From c5e603ee182b40ede7713c6e229c15a8f3fdb58a Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Mon, 2 May 2016 17:33:50 +0100
Subject: [PATCH] Fix i2d_X509_AUX: pp can be NULL.
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Reported by David Benjamin

Reviewed-by: Emilia Käsper <emilia@openssl.org>
(cherry picked from commit 05aef4bbdbc18e7b9490512cdee41e8a608bcc0e)
---
 crypto/asn1/x_x509.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/crypto/asn1/x_x509.c b/crypto/asn1/x_x509.c
index ccdf6dfe13..e31e1e750d 100644
--- a/crypto/asn1/x_x509.c
+++ b/crypto/asn1/x_x509.c
@@ -202,14 +202,15 @@ X509 *d2i_X509_AUX(X509 **a, const unsigned char **pp, long length)
 int i2d_X509_AUX(X509 *a, unsigned char **pp)
 {
     int length, tmplen;
-    unsigned char *start = *pp;
+    unsigned char *start = pp != NULL ? *pp : NULL;
     length = i2d_X509(a, pp);
     if (length < 0 || a == NULL)
         return length;
 
     tmplen = i2d_X509_CERT_AUX(a->aux, pp);
     if (tmplen < 0) {
-        *pp = start;
+        if (start != NULL)
+            *pp = start;
         return tmplen;
     }
     length += tmplen;