Fix BIO_printf format warnings

[oweals/openssl.git] / crypto / hmac / hmac.c

diff --git a/crypto/hmac/hmac.c b/crypto/hmac/hmac.c
index e78f66a732ee65e9213797e75255ed15b61b79f1..5d934e95888bd0309f62ef70b7c479ec037b57eb 100644 (file)
--- a/crypto/hmac/hmac.c
+++ b/crypto/hmac/hmac.c
@@ -35,6 +35,13 @@ int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
         return 0;
     }
 
+    /*
+     * The HMAC construction is not allowed to be used with the
+     * extendable-output functions (XOF) shake128 and shake256.
+     */
+    if ((EVP_MD_meth_get_flags(md) & EVP_MD_FLAG_XOF) != 0)
+        return 0;
+
     if (key != NULL) {
         reset = 1;
         j = EVP_MD_block_size(md);