From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Mon, 19 Aug 2024 22:34:13 +0200
Subject: [PATCH] lib: Detect integer overflow in dtdCopy
Reported by TaiYou
---
lib/xmlparse.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index 3dc9673b..158cb4ea 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -6616,6 +6616,16 @@ dtdCopy(XML_Parser oldParser, DTD *newDtd, const DTD *oldDtd, const XML_Memory_H
if (!newE)
return 0;
if (oldE->nDefaultAtts) {
+ /* Detect and prevent integer overflow.
+ * The preprocessor guard addresses the "always false" warning
+ * from -Wtype-limits on platforms where
+ * sizeof(int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+ if ((size_t)oldE->nDefaultAtts
+ > ((size_t)(-1) / sizeof(DEFAULT_ATTRIBUTE))) {
+ return 0;
+ }
+#endif
newE->defaultAtts = (DEFAULT_ATTRIBUTE *)
ms->malloc_fcn(oldE->nDefaultAtts * sizeof(DEFAULT_ATTRIBUTE));
if (!newE->defaultAtts) {