crypto: af_alg - Allow additional ciphers for cryptsetup

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>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

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 */
 	{},
 };