user/sven/linux.git/include/linux/netlink.h, branch v3.16.42

netlink, mmap: fix edge-case leakages in nf queue zero-copy

2015-09-30T12:20:51Z

commit 6bb0fef489f667cf701853054f44579754f00a06 upstream. When netlink mmap on receive side is the consumer of nf queue data, it can happen that in some edge cases, we write skb shared info into the user space mmap buffer: Assume a possible rx ring frame size of only 4096, and the network skb, which is being zero-copied into the netlink skb, contains page frags with an overall skb->len larger than the linear part of the netlink skb. skb_zerocopy(), which is generic and thus not aware of the fact that shared info cannot be accessed for such skbs then tries to write and fill frags, thus leaking kernel data/pointers and in some corner cases possibly writing out of bounds of the mmap area (when filling the last slot in the ring buffer this way). I.e. the ring buffer slot is then of status NL_MMAP_STATUS_VALID, has an advertised length larger than 4096, where the linear part is visible at the slot beginning, and the leaked sizeof(struct skb_shared_info) has been written to the beginning of the next slot (also corrupting the struct nl_mmap_hdr slot header incl. status etc), since skb->end points to skb->data + ring->frame_size - NL_MMAP_HDRLEN. The fix adds and lets __netlink_alloc_skb() take the actual needed linear room for the network skb + meta data into account. It's completely irrelevant for non-mmaped netlink sockets, but in case mmap sockets are used, it can be decided whether the available skb_tailroom() is really large enough for the buffer, or whether it needs to internally fallback to a normal alloc_skb(). >From nf queue side, the information whether the destination port is an mmap RX ring is not really available without extra port-to-socket lookup, thus it can only be determined in lower layers i.e. when __netlink_alloc_skb() is called that checks internally for this. I chose to add the extra ldiff parameter as mmap will then still work: We have data_len and hlen in nfqnl_build_packet_message(), data_len is the full length (capped at queue->copy_range) for skb_zerocopy() and hlen some possible part of data_len that needs to be copied; the rem_len variable indicates the needed remaining linear mmap space. The only other workaround in nf queue internally would be after allocation time by f.e. cap'ing the data_len to the skb_tailroom() iff we deal with an mmap skb, but that would 1) expose the fact that we use a mmap skb to upper layers, and 2) trim the skb where we otherwise could just have moved the full skb into the normal receive queue. After the patch, in my test case the ring slot doesn't fit and therefore shows NL_MMAP_STATUS_COPY, where a full skb carries all the data and thus needs to be picked up via recv(). Fixes: 3ab1f683bf8b ("nfnetlink: add support for memory mapped netlink") Signed-off-by: Daniel Borkmann Signed-off-by: David S. Miller [ luis: backported to 3.16: adjusted context ] Signed-off-by: Luis Henriques

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2014-06-04T06:32:12Z

Conflicts: include/net/inetpeer.h net/ipv6/output_core.c Changes in net were fixing bugs in code removed in net-next. Signed-off-by: David S. Miller

netlink: Only check file credentials for implicit destinations

2014-06-02T23:34:09Z

It was possible to get a setuid root or setcap executable to write to it's stdout or stderr (which has been set made a netlink socket) and inadvertently reconfigure the networking stack. To prevent this we check that both the creator of the socket and the currentl applications has permission to reconfigure the network stack. Unfortunately this breaks Zebra which always uses sendto/sendmsg and creates it's socket without any privileges. To keep Zebra working don't bother checking if the creator of the socket has privilege when a destination address is specified. Instead rely exclusively on the privileges of the sender of the socket. Note from Andy: This is exactly Eric's code except for some comment clarifications and formatting fixes. Neither I nor, I think, anyone else is thrilled with this approach, but I'm hesitant to wait on a better fix since 3.15 is almost here. Note to stable maintainers: This is a mess. An earlier series of patches in 3.15 fix a rather serious security issue (CVE-2014-0181), but they did so in a way that breaks Zebra. The offending series includes: commit aa4cf9452f469f16cea8c96283b641b4576d4a7b Author: Eric W. Biederman Date: Wed Apr 23 14:28:03 2014 -0700 net: Add variants of capable for use on netlink messages If a given kernel version is missing that series of fixes, it's probably worth backporting it and this patch. if that series is present, then this fix is critical if you care about Zebra. Cc: stable@vger.kernel.org Signed-off-by: "Eric W. Biederman" Signed-off-by: Andy Lutomirski Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2014-05-12T17:19:14Z

Conflicts: drivers/net/ethernet/altera/altera_sgdma.c net/netlink/af_netlink.c net/sched/cls_api.c net/sched/sch_api.c The netlink conflict dealt with moving to netlink_capable() and netlink_ns_capable() in the 'net' tree vs. supporting 'tc' operations in non-init namespaces. These were simple transformations from netlink_capable to netlink_ns_capable. The Altera driver conflict was simply code removal overlapping some void pointer cast cleanups in net-next. Signed-off-by: David S. Miller

net: Add variants of capable for use on netlink messages

2014-04-24T17:44:54Z

netlink_net_capable - The common case use, for operations that are safe on a network namespace netlink_capable - For operations that are only known to be safe for the global root netlink_ns_capable - The general case of capable used to handle special cases __netlink_ns_capable - Same as netlink_ns_capable except taking a netlink_skb_parms instead of the skbuff of a netlink message. Signed-off-by: "Eric W. Biederman" Signed-off-by: David S. Miller

netlink: have netlink per-protocol bind function return an error code.

2014-04-23T01:42:26Z

Have the netlink per-protocol optional bind function return an int error code rather than void to signal a failure. This will enable netlink protocols to perform extra checks including capabilities and permissions verifications when updating memberships in multicast groups. In netlink_bind() and netlink_setsockopt() the call to the per-protocol bind function was moved above the multicast group update to prevent any access to the multicast socket groups before checking with the per-protocol bind function. This will enable the per-protocol bind function to be used to check permissions which could be denied before making them available, and to avoid the messy job of undoing the addition should the per-protocol bind function fail. The netfilter subsystem seems to be the only one currently using the per-protocol bind function. Signed-off-by: Richard Guy Briggs Signed-off-by: David S. Miller

netlink: cleanup tap related functions

2014-01-02T04:43:36Z

Cleanups in netlink_tap code * remove unused function netlink_clear_multicast_users * make local function static Signed-off-by: Stephen Hemminger Reviewed-by: Johannes Berg Signed-off-by: David S. Miller

netlink: fix splat in skb_clone with large messages

2013-06-28T05:44:16Z

Since (c05cdb1 netlink: allow large data transfers from user-space), netlink splats if it invokes skb_clone on large netlink skbs since: * skb_shared_info was not correctly initialized. * skb->destructor is not set in the cloned skb. This was spotted by trinity: [ 894.990671] BUG: unable to handle kernel paging request at ffffc9000047b001 [ 894.991034] IP: [] skb_clone+0x24/0xc0 [...] [ 894.991034] Call Trace: [ 894.991034] [] nl_fib_input+0x6a/0x240 [ 894.991034] [] ? _raw_read_unlock+0x26/0x40 [ 894.991034] [] netlink_unicast+0x169/0x1e0 [ 894.991034] [] netlink_sendmsg+0x251/0x3d0 Fix it by: 1) introducing a new netlink_skb_clone function that is used in nl_fib_input, that sets our special skb->destructor in the cloned skb. Moreover, handle the release of the large cloned skb head area in the destructor path. 2) not allowing large skbuffs in the netlink broadcast path. I cannot find any reasonable use of the large data transfer using netlink in that path, moreover this helps to skip extra skb_clone handling. I found two more netlink clients that are cloning the skbs, but they are not in the sendmsg path. Therefore, the sole client cloning that I found seems to be the fib frontend. Thanks to Eric Dumazet for helping to address this issue. Reported-by: Fengguang Wu Signed-off-by: Pablo Neira Ayuso Signed-off-by: David S. Miller

net: netlink: virtual tap device management

2013-06-24T23:39:05Z

Similarly to the networking receive path with ptype_all taps, we add the possibility to register netdevices that are for ARPHRD_NETLINK to the netlink subsystem, so that those can be used for netlink analyzers resp. debuggers. We do not offer a direct callback function as out-of-tree modules could do crap with it. Instead, a netdevice must be registered properly and only receives a clone, managed by the netlink layer. Symbols are exported as GPL-only. Signed-off-by: Daniel Borkmann Signed-off-by: David S. Miller

netlink: Add compare function for netlink_table

2013-06-11T09:39:42Z

As we know, netlink sockets are private resource of net namespace, they can communicate with each other only when they in the same net namespace. this works well until we try to add namespace support for other subsystems which use netlink. Don't like ipv4 and route table.., it is not suited to make these subsytems belong to net namespace, Such as audit and crypto subsystems,they are more suitable to user namespace. So we must have the ability to make the netlink sockets in same user namespace can communicate with each other. This patch adds a new function pointer "compare" for netlink_table, we can decide if the netlink sockets can communicate with each other through this netlink_table self-defined compare function. The behavior isn't changed if we don't provide the compare function for netlink_table. Signed-off-by: Gao feng Acked-by: Serge E. Hallyn Signed-off-by: David S. Miller