CVE-2026-89506: RDMA/uverbs: Add UVERBS_ATTR_UHW to UVERBS_METHOD_REG_MR

CVE-2026-89506: RDMA/uverbs: Add UVERBS_ATTR_UHW to UVERBS_METHOD_REG_MR

[Greg Kroah-Hartman]

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

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

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

RDMA/uverbs: Add UVERBS_ATTR_UHW to UVERBS_METHOD_REG_MR

The original commit missed that three drivers (mthca, irdma, siw) have UHW
data associated with reg_mr that cannot be passed through the ioctl. They
also assume that the udata cannot be NULL, so failing to pass a valid
udata can trigger a NULL udata crash in those drivers.

This never happens in real systems since in rdma-core ibv_cmd_reg_mr_ex()
does not accept a udata and those three drivers don't use it, however a
malicious userspace could trigger it.

The Linux kernel CVE team has assigned CVE-2026-89506 to this issue.


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

	Issue introduced in 6.17 with commit 5b2e45049dc06a876bc6b138218ddeb0814502ef and fixed in 6.18.50 with commit 71d5c41ac583df09a7c32199bef7d42de7267d07
	Issue introduced in 6.17 with commit 5b2e45049dc06a876bc6b138218ddeb0814502ef and fixed in 7.2.4 with commit 9e71d0f4944ba5641e01db29b3256c963656d671
	Issue introduced in 6.17 with commit 5b2e45049dc06a876bc6b138218ddeb0814502ef and fixed in 7.3-rc1 with commit 011199f46f44a9fd93a9e5ab5d7fd1328d80e9bf

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-2026-89506
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/core/uverbs_std_types_mr.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/71d5c41ac583df09a7c32199bef7d42de7267d07
	https://git.kernel.org/stable/c/9e71d0f4944ba5641e01db29b3256c963656d671
	https://git.kernel.org/stable/c/011199f46f44a9fd93a9e5ab5d7fd1328d80e9bf