CVE-2022-49877

In the Linux kernel, the following vulnerability has been resolved:

bpf, sockmap: Fix the sk->sk_forward_alloc warning of sk_stream_kill_queues

When running test_sockmap selftests, the following warning appears:

WARNING: CPU: 2 PID: 197 at net/core/stream.c:205 sk_stream_kill_queues+0xd3/0xf0 Call Trace: <TASK> inet_csk_destroy_sock+0x55/0x110 tcp_rcv_state_process+0xd28/0x1380 ? tcp_v4_do_rcv+0x77/0x2c0 tcp_v4_do_rcv+0x77/0x2c0 __release_sock+0x106/0x130 __tcp_close+0x1a7/0x4e0 tcp_close+0x20/0x70 inet_release+0x3c/0x80 __sock_release+0x3a/0xb0 sock_close+0x14/0x20 __fput+0xa3/0x260 task_work_run+0x59/0xb0 exit_to_user_mode_prepare+0x1b3/0x1c0 syscall_exit_to_user_mode+0x19/0x50 do_syscall_64+0x48/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae

The root case is in commit 84472b436e76 ("bpf, sockmap: Fix more uncharged while msg has more_data"), where I used msg->sg.size to replace the tosend, causing breakage:

if (msg->apply_bytes && msg->apply_bytes < tosend) tosend = psock->apply_bytes;

A bug in the bpf, sockmap implementation was identified, where incorrect accounting of memory (using msg->sg.size instead of tosend) could lead to issues during sk_stream_kill_queues, triggering kernel warnings under test_sockmap. The issue stems from commit 84472b436e76. This bug may result in improper memory charging and unbalanced accounting in socket buffer operations, potentially triggering warnings or instability during socket teardown. The BPF disabled by default in Red Hat Enterprise Linux (and only admin can enable it).

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.