CVE-2026-80836: crypto: virtio - bound the akcipher result length

CVE-2026-80836: crypto: virtio - bound the akcipher result length

[Greg Kroah-Hartman]

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

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

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

crypto: virtio - bound the akcipher result length

virtio_crypto_dataq_akcipher_callback() sets the result length from the
device-reported response length without bounding it to the destination
buffer, which was allocated for the original request length.
sg_copy_from_buffer() then reads that many bytes from the destination
buffer; a backend reporting a larger length over-reads adjacent kernel
heap into the caller's scatterlist (an out-of-bounds read).

Clamp the reported length to the originally requested destination length.
A conforming device reports no more than that, so valid results are
unaffected.

The Linux kernel CVE team has assigned CVE-2026-80836 to this issue.


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

	Issue introduced in 5.19 with commit a36bd0ad9fbf69d0d711b1c105954ce8d6cc144a and fixed in 6.18.49 with commit 5545de5050cbc3594506d74f2c392b0716cf8bca
	Issue introduced in 5.19 with commit a36bd0ad9fbf69d0d711b1c105954ce8d6cc144a and fixed in 7.1.13 with commit 3fda114a42f1510a4ec8a0b17a0cfc997952ccc2
	Issue introduced in 5.19 with commit a36bd0ad9fbf69d0d711b1c105954ce8d6cc144a and fixed in 7.2.3 with commit 1f9f877b1ef1fbd4ee95571cddf39c8002cee252
	Issue introduced in 5.19 with commit a36bd0ad9fbf69d0d711b1c105954ce8d6cc144a and fixed in 7.3-rc1 with commit f77a956f6a19f9463ef1527c9d0cda50dded6b92

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-2026-80836
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/crypto/virtio/virtio_crypto_akcipher_algs.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/5545de5050cbc3594506d74f2c392b0716cf8bca
	https://git.kernel.org/stable/c/3fda114a42f1510a4ec8a0b17a0cfc997952ccc2
	https://git.kernel.org/stable/c/1f9f877b1ef1fbd4ee95571cddf39c8002cee252
	https://git.kernel.org/stable/c/f77a956f6a19f9463ef1527c9d0cda50dded6b92