crypto: xts - consolidate sanity check for keys

The patch centralizes the XTS key check logic into the service function
xts_check_key which is invoked from the different XTS implementations.
With this, the XTS implementations in ARM, ARM64, PPC and S390 have now
a sanity check for the XTS keys similar to the other arches.

In addition, this service function received a check to ensure that the
key != the tweak key which is mandated by FIPS 140-2 IG A.9. As the
check is not present in the standards defining XTS, it is only enforced
in FIPS mode of the kernel.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 3 insertions, 8 deletions

diff --git a/arch/x86/crypto/serpent_sse2_glue.c b/arch/x86/crypto/serpent_sse2_glue.c
index 3643dd508f45..8943407e8917 100644
--- a/arch/x86/crypto/serpent_sse2_glue.c
+++ b/arch/x86/crypto/serpent_sse2_glue.c
@@ -309,16 +309,11 @@ static int xts_serpent_setkey(struct crypto_tfm *tfm, const u8 *key,
                               unsigned int keylen)
 {
         struct serpent_xts_ctx *ctx = crypto_tfm_ctx(tfm);
-        u32 *flags = &tfm->crt_flags;
         int err;
 
-        /* key consists of keys of equal size concatenated, therefore
-         * the length must be even
-         */
-        if (keylen % 2) {
-                *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
-                return -EINVAL;
-        }
+        err = xts_check_key(tfm, key, keylen);
+        if (err)
+                return err;
 
         /* first half of xts-key is for crypt */
         err = __serpent_setkey(&ctx->crypt_ctx, key, keylen / 2);