1 files changed, 4 insertions, 1 deletions
diff --git a/crypto/hmac/hmac.c b/crypto/hmac/hmac.c
index 3374105cbb..a2c9dd9845 100644
--- a/crypto/hmac/hmac.c
+++ b/crypto/hmac/hmac.c
@@ -118,7 +118,10 @@ int HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
 
 size_t HMAC_size(const HMAC_CTX *ctx)
 {
-    return EVP_MD_size((ctx)->md);
+    int size = EVP_MD_size((ctx)->md);
+    if (size < 0)
+        return 0;
+    return size;
 }
 
 HMAC_CTX *HMAC_CTX_new(void)