According to FIPS 140-3 IG C.I., only (total) key lengths of either 256 bits or 512 bits are allowed with xts(aes). Make xts_verify_key() to reject anything else in FIPS mode. As xts(aes) is the only approved xts() template instantiation in FIPS mode, the new restriction implemented in xts_verify_key() effectively only applies to this particular construction. Signed-off-by: Nicolai Stange <nstange@xxxxxxx> --- include/crypto/xts.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/include/crypto/xts.h b/include/crypto/xts.h index 0f8dba69feb4..a233c1054df2 100644 --- 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
