user/sven/linux.git/include/linux/skmsg.h, branch v5.10.178

net: fix refcount bug in sk_psock_get (2)

2022-09-05T08:28:56Z

commit 2a0133723f9ebeb751cfce19f74ec07e108bef1f upstream. Syzkaller reports refcount bug as follows: ------------[ cut here ]------------ refcount_t: saturated; leaking memory. WARNING: CPU: 1 PID: 3605 at lib/refcount.c:19 refcount_warn_saturate+0xf4/0x1e0 lib/refcount.c:19 Modules linked in: CPU: 1 PID: 3605 Comm: syz-executor208 Not tainted 5.18.0-syzkaller-03023-g7e062cda7d90 #0 __refcount_add_not_zero include/linux/refcount.h:163 [inline] __refcount_inc_not_zero include/linux/refcount.h:227 [inline] refcount_inc_not_zero include/linux/refcount.h:245 [inline] sk_psock_get+0x3bc/0x410 include/linux/skmsg.h:439 tls_data_ready+0x6d/0x1b0 net/tls/tls_sw.c:2091 tcp_data_ready+0x106/0x520 net/ipv4/tcp_input.c:4983 tcp_data_queue+0x25f2/0x4c90 net/ipv4/tcp_input.c:5057 tcp_rcv_state_process+0x1774/0x4e80 net/ipv4/tcp_input.c:6659 tcp_v4_do_rcv+0x339/0x980 net/ipv4/tcp_ipv4.c:1682 sk_backlog_rcv include/net/sock.h:1061 [inline] __release_sock+0x134/0x3b0 net/core/sock.c:2849 release_sock+0x54/0x1b0 net/core/sock.c:3404 inet_shutdown+0x1e0/0x430 net/ipv4/af_inet.c:909 __sys_shutdown_sock net/socket.c:2331 [inline] __sys_shutdown_sock net/socket.c:2325 [inline] __sys_shutdown+0xf1/0x1b0 net/socket.c:2343 __do_sys_shutdown net/socket.c:2351 [inline] __se_sys_shutdown net/socket.c:2349 [inline] __x64_sys_shutdown+0x50/0x70 net/socket.c:2349 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 During SMC fallback process in connect syscall, kernel will replaces TCP with SMC. In order to forward wakeup smc socket waitqueue after fallback, kernel will sets clcsk->sk_user_data to origin smc socket in smc_fback_replace_callbacks(). Later, in shutdown syscall, kernel will calls sk_psock_get(), which treats the clcsk->sk_user_data as psock type, triggering the refcnt warning. So, the root cause is that smc and psock, both will use sk_user_data field. So they will mismatch this field easily. This patch solves it by using another bit(defined as SK_USER_DATA_PSOCK) in PTRMASK, to mark whether sk_user_data points to a psock object or not. This patch depends on a PTRMASK introduced in commit f1ff5ce2cd5e ("net, sk_msg: Clear sk_user_data pointer on clone if tagged"). For there will possibly be more flags in the sk_user_data field, this patch also refactor sk_user_data flags code to be more generic to improve its maintainability. Reported-and-tested-by: syzbot+5f26f85569bd179c18ce@syzkaller.appspotmail.com Suggested-by: Jakub Kicinski Acked-by: Wen Gu Signed-off-by: Hawkins Jiawei Reviewed-by: Jakub Sitnicki Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

skmsg: Make sk_psock_destroy() static

2021-08-04T10:46:44Z

[ Upstream commit 8063e184e49011f6f3f34f6c358dc8a83890bb5b ] sk_psock_destroy() is a RCU callback, I can't see any reason why it could be used outside. Signed-off-by: Cong Wang Signed-off-by: Daniel Borkmann Cc: John Fastabend Cc: Jakub Sitnicki Cc: Lorenz Bauer Link: https://lore.kernel.org/bpf/20210127221501.46866-1-xiyou.wangcong@gmail.com Signed-off-by: Sasha Levin

bpf, sockmap: Fix sk->prot unhash op reset

2021-04-14T06:42:01Z

commit 1c84b33101c82683dee8b06761ca1f69e78c8ee7 upstream. In '4da6a196f93b1' we fixed a potential unhash loop caused when a TLS socket in a sockmap was removed from the sockmap. This happened because the unhash operation on the TLS ctx continued to point at the sockmap implementation of unhash even though the psock has already been removed. The sockmap unhash handler when a psock is removed does the following, void sock_map_unhash(struct sock *sk) { void (*saved_unhash)(struct sock *sk); struct sk_psock *psock; rcu_read_lock(); psock = sk_psock(sk); if (unlikely(!psock)) { rcu_read_unlock(); if (sk->sk_prot->unhash) sk->sk_prot->unhash(sk); return; } [...] } The unlikely() case is there to handle the case where psock is detached but the proto ops have not been updated yet. But, in the above case with TLS and removed psock we never fixed sk_prot->unhash() and unhash() points back to sock_map_unhash resulting in a loop. To fix this we added this bit of code, static inline void sk_psock_restore_proto(struct sock *sk, struct sk_psock *psock) { sk->sk_prot->unhash = psock->saved_unhash; This will set the sk_prot->unhash back to its saved value. This is the correct callback for a TLS socket that has been removed from the sock_map. Unfortunately, this also overwrites the unhash pointer for all psocks. We effectively break sockmap unhash handling for any future socks. Omitting the unhash operation will leave stale entries in the map if a socket transition through unhash, but does not do close() op. To fix set unhash correctly before calling into tls_update. This way the TLS enabled socket will point to the saved unhash() handler. Fixes: 4da6a196f93b1 ("bpf: Sockmap/tls, during free we may call tcp_bpf_unhash() in loop") Reported-by: Cong Wang Reported-by: Lorenz Bauer Suggested-by: Cong Wang Signed-off-by: John Fastabend Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/161731441904.68884.15593917809745631972.stgit@john-XPS-13-9370 Signed-off-by: Greg Kroah-Hartman

bpf, sockmap: Allow skipping sk_skb parser program

2020-10-12T01:09:44Z

Currently, we often run with a nop parser namely one that just does this, 'return skb->len'. This happens when either our verdict program can handle streaming data or it is only looking at socket data such as IP addresses and other metadata associated with the flow. The second case is common for a L3/L4 proxy for instance. So lets allow loading programs without the parser then we can skip the stream parser logic and avoid having to add a BPF program that is effectively a nop. Signed-off-by: John Fastabend Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/160239297866.8495.13345662302749219672.stgit@john-Precision-5820-Tower

net: sk_msg: Simplify sk_psock initialization

2020-08-21T22:16:11Z

Initializing psock->sk_proto and other saved callbacks is only done in sk_psock_update_proto, after sk_psock_init has returned. The logic for this is difficult to follow, and needlessly complex. Instead, initialize psock->sk_proto whenever we allocate a new psock. Additionally, assert the following invariants: * The SK has no ULP: ULP does it's own finagling of sk->sk_prot * sk_user_data is unused: we need it to store sk_psock Protect our access to sk_user_data with sk_callback_lock, which is what other users like reuseport arrays, etc. do. The result is that an sk_psock is always fully initialized, and that psock->sk_proto is always the "original" struct proto. The latter allows us to use psock->sk_proto when initializing IPv6 TCP / UDP callbacks for sockmap. Signed-off-by: Lorenz Bauer Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200821102948.21918-2-lmb@cloudflare.com

bpf: sockmap: Require attach_bpf_fd when detaching a program

2020-06-30T17:46:39Z

The sockmap code currently ignores the value of attach_bpf_fd when detaching a program. This is contrary to the usual behaviour of checking that attach_bpf_fd represents the currently attached program. Ensure that attach_bpf_fd is indeed the currently attached program. It turns out that all sockmap selftests already do this, which indicates that this is unlikely to cause breakage. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Lorenz Bauer Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200629095630.7933-5-lmb@cloudflare.com

bpf: Fix running sk_skb program types with ktls

2020-06-01T21:48:32Z

KTLS uses a stream parser to collect TLS messages and send them to the upper layer tls receive handler. This ensures the tls receiver has a full TLS header to parse when it is run. However, when a socket has BPF_SK_SKB_STREAM_VERDICT program attached before KTLS is enabled we end up with two stream parsers running on the same socket. The result is both try to run on the same socket. First the KTLS stream parser runs and calls read_sock() which will tcp_read_sock which in turn calls tcp_rcv_skb(). This dequeues the skb from the sk_receive_queue. When this is done KTLS code then data_ready() callback which because we stacked KTLS on top of the bpf stream verdict program has been replaced with sk_psock_start_strp(). This will in turn kick the stream parser again and eventually do the same thing KTLS did above calling into tcp_rcv_skb() and dequeuing a skb from the sk_receive_queue. At this point the data stream is broke. Part of the stream was handled by the KTLS side some other bytes may have been handled by the BPF side. Generally this results in either missing data or more likely a "Bad Message" complaint from the kTLS receive handler as the BPF program steals some bytes meant to be in a TLS header and/or the TLS header length is no longer correct. We've already broke the idealized model where we can stack ULPs in any order with generic callbacks on the TX side to handle this. So in this patch we do the same thing but for RX side. We add a sk_psock_strp_enabled() helper so TLS can learn a BPF verdict program is running and add a tls_sw_has_ctx_rx() helper so BPF side can learn there is a TLS ULP on the socket. Then on BPF side we omit calling our stream parser to avoid breaking the data stream for the KTLS receiver. Then on the KTLS side we call BPF_SK_SKB_STREAM_VERDICT once the KTLS receiver is done with the packet but before it posts the msg to userspace. This gives us symmetry between the TX and RX halfs and IMO makes it usable again. On the TX side we process packets in this order BPF -> TLS -> TCP and on the receive side in the reverse order TCP -> TLS -> BPF. Discovered while testing OpenSSL 3.0 Alpha2.0 release. Fixes: d829e9c4112b5 ("tls: convert to generic sk_msg interface") Signed-off-by: John Fastabend Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/159079361946.5745.605854335665044485.stgit@john-Precision-5820-Tower Signed-off-by: Alexei Starovoitov

bpf, sockmap: bpf_tcp_ingress needs to subtract bytes from sg.size

2020-05-05T22:22:22Z

In bpf_tcp_ingress we used apply_bytes to subtract bytes from sg.size which is used to track total bytes in a message. But this is not correct because apply_bytes is itself modified in the main loop doing the mem_charge. Then at the end of this we have sg.size incorrectly set and out of sync with actual sk values. Then we can get a splat if we try to cork the data later and again try to redirect the msg to ingress. To fix instead of trying to track msg.size do the easy thing and include it as part of the sk_msg_xfer logic so that when the msg is moved the sg.size is always correct. To reproduce the below users will need ingress + cork and hit an error path that will then try to 'free' the skmsg. [ 173.699981] BUG: KASAN: null-ptr-deref in sk_msg_free_elem+0xdd/0x120 [ 173.699987] Read of size 8 at addr 0000000000000008 by task test_sockmap/5317 [ 173.700000] CPU: 2 PID: 5317 Comm: test_sockmap Tainted: G I 5.7.0-rc1+ #43 [ 173.700005] Hardware name: Dell Inc. Precision 5820 Tower/002KVM, BIOS 1.9.2 01/24/2019 [ 173.700009] Call Trace: [ 173.700021] dump_stack+0x8e/0xcb [ 173.700029] ? sk_msg_free_elem+0xdd/0x120 [ 173.700034] ? sk_msg_free_elem+0xdd/0x120 [ 173.700042] __kasan_report+0x102/0x15f [ 173.700052] ? sk_msg_free_elem+0xdd/0x120 [ 173.700060] kasan_report+0x32/0x50 [ 173.700070] sk_msg_free_elem+0xdd/0x120 [ 173.700080] __sk_msg_free+0x87/0x150 [ 173.700094] tcp_bpf_send_verdict+0x179/0x4f0 [ 173.700109] tcp_bpf_sendpage+0x3ce/0x5d0 Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: John Fastabend Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Sitnicki Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/158861290407.14306.5327773422227552482.stgit@john-Precision-5820-Tower

bpf: sockmap: Move generic sockmap hooks from BPF TCP

2020-03-09T21:34:58Z

The init, close and unhash handlers from TCP sockmap are generic, and can be reused by UDP sockmap. Move the helpers into the sockmap code base and expose them. This requires tcp_bpf_get_proto and tcp_bpf_clone to be conditional on BPF_STREAM_PARSER. The moved functions are unmodified, except that sk_psock_unlink is renamed to sock_map_unlink to better match its behaviour. Signed-off-by: Lorenz Bauer Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Sitnicki Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200309111243.6982-6-lmb@cloudflare.com

skmsg: Update saved hooks only once

2020-03-09T21:34:58Z

Only update psock->saved_* if psock->sk_proto has not been initialized yet. This allows us to get rid of tcp_bpf_reinit_sk_prot. Signed-off-by: Lorenz Bauer Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Sitnicki Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200309111243.6982-3-lmb@cloudflare.com