Re: [PATCH 03/33] lib/crypto: aes: Add CBC and CBC-CTS support

[Eric Biggers <ebiggers@kernel.org>]

On Tue, Jul 14, 2026 at 09:02:08AM +0100, David Laight wrote:
> On Mon,  6 Jul 2026 22:34:33 -0700
> Eric Biggers <ebiggers@kernel.org> wrote:
> 
> > Add support for AES-CBC and AES-CBC-CTS to the crypto library.
> > 
> > These will be used to provide streamlined implementations of the
> > "cbc(aes)" and "cts(cbc(aes))" crypto_skcipher algorithms.  Most users
> > of these crypto_skcipher algorithms will also be able to switch to the
> > library, which as usual will be simpler and faster, e.g.:
> > 
> >     - block/blk-crypto-fallback.c (for AES-128-CBC-ESSIV)
> >     - fs/crypto/crypto.c (for AES-128-CBC-ESSIV)
> >     - fs/crypto/fname.c (for AES-256-CTS and AES-128-CBC)
> >     - kernel/bpf/crypto.c
> >     - net/ceph/crypto.c
> >     - security/keys/encrypted-keys/encrypted.c
> > 
> ...
> > +void aes_cbc_encrypt(u8 *dst, const u8 *src, size_t len, u8 iv[AES_BLOCK_SIZE],
> > +		     aes_encrypt_arg key)
> 
> 
> Does embedding the 'u8 iv[]' in a structure work?
> It gives better type-checking for the length of the array.

It doesn't work very well, since callers tend to just have a u8 array.

- Eric