CVE-2026-64304: crypto: qat - validate RSA CRT component lengths

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

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

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

crypto: qat - validate RSA CRT component lengths

The generic RSA key parser (rsa_helper.c) bounds each CRT component (p,
q, dp, dq, qinv) by the modulus size n_sz, but qat_rsa_setkey_crt()
allocates half-size DMA buffers (key_sz / 2) and right-aligns each
component with:

    memcpy(dst + half_key_sz - len, src, len)

When a CRT component is larger than half_key_sz the subtraction
underflows and memcpy writes past the DMA buffer, causing memory
corruption.

Add a len > half_key_sz check next to the existing !len check for each
of the five CRT components so the driver falls back to the non-CRT path
instead of writing out of bounds.

The Linux kernel CVE team has assigned CVE-2026-64304 to this issue.


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

	Issue introduced in 4.8 with commit 879f77e9071f029e1c9bd5a75814ecf51370f846 and fixed in 5.10.261 with commit 6d99c5fadd2df488103f64d6475b63ba6852202b
	Issue introduced in 4.8 with commit 879f77e9071f029e1c9bd5a75814ecf51370f846 and fixed in 5.15.212 with commit c34369473bfe92a0b46ec78d6358e30341c7f481
	Issue introduced in 4.8 with commit 879f77e9071f029e1c9bd5a75814ecf51370f846 and fixed in 6.1.178 with commit 1002719d13072a5e4be1e993aa61dffb4a604e82
	Issue introduced in 4.8 with commit 879f77e9071f029e1c9bd5a75814ecf51370f846 and fixed in 6.6.145 with commit 500319830d76911c120dc0b9605f8c16d7702844
	Issue introduced in 4.8 with commit 879f77e9071f029e1c9bd5a75814ecf51370f846 and fixed in 6.12.96 with commit 3d61a214fdcda41f1ebfabbb483404032a7b4d91
	Issue introduced in 4.8 with commit 879f77e9071f029e1c9bd5a75814ecf51370f846 and fixed in 6.18.39 with commit 6fb62b767f3e27661e8f8d2f7b85f4e098fcdb1a
	Issue introduced in 4.8 with commit 879f77e9071f029e1c9bd5a75814ecf51370f846 and fixed in 7.1.4 with commit ce42224487c504aee4b7ff3a7342e7b4d7e28cc9
	Issue introduced in 4.8 with commit 879f77e9071f029e1c9bd5a75814ecf51370f846 and fixed in 7.2-rc1 with commit b3ac78756588059729b9195fcc9f4b37d54057a5

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-2026-64304
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/intel/qat/qat_common/qat_asym_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/6d99c5fadd2df488103f64d6475b63ba6852202b
	https://git.kernel.org/stable/c/c34369473bfe92a0b46ec78d6358e30341c7f481
	https://git.kernel.org/stable/c/1002719d13072a5e4be1e993aa61dffb4a604e82
	https://git.kernel.org/stable/c/500319830d76911c120dc0b9605f8c16d7702844
	https://git.kernel.org/stable/c/3d61a214fdcda41f1ebfabbb483404032a7b4d91
	https://git.kernel.org/stable/c/6fb62b767f3e27661e8f8d2f7b85f4e098fcdb1a
	https://git.kernel.org/stable/c/ce42224487c504aee4b7ff3a7342e7b4d7e28cc9
	https://git.kernel.org/stable/c/b3ac78756588059729b9195fcc9f4b37d54057a5