CVE-2026-98222: KEYS: encrypted: fix integer overflow of datablob_len

CVE-2026-98222: KEYS: encrypted: fix integer overflow of datablob_len

[Greg Kroah-Hartman]

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

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

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

KEYS: encrypted: fix integer overflow of datablob_len

encrypted_key_alloc() stores datablob_len in a u16. It is computed from
multiple string and payload lengths. If the result exceeds U16_MAX, the
assignment truncates the allocation size. KASAN reports a 32760-byte
slab-out-of-bounds write when __ekey_init() copies the master key
description into the undersized buffer.

The total payload length stored in key->datalen is also a u16. Use
check_add_overflow() to reject values that do not fit either destination,
and use kzalloc_flex() for the flexible-array allocation.

The Linux kernel CVE team has assigned CVE-2026-98222 to this issue.


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

	Issue introduced in 2.6.38 with commit 7e70cb4978507cf31d76b90e4cfb4c28cad87f0c and fixed in 6.12.112 with commit 1e720f63dbafc093a8f5d519f05b67724993edd4
	Issue introduced in 2.6.38 with commit 7e70cb4978507cf31d76b90e4cfb4c28cad87f0c and fixed in 6.18.54 with commit a1a98eca102b1cbbc37ff9eaa197ae4e6a3ea4b0
	Issue introduced in 2.6.38 with commit 7e70cb4978507cf31d76b90e4cfb4c28cad87f0c and fixed in 7.2.8 with commit cca38f2102a4cd35eda8d48950df4817b4b24757
	Issue introduced in 2.6.38 with commit 7e70cb4978507cf31d76b90e4cfb4c28cad87f0c and fixed in 7.3-rc4 with commit 8697c431e297eb0d0ab13dda6bc172b48a34f05c

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-2026-98222
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:
	security/keys/encrypted-keys/encrypted.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/1e720f63dbafc093a8f5d519f05b67724993edd4
	https://git.kernel.org/stable/c/a1a98eca102b1cbbc37ff9eaa197ae4e6a3ea4b0
	https://git.kernel.org/stable/c/cca38f2102a4cd35eda8d48950df4817b4b24757
	https://git.kernel.org/stable/c/8697c431e297eb0d0ab13dda6bc172b48a34f05c