From 064cfce0d906e9ec2f4f16caf3e497c87df4d861 Mon Sep 17 00:00:00 2001
From: John Safranek <john@wolfssl.com>
Date: Tue, 20 Jul 2021 16:23:15 -0700
Subject: [PATCH] Fuzzing Fixes 1. Fixed a leak. 2. Fixed a branch on
 uninitialized. (ZD 12640 and 12642)

---
 src/internal.c | 4 ++++
 src/misc.c     | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/src/internal.c b/src/internal.c
index 7c3384cd6..5ac3ae3c6 100644
--- a/src/internal.c
+++ b/src/internal.c
@@ -3533,6 +3533,8 @@ static int DoKexDhGexGroup(WOLFSSH* ssh,
         ret = GetMpint(&generatorSz, &generator, buf, len, &begin);
 
     if (ret == WS_SUCCESS) {
+        if (ssh->handshake->primeGroup)
+            WFREE(ssh->handshake->primeGroup, ssh->ctx->heap, DYNTYPE_MPINT);
         ssh->handshake->primeGroup =
             (byte*)WMALLOC(primeGroupSz, ssh->ctx->heap, DYNTYPE_MPINT);
         if (ssh->handshake->primeGroup == NULL)
@@ -3540,6 +3542,8 @@ static int DoKexDhGexGroup(WOLFSSH* ssh,
     }
 
     if (ret == WS_SUCCESS) {
+        if (ssh->handshake->generator)
+            WFREE(ssh->handshake->generator, ssh->ctx->heap, DYNTYPE_MPINT);
         ssh->handshake->generator =
             (byte*)WMALLOC(generatorSz, ssh->ctx->heap, DYNTYPE_MPINT);
         if (ssh->handshake->generator == NULL) {
diff --git a/src/misc.c b/src/misc.c
index 95f00256b..aa86e328f 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -130,6 +130,9 @@ STATIC INLINE void CreateMpint(byte* buf, word32* sz, byte* pad)
         WLOG(WS_LOG_ERROR, "Internal argument error with CreateMpint");
     }
 
+    if (*sz == 0)
+        return;
+
     /* check for leading 0's */
     for (i = 0; i < *sz; i++) {
         if (buf[i] != 0x00)