CVE-2026-43463: rxrpc, afs: Fix missing error pointer check after rxrpc_kernel_lookup_peer()

CVE-2026-43463: rxrpc, afs: Fix missing error pointer check after rxrpc_kernel_lookup_peer()

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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

rxrpc, afs: Fix missing error pointer check after rxrpc_kernel_lookup_peer()

rxrpc_kernel_lookup_peer() can also return error pointers in addition to
NULL, so just checking for NULL is not sufficient.

Fix this by:

 (1) Changing rxrpc_kernel_lookup_peer() to return -ENOMEM rather than NULL
     on allocation failure.

 (2) Making the callers in afs use IS_ERR() and PTR_ERR() to pass on the
     error code returned.

The Linux kernel CVE team has assigned CVE-2026-43463 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.8 with commit 72904d7b9bfbf2dd146254edea93958bc35bbbfe and fixed in 6.18.19 with commit d55fa7cd4b19ba91b34b307d769c149e56ad0a75
	Issue introduced in 6.8 with commit 72904d7b9bfbf2dd146254edea93958bc35bbbfe and fixed in 6.19.9 with commit 54331c5dcc6d97683d7ca2788e7ef9c9505e1477
	Issue introduced in 6.8 with commit 72904d7b9bfbf2dd146254edea93958bc35bbbfe and fixed in 7.0 with commit 4245a79003adf30e67f8e9060915bd05cb31d142
	Issue introduced in 6.7.3 with commit 056fc740be000d39a7dba700a935f3bbfbc664e6

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-43463
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	fs/afs/addr_list.c
	net/rxrpc/af_rxrpc.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/d55fa7cd4b19ba91b34b307d769c149e56ad0a75
	https://git.kernel.org/stable/c/54331c5dcc6d97683d7ca2788e7ef9c9505e1477
	https://git.kernel.org/stable/c/4245a79003adf30e67f8e9060915bd05cb31d142