"Elliott, Robert (Servers)" <elliott@xxxxxxx> writes: >> diff --git a/include/crypto/xts.h b/include/crypto/xts.h > ... >> @@ -35,6 +35,13 @@ static inline int xts_verify_key(struct crypto_skcipher >> *tfm, >> if (keylen % 2) >> return -EINVAL; >> >> + /* >> + * In FIPS mode only a combined key length of either 256 or >> + * 512 bits is allowed, c.f. FIPS 140-3 IG C.I. >> + */ >> + if (fips_enabled && keylen != 32 && keylen != 64) >> + return -EINVAL; >> + >> /* ensure that the AES and tweak key are not identical */ >> if ((fips_enabled || (crypto_skcipher_get_flags(tfm) & >> CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)) && >> -- >> 2.38.0 > > arch/s390/crypto/aes_s390.c has similar lines: > > static int xts_aes_set_key(struct crypto_skcipher *tfm, const u8 *in_key, > unsigned int key_len) > { > struct s390_xts_ctx *xts_ctx = crypto_skcipher_ctx(tfm); > unsigned long fc; > int err; > > err = xts_fallback_setkey(tfm, in_key, key_len); > if (err) > return err; > > /* In fips mode only 128 bit or 256 bit keys are valid */ > if (fips_enabled && key_len != 32 && key_len != 64) > return -EINVAL; > > > xts_fallback_setkey will now enforce that rule when setting up the > fallback algorithm keys, which makes the xts_aes_set_key check > unreachable. Good finding! > > If that fallback setup were not present, then a call to xts_verify_key > might be preferable to enforce any other rules like the WEAK_KEYS > rule. > So if this patch here would get accepted, I'd propose to remove the then dead code from aes_s390 afterwards and make an explicit call to xts_verify_key() instead. Or shall I split out the XTS patch from this series here and post these two changes separately then? Herbert, any preferences? Thanks! Nicolai -- SUSE Software Solutions Germany GmbH, Frankenstraße 146, 90461 Nürnberg, Germany GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman (HRB 36809, AG Nürnberg)