CVE-2026-74377: RDMA/rxe: Copy WQE to local buffer in non-SRQ receive path

From: Greg Kroah-Hartman <[email protected]>

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

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

RDMA/rxe: Copy WQE to local buffer in non-SRQ receive path

For non-SRQ QPs, the responder reads WQE fields directly from the
shared queue buffer mapped into userspace. This allows a malicious
user to modify fields like num_sge or sge entries while the kernel
is processing the WQE, leading to out-of-bounds reads in
rxe_resp_check_length() and copy_data().

Introduce get_recv_wqe() that validates num_sge and copies the WQE
to a kernel-local buffer before processing, matching the approach
already used for SRQ WQEs in get_srq_wqe(). The srq_wqe buffer is
reused since SRQ and non-SRQ paths are mutually exclusive per QP.

The Linux kernel CVE team has assigned CVE-2026-74377 to this issue.


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

	Issue introduced in 4.8 with commit 8700e3e7c4857d28ebaa824509934556da0b3e76 and fixed in 6.1.178 with commit 2e60378fb3c8b51c94103bb40014c4fe38fa5033
	Issue introduced in 4.8 with commit 8700e3e7c4857d28ebaa824509934556da0b3e76 and fixed in 6.6.145 with commit fc72fd61cc8b2e2e3e92ae4c0e9cc30c9a7ecb78
	Issue introduced in 4.8 with commit 8700e3e7c4857d28ebaa824509934556da0b3e76 and fixed in 6.12.97 with commit 9fa785137303f7109c23dea779b8dedc67c9b531
	Issue introduced in 4.8 with commit 8700e3e7c4857d28ebaa824509934556da0b3e76 and fixed in 6.18.40 with commit 5420eebf3b3c162bfaf965f30e61cd1d689e5732
	Issue introduced in 4.8 with commit 8700e3e7c4857d28ebaa824509934556da0b3e76 and fixed in 7.1.5 with commit a211b7904aed365e4e4f08a48ec6e6dd1ea7b16b
	Issue introduced in 4.8 with commit 8700e3e7c4857d28ebaa824509934556da0b3e76 and fixed in 7.2-rc1 with commit d6ab440240a04b8737ee4c7bb21af9182e451733

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-2026-74377
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:
	drivers/infiniband/sw/rxe/rxe_resp.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/2e60378fb3c8b51c94103bb40014c4fe38fa5033
	https://git.kernel.org/stable/c/fc72fd61cc8b2e2e3e92ae4c0e9cc30c9a7ecb78
	https://git.kernel.org/stable/c/9fa785137303f7109c23dea779b8dedc67c9b531
	https://git.kernel.org/stable/c/5420eebf3b3c162bfaf965f30e61cd1d689e5732
	https://git.kernel.org/stable/c/a211b7904aed365e4e4f08a48ec6e6dd1ea7b16b
	https://git.kernel.org/stable/c/d6ab440240a04b8737ee4c7bb21af9182e451733