kernel/linux.git/net/socket.c, branch v6.6.131

net: Remove RTNL dance for SIOCBRADDIF and SIOCBRDELIF.

2026-01-11T14:22:25+00:00

commit ed3ba9b6e280e14cc3148c1b226ba453f02fa76c upstream. SIOCBRDELIF is passed to dev_ioctl() first and later forwarded to br_ioctl_call(), which causes unnecessary RTNL dance and the splat below [0] under RTNL pressure. Let's say Thread A is trying to detach a device from a bridge and Thread B is trying to remove the bridge. In dev_ioctl(), Thread A bumps the bridge device's refcnt by netdev_hold() and releases RTNL because the following br_ioctl_call() also re-acquires RTNL. In the race window, Thread B could acquire RTNL and try to remove the bridge device. Then, rtnl_unlock() by Thread B will release RTNL and wait for netdev_put() by Thread A. Thread A, however, must hold RTNL after the unlock in dev_ifsioc(), which may take long under RTNL pressure, resulting in the splat by Thread B. Thread A (SIOCBRDELIF) Thread B (SIOCBRDELBR) ---------------------- ---------------------- sock_ioctl sock_ioctl `- sock_do_ioctl `- br_ioctl_call `- dev_ioctl `- br_ioctl_stub |- rtnl_lock | |- dev_ifsioc ' ' |- dev = __dev_get_by_name(...) |- netdev_hold(dev, ...) . / |- rtnl_unlock ------. | | |- br_ioctl_call `---> |- rtnl_lock Race | | `- br_ioctl_stub |- br_del_bridge Window | | | |- dev = __dev_get_by_name(...) | | | May take long | `- br_dev_delete(dev, ...) | | | under RTNL pressure | `- unregister_netdevice_queue(dev, ...) | | | | `- rtnl_unlock \ | |- rtnl_lock <-' `- netdev_run_todo | |- ... `- netdev_run_todo | `- rtnl_unlock |- __rtnl_unlock | |- netdev_wait_allrefs_any |- netdev_put(dev, ...) <----------------' Wait refcnt decrement and log splat below To avoid blocking SIOCBRDELBR unnecessarily, let's not call dev_ioctl() for SIOCBRADDIF and SIOCBRDELIF. In the dev_ioctl() path, we do the following: 1. Copy struct ifreq by get_user_ifreq in sock_do_ioctl() 2. Check CAP_NET_ADMIN in dev_ioctl() 3. Call dev_load() in dev_ioctl() 4. Fetch the master dev from ifr.ifr_name in dev_ifsioc() 3. can be done by request_module() in br_ioctl_call(), so we move 1., 2., and 4. to br_ioctl_stub(). Note that 2. is also checked later in add_del_if(), but it's better performed before RTNL. SIOCBRADDIF and SIOCBRDELIF have been processed in dev_ioctl() since the pre-git era, and there seems to be no specific reason to process them there. [0]: unregister_netdevice: waiting for wpan3 to become free. Usage count = 2 ref_tracker: wpan3@ffff8880662d8608 has 1/1 users at __netdev_tracker_alloc include/linux/netdevice.h:4282 [inline] netdev_hold include/linux/netdevice.h:4311 [inline] dev_ifsioc+0xc6a/0x1160 net/core/dev_ioctl.c:624 dev_ioctl+0x255/0x10c0 net/core/dev_ioctl.c:826 sock_do_ioctl+0x1ca/0x260 net/socket.c:1213 sock_ioctl+0x23a/0x6c0 net/socket.c:1318 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x1a4/0x210 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcb/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: 893b19587534 ("net: bridge: fix ioctl locking") Reported-by: syzkaller Reported-by: yan kang Reported-by: yue sun Closes: https://lore.kernel.org/netdev/SY8P300MB0421225D54EB92762AE8F0F2A1D32@SY8P300MB0421.AUSP300.PROD.OUTLOOK.COM/ Signed-off-by: Kuniyuki Iwashima Acked-by: Stanislav Fomichev Reviewed-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20250316192851.19781-1-kuniyu@amazon.com Signed-off-by: Paolo Abeni [cascardo: fixed conflict at dev_ifsioc] Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

net: explicitly clear the sk pointer, when pf->create fails

2024-10-17T13:24:35+00:00

commit 631083143315d1b192bd7d915b967b37819e88ea upstream. We have recently noticed the exact same KASAN splat as in commit 6cd4a78d962b ("net: do not leave a dangling sk pointer, when socket creation fails"). The problem is that commit did not fully address the problem, as some pf->create implementations do not use sk_common_release in their error paths. For example, we can use the same reproducer as in the above commit, but changing ping to arping. arping uses AF_PACKET socket and if packet_create fails, it will just sk_free the allocated sk object. While we could chase all the pf->create implementations and make sure they NULL the freed sk object on error from the socket, we can't guarantee future protocols will not make the same mistake. So it is easier to just explicitly NULL the sk pointer upon return from pf->create in __sock_create. We do know that pf->create always releases the allocated sk object on error, so if the pointer is not NULL, it is definitely dangling. Fixes: 6cd4a78d962b ("net: do not leave a dangling sk pointer, when socket creation fails") Signed-off-by: Ignat Korchagin Cc: stable@vger.kernel.org Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20241003170151.69445-1-ignat@cloudflare.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

bpf, net: Fix a potential race in do_sock_getsockopt()

2024-09-12T09:11:34+00:00

[ Upstream commit 33f339a1ba54e56bba57ee9a77c71e385ab4825c ] There's a potential race when `cgroup_bpf_enabled(CGROUP_GETSOCKOPT)` is false during the execution of `BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN`, but becomes true when `BPF_CGROUP_RUN_PROG_GETSOCKOPT` is called. This inconsistency can lead to `BPF_CGROUP_RUN_PROG_GETSOCKOPT` receiving an "-EFAULT" from `__cgroup_bpf_run_filter_getsockopt(max_optlen=0)`. Scenario shown as below: `process A` `process B` ----------- ------------ BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN enable CGROUP_GETSOCKOPT BPF_CGROUP_RUN_PROG_GETSOCKOPT (-EFAULT) To resolve this, remove the `BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN` macro and directly uses `copy_from_sockptr` to ensure that `max_optlen` is always set before `BPF_CGROUP_RUN_PROG_GETSOCKOPT` is invoked. Fixes: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks") Co-developed-by: Yanghui Li Signed-off-by: Yanghui Li Co-developed-by: Cheng-Jui Wang Signed-off-by: Cheng-Jui Wang Signed-off-by: Tze-nan Wu Acked-by: Stanislav Fomichev Acked-by: Alexei Starovoitov Link: https://patch.msgid.link/20240830082518.23243-1-Tze-nan.Wu@mediatek.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net/socket: Break down __sys_getsockopt

2024-09-12T09:11:34+00:00

[ Upstream commit 0b05b0cd78c92371fdde6333d006f39eaf9e0860 ] Split __sys_getsockopt() into two functions by removing the core logic into a sub-function (do_sock_getsockopt()). This will avoid code duplication when doing the same operation in other callers, for instance. do_sock_getsockopt() will be called by io_uring getsockopt() command operation in the following patch. The same was done for the setsockopt pair. Suggested-by: Martin KaFai Lau Signed-off-by: Breno Leitao Acked-by: Jakub Kicinski Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20231016134750.1381153-5-leitao@debian.org Signed-off-by: Jens Axboe Stable-dep-of: 33f339a1ba54 ("bpf, net: Fix a potential race in do_sock_getsockopt()") Signed-off-by: Sasha Levin

net/socket: Break down __sys_setsockopt

2024-09-12T09:11:34+00:00

[ Upstream commit 1406245c29454ff84919736be83e14cdaba7fec1 ] Split __sys_setsockopt() into two functions by removing the core logic into a sub-function (do_sock_setsockopt()). This will avoid code duplication when doing the same operation in other callers, for instance. do_sock_setsockopt() will be called by io_uring setsockopt() command operation in the following patch. Signed-off-by: Breno Leitao Reviewed-by: Willem de Bruijn Acked-by: Jakub Kicinski Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20231016134750.1381153-4-leitao@debian.org Signed-off-by: Jens Axboe Stable-dep-of: 33f339a1ba54 ("bpf, net: Fix a potential race in do_sock_getsockopt()") Signed-off-by: Sasha Levin

bpf: Add sockptr support for setsockopt

2024-09-12T09:11:34+00:00

[ Upstream commit 3f31e0d14d44ad491a81b7c1f83f32fbc300a867 ] The whole network stack uses sockptr, and while it doesn't move to something more modern, let's use sockptr in setsockptr BPF hooks, so, it could be used by other callers. The main motivation for this change is to use it in the io_uring {g,s}etsockopt(), which will use a userspace pointer for *optval, but, a kernel value for optlen. Link: https://lore.kernel.org/all/ZSArfLaaGcfd8LH8@gmail.com/ Signed-off-by: Breno Leitao Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20231016134750.1381153-3-leitao@debian.org Signed-off-by: Jens Axboe Stable-dep-of: 33f339a1ba54 ("bpf, net: Fix a potential race in do_sock_getsockopt()") Signed-off-by: Sasha Levin

bpf: Add sockptr support for getsockopt

2024-09-12T09:11:34+00:00

[ Upstream commit a615f67e1a426f35366b8398c11f31c148e7df48 ] The whole network stack uses sockptr, and while it doesn't move to something more modern, let's use sockptr in getsockptr BPF hooks, so, it could be used by other callers. The main motivation for this change is to use it in the io_uring {g,s}etsockopt(), which will use a userspace pointer for *optval, but, a kernel value for optlen. Link: https://lore.kernel.org/all/ZSArfLaaGcfd8LH8@gmail.com/ Signed-off-by: Breno Leitao Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20231016134750.1381153-2-leitao@debian.org Signed-off-by: Jens Axboe Stable-dep-of: 33f339a1ba54 ("bpf, net: Fix a potential race in do_sock_getsockopt()") Signed-off-by: Sasha Levin

net: Save and restore msg_namelen in sock_sendmsg

2024-01-10T16:16:51+00:00

[ Upstream commit 01b2885d9415152bcb12ff1f7788f500a74ea0ed ] Commit 86a7e0b69bd5 ("net: prevent rewrite of msg_name in sock_sendmsg()") made sock_sendmsg save the incoming msg_name pointer and restore it before returning, to insulate the caller against msg_name being changed by the called code. If the address length was also changed however, we may return with an inconsistent structure where the length doesn't match the address, and attempts to reuse it may lead to lost packets. For example, a kernel that doesn't have commit 1c5950fc6fe9 ("udp6: fix potential access to stale information") will replace a v4 mapped address with its ipv4 equivalent, and shorten namelen accordingly from 28 to 16. If the caller attempts to reuse the resulting msg structure, it will have the original ipv6 (v4 mapped) address but an incorrect v4 length. Fixes: 86a7e0b69bd5 ("net: prevent rewrite of msg_name in sock_sendmsg()") Signed-off-by: Marc Dionne Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: prevent address rewrite in kernel_bind()

2023-10-01T18:31:29+00:00

Similar to the change in commit 0bdf399342c5("net: Avoid address overwrite in kernel_connect"), BPF hooks run on bind may rewrite the address passed to kernel_bind(). This change 1) Makes a copy of the bind address in kernel_bind() to insulate callers. 2) Replaces direct calls to sock->ops->bind() in net with kernel_bind() Link: https://lore.kernel.org/netdev/20230912013332.2048422-1-jrife@google.com/ Fixes: 4fbac77d2d09 ("bpf: Hooks for sys_bind") Cc: stable@vger.kernel.org Reviewed-by: Willem de Bruijn Signed-off-by: Jordan Rife Reviewed-by: Simon Horman Signed-off-by: David S. Miller

net: prevent rewrite of msg_name in sock_sendmsg()

2023-10-01T18:31:29+00:00

Callers of sock_sendmsg(), and similarly kernel_sendmsg(), in kernel space may observe their value of msg_name change in cases where BPF sendmsg hooks rewrite the send address. This has been confirmed to break NFS mounts running in UDP mode and has the potential to break other systems. This patch: 1) Creates a new function called __sock_sendmsg() with same logic as the old sock_sendmsg() function. 2) Replaces calls to sock_sendmsg() made by __sys_sendto() and __sys_sendmsg() with __sock_sendmsg() to avoid an unnecessary copy, as these system calls are already protected. 3) Modifies sock_sendmsg() so that it makes a copy of msg_name if present before passing it down the stack to insulate callers from changes to the send address. Link: https://lore.kernel.org/netdev/20230912013332.2048422-1-jrife@google.com/ Fixes: 1cedee13d25a ("bpf: Hooks for sys_sendmsg") Cc: stable@vger.kernel.org Reviewed-by: Willem de Bruijn Signed-off-by: Jordan Rife Reviewed-by: Simon Horman Signed-off-by: David S. Miller