->u32_min_value >>= umax_val; + dst_reg->u32_max_value >>= umin_val; + + __mark_reg64_unbounded(dst_reg); + __update_reg32_bounds(dst_reg); +} + static void scalar_min_max_rsh(struct bpf_reg_state *dst_reg, struct bpf_reg_state *src_reg) { @@ -5039,35 +5529,62 @@ static void scalar_min_max_rsh(struct bpf_reg_state *dst_reg, dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val); dst_reg->umin_value >>= umax_val; dst_reg->umax_value >>= umin_val; - /* We may learn something more from the var_off */ + + /* Its not easy to operate on alu32 bounds here because it depends + * on bits being shifted in. Take easy way out and mark unbounded + * so we can recalculate later from tnum. + */ + __mark_reg32_unbounded(dst_reg); __update_reg_bounds(dst_reg); } -static void scalar_min_max_arsh(struct bpf_reg_state *dst_reg, - struct bpf_reg_state *src_reg, - u64 insn_bitness) +static void scalar32_min_max_arsh(struct bpf_reg_state *dst_reg, + struct bpf_reg_state *src_reg) { - u64 umin_val = src_reg->umin_value; + u64 umin_val = src_reg->u32_min_value; /* Upon reaching here, src_known is true and * umax_val is equal to umin_val. */ - if (insn_bitness == 32) { - dst_reg->smin_value = (u32)(((s32)dst_reg->smin_value) >> umin_val); - dst_reg->smax_value = (u32)(((s32)dst_reg->smax_value) >> umin_val); - } else { - dst_reg->smin_value >>= umin_val; - dst_reg->smax_value >>= umin_val; - } + dst_reg->s32_min_value = (u32)(((s32)dst_reg->s32_min_value) >> umin_val); + dst_reg->s32_max_value = (u32)(((s32)dst_reg->s32_max_value) >> umin_val); - dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val, - insn_bitness); + dst_reg->var_off = tnum_arshift(tnum_subreg(dst_reg->var_off), umin_val, 32); + + /* blow away the dst_reg umin_value/umax_value and rely on + * dst_reg var_off to refine the result. + */ + dst_reg->u32_min_value = 0; + dst_reg->u32_max_value = U32_MAX; + + __mark_reg64_unbounded(dst_reg); + __update_reg32_bounds(dst_reg); +} + +static void scalar_min_max_arsh(struct bpf_reg_state *dst_reg, + struct bpf_reg_state *src_reg) +{ + u64 umin_val = src_reg->umin_value; + + /* Upon reaching here, src_known is true and umax_val is equal + * to umin_val. + */ + dst_reg->smin_value >>= umin_val; + dst_reg->smax_value >>= umin_val; + + dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val, 64); /* blow away the dst_reg umin_value/umax_value and rely on * dst_reg var_off to refine the result. */ dst_reg->umin_value = 0; dst_reg->umax_value = U64_MAX; + + /* Its not easy to operate on alu32 bounds here because it depends + * on bits being shifted in from upper 32-bits. Take easy way out + * and mark unbounded so we can recalculate later from tnum. + */ + __mark_reg32_unbounded(dst_reg); __update_reg_bounds(dst_reg); } @@ -5085,33 +5602,47 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, bool src_known, dst_known; s64 smin_val, smax_val; u64 umin_val, umax_val; + s32 s32_min_val, s32_max_val; + u32 u32_min_val, u32_max_val; u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32; u32 dst = insn->dst_reg; int ret; - - if (insn_bitness == 32) { - /* Relevant for 32-bit RSH: Information can propagate towards - * LSB, so it isn't sufficient to only truncate the output to - * 32 bits. - */ - coerce_reg_to_size(dst_reg, 4); - coerce_reg_to_size(&src_reg, 4); - } + bool alu32 = (BPF_CLASS(insn->code) != BPF_ALU64); smin_val = src_reg.smin_value; smax_val = src_reg.smax_value; umin_val = src_reg.umin_value; umax_val = src_reg.umax_value; - src_known = tnum_is_const(src_reg.var_off); - dst_known = tnum_is_const(dst_reg->var_off); - if ((src_known && (smin_val != smax_val || umin_val != umax_val)) || - smin_val > smax_val || umin_val > umax_val) { - /* Taint dst register if offset had invalid bounds derived from - * e.g. dead branches. - */ - __mark_reg_unknown(env, dst_reg); - return 0; + s32_min_val = src_reg.s32_min_value; + s32_max_val = src_reg.s32_max_value; + u32_min_val = src_reg.u32_min_value; + u32_max_val = src_reg.u32_max_value; + + if (alu32) { + src_known = tnum_subreg_is_const(src_reg.var_off); + dst_known = tnum_subreg_is_const(dst_reg->var_off); + if ((src_known && + (s32_min_val != s32_max_val || u32_min_val != u32_max_val)) || + s32_min_val > s32_max_val || u32_min_val > u32_max_val) { + /* Taint dst register if offset had invalid bounds + * derived from e.g. dead branches. + */ + __mark_reg_unknown(env, dst_reg); + return 0; + } + } else { + src_known = tnum_is_const(src_reg.var_off); + dst_known = tnum_is_const(dst_reg->var_off); + if ((src_known && + (smin_val != smax_val || umin_val != umax_val)) || + smin_val > smax_val || umin_val > umax_val) { + /* Taint dst register if offset had invalid bounds + * derived from e.g. dead branches. + */ + __mark_reg_unknown(env, dst_reg); + return 0; + } } if (!src_known && @@ -5120,6 +5651,20 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, return 0; } + /* Calculate sign/unsigned bounds and tnum for alu32 and alu64 bit ops. + * There are two classes of instructions: The first class we track both + * alu32 and alu64 sign/unsigned bounds independently this provides the + * greatest amount of precision when alu operations are mixed with jmp32 + * operations. These operations are BPF_ADD, BPF_SUB, BPF_MUL, BPF_ADD, + * and BPF_OR. This is possible because these ops have fairly easy to + * understand and calculate behavior in both 32-bit and 64-bit alu ops. + * See alu32 verifier tests for examples. The second class of + * operations, BPF_LSH, BPF_RSH, and BPF_ARSH, however are not so easy + * with regards to tracking sign/unsigned bounds because the bits may + * cross subreg boundaries in the alu64 case. When this happens we mark + * the reg unbounded in the subreg bound space and use the resulting + * tnum to calculate an approximation of the sign/unsigned bounds. + */ switch (opcode) { case BPF_ADD: ret = sanitize_val_alu(env, insn); @@ -5127,7 +5672,9 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, verbose(env, "R%d tried to add from different pointers or scalars\n", dst); return ret; } + scalar32_min_max_add(dst_reg, &src_reg); scalar_min_max_add(dst_reg, &src_reg); + dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off); break; case BPF_SUB: ret = sanitize_val_alu(env, insn); @@ -5135,25 +5682,23 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, verbose(env, "R%d tried to sub from different pointers or scalars\n", dst); return ret; } + scalar32_min_max_sub(dst_reg, &src_reg); scalar_min_max_sub(dst_reg, &src_reg); + dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off); break; case BPF_MUL: + dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off); + scalar32_min_max_mul(dst_reg, &src_reg); scalar_min_max_mul(dst_reg, &src_reg); break; case BPF_AND: - if (src_known && dst_known) { - __mark_reg_known(dst_reg, dst_reg->var_off.value & - src_reg.var_off.value); - break; - } + dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg.var_off); + scalar32_min_max_and(dst_reg, &src_reg); scalar_min_max_and(dst_reg, &src_reg); break; case BPF_OR: - if (src_known && dst_known) { - __mark_reg_known(dst_reg, dst_reg->var_off.value | - src_reg.var_off.value); - break; - } + dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg.var_off); + scalar32_min_max_or(dst_reg, &src_reg); scalar_min_max_or(dst_reg, &src_reg); break; case BPF_LSH: @@ -5164,7 +5709,10 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, mark_reg_unknown(env, regs, insn->dst_reg); break; } - scalar_min_max_lsh(dst_reg, &src_reg); + if (alu32) + scalar32_min_max_lsh(dst_reg, &src_reg); + else + scalar_min_max_lsh(dst_reg, &src_reg); break; case BPF_RSH: if (umax_val >= insn_bitness) { @@ -5174,7 +5722,10 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, mark_reg_unknown(env, regs, insn->dst_reg); break; } - scalar_min_max_rsh(dst_reg, &src_reg); + if (alu32) + scalar32_min_max_rsh(dst_reg, &src_reg); + else + scalar_min_max_rsh(dst_reg, &src_reg); break; case BPF_ARSH: if (umax_val >= insn_bitness) { @@ -5184,17 +5735,19 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, mark_reg_unknown(env, regs, insn->dst_reg); break; } - scalar_min_max_arsh(dst_reg, &src_reg, insn_bitness); + if (alu32) + scalar32_min_max_arsh(dst_reg, &src_reg); + else + scalar_min_max_arsh(dst_reg, &src_reg); break; default: mark_reg_unknown(env, regs, insn->dst_reg); break; } - if (BPF_CLASS(insn->code) != BPF_ALU64) { - /* 32-bit ALU ops are (32,32)->32 */ - coerce_reg_to_size(dst_reg, 4); - } + /* ALU32 ops are zero extended into 64bit register */ + if (alu32) + zext_32_to_64(dst_reg); __update_reg_bounds(dst_reg); __reg_deduce_bounds(dst_reg); @@ -5370,7 +5923,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) mark_reg_unknown(env, regs, insn->dst_reg); } - coerce_reg_to_size(dst_reg, 4); + zext_32_to_64(dst_reg); } } else { /* case: R = imm @@ -5540,55 +6093,83 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, new_range); } -/* compute branch direction of the expression "if (reg opcode val) goto target;" - * and return: - * 1 - branch will be taken and "goto target" will be executed - * 0 - branch will not be taken and fall-through to next insn - * -1 - unknown. Example: "if (reg < 5)" is unknown when register value range [0,10] - */ -static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode, - bool is_jmp32) +static int is_branch32_taken(struct bpf_reg_state *reg, u32 val, u8 opcode) { - struct bpf_reg_state reg_lo; - s64 sval; + struct tnum subreg = tnum_subreg(reg->var_off); + s32 sval = (s32)val; - if (__is_pointer_value(false, reg)) - return -1; + switch (opcode) { + case BPF_JEQ: + if (tnum_is_const(subreg)) + return !!tnum_equals_const(subreg, val); + break; + case BPF_JNE: + if (tnum_is_const(subreg)) + return !tnum_equals_const(subreg, val); + break; + case BPF_JSET: + if ((~subreg.mask & subreg.value) & val) + return 1; + if (!((subreg.mask | subreg.value) & val)) + return 0; + break; + case BPF_JGT: + if (reg->u32_min_value > val) + return 1; + else if (reg->u32_max_value <= val) + return 0; + break; + case BPF_JSGT: + if (reg->s32_min_value > sval) + return 1; + else if (reg->s32_max_value < sval) + return 0; + break; + case BPF_JLT: + if (reg->u32_max_value < val) + return 1; + else if (reg->u32_min_value >= val) + return 0; + break; + case BPF_JSLT: + if (reg->s32_max_value < sval) + return 1; + else if (reg->s32_min_value >= sval) + return 0; + break; + case BPF_JGE: + if (reg->u32_min_value >= val) + return 1; + else if (reg->u32_max_value < val) + return 0; + break; + case BPF_JSGE: + if (reg->s32_min_value >= sval) + return 1; + else if (reg->s32_max_value < sval) + return 0; + break; + case BPF_JLE: + if (reg->u32_max_value <= val) + return 1; + else if (reg->u32_min_value > val) + return 0; + break; + case BPF_JSLE: + if (reg->s32_max_value <= sval) + return 1; + else if (reg->s32_min_value > sval) + return 0; + break; + } - if (is_jmp32) { - reg_lo = *reg; - reg = ®_lo; - /* For JMP32, only low 32 bits are compared, coerce_reg_to_size - * could truncate high bits and update umin/umax according to - * information of low bits. - */ - coerce_reg_to_size(reg, 4); - /* smin/smax need special handling. For example, after coerce, - * if smin_value is 0x00000000ffffffffLL, the value is -1 when - * used as operand to JMP32. It is a negative number from s32's - * point of view, while it is a positive number when seen as - * s64. The smin/smax are kept as s64, therefore, when used with - * JMP32, they need to be transformed into s32, then sign - * extended back to s64. - * - * Also, smin/smax were copied from umin/umax. If umin/umax has - * different sign bit, then min/max relationship doesn't - * maintain after casting into s32, for this case, set smin/smax - * to safest range. - */ - if ((reg->umax_value ^ reg->umin_value) & - (1ULL << 31)) { - reg->smin_value = S32_MIN; - reg->smax_value = S32_MAX; - } - reg->smin_value = (s64)(s32)reg->smin_value; - reg->smax_value = (s64)(s32)reg->smax_value; + return -1; +} - val = (u32)val; - sval = (s64)(s32)val; - } else { - sval = (s64)val; - } + +static int is_branch64_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) +{ + s64 sval = (s64)val; switch (opcode) { case BPF_JEQ: @@ -5658,91 +6239,22 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode, return -1; } -/* Generate min value of the high 32-bit from TNUM info. */ -static u64 gen_hi_min(struct tnum var) -{ - return var.value & ~0xffffffffULL; -} - -/* Generate max value of the high 32-bit from TNUM info. */ -static u64 gen_hi_max(struct tnum var) -{ - return (var.value | var.mask) & ~0xffffffffULL; -} - -/* Return true if VAL is compared with a s64 sign extended from s32, and they - * are with the same signedness. - */ -static bool cmp_val_with_extended_s64(s64 sval, struct bpf_reg_state *reg) -{ - return ((s32)sval >= 0 && - reg->smin_value >= 0 && reg->smax_value <= S32_MAX) || - ((s32)sval < 0 && - reg->smax_value <= 0 && reg->smin_value >= S32_MIN); -} - -/* Constrain the possible values of @reg with unsigned upper bound @bound. - * If @is_exclusive, @bound is an exclusive limit, otherwise it is inclusive. - * If @is_jmp32, @bound is a 32-bit value that only constrains the low 32 bits - * of @reg. - */ -static void set_upper_bound(struct bpf_reg_state *reg, u64 bound, bool is_jmp32, - bool is_exclusive) -{ - if (is_exclusive) { - /* There are no values for `reg` that make `reg<0` true. */ - if (bound == 0) - return; - bound--; - } - if (is_jmp32) { - /* Constrain the register's value in the tnum representation. - * For 64-bit comparisons this happens later in - * __reg_bound_offset(), but for 32-bit comparisons, we can be - * more precise than what can be derived from the updated - * numeric bounds. - */ - struct tnum t = tnum_range(0, bound); - - t.mask |= ~0xffffffffULL; /* upper half is unknown */ - reg->var_off = tnum_intersect(reg->var_off, t); - - /* Compute the 64-bit bound from the 32-bit bound. */ - bound += gen_hi_max(reg->var_off); - } - reg->umax_value = min(reg->umax_value, bound); -} - -/* Constrain the possible values of @reg with unsigned lower bound @bound. - * If @is_exclusive, @bound is an exclusive limit, otherwise it is inclusive. - * If @is_jmp32, @bound is a 32-bit value that only constrains the low 32 bits - * of @reg. +/* compute branch direction of the expression "if (reg opcode val) goto target;" + * and return: + * 1 - branch will be taken and "goto target" will be executed + * 0 - branch will not be taken and fall-through to next insn + * -1 - unknown. Example: "if (reg < 5)" is unknown when register value + * range [0,10] */ -static void set_lower_bound(struct bpf_reg_state *reg, u64 bound, bool is_jmp32, - bool is_exclusive) +static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode, + bool is_jmp32) { - if (is_exclusive) { - /* There are no values for `reg` that make `reg>MAX` true. */ - if (bound == (is_jmp32 ? U32_MAX : U64_MAX)) - return; - bound++; - } - if (is_jmp32) { - /* Constrain the register's value in the tnum representation. - * For 64-bit comparisons this happens later in - * __reg_bound_offset(), but for 32-bit comparisons, we can be - * more precise than what can be derived from the updated - * numeric bounds. - */ - struct tnum t = tnum_range(bound, U32_MAX); - - t.mask |= ~0xffffffffULL; /* upper half is unknown */ - reg->var_off = tnum_intersect(reg->var_off, t); + if (__is_pointer_value(false, reg)) + return -1; - /* Compute the 64-bit bound from the 32-bit bound. */ - bound += gen_hi_min(reg->var_off); - } - reg->umin_value = max(reg->umin_value, bound); + if (is_jmp32) + return is_branch32_taken(reg, val, opcode); + return is_branch64_taken(reg, val, opcode); } /* Adjusts the register min/max values in the case that the dst_reg is the @@ -5751,10 +6263,16 @@ static void set_lower_bound(struct bpf_reg_state *reg, u64 bound, bool is_jmp32, * In JEQ/JNE cases we also adjust the var_off values. */ static void reg_set_min_max(struct bpf_reg_state *true_reg, - struct bpf_reg_state *false_reg, u64 val, + struct bpf_reg_state *false_reg, + u64 val, u32 val32, u8 opcode, bool is_jmp32) { - s64 sval; + struct tnum false_32off = tnum_subreg(false_reg->var_off); + struct tnum false_64off = false_reg->var_off; + struct tnum true_32off = tnum_subreg(true_reg->var_off); + struct tnum true_64off = true_reg->var_off; + s64 sval = (s64)val; + s32 sval32 = (s32)val32; /* If the dst_reg is a pointer, we can't learn anything about its * variable offset from the compare (unless src_reg were a pointer into @@ -5765,9 +6283,6 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, if (__is_pointer_value(false, false_reg)) return; - val = is_jmp32 ? (u32)val : val; - sval = is_jmp32 ? (s64)(s32)val : (s64)val; - switch (opcode) { case BPF_JEQ: case BPF_JNE: @@ -5779,87 +6294,126 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, * if it is true we know the value for sure. Likewise for * BPF_JNE. */ - if (is_jmp32) { - u64 old_v = reg->var_off.value; - u64 hi_mask = ~0xffffffffULL; - - reg->var_off.value = (old_v & hi_mask) | val; - reg->var_off.mask &= hi_mask; - } else { + if (is_jmp32) + __mark_reg32_known(reg, val32); + else __mark_reg_known(reg, val); - } break; } case BPF_JSET: - false_reg->var_off = tnum_and(false_reg->var_off, - tnum_const(~val)); - if (is_power_of_2(val)) - true_reg->var_off = tnum_or(true_reg->var_off, - tnum_const(val)); + if (is_jmp32) { + false_32off = tnum_and(false_32off, tnum_const(~val32)); + if (is_power_of_2(val32)) + true_32off = tnum_or(true_32off, + tnum_const(val32)); + } else { + false_64off = tnum_and(false_64off, tnum_const(~val)); + if (is_power_of_2(val)) + true_64off = tnum_or(true_64off, + tnum_const(val)); + } break; case BPF_JGE: case BPF_JGT: { - set_upper_bound(false_reg, val, is_jmp32, opcode == BPF_JGE); - set_lower_bound(true_reg, val, is_jmp32, opcode == BPF_JGT); + if (is_jmp32) { + u32 false_umax = opcode == BPF_JGT ? val32 : val32 - 1; + u32 true_umin = opcode == BPF_JGT ? val32 + 1 : val32; + + false_reg->u32_max_value = min(false_reg->u32_max_value, + false_umax); + true_reg->u32_min_value = max(true_reg->u32_min_value, + true_umin); + } else { + u64 false_umax = opcode == BPF_JGT ? val : val - 1; + u64 true_umin = opcode == BPF_JGT ? val + 1 : val; + + false_reg->umax_value = min(false_reg->umax_value, false_umax); + true_reg->umin_value = max(true_reg->umin_value, true_umin); + } break; } case BPF_JSGE: case BPF_JSGT: { - s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1; - s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval; + if (is_jmp32) { + s32 false_smax = opcode == BPF_JSGT ? sval32 : sval32 - 1; + s32 true_smin = opcode == BPF_JSGT ? sval32 + 1 : sval32; - /* If the full s64 was not sign-extended from s32 then don't - * deduct further info. - */ - if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) - break; - false_reg->smax_value = min(false_reg->smax_value, false_smax); - true_reg->smin_value = max(true_reg->smin_value, true_smin); + false_reg->s32_max_value = min(false_reg->s32_max_value, false_smax); + true_reg->s32_min_value = max(true_reg->s32_min_value, true_smin); + } else { + s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1; + s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval; + + false_reg->smax_value = min(false_reg->smax_value, false_smax); + true_reg->smin_value = max(true_reg->smin_value, true_smin); + } break; } case BPF_JLE: case BPF_JLT: { - set_lower_bound(false_reg, val, is_jmp32, opcode == BPF_JLE); - set_upper_bound(true_reg, val, is_jmp32, opcode == BPF_JLT); + if (is_jmp32) { + u32 false_umin = opcode == BPF_JLT ? val32 : val32 + 1; + u32 true_umax = opcode == BPF_JLT ? val32 - 1 : val32; + + false_reg->u32_min_value = max(false_reg->u32_min_value, + false_umin); + true_reg->u32_max_value = min(true_reg->u32_max_value, + true_umax); + } else { + u64 false_umin = opcode == BPF_JLT ? val : val + 1; + u64 true_umax = opcode == BPF_JLT ? val - 1 : val; + + false_reg->umin_value = max(false_reg->umin_value, false_umin); + true_reg->umax_value = min(true_reg->umax_value, true_umax); + } break; } case BPF_JSLE: case BPF_JSLT: { - s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1; - s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval; + if (is_jmp32) { + s32 false_smin = opcode == BPF_JSLT ? sval32 : sval32 + 1; + s32 true_smax = opcode == BPF_JSLT ? sval32 - 1 : sval32; - if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) - break; - false_reg->smin_value = max(false_reg->smin_value, false_smin); - true_reg->smax_value = min(true_reg->smax_value, true_smax); + false_reg->s32_min_value = max(false_reg->s32_min_value, false_smin); + true_reg->s32_max_value = min(true_reg->s32_max_value, true_smax); + } else { + s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1; + s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval; + + false_reg->smin_value = max(false_reg->smin_value, false_smin); + true_reg->smax_value = min(true_reg->smax_value, true_smax); + } break; } default: return; } - __reg_deduce_bounds(false_reg); - __reg_deduce_bounds(true_reg); - /* We might have learned some bits from the bounds. */ - __reg_bound_offset(false_reg); - __reg_bound_offset(true_reg); - /* Intersecting with the old var_off might have improved our bounds - * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), - * then new var_off is (0; 0x7f...fc) which improves our umax. - */ - __update_reg_bounds(false_reg); - __update_reg_bounds(true_reg); + if (is_jmp32) { + false_reg->var_off = tnum_or(tnum_clear_subreg(false_64off), + tnum_subreg(false_32off)); + true_reg->var_off = tnum_or(tnum_clear_subreg(true_64off), + tnum_subreg(true_32off)); + __reg_combine_32_into_64(false_reg); + __reg_combine_32_into_64(true_reg); + } else { + false_reg->var_off = false_64off; + true_reg->var_off = true_64off; + __reg_combine_64_into_32(false_reg); + __reg_combine_64_into_32(true_reg); + } } /* Same as above, but for the case that dst_reg holds a constant and src_reg is * the variable reg. */ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, - struct bpf_reg_state *false_reg, u64 val, + struct bpf_reg_state *false_reg, + u64 val, u32 val32, u8 opcode, bool is_jmp32) { /* How can we transform "a b" into "b a"? */ @@ -5883,7 +6437,7 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, * BPF_JA, can't get here. */ if (opcode) - reg_set_min_max(true_reg, false_reg, val, opcode, is_jmp32); + reg_set_min_max(true_reg, false_reg, val, val32, opcode, is_jmp32); } /* Regs are known to be equal, so intersect their min/max/var_off */ @@ -6172,13 +6726,22 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, dst_reg = ®s[insn->dst_reg]; is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32; - if (BPF_SRC(insn->code) == BPF_K) - pred = is_branch_taken(dst_reg, insn->imm, - opcode, is_jmp32); - else if (src_reg->type == SCALAR_VALUE && - tnum_is_const(src_reg->var_off)) - pred = is_branch_taken(dst_reg, src_reg->var_off.value, - opcode, is_jmp32); + if (BPF_SRC(insn->code) == BPF_K) { + pred = is_branch_taken(dst_reg, insn->imm, opcode, is_jmp32); + } else if (src_reg->type == SCALAR_VALUE && + is_jmp32 && tnum_is_const(tnum_subreg(src_reg->var_off))) { + pred = is_branch_taken(dst_reg, + tnum_subreg(src_reg->var_off).value, + opcode, + is_jmp32); + } else if (src_reg->type == SCALAR_VALUE && + !is_jmp32 && tnum_is_const(src_reg->var_off)) { + pred = is_branch_taken(dst_reg, + src_reg->var_off.value, + opcode, + is_jmp32); + } + if (pred >= 0) { err = mark_chain_precision(env, insn->dst_reg); if (BPF_SRC(insn->code) == BPF_X && !err) @@ -6212,32 +6775,24 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, */ if (BPF_SRC(insn->code) == BPF_X) { struct bpf_reg_state *src_reg = ®s[insn->src_reg]; - struct bpf_reg_state lo_reg0 = *dst_reg; - struct bpf_reg_state lo_reg1 = *src_reg; - struct bpf_reg_state *src_lo, *dst_lo; - - dst_lo = &lo_reg0; - src_lo = &lo_reg1; - coerce_reg_to_size(dst_lo, 4); - coerce_reg_to_size(src_lo, 4); if (dst_reg->type == SCALAR_VALUE && src_reg->type == SCALAR_VALUE) { if (tnum_is_const(src_reg->var_off) || - (is_jmp32 && tnum_is_const(src_lo->var_off))) + (is_jmp32 && + tnum_is_const(tnum_subreg(src_reg->var_off)))) reg_set_min_max(&other_branch_regs[insn->dst_reg], dst_reg, - is_jmp32 - ? src_lo->var_off.value - : src_reg->var_off.value, + src_reg->var_off.value, + tnum_subreg(src_reg->var_off).value, opcode, is_jmp32); else if (tnum_is_const(dst_reg->var_off) || - (is_jmp32 && tnum_is_const(dst_lo->var_off))) + (is_jmp32 && + tnum_is_const(tnum_subreg(dst_reg->var_off)))) reg_set_min_max_inv(&other_branch_regs[insn->src_reg], src_reg, - is_jmp32 - ? dst_lo->var_off.value - : dst_reg->var_off.value, + dst_reg->var_off.value, + tnum_subreg(dst_reg->var_off).value, opcode, is_jmp32); else if (!is_jmp32 && (opcode == BPF_JEQ || opcode == BPF_JNE)) @@ -6248,7 +6803,8 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, } } else if (dst_reg->type == SCALAR_VALUE) { reg_set_min_max(&other_branch_regs[insn->dst_reg], - dst_reg, insn->imm, opcode, is_jmp32); + dst_reg, insn->imm, (u32)insn->imm, + opcode, is_jmp32); } /* detect if R == 0 where R is returned from bpf_map_lookup_elem(). -- cgit v1.2.3 From af6eea57437a830293eab56246b6025cc7d46ee7 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Sun, 29 Mar 2020 19:59:58 -0700 Subject: bpf: Implement bpf_link-based cgroup BPF program attachment Implement new sub-command to attach cgroup BPF programs and return FD-based bpf_link back on success. bpf_link, once attached to cgroup, cannot be replaced, except by owner having its FD. Cgroup bpf_link supports only BPF_F_ALLOW_MULTI semantics. Both link-based and prog-based BPF_F_ALLOW_MULTI attachments can be freely intermixed. To prevent bpf_cgroup_link from keeping cgroup alive past the point when no BPF program can be executed, implement auto-detachment of link. When cgroup_bpf_release() is called, all attached bpf_links are forced to release cgroup refcounts, but they leave bpf_link otherwise active and allocated, as well as still owning underlying bpf_prog. This is because user-space might still have FDs open and active, so bpf_link as a user-referenced object can't be freed yet. Once last active FD is closed, bpf_link will be freed and underlying bpf_prog refcount will be dropped. But cgroup refcount won't be touched, because cgroup is released already. The inherent race between bpf_cgroup_link release (from closing last FD) and cgroup_bpf_release() is resolved by both operations taking cgroup_mutex. So the only additional check required is when bpf_cgroup_link attempts to detach itself from cgroup. At that time we need to check whether there is still cgroup associated with that link. And if not, exit with success, because bpf_cgroup_link was already successfully detached. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: Roman Gushchin Link: https://lore.kernel.org/bpf/20200330030001.2312810-2-andriin@fb.com --- include/linux/bpf-cgroup.h | 29 +++- include/linux/bpf.h | 10 +- include/uapi/linux/bpf.h | 10 +- kernel/bpf/cgroup.c | 315 +++++++++++++++++++++++++++++++---------- kernel/bpf/syscall.c | 64 +++++++-- kernel/cgroup/cgroup.c | 14 +- tools/include/uapi/linux/bpf.h | 10 +- 7 files changed, 354 insertions(+), 98 deletions(-) (limited to 'include/linux') diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index a7cd5c7a2509..d2d969669564 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -51,9 +51,18 @@ struct bpf_cgroup_storage { struct rcu_head rcu; }; +struct bpf_cgroup_link { + struct bpf_link link; + struct cgroup *cgroup; + enum bpf_attach_type type; +}; + +extern const struct bpf_link_ops bpf_cgroup_link_lops; + struct bpf_prog_list { struct list_head node; struct bpf_prog *prog; + struct bpf_cgroup_link *link; struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE]; }; @@ -84,20 +93,23 @@ struct cgroup_bpf { int cgroup_bpf_inherit(struct cgroup *cgrp); void cgroup_bpf_offline(struct cgroup *cgrp); -int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog, - struct bpf_prog *replace_prog, +int __cgroup_bpf_attach(struct cgroup *cgrp, + struct bpf_prog *prog, struct bpf_prog *replace_prog, + struct bpf_cgroup_link *link, enum bpf_attach_type type, u32 flags); int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, + struct bpf_cgroup_link *link, enum bpf_attach_type type); int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, union bpf_attr __user *uattr); /* Wrapper for __cgroup_bpf_*() protected by cgroup_mutex */ -int cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog, - struct bpf_prog *replace_prog, enum bpf_attach_type type, +int cgroup_bpf_attach(struct cgroup *cgrp, + struct bpf_prog *prog, struct bpf_prog *replace_prog, + struct bpf_cgroup_link *link, enum bpf_attach_type type, u32 flags); int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, - enum bpf_attach_type type, u32 flags); + enum bpf_attach_type type); int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, union bpf_attr __user *uattr); @@ -332,6 +344,7 @@ int cgroup_bpf_prog_attach(const union bpf_attr *attr, enum bpf_prog_type ptype, struct bpf_prog *prog); int cgroup_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype); +int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog); int cgroup_bpf_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr); #else @@ -354,6 +367,12 @@ static inline int cgroup_bpf_prog_detach(const union bpf_attr *attr, return -EINVAL; } +static inline int cgroup_bpf_link_attach(const union bpf_attr *attr, + struct bpf_prog *prog) +{ + return -EINVAL; +} + static inline int cgroup_bpf_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) { diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 3bde59a8453b..56254d880293 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1082,15 +1082,23 @@ extern int sysctl_unprivileged_bpf_disabled; int bpf_map_new_fd(struct bpf_map *map, int flags); int bpf_prog_new_fd(struct bpf_prog *prog); -struct bpf_link; +struct bpf_link { + atomic64_t refcnt; + const struct bpf_link_ops *ops; + struct bpf_prog *prog; + struct work_struct work; +}; struct bpf_link_ops { void (*release)(struct bpf_link *link); void (*dealloc)(struct bpf_link *link); + }; void bpf_link_init(struct bpf_link *link, const struct bpf_link_ops *ops, struct bpf_prog *prog); +void bpf_link_cleanup(struct bpf_link *link, struct file *link_file, + int link_fd); void bpf_link_inc(struct bpf_link *link); void bpf_link_put(struct bpf_link *link); int bpf_link_new_fd(struct bpf_link *link); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 9f786a5a44ac..37dffe5089a0 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -111,6 +111,7 @@ enum bpf_cmd { BPF_MAP_LOOKUP_AND_DELETE_BATCH, BPF_MAP_UPDATE_BATCH, BPF_MAP_DELETE_BATCH, + BPF_LINK_CREATE, }; enum bpf_map_type { @@ -541,7 +542,7 @@ union bpf_attr { __u32 prog_cnt; } query; - struct { + struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */ __u64 name; __u32 prog_fd; } raw_tracepoint; @@ -569,6 +570,13 @@ union bpf_attr { __u64 probe_offset; /* output: probe_offset */ __u64 probe_addr; /* output: probe_addr */ } task_fd_query; + + struct { /* struct used by BPF_LINK_CREATE command */ + __u32 prog_fd; /* eBPF program to attach */ + __u32 target_fd; /* object to attach to */ + __u32 attach_type; /* attach type */ + __u32 flags; /* extra flags */ + } link_create; } __attribute__((aligned(8))); /* The description below is an attempt at providing documentation to eBPF diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index 9c8472823a7f..c24029937431 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -80,6 +80,17 @@ static void bpf_cgroup_storages_unlink(struct bpf_cgroup_storage *storages[]) bpf_cgroup_storage_unlink(storages[stype]); } +/* Called when bpf_cgroup_link is auto-detached from dying cgroup. + * It drops cgroup and bpf_prog refcounts, and marks bpf_link as defunct. It + * doesn't free link memory, which will eventually be done by bpf_link's + * release() callback, when its last FD is closed. + */ +static void bpf_cgroup_link_auto_detach(struct bpf_cgroup_link *link) +{ + cgroup_put(link->cgroup); + link->cgroup = NULL; +} + /** * cgroup_bpf_release() - put references of all bpf programs and * release all cgroup bpf data @@ -100,7 +111,10 @@ static void cgroup_bpf_release(struct work_struct *work) list_for_each_entry_safe(pl, tmp, progs, node) { list_del(&pl->node); - bpf_prog_put(pl->prog); + if (pl->prog) + bpf_prog_put(pl->prog); + if (pl->link) + bpf_cgroup_link_auto_detach(pl->link); bpf_cgroup_storages_unlink(pl->storage); bpf_cgroup_storages_free(pl->storage); kfree(pl); @@ -134,6 +148,18 @@ static void cgroup_bpf_release_fn(struct percpu_ref *ref) queue_work(system_wq, &cgrp->bpf.release_work); } +/* Get underlying bpf_prog of bpf_prog_list entry, regardless if it's through + * link or direct prog. + */ +static struct bpf_prog *prog_list_prog(struct bpf_prog_list *pl) +{ + if (pl->prog) + return pl->prog; + if (pl->link) + return pl->link->link.prog; + return NULL; +} + /* count number of elements in the list. * it's slow but the list cannot be long */ @@ -143,7 +169,7 @@ static u32 prog_list_length(struct list_head *head) u32 cnt = 0; list_for_each_entry(pl, head, node) { - if (!pl->prog) + if (!prog_list_prog(pl)) continue; cnt++; } @@ -212,11 +238,11 @@ static int compute_effective_progs(struct cgroup *cgrp, continue; list_for_each_entry(pl, &p->bpf.progs[type], node) { - if (!pl->prog) + if (!prog_list_prog(pl)) continue; item = &progs->items[cnt]; - item->prog = pl->prog; + item->prog = prog_list_prog(pl); bpf_cgroup_storages_assign(item->cgroup_storage, pl->storage); cnt++; @@ -333,19 +359,60 @@ cleanup: #define BPF_CGROUP_MAX_PROGS 64 +static struct bpf_prog_list *find_attach_entry(struct list_head *progs, + struct bpf_prog *prog, + struct bpf_cgroup_link *link, + struct bpf_prog *replace_prog, + bool allow_multi) +{ + struct bpf_prog_list *pl; + + /* single-attach case */ + if (!allow_multi) { + if (list_empty(progs)) + return NULL; + return list_first_entry(progs, typeof(*pl), node); + } + + list_for_each_entry(pl, progs, node) { + if (prog && pl->prog == prog) + /* disallow attaching the same prog twice */ + return ERR_PTR(-EINVAL); + if (link && pl->link == link) + /* disallow attaching the same link twice */ + return ERR_PTR(-EINVAL); + } + + /* direct prog multi-attach w/ replacement case */ + if (replace_prog) { + list_for_each_entry(pl, progs, node) { + if (pl->prog == replace_prog) + /* a match found */ + return pl; + } + /* prog to replace not found for cgroup */ + return ERR_PTR(-ENOENT); + } + + return NULL; +} + /** - * __cgroup_bpf_attach() - Attach the program to a cgroup, and + * __cgroup_bpf_attach() - Attach the program or the link to a cgroup, and * propagate the change to descendants * @cgrp: The cgroup which descendants to traverse * @prog: A program to attach + * @link: A link to attach * @replace_prog: Previously attached program to replace if BPF_F_REPLACE is set * @type: Type of attach operation * @flags: Option flags * + * Exactly one of @prog or @link can be non-null. * Must be called with cgroup_mutex held. */ -int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog, - struct bpf_prog *replace_prog, +int __cgroup_bpf_attach(struct cgroup *cgrp, + struct bpf_prog *prog, struct bpf_prog *replace_prog, + struct bpf_cgroup_link *link, enum bpf_attach_type type, u32 flags) { u32 saved_flags = (flags & (BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI)); @@ -353,13 +420,19 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog, struct bpf_prog *old_prog = NULL; struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE], *old_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {NULL}; - struct bpf_prog_list *pl, *replace_pl = NULL; + struct bpf_prog_list *pl; int err; if (((flags & BPF_F_ALLOW_OVERRIDE) && (flags & BPF_F_ALLOW_MULTI)) || ((flags & BPF_F_REPLACE) && !(flags & BPF_F_ALLOW_MULTI))) /* invalid combination */ return -EINVAL; + if (link && (prog || replace_prog)) + /* only either link or prog/replace_prog can be specified */ + return -EINVAL; + if (!!replace_prog != !!(flags & BPF_F_REPLACE)) + /* replace_prog implies BPF_F_REPLACE, and vice versa */ + return -EINVAL; if (!hierarchy_allows_attach(cgrp, type)) return -EPERM; @@ -374,26 +447,15 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog, if (prog_list_length(progs) >= BPF_CGROUP_MAX_PROGS) return -E2BIG; - if (flags & BPF_F_ALLOW_MULTI) { - list_for_each_entry(pl, progs, node) { - if (pl->prog == prog) - /* disallow attaching the same prog twice */ - return -EINVAL; - if (pl->prog == replace_prog) - replace_pl = pl; - } - if ((flags & BPF_F_REPLACE) && !replace_pl) - /* prog to replace not found for cgroup */ - return -ENOENT; - } else if (!list_empty(progs)) { - replace_pl = list_first_entry(progs, typeof(*pl), node); - } + pl = find_attach_entry(progs, prog, link, replace_prog, + flags & BPF_F_ALLOW_MULTI); + if (IS_ERR(pl)) + return PTR_ERR(pl); - if (bpf_cgroup_storages_alloc(storage, prog)) + if (bpf_cgroup_storages_alloc(storage, prog ? : link->link.prog)) return -ENOMEM; - if (replace_pl) { - pl = replace_pl; + if (pl) { old_prog = pl->prog; bpf_cgroup_storages_unlink(pl->storage); bpf_cgroup_storages_assign(old_storage, pl->storage); @@ -407,6 +469,7 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog, } pl->prog = prog; + pl->link = link; bpf_cgroup_storages_assign(pl->storage, storage); cgrp->bpf.flags[type] = saved_flags; @@ -414,80 +477,93 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog, if (err) goto cleanup; - static_branch_inc(&cgroup_bpf_enabled_key); bpf_cgroup_storages_free(old_storage); - if (old_prog) { + if (old_prog) bpf_prog_put(old_prog); - static_branch_dec(&cgroup_bpf_enabled_key); - } - bpf_cgroup_storages_link(storage, cgrp, type); + else + static_branch_inc(&cgroup_bpf_enabled_key); + bpf_cgroup_storages_link(pl->storage, cgrp, type); return 0; cleanup: - /* and cleanup the prog list */ - pl->prog = old_prog; + if (old_prog) { + pl->prog = old_prog; + pl->link = NULL; + } bpf_cgroup_storages_free(pl->storage); bpf_cgroup_storages_assign(pl->storage, old_storage); bpf_cgroup_storages_link(pl->storage, cgrp, type); - if (!replace_pl) { + if (!old_prog) { list_del(&pl->node); kfree(pl); } return err; } +static struct bpf_prog_list *find_detach_entry(struct list_head *progs, + struct bpf_prog *prog, + struct bpf_cgroup_link *link, + bool allow_multi) +{ + struct bpf_prog_list *pl; + + if (!allow_multi) { + if (list_empty(progs)) + /* report error when trying to detach and nothing is attached */ + return ERR_PTR(-ENOENT); + + /* to maintain backward compatibility NONE and OVERRIDE cgroups + * allow detaching with invalid FD (prog==NULL) in legacy mode + */ + return list_first_entry(progs, typeof(*pl), node); + } + + if (!prog && !link) + /* to detach MULTI prog the user has to specify valid FD + * of the program or link to be detached + */ + return ERR_PTR(-EINVAL); + + /* find the prog or link and detach it */ + list_for_each_entry(pl, progs, node) { + if (pl->prog == prog && pl->link == link) + return pl; + } + return ERR_PTR(-ENOENT); +} + /** - * __cgroup_bpf_detach() - Detach the program from a cgroup, and + * __cgroup_bpf_detach() - Detach the program or link from a cgroup, and * propagate the change to descendants * @cgrp: The cgroup which descendants to traverse * @prog: A program to detach or NULL + * @prog: A link to detach or NULL * @type: Type of detach operation * + * At most one of @prog or @link can be non-NULL. * Must be called with cgroup_mutex held. */ int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, - enum bpf_attach_type type) + struct bpf_cgroup_link *link, enum bpf_attach_type type) { struct list_head *progs = &cgrp->bpf.progs[type]; u32 flags = cgrp->bpf.flags[type]; - struct bpf_prog *old_prog = NULL; struct bpf_prog_list *pl; + struct bpf_prog *old_prog; int err; - if (flags & BPF_F_ALLOW_MULTI) { - if (!prog) - /* to detach MULTI prog the user has to specify valid FD - * of the program to be detached - */ - return -EINVAL; - } else { - if (list_empty(progs)) - /* report error when trying to detach and nothing is attached */ - return -ENOENT; - } + if (prog && link) + /* only one of prog or link can be specified */ + return -EINVAL; - if (flags & BPF_F_ALLOW_MULTI) { - /* find the prog and detach it */ - list_for_each_entry(pl, progs, node) { - if (pl->prog != prog) - continue; - old_prog = prog; - /* mark it deleted, so it's ignored while - * recomputing effective - */ - pl->prog = NULL; - break; - } - if (!old_prog) - return -ENOENT; - } else { - /* to maintain backward compatibility NONE and OVERRIDE cgroups - * allow detaching with invalid FD (prog==NULL) - */ - pl = list_first_entry(progs, typeof(*pl), node); - old_prog = pl->prog; - pl->prog = NULL; - } + pl = find_detach_entry(progs, prog, link, flags & BPF_F_ALLOW_MULTI); + if (IS_ERR(pl)) + return PTR_ERR(pl); + + /* mark it deleted, so it's ignored while recomputing effective */ + old_prog = pl->prog; + pl->prog = NULL; + pl->link = NULL; err = update_effective_progs(cgrp, type); if (err) @@ -501,14 +577,15 @@ int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, if (list_empty(progs)) /* last program was detached, reset flags to zero */ cgrp->bpf.flags[type] = 0; - - bpf_prog_put(old_prog); + if (old_prog) + bpf_prog_put(old_prog); static_branch_dec(&cgroup_bpf_enabled_key); return 0; cleanup: - /* and restore back old_prog */ + /* restore back prog or link */ pl->prog = old_prog; + pl->link = link; return err; } @@ -521,6 +598,7 @@ int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, struct list_head *progs = &cgrp->bpf.progs[type]; u32 flags = cgrp->bpf.flags[type]; struct bpf_prog_array *effective; + struct bpf_prog *prog; int cnt, ret = 0, i; effective = rcu_dereference_protected(cgrp->bpf.effective[type], @@ -551,7 +629,8 @@ int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, i = 0; list_for_each_entry(pl, progs, node) { - id = pl->prog->aux->id; + prog = prog_list_prog(pl); + id = prog->aux->id; if (copy_to_user(prog_ids + i, &id, sizeof(id))) return -EFAULT; if (++i == cnt) @@ -581,8 +660,8 @@ int cgroup_bpf_prog_attach(const union bpf_attr *attr, } } - ret = cgroup_bpf_attach(cgrp, prog, replace_prog, attr->attach_type, - attr->attach_flags); + ret = cgroup_bpf_attach(cgrp, prog, replace_prog, NULL, + attr->attach_type, attr->attach_flags); if (replace_prog) bpf_prog_put(replace_prog); @@ -604,7 +683,7 @@ int cgroup_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype) if (IS_ERR(prog)) prog = NULL; - ret = cgroup_bpf_detach(cgrp, prog, attr->attach_type, 0); + ret = cgroup_bpf_detach(cgrp, prog, attr->attach_type); if (prog) bpf_prog_put(prog); @@ -612,6 +691,90 @@ int cgroup_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype) return ret; } +static void bpf_cgroup_link_release(struct bpf_link *link) +{ + struct bpf_cgroup_link *cg_link = + container_of(link, struct bpf_cgroup_link, link); + + /* link might have been auto-detached by dying cgroup already, + * in that case our work is done here + */ + if (!cg_link->cgroup) + return; + + mutex_lock(&cgroup_mutex); + + /* re-check cgroup under lock again */ + if (!cg_link->cgroup) { + mutex_unlock(&cgroup_mutex); + return; + } + + WARN_ON(__cgroup_bpf_detach(cg_link->cgroup, NULL, cg_link, + cg_link->type)); + + mutex_unlock(&cgroup_mutex); + cgroup_put(cg_link->cgroup); +} + +static void bpf_cgroup_link_dealloc(struct bpf_link *link) +{ + struct bpf_cgroup_link *cg_link = + container_of(link, struct bpf_cgroup_link, link); + + kfree(cg_link); +} + +const struct bpf_link_ops bpf_cgroup_link_lops = { + .release = bpf_cgroup_link_release, + .dealloc = bpf_cgroup_link_dealloc, +}; + +int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) +{ + struct bpf_cgroup_link *link; + struct file *link_file; + struct cgroup *cgrp; + int err, link_fd; + + if (attr->link_create.flags) + return -EINVAL; + + cgrp = cgroup_get_from_fd(attr->link_create.target_fd); + if (IS_ERR(cgrp)) + return PTR_ERR(cgrp); + + link = kzalloc(sizeof(*link), GFP_USER); + if (!link) { + err = -ENOMEM; + goto out_put_cgroup; + } + bpf_link_init(&link->link, &bpf_cgroup_link_lops, prog); + link->cgroup = cgrp; + link->type = attr->link_create.attach_type; + + link_file = bpf_link_new_file(&link->link, &link_fd); + if (IS_ERR(link_file)) { + kfree(link); + err = PTR_ERR(link_file); + goto out_put_cgroup; + } + + err = cgroup_bpf_attach(cgrp, NULL, NULL, link, link->type, + BPF_F_ALLOW_MULTI); + if (err) { + bpf_link_cleanup(&link->link, link_file, link_fd); + goto out_put_cgroup; + } + + fd_install(link_fd, link_file); + return link_fd; + +out_put_cgroup: + cgroup_put(cgrp); + return err; +} + int cgroup_bpf_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) { diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a616b63f23b4..97d5c6fb63cd 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2175,13 +2175,6 @@ static int bpf_obj_get(const union bpf_attr *attr) attr->file_flags); } -struct bpf_link { - atomic64_t refcnt; - const struct bpf_link_ops *ops; - struct bpf_prog *prog; - struct work_struct work; -}; - void bpf_link_init(struct bpf_link *link, const struct bpf_link_ops *ops, struct bpf_prog *prog) { @@ -2195,8 +2188,8 @@ void bpf_link_init(struct bpf_link *link, const struct bpf_link_ops *ops, * anon_inode's release() call. This helper manages marking bpf_link as * defunct, releases anon_inode file and puts reserved FD. */ -static void bpf_link_cleanup(struct bpf_link *link, struct file *link_file, - int link_fd) +void bpf_link_cleanup(struct bpf_link *link, struct file *link_file, + int link_fd) { link->prog = NULL; fput(link_file); @@ -2266,6 +2259,10 @@ static void bpf_link_show_fdinfo(struct seq_file *m, struct file *filp) link_type = "raw_tracepoint"; else if (link->ops == &bpf_tracing_link_lops) link_type = "tracing"; +#ifdef CONFIG_CGROUP_BPF + else if (link->ops == &bpf_cgroup_link_lops) + link_type = "cgroup"; +#endif else link_type = "unknown"; @@ -3553,6 +3550,52 @@ err_put: return err; } +#define BPF_LINK_CREATE_LAST_FIELD link_create.flags +static int link_create(union bpf_attr *attr) +{ + enum bpf_prog_type ptype; + struct bpf_prog *prog; + int ret; + + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + + if (CHECK_ATTR(BPF_LINK_CREATE)) + return -EINVAL; + + ptype = attach_type_to_prog_type(attr->link_create.attach_type); + if (ptype == BPF_PROG_TYPE_UNSPEC) + return -EINVAL; + + prog = bpf_prog_get_type(attr->link_create.prog_fd, ptype); + if (IS_ERR(prog)) + return PTR_ERR(prog); + + ret = bpf_prog_attach_check_attach_type(prog, + attr->link_create.attach_type); + if (ret) + goto err_out; + + switch (ptype) { + case BPF_PROG_TYPE_CGROUP_SKB: + case BPF_PROG_TYPE_CGROUP_SOCK: + case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: + case BPF_PROG_TYPE_SOCK_OPS: + case BPF_PROG_TYPE_CGROUP_DEVICE: + case BPF_PROG_TYPE_CGROUP_SYSCTL: + case BPF_PROG_TYPE_CGROUP_SOCKOPT: + ret = cgroup_bpf_link_attach(attr, prog); + break; + default: + ret = -EINVAL; + } + +err_out: + if (ret < 0) + bpf_prog_put(prog); + return ret; +} + SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size) { union bpf_attr attr = {}; @@ -3663,6 +3706,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz case BPF_MAP_DELETE_BATCH: err = bpf_map_do_batch(&attr, uattr, BPF_MAP_DELETE_BATCH); break; + case BPF_LINK_CREATE: + err = link_create(&attr); + break; default: err = -EINVAL; break; diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 3dead0416b91..219624fba9ba 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -6303,27 +6303,31 @@ void cgroup_sk_free(struct sock_cgroup_data *skcd) #endif /* CONFIG_SOCK_CGROUP_DATA */ #ifdef CONFIG_CGROUP_BPF -int cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog, - struct bpf_prog *replace_prog, enum bpf_attach_type type, +int cgroup_bpf_attach(struct cgroup *cgrp, + struct bpf_prog *prog, struct bpf_prog *replace_prog, + struct bpf_cgroup_link *link, + enum bpf_attach_type type, u32 flags) { int ret; mutex_lock(&cgroup_mutex); - ret = __cgroup_bpf_attach(cgrp, prog, replace_prog, type, flags); + ret = __cgroup_bpf_attach(cgrp, prog, replace_prog, link, type, flags); mutex_unlock(&cgroup_mutex); return ret; } + int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, - enum bpf_attach_type type, u32 flags) + enum bpf_attach_type type) { int ret; mutex_lock(&cgroup_mutex); - ret = __cgroup_bpf_detach(cgrp, prog, type); + ret = __cgroup_bpf_detach(cgrp, prog, NULL, type); mutex_unlock(&cgroup_mutex); return ret; } + int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, union bpf_attr __user *uattr) { diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 9f786a5a44ac..37dffe5089a0 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -111,6 +111,7 @@ enum bpf_cmd { BPF_MAP_LOOKUP_AND_DELETE_BATCH, BPF_MAP_UPDATE_BATCH, BPF_MAP_DELETE_BATCH, + BPF_LINK_CREATE, }; enum bpf_map_type { @@ -541,7 +542,7 @@ union bpf_attr { __u32 prog_cnt; } query; - struct { + struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */ __u64 name; __u32 prog_fd; } raw_tracepoint; @@ -569,6 +570,13 @@ union bpf_attr { __u64 probe_offset; /* output: probe_offset */ __u64 probe_addr; /* output: probe_addr */ } task_fd_query; + + struct { /* struct used by BPF_LINK_CREATE command */ + __u32 prog_fd; /* eBPF program to attach */ + __u32 target_fd; /* object to attach to */ + __u32 attach_type; /* attach type */ + __u32 flags; /* extra flags */ + } link_create; } __attribute__((aligned(8))); /* The description below is an attempt at providing documentation to eBPF -- cgit v1.2.3 From 0c991ebc8c69d29b7fc44db17075c5aa5253e2ab Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Sun, 29 Mar 2020 19:59:59 -0700 Subject: bpf: Implement bpf_prog replacement for an active bpf_cgroup_link Add new operation (LINK_UPDATE), which allows to replace active bpf_prog from under given bpf_link. Currently this is only supported for bpf_cgroup_link, but will be extended to other kinds of bpf_links in follow-up patches. For bpf_cgroup_link, implemented functionality matches existing semantics for direct bpf_prog attachment (including BPF_F_REPLACE flag). User can either unconditionally set new bpf_prog regardless of which bpf_prog is currently active under given bpf_link, or, optionally, can specify expected active bpf_prog. If active bpf_prog doesn't match expected one, no changes are performed, old bpf_link stays intact and attached, operation returns a failure. cgroup_bpf_replace() operation is resolving race between auto-detachment and bpf_prog update in the same fashion as it's done for bpf_link detachment, except in this case update has no way of succeeding because of target cgroup marked as dying. So in this case error is returned. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200330030001.2312810-3-andriin@fb.com --- include/linux/bpf-cgroup.h | 12 +++++++ include/uapi/linux/bpf.h | 12 +++++++ kernel/bpf/cgroup.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++ kernel/bpf/syscall.c | 55 +++++++++++++++++++++++++++++++ kernel/cgroup/cgroup.c | 27 ++++++++++++++++ 5 files changed, 186 insertions(+) (limited to 'include/linux') diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index d2d969669564..c11b413d5b1a 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -100,6 +100,8 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, struct bpf_cgroup_link *link, enum bpf_attach_type type); +int __cgroup_bpf_replace(struct cgroup *cgrp, struct bpf_cgroup_link *link, + struct bpf_prog *new_prog); int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, union bpf_attr __user *uattr); @@ -110,6 +112,8 @@ int cgroup_bpf_attach(struct cgroup *cgrp, u32 flags); int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, enum bpf_attach_type type); +int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *old_prog, + struct bpf_prog *new_prog); int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, union bpf_attr __user *uattr); @@ -350,6 +354,7 @@ int cgroup_bpf_prog_query(const union bpf_attr *attr, #else struct bpf_prog; +struct bpf_link; struct cgroup_bpf {}; static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; } static inline void cgroup_bpf_offline(struct cgroup *cgrp) {} @@ -373,6 +378,13 @@ static inline int cgroup_bpf_link_attach(const union bpf_attr *attr, return -EINVAL; } +static inline int cgroup_bpf_replace(struct bpf_link *link, + struct bpf_prog *old_prog, + struct bpf_prog *new_prog) +{ + return -EINVAL; +} + static inline int cgroup_bpf_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) { diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 37dffe5089a0..2e29a671d67e 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -112,6 +112,7 @@ enum bpf_cmd { BPF_MAP_UPDATE_BATCH, BPF_MAP_DELETE_BATCH, BPF_LINK_CREATE, + BPF_LINK_UPDATE, }; enum bpf_map_type { @@ -577,6 +578,17 @@ union bpf_attr { __u32 attach_type; /* attach type */ __u32 flags; /* extra flags */ } link_create; + + struct { /* struct used by BPF_LINK_UPDATE command */ + __u32 link_fd; /* link fd */ + /* new program fd to update link with */ + __u32 new_prog_fd; + __u32 flags; /* extra flags */ + /* expected link's program fd; is specified only if + * BPF_F_REPLACE flag is set in flags */ + __u32 old_prog_fd; + } link_update; + } __attribute__((aligned(8))); /* The description below is an attempt at providing documentation to eBPF diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index c24029937431..80676fc00d81 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -500,6 +500,86 @@ cleanup: return err; } +/* Swap updated BPF program for given link in effective program arrays across + * all descendant cgroups. This function is guaranteed to succeed. + */ +static void replace_effective_prog(struct cgroup *cgrp, + enum bpf_attach_type type, + struct bpf_cgroup_link *link) +{ + struct bpf_prog_array_item *item; + struct cgroup_subsys_state *css; + struct bpf_prog_array *progs; + struct bpf_prog_list *pl; + struct list_head *head; + struct cgroup *cg; + int pos; + + css_for_each_descendant_pre(css, &cgrp->self) { + struct cgroup *desc = container_of(css, struct cgroup, self); + + if (percpu_ref_is_zero(&desc->bpf.refcnt)) + continue; + + /* find position of link in effective progs array */ + for (pos = 0, cg = desc; cg; cg = cgroup_parent(cg)) { + if (pos && !(cg->bpf.flags[type] & BPF_F_ALLOW_MULTI)) + continue; + + head = &cg->bpf.progs[type]; + list_for_each_entry(pl, head, node) { + if (!prog_list_prog(pl)) + continue; + if (pl->link == link) + goto found; + pos++; + } + } +found: + BUG_ON(!cg); + progs = rcu_dereference_protected( + desc->bpf.effective[type], + lockdep_is_held(&cgroup_mutex)); + item = &progs->items[pos]; + WRITE_ONCE(item->prog, link->link.prog); + } +} + +/** + * __cgroup_bpf_replace() - Replace link's program and propagate the change + * to descendants + * @cgrp: The cgroup which descendants to traverse + * @link: A link for which to replace BPF program + * @type: Type of attach operation + * + * Must be called with cgroup_mutex held. + */ +int __cgroup_bpf_replace(struct cgroup *cgrp, struct bpf_cgroup_link *link, + struct bpf_prog *new_prog) +{ + struct list_head *progs = &cgrp->bpf.progs[link->type]; + struct bpf_prog *old_prog; + struct bpf_prog_list *pl; + bool found = false; + + if (link->link.prog->type != new_prog->type) + return -EINVAL; + + list_for_each_entry(pl, progs, node) { + if (pl->link == link) { + found = true; + break; + } + } + if (!found) + return -ENOENT; + + old_prog = xchg(&link->link.prog, new_prog); + replace_effective_prog(cgrp, link->type, link); + bpf_prog_put(old_prog); + return 0; +} + static struct bpf_prog_list *find_detach_entry(struct list_head *progs, struct bpf_prog *prog, struct bpf_cgroup_link *link, diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 97d5c6fb63cd..e0a3b34d7039 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3596,6 +3596,58 @@ err_out: return ret; } +#define BPF_LINK_UPDATE_LAST_FIELD link_update.old_prog_fd + +static int link_update(union bpf_attr *attr) +{ + struct bpf_prog *old_prog = NULL, *new_prog; + struct bpf_link *link; + u32 flags; + int ret; + + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + + if (CHECK_ATTR(BPF_LINK_UPDATE)) + return -EINVAL; + + flags = attr->link_update.flags; + if (flags & ~BPF_F_REPLACE) + return -EINVAL; + + link = bpf_link_get_from_fd(attr->link_update.link_fd); + if (IS_ERR(link)) + return PTR_ERR(link); + + new_prog = bpf_prog_get(attr->link_update.new_prog_fd); + if (IS_ERR(new_prog)) + return PTR_ERR(new_prog); + + if (flags & BPF_F_REPLACE) { + old_prog = bpf_prog_get(attr->link_update.old_prog_fd); + if (IS_ERR(old_prog)) { + ret = PTR_ERR(old_prog); + old_prog = NULL; + goto out_put_progs; + } + } + +#ifdef CONFIG_CGROUP_BPF + if (link->ops == &bpf_cgroup_link_lops) { + ret = cgroup_bpf_replace(link, old_prog, new_prog); + goto out_put_progs; + } +#endif + ret = -EINVAL; + +out_put_progs: + if (old_prog) + bpf_prog_put(old_prog); + if (ret) + bpf_prog_put(new_prog); + return ret; +} + SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size) { union bpf_attr attr = {}; @@ -3709,6 +3761,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz case BPF_LINK_CREATE: err = link_create(&attr); break; + case BPF_LINK_UPDATE: + err = link_update(&attr); + break; default: err = -EINVAL; break; diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 219624fba9ba..915dda3f7f19 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -6317,6 +6317,33 @@ int cgroup_bpf_attach(struct cgroup *cgrp, return ret; } +int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *old_prog, + struct bpf_prog *new_prog) +{ + struct bpf_cgroup_link *cg_link; + int ret; + + if (link->ops != &bpf_cgroup_link_lops) + return -EINVAL; + + cg_link = container_of(link, struct bpf_cgroup_link, link); + + mutex_lock(&cgroup_mutex); + /* link might have been auto-released by dying cgroup, so fail */ + if (!cg_link->cgroup) { + ret = -EINVAL; + goto out_unlock; + } + if (old_prog && link->prog != old_prog) { + ret = -EPERM; + goto out_unlock; + } + ret = __cgroup_bpf_replace(cg_link->cgroup, cg_link, new_prog); +out_unlock: + mutex_unlock(&cgroup_mutex); + return ret; +} + int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, enum bpf_attach_type type) { -- cgit v1.2.3