[CRYPTO] Check cra_alignmask against cra_blocksize

The cipher code relies on the fact that the block size is a multiple
of the required alignment.  So we should check this at the time of
algorith registration.  We also ensure that the block size is bounded
by the page size.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

crypto/api.c

@@ -215,7 +215,10 @@ int crypto_register_alg(struct crypto_alg *alg)
 	if (alg->cra_alignmask & (alg->cra_alignmask + 1))
 		return -EINVAL;
 
-	if (alg->cra_alignmask > PAGE_SIZE)
+	if (alg->cra_alignmask & alg->cra_blocksize)
+		return -EINVAL;
+
+	if (alg->cra_blocksize > PAGE_SIZE)
 		return -EINVAL;
 	
 	down_write(&crypto_alg_sem);