1 files changed, 5 insertions, 0 deletions
diff --git a/crypto/ec/ecdsa_ossl.c b/crypto/ec/ecdsa_ossl.c
index 0bf4635e2f..0bdf45e6e7 100644
--- a/crypto/ec/ecdsa_ossl.c
+++ b/crypto/ec/ecdsa_ossl.c
@@ -70,6 +70,11 @@ int ossl_ecdsa_sign(int type, const unsigned char *dgst, int dlen,
 {
     ECDSA_SIG *s;
 
+    if (sig == NULL && (kinv == NULL || r == NULL)) {
+        *siglen = ECDSA_size(eckey);
+        return 1;
+    }
+
     s = ECDSA_do_sign_ex(dgst, dlen, kinv, r, eckey);
     if (s == NULL) {
         *siglen = 0;