crypto: hisilicon/hpre - add check before gx modulo p

The result of gx modulo p is zero if gx is equal to p, so return
error immediately if gx is equal to p.

Signed-off-by: Hui Tang <tanghui20@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/hisilicon/hpre/hpre_crypto.c b/drivers/crypto/hisilicon/hpre/hpre_crypto.c
index 6ba5d8af3875503679fff551de0cd8b70e984e1e..323418bf66ab7c657fe2baa4b6c6789ba8940383 100644 (file)
--- a/drivers/crypto/hisilicon/hpre/hpre_crypto.c
+++ b/drivers/crypto/hisilicon/hpre/hpre_crypto.c
@@ -1841,8 +1841,12 @@ static int hpre_curve25519_src_init(struct hpre_asym_request *hpre_req,
         * When src_data equals (2^255 - 19) ~  (2^255 - 1), it is out of p,
         * we get its modulus to p, and then use it.
         */
-       if (memcmp(ptr, p, ctx->key_sz) >= 0)
+       if (memcmp(ptr, p, ctx->key_sz) == 0) {
+               dev_err(dev, "gx is p!\n");
+               return -EINVAL;
+       } else if (memcmp(ptr, p, ctx->key_sz) > 0) {
                hpre_curve25519_src_modulo_p(ptr);
+       }
 
        hpre_req->src = ptr;
        msg->in = cpu_to_le64(dma);