linux-cve-announce - CVE-2023-53599: crypto: af_alg - Fix missing initialisation affecting gcm-aes-s390

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Message-ID: <2025100430-CVE-2023-53599-2a93@gregkh>
Date: Sat,  4 Oct 2025 17:51:53 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53599: crypto: af_alg - Fix missing initialisation affecting gcm-aes-s390

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

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

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

crypto: af_alg - Fix missing initialisation affecting gcm-aes-s390

Fix af_alg_alloc_areq() to initialise areq->first_rsgl.sgl.sgt.sgl to point
to the scatterlist array in areq->first_rsgl.sgl.sgl.

Without this, the gcm-aes-s390 driver will oops when it tries to do
gcm_walk_start() on req->dst because req->dst is set to the value of
areq->first_rsgl.sgl.sgl by _aead_recvmsg() calling
aead_request_set_crypt().

The problem comes if an empty ciphertext is passed: the loop in
af_alg_get_rsgl() just passes straight out and doesn't set areq->first_rsgl
up.

This isn't a problem on x86_64 using gcmaes_crypt_by_sg() because, as far
as I can tell, that ignores req->dst and only uses req->src[*].

[*] Is this a bug in aesni-intel_glue.c?

The s390x oops looks something like:

 Unable to handle kernel pointer dereference in virtual kernel address space
 Failing address: 0000000a00000000 TEID: 0000000a00000803
 Fault in home space mode while using kernel ASCE.
 AS:00000000a43a0007 R3:0000000000000024
 Oops: 003b ilc:2 [#1] SMP
 ...
 Call Trace:
  [<000003ff7fc3d47e>] gcm_walk_start+0x16/0x28 [aes_s390]
  [<00000000a2a342f2>] crypto_aead_decrypt+0x9a/0xb8
  [<00000000a2a60888>] aead_recvmsg+0x478/0x698
  [<00000000a2e519a0>] sock_recvmsg+0x70/0xb0
  [<00000000a2e51a56>] sock_read_iter+0x76/0xa0
  [<00000000a273e066>] vfs_read+0x26e/0x2a8
  [<00000000a273e8c4>] ksys_read+0xbc/0x100
  [<00000000a311d808>] __do_syscall+0x1d0/0x1f8
  [<00000000a312ff30>] system_call+0x70/0x98
 Last Breaking-Event-Address:
  [<000003ff7fc3e6b4>] gcm_aes_crypt+0x104/0xa68 [aes_s390]

The Linux kernel CVE team has assigned CVE-2023-53599 to this issue.


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

	Issue introduced in 6.5 with commit c1abe6f570aff4b6d396dc551e60570d2f50bd79 and fixed in 6.5.3 with commit 2c9d205040d7c0eaccc473917f9b0bb0a923e440
	Issue introduced in 6.5 with commit c1abe6f570aff4b6d396dc551e60570d2f50bd79 and fixed in 6.6 with commit 6a4b8aa0a916b39a39175584c07222434fa6c6ef

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-2023-53599
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:
	crypto/af_alg.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/2c9d205040d7c0eaccc473917f9b0bb0a923e440
	https://git.kernel.org/stable/c/6a4b8aa0a916b39a39175584c07222434fa6c6ef