]> git.ipfire.org Git - thirdparty/kernel/linux.git/commit
crypto: aes - Fix conditions for selecting MAC dependencies
authorEric Biggers <ebiggers@kernel.org>
Thu, 9 Jul 2026 02:29:54 +0000 (22:29 -0400)
committerEric Biggers <ebiggers@kernel.org>
Thu, 9 Jul 2026 15:06:22 +0000 (11:06 -0400)
commite073f1238ecaea366f53e98724c40b31856da56a
tree580e032b7d47954ebbc40df80b2c95203a7b05b8
parent9665e22579ee4324a14e035b5b29d3d1fdc929e2
crypto: aes - Fix conditions for selecting MAC dependencies

Starting in commit 7137cbf2b5c9 ("crypto: aes - Add cmac, xcbc, and
cbcmac algorithms using library"), the aes module (CRYPTO_AES) supports
CBC based MACs using the corresponding library functions.

To avoid including unneeded functionality, that support honors the
existing CRYPTO_CMAC, CRYPTO_XCBC, and CRYPTO_CCM kconfig options.  The
dependencies are selected if at least one of those is enabled.

However, the select statements don't correctly handle the case where
CRYPTO_AES=y and (for example) CRYPTO_CMAC=m.  In that case the
dependencies get selected at level 'm', due to how the kconfig language
works.  That causes a linker error.

Fix this by changing the selection conditions to use '!= n'.

A similar issue also exists for CRYPTO_LIB_AES's conditional selection
of CRYPTO_LIB_UTILS.  The same '!= n' would work, but instead just make
CRYPTO_LIB_AES always select CRYPTO_LIB_UTILS.  CRYPTO_LIB_UTILS is
lightweight, and it's needed by most AES modes and many other things.

Fixes: 7137cbf2b5c9 ("crypto: aes - Add cmac, xcbc, and cbcmac algorithms using library")
Fixes: 309a7e514da7 ("lib/crypto: aes: Add support for CBC-based MACs")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260709022954.45113-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
crypto/Kconfig
lib/crypto/Kconfig