do_sigver_init: Allow reinitialization of an existing operation.

Fixes #16936

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/16964)

(cherry picked from commit ae6b68b761b9c5f30897747487ea943ccfab53ba)

1 files changed, 8 insertions, 5 deletions

diff --git a/providers/implementations/signature/mac_legacy_sig.c b/providers/implementations/signature/mac_legacy_sig.c
index 06f79505ff..0866e68d9b 100644
--- a/providers/implementations/signature/mac_legacy_sig.c
+++ b/providers/implementations/signature/mac_legacy_sig.c
@@ -101,13 +101,16 @@ static int mac_digest_sign_init(void *vpmacctx, const char *mdname, void *vkey,
     const char *ciphername = NULL, *engine = NULL;
 
     if (!ossl_prov_is_running()
-            || pmacctx == NULL
-            || vkey == NULL
-            || !ossl_mac_key_up_ref(vkey))
+        || pmacctx == NULL
+        || (pmacctx->key == NULL && vkey == NULL))
         return 0;
 
-    ossl_mac_key_free(pmacctx->key);
-    pmacctx->key = vkey;
+    if (vkey != NULL) {
+        if (!ossl_mac_key_up_ref(vkey))
+            return 0;
+        ossl_mac_key_free(pmacctx->key);
+        pmacctx->key = vkey;
+    }
 
     if (pmacctx->key->cipher.cipher != NULL)
         ciphername = (char *)EVP_CIPHER_get0_name(pmacctx->key->cipher.cipher);