From a1257429bdebb58ffef2eb0ff99952e08c927ca2 Mon Sep 17 00:00:00 2001
From: Guido Vranken <guidovranken@gmail.com>
Date: Sun, 6 Jun 2021 03:54:15 +0200
Subject: [PATCH] Improve checking of XSNPRINTF return value in DecodePolicyOID

---
 wolfcrypt/src/asn.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/wolfcrypt/src/asn.c b/wolfcrypt/src/asn.c
index 9df7aaa3d..c0ee6c73e 100644
--- a/wolfcrypt/src/asn.c
+++ b/wolfcrypt/src/asn.c
@@ -8887,7 +8887,7 @@ int DecodePolicyOID(char *out, word32 outSz, const byte *in, word32 inSz)
             /* write val as text into out */
             val += in[inIdx];
             w = XSNPRINTF(out + outIdx, outSz - outIdx, ".%u", val);
-            if (w < 0)
+            if (w < 0 || (word32)w > outSz - outIdx)
                 goto exit;
             outIdx += w;
             val = 0;