Re: [PATCH] crypto: af_alg - Allow additional ciphers for cryptsetup

[Milan Broz <gmazyland@gmail.com>]

On 7/5/26 8:44 PM, Eric Biggers wrote:
> Add "xts(camellia)", "xts(serpent)", and "xts(twofish)" to the allowlist
> for af_alg_restrict=1.  These niche AES alternatives have continued to
> see rare but persistent use via cryptsetup, which has historically
> relied on the AF_ALG support for these ciphers in XTS mode for
> performing the keyslot encryption.  (cryptsetup v2.8.7 and later fall
> back to a temporary dm-crypt mapping, but that requires root.)
> 
> Signed-off-by: Eric Biggers <ebiggers@kernel.org>
> ---
>   crypto/algif_skcipher.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
> index 2b8069667974..49ae779b3b6b 100644
> --- a/crypto/algif_skcipher.c
> +++ b/crypto/algif_skcipher.c
> @@ -45,6 +45,9 @@ static const struct af_alg_allowlist_entry skcipher_allowlist[] = {
>   	{ "ecb(des)", true }, /* iwd */
>   	{ "hctr2(aes)", false }, /* cryptsetup */
>   	{ "xts(aes)", false }, /* cryptsetup benchmark */
> +	{ "xts(camellia)", false }, /* cryptsetup */
> +	{ "xts(serpent)", false }, /* cryptsetup */
> +	{ "xts(twofish)", false }, /* cryptsetup */
>   	{},

Well, if we are going this way, I would also add Aria and SM4 (currently usable only in cryptsetup main branch).

Milan

p.s.
There is another user of AF_ALG hash, hardlink in util-linux, see
https://github.com/util-linux/util-linux/blob/master/lib/fileeq.c