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From 85ae9a2d7d0e9358f356b33977b842df8ebaec2b Mon Sep 17 00:00:00 2001
From: Sebastian Pipping <sebastian@pipping.org>
Date: Sat, 25 Dec 2021 20:52:08 +0100
Subject: [PATCH] lib: Prevent integer overflow on m_groupSize in function
doProlog (CVE-2021-46143)
Upstream-Status: Backport:
https://github.com/libexpat/libexpat/pull/538/commits/85ae9a2d7d0e9358f356b33977b842df8ebaec2b
CVE: CVE-2021-46143
Signed-off-by: Steve Sakoman <steve@sakoman.com>
---
expat/lib/xmlparse.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
index b47c31b0..8f243126 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -5046,6 +5046,11 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
if (parser->m_prologState.level >= parser->m_groupSize) {
if (parser->m_groupSize) {
{
+ /* Detect and prevent integer overflow */
+ if (parser->m_groupSize > (unsigned int)(-1) / 2u) {
+ return XML_ERROR_NO_MEMORY;
+ }
+
char *const new_connector = (char *)REALLOC(
parser, parser->m_groupConnector, parser->m_groupSize *= 2);
if (new_connector == NULL) {
@@ -5056,6 +5061,16 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
}
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 XML_ERROR_NO_MEMORY;
+ }
+#endif
+
int *const new_scaff_index = (int *)REALLOC(
parser, dtd->scaffIndex, parser->m_groupSize * sizeof(int));
if (new_scaff_index == NULL)
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