Re: [PATCH] crypto: Drop unused cipher_null crypto_alg

On Mon, Apr 20, 2026 at 11:41:20AM +0200, Ard Biesheuvel wrote:

The cipher_null crypto_alg cipher is never used in a meaningful way,
given that it is always wrapped in ecb(), which has its own dedicated
implementation. IOW, the cipher_null crypto_alg should never be used to
implement the ecb(cipher_null) skcipher, and using it for other things
is bogus.

However, it is accessible from user space, and due to the nature of the
AF_ALG interface, it may be wrapped in arbitrary ways, exposing issues
in template code that wasn't written with block ciphers with a block
size of '1' in mind.

So drop this code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 crypto/crypto_null.c | 35 ++------------------
 1 file changed, 2 insertions(+), 33 deletions(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu [off-list ref]
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt