From fc06a529a3283c9b0ec5e253e98f4c23d3b9caa8 Mon Sep 17 00:00:00 2001
From: Rhodri James <rhodri@kynesim.co.uk>
Date: Tue, 6 Jun 2017 17:54:32 +0100
Subject: [PATCH] Reject multi-byte encodings with no converter function.

Not supplying a character encoding convert function when one was
needed previously caused a segfault if a multi-byte character was
encountered.  This errors at the start of parse instead.
---
 expat/lib/xmltok.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/expat/lib/xmltok.c b/expat/lib/xmltok.c
index ebcc05b9..07b5d8fc 100644
--- a/expat/lib/xmltok.c
+++ b/expat/lib/xmltok.c
@@ -1469,6 +1469,9 @@ XmlInitUnknownEncoding(void *mem,
     else if (c < 0) {
       if (c < -4)
         return 0;
+      /* Multi-byte sequences need a converter function */
+      if (!convert)
+        return 0;
       e->normal.type[i] = (unsigned char)(BT_LEAD2 - (c + 2));
       e->utf8[i][0] = 0;
       e->utf16[i] = 0;