CVE-2026-63971sctp: fix race between sctp_wait_for_connect and peeloff

Official description

In the Linux kernel, the following vulnerability has been resolved: sctp: fix race between sctp_wait_for_connect and peeloff sctp_wait_for_connect() drops and re-acquires the socket lock while waiting for the association to reach ESTABLISHED state. During this window, another thread can peeloff the association to a new socket via getsockopt(SCTP_SOCKOPT_PEELOFF), changing asoc->base.sk. After re-acquiring the old socket lock, sctp_wait_for_connect() returns success without noticing the migration — the caller then accesses the association under the wrong lock in sctp_datamsg_from_user(). Add the same sk != asoc->base.sk check that sctp_wait_for_sndbuf() already has, returning an error if the association was migrated while we slept.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/0e0d5bc76fd4267a71334fcc8f1a5fbcf997845d
• https://git.kernel.org/stable/c/bcfeac79af740735ace44008b4a11b8e5add20f5
• https://git.kernel.org/stable/c/8e9b56051d24540cfbf39194618708c4a7633549
• https://git.kernel.org/stable/c/634a9af8a26a84d8b0d7b3b643204b344b42d9fb
• https://git.kernel.org/stable/c/7d2038d4b80166f7bead8d07eba3b97405816c21
• https://git.kernel.org/stable/c/68667ee4c7dadf7f63167234e2a1af09b3f7874e
• https://git.kernel.org/stable/c/6140cfa721451fa6e18e134e709703c2bf34d0fb
• https://git.kernel.org/stable/c/f14fe6395a8b3d961a61e138ad7b36ba3626dd4e