From 9bf0f2c16ee86f644dd1432507edff94c08dc232 Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Mon, 19 Aug 2024 22:37:16 +0200
Subject: [PATCH] lib: Detect integer overflow in function nextScaffoldPart

Reported by TaiYou
---
 expat/lib/xmlparse.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
index 91682c188..f737575ea 100644
--- a/expat/lib/xmlparse.c
+++ b/expat/lib/xmlparse.c
@@ -7558,6 +7558,15 @@ nextScaffoldPart(XML_Parser parser) {
   int next;
 
   if (! dtd->scaffIndex) {
+    /* Detect and prevent integer overflow.
+     * The preprocessor guard addresses the "always false" warning
+     * from -Wtype-limits on platforms where
+     * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+    if (parser->m_groupSize > ((size_t)(-1) / sizeof(int))) {
+      return -1;
+    }
+#endif
     dtd->scaffIndex = (int *)MALLOC(parser, parser->m_groupSize * sizeof(int));
     if (! dtd->scaffIndex)
       return -1;