crypto: omap-des - add check for weak keys

OMAP DES crypto accelerator itself is unable to detect weak keys, so
add a specific call to the generic des driver to check the key strength
if requested.
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/omap-des.c

@@ -699,16 +699,28 @@ static int omap_des_crypt(struct ablkcipher_request *req, unsigned long mode)
 
 /* ********************** ALG API ************************************ */
 
-static int omap_des_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
+static int omap_des_setkey(struct crypto_ablkcipher *cipher, const u8 *key,
 			   unsigned int keylen)
 {
-	struct omap_des_ctx *ctx = crypto_ablkcipher_ctx(tfm);
+	struct omap_des_ctx *ctx = crypto_ablkcipher_ctx(cipher);
+	struct crypto_tfm *tfm = crypto_ablkcipher_tfm(cipher);
 
 	if (keylen != DES_KEY_SIZE && keylen != (3*DES_KEY_SIZE))
 		return -EINVAL;
 
 	pr_debug("enter, keylen: %d\n", keylen);
 
+	/* Do we need to test against weak key? */
+	if (tfm->crt_flags & CRYPTO_TFM_REQ_WEAK_KEY) {
+		u32 tmp[DES_EXPKEY_WORDS];
+		int ret = des_ekey(tmp, key);
+
+		if (!ret) {
+			tfm->crt_flags |= CRYPTO_TFM_RES_WEAK_KEY;
+			return -EINVAL;
+		}
+	}
+
 	memcpy(ctx->key, key, keylen);
 	ctx->keylen = keylen;