title: mptcp: fix sk_forward_memory corruption on retransmission
description: In the Linux kernel, the following vulnerability has been resolved:
mptcp: fix sk_forward_memory corruption on retransmission
MPTCP sk_forward_memory handling is a bit special, as such field
is protected by the msk socket spin_lock, instead of the plain
socket lock.
Currently we have a code path updating such field without handling
the relevant lock:
__mptcp_retrans() -> __mptcp_clean_una_wakeup()
Several helpers in __mptcp_clean_una_wakeup() will update
sk_forward_alloc, possibly causing such field corruption, as reported
by Matthieu.
Address the issue providing and using a new variant of blamed function
which explicitly acquires the msk spin lock.
affected:
{
product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 64b9cea7a0af, lessThan: b9c78b1a9596, status: affected, versionType: git
version: 64b9cea7a0af, lessThan: b5941f066b4c, status: affected, versionType: git
}
{
product: Linux
vendor: Linux
defaultStatus: affected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 5.12, status: affected
version: 0, lessThan: 5.12, status: unaffected, versionType: custom
version: 5.12.10, lessThanOrEqual: 5.12.*, status: unaffected, versionType: custom
version: 5.13, lessThanOrEqual: *, status: unaffected, versionType: original_commit_for_fix
}
