crypto: ecdh - comply with crypto_kpp_maxsize()

crypto_kpp_maxsize() asks for the output buffer size without caring for errors. It allways assume that will be called after a valid setkey. Comply with it and return what he wants. nbytes has no sense now, remove it and directly return the maxsize. Signed-off-by: Tudor Ambarus <[email protected]> Signed-off-by: Herbert Xu <[email protected]>
opendata26 · Jun 10, 2017 · d0efb48 · d0efb48
1 parent 7f69105
commit d0efb48
Showing 1 changed file with 3 additions and 4 deletions.
diff --git a/crypto/ecdh.c b/crypto/ecdh.c
@@ -104,13 +104,12 @@ static int ecdh_compute_value(struct kpp_request *req)
 	return ret;
 }
 
-static int ecdh_max_size(struct crypto_kpp *tfm)
+static unsigned int ecdh_max_size(struct crypto_kpp *tfm)
 {
 	struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
-	int nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
 
-	/* Public key is made of two coordinates */
-	return 2 * nbytes;
+	/* Public key is made of two coordinates, add one to the left shift */
+	return ctx->ndigits << (ECC_DIGITS_TO_BYTES_SHIFT + 1);
 }
 
 static void no_exit_tfm(struct crypto_kpp *tfm)