linux-cve-announce - CVE-2023-53817: crypto: lib/mpi - avoid null pointer deref in mpi_cmp

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Message-ID: <2025120945-CVE-2023-53817-49a5@gregkh>
Date: Tue,  9 Dec 2025 09:02:38 +0900
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53817: crypto: lib/mpi - avoid null pointer deref in mpi_cmp_ui()

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

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

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

crypto: lib/mpi - avoid null pointer deref in mpi_cmp_ui()

During NVMeTCP Authentication a controller can trigger a kernel
oops by specifying the 8192 bit Diffie Hellman group and passing
a correctly sized, but zeroed Diffie Hellamn value.
mpi_cmp_ui() was detecting this if the second parameter was 0,
but 1 is passed from dh_is_pubkey_valid(). This causes the null
pointer u->d to be dereferenced towards the end of mpi_cmp_ui()

The Linux kernel CVE team has assigned CVE-2023-53817 to this issue.


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

	Fixed in 4.14.326 with commit fde791e8a96a64ea7b0ad2440e43586447a209c6
	Fixed in 4.19.295 with commit ae63e84ffda74267bf7277c38415ba38389229a0
	Fixed in 5.4.257 with commit 61f5453e9706e99713825594e0c8f9031485fb5f
	Fixed in 5.10.197 with commit 0fc7147c694394f8a8cbc19570c6bc918cac0906
	Fixed in 5.15.133 with commit 67589d247909043e94d2dd5fb590958e0f99d58d
	Fixed in 6.1.55 with commit d3ad023a39f1127dcfd331c562673355dc078650
	Fixed in 6.5.5 with commit 12ac013ad7ff0df066451e825801d805095b3776
	Fixed in 6.6 with commit 9e47a758b70167c9301d2b44d2569f86c7796f2d

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-2023-53817
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:
	lib/crypto/mpi/mpi-cmp.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/fde791e8a96a64ea7b0ad2440e43586447a209c6
	https://git.kernel.org/stable/c/ae63e84ffda74267bf7277c38415ba38389229a0
	https://git.kernel.org/stable/c/61f5453e9706e99713825594e0c8f9031485fb5f
	https://git.kernel.org/stable/c/0fc7147c694394f8a8cbc19570c6bc918cac0906
	https://git.kernel.org/stable/c/67589d247909043e94d2dd5fb590958e0f99d58d
	https://git.kernel.org/stable/c/d3ad023a39f1127dcfd331c562673355dc078650
	https://git.kernel.org/stable/c/12ac013ad7ff0df066451e825801d805095b3776
	https://git.kernel.org/stable/c/9e47a758b70167c9301d2b44d2569f86c7796f2d