From 8b9afbc0fc7f8be0049d389d34d9416fa377e2aa Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Fri, 5 Aug 2016 14:33:03 +0100
Subject: [PATCH] Check for errors in a2d_ASN1_OBJECT()

Check for error return in BN_div_word().

Reviewed-by: Tim Hudson <tjh@openssl.org>
---
 crypto/asn1/a_object.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/crypto/asn1/a_object.c b/crypto/asn1/a_object.c
index 6fc7681c23..79f0ecd2a8 100644
--- a/crypto/asn1/a_object.c
+++ b/crypto/asn1/a_object.c
@@ -127,8 +127,12 @@ int a2d_ASN1_OBJECT(unsigned char *out, int olen, const char *buf, int num)
                 if (tmp == NULL)
                     goto err;
             }
-            while (blsize--)
-                tmp[i++] = (unsigned char)BN_div_word(bl, 0x80L);
+            while (blsize--) {
+                BN_ULONG t = BN_div_word(bl, 0x80L);
+                if (t == (BN_ULONG)-1)
+                    goto err;
+                tmp[i++] = (unsigned char)t;
+            }
         } else {
 
             for (;;) {