From 5c1a31642e243f4870c0bd1f2afc7597976521bf Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Mon, 19 Aug 2024 22:26:07 +0200
Subject: [PATCH 1/3] lib: Reject negative len for XML_ParseBuffer

Reported by TaiYou
---
 expat/lib/xmlparse.c | 6 ++++++
 1 file changed, 6 insertions(+)

Index: expat-2.5.0/lib/xmlparse.c
===================================================================
--- expat-2.5.0.orig/lib/xmlparse.c
+++ expat-2.5.0/lib/xmlparse.c
@@ -1985,6 +1985,12 @@ XML_ParseBuffer(XML_Parser parser, int l
 
   if (parser == NULL)
     return XML_STATUS_ERROR;
+
+  if (len < 0) {
+    parser->m_errorCode = XML_ERROR_INVALID_ARGUMENT;
+    return XML_STATUS_ERROR;
+  }
+
   switch (parser->m_parsingStatus.parsing) {
   case XML_SUSPENDED:
     parser->m_errorCode = XML_ERROR_SUSPENDED;
Index: expat-2.5.0/doc/reference.html
===================================================================
--- expat-2.5.0.orig/doc/reference.html
+++ expat-2.5.0/doc/reference.html
@@ -1097,7 +1097,9 @@ containing part (or perhaps all) of the
 that are part of the document is indicated by <code>len</code>. This means
 that <code>s</code> doesn't have to be null terminated. It also means that
 if <code>len</code> is larger than the number of bytes in the block of
-memory that <code>s</code> points at, then a memory fault is likely. The
+memory that <code>s</code> points at, then a memory fault is likely.
+Negative values for <code>len</code> are rejected since Expat 2.2.1.
+The
 <code>isFinal</code> parameter informs the parser that this is the last
 piece of the document. Frequently, the last piece is empty (i.e.
 <code>len</code> is zero.)
@@ -1113,11 +1115,17 @@ XML_ParseBuffer(XML_Parser p,
                 int isFinal);
 </pre>
 <div class="fcndef">
+<p>
 This is just like <code><a href= "#XML_Parse" >XML_Parse</a></code>,
 except in this case Expat provides the buffer.  By obtaining the
 buffer from Expat with the <code><a href= "#XML_GetBuffer"
 >XML_GetBuffer</a></code> function, the application can avoid double
 copying of the input.
+</p>
+
+<p>
+Negative values for <code>len</code> are rejected since Expat 2.6.3.
+</p>
 </div>
 
 <h4 id="XML_GetBuffer">XML_GetBuffer</h4>