CVE-2026-68418: RDMA/irdma: Prevent user-triggered null deref on QP create

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

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

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

RDMA/irdma: Prevent user-triggered null deref on QP create

Previously, the user QP creation path would only attempt to
populate iwqp->iwpbl if the user-provided req.user_wqe_bufs
field was non-zero. The problem is that iwqp->iwpbl is
unconditionally dereferenced later on in irdma_setup_virt_qp.

While there was a check for iwqp->iwpbl != NULL, this check
would only occur if req.user_wqe_bufs was non-zero. The end
result is that a user could send a zero user_wqe_bufs value
and trigger a null ptr deref.

Fix this by unconditionally calling irdma_get_pbl and bailing
if it fails, similar to the CQ and SRQ paths.

The Linux kernel CVE team has assigned CVE-2026-68418 to this issue.


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

	Issue introduced in 5.14 with commit b48c24c2d710cf34810c555dcef883a3d35a9c08 and fixed in 6.18.42 with commit ec675b4cdfd378d8c9dd8c93126c024f2469bd79
	Issue introduced in 5.14 with commit b48c24c2d710cf34810c555dcef883a3d35a9c08 and fixed in 7.1.6 with commit 728211c815f6eef28dd3df2a5b6297483185aa20
	Issue introduced in 5.14 with commit b48c24c2d710cf34810c555dcef883a3d35a9c08 and fixed in 7.2-rc4 with commit b9b0889071569d43623c260074e159cd8f26adb1

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-2026-68418
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/hw/irdma/verbs.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/ec675b4cdfd378d8c9dd8c93126c024f2469bd79
	https://git.kernel.org/stable/c/728211c815f6eef28dd3df2a5b6297483185aa20
	https://git.kernel.org/stable/c/b9b0889071569d43623c260074e159cd8f26adb1