sm2_dupctx: Avoid potential use after free of the md

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18494)

diff --git a/providers/implementations/asymciphers/sm2_enc.c b/providers/implementations/asymciphers/sm2_enc.c
index 9577d16e8384153c5cbf934c6c6401185f505562..ddb2cfc14a12a32a67ad26e56b0131df37c2267f 100644 (file)
--- a/providers/implementations/asymciphers/sm2_enc.c
+++ b/providers/implementations/asymciphers/sm2_enc.c
@@ -138,6 +138,8 @@ static void *sm2_dupctx(void *vpsm2ctx)
         return NULL;
 
     *dstctx = *srcctx;
+    memset(&dstctx->md, 0, sizeof(dstctx->md));
+
     if (dstctx->key != NULL && !EC_KEY_up_ref(dstctx->key)) {
         OPENSSL_free(dstctx);
         return NULL;