lib/crypto: aes: Add CTR and XCTR support

Add support for AES-CTR and AES-XCTR to the crypto library.

These will be used to provide streamlined implementations of the
"ctr(aes)" and "xctr(aes)" crypto_skcipher algorithms.  Most users of
"ctr(aes)" will also be able to switch to the library, which as usual
will be simpler and faster, e.g.:

  - net/mac80211/fils_aead.c
  - net/mac802154/llsec.c

As usual, the architecture-optimized AES-CTR and AES-XCTR code will be
migrated into the library as well (using the hooks provided in this
commit), eliminating lots of repetitive boilerplate code.

This is also a prerequisite for supporting AES-GCM, AES-CCM, and
AES-HCTR2 in the crypto library.

Initial test coverage is provided by the crypto_skcipher support added
in a later commit.  I'm planning a KUnit test suite as well.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Link: https://patch.msgid.link/20260715221153.246410-5-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/Documentation/crypto/libcrypto-unauth-encryption.rst b/Documentation/crypto/libcrypto-unauth-encryption.rst
index 82bdb0d1b93e..4d3555ee81b7 100644
--- a/Documentation/crypto/libcrypto-unauth-encryption.rst
+++ b/Documentation/crypto/libcrypto-unauth-encryption.rst
@@ -27,6 +27,13 @@ This API provides support for AES in the CBC and CBC-CTS modes of operation.
 
 .. kernel-doc:: include/crypto/aes-cbc.h
 
+AES-CTR and AES-XCTR
+--------------------
+
+This API provides support for AES in the CTR and XCTR modes of operation.
+
+.. kernel-doc:: include/crypto/aes-ctr.h
+
 AES-ECB
 -------