|
 |
463a2a |
From 0adcb34c49bee5b19bd29b16a578c510c23597ea Mon Sep 17 00:00:00 2001
|
|
|
463a2a |
From: Sebastian Pipping <sebastian@pipping.org>
|
|
|
463a2a |
Date: Mon, 27 Dec 2021 20:15:02 +0100
|
|
|
463a2a |
Subject: [PATCH] lib: Detect and prevent troublesome left shifts in function
|
|
|
463a2a |
storeAtts (CVE-2021-45960)
|
|
|
463a2a |
|
|
|
463a2a |
---
|
|
|
463a2a |
expat/lib/xmlparse.c | 31 +++++++++++++++++++++++++++++--
|
|
|
463a2a |
1 file changed, 29 insertions(+), 2 deletions(-)
|
|
|
463a2a |
|
|
|
463a2a |
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
|
|
|
463a2a |
index d730f41c3..b47c31b05 100644
|
|
|
463a2a |
--- a/lib/xmlparse.c
|
|
|
463a2a |
+++ b/lib/xmlparse.c
|
|
|
463a2a |
@@ -3414,7 +3414,13 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr,
|
|
|
463a2a |
if (nPrefixes) {
|
|
|
463a2a |
int j; /* hash table index */
|
|
|
463a2a |
unsigned long version = parser->m_nsAttsVersion;
|
|
|
463a2a |
- int nsAttsSize = (int)1 << parser->m_nsAttsPower;
|
|
|
463a2a |
+
|
|
|
463a2a |
+ /* Detect and prevent invalid shift */
|
|
|
463a2a |
+ if (parser->m_nsAttsPower >= sizeof(unsigned int) * 8 /* bits per byte */) {
|
|
|
463a2a |
+ return XML_ERROR_NO_MEMORY;
|
|
|
463a2a |
+ }
|
|
|
463a2a |
+
|
|
|
463a2a |
+ unsigned int nsAttsSize = 1u << parser->m_nsAttsPower;
|
|
|
463a2a |
unsigned char oldNsAttsPower = parser->m_nsAttsPower;
|
|
|
463a2a |
/* size of hash table must be at least 2 * (# of prefixed attributes) */
|
|
|
463a2a |
if ((nPrefixes << 1)
|
|
|
463a2a |
@@ -3425,7 +3431,28 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr,
|
|
|
463a2a |
;
|
|
|
463a2a |
if (parser->m_nsAttsPower < 3)
|
|
|
463a2a |
parser->m_nsAttsPower = 3;
|
|
|
463a2a |
- nsAttsSize = (int)1 << parser->m_nsAttsPower;
|
|
|
463a2a |
+
|
|
|
463a2a |
+ /* Detect and prevent invalid shift */
|
|
|
463a2a |
+ if (parser->m_nsAttsPower >= sizeof(nsAttsSize) * 8 /* bits per byte */) {
|
|
|
463a2a |
+ /* Restore actual size of memory in m_nsAtts */
|
|
|
463a2a |
+ parser->m_nsAttsPower = oldNsAttsPower;
|
|
|
463a2a |
+ return XML_ERROR_NO_MEMORY;
|
|
|
463a2a |
+ }
|
|
|
463a2a |
+
|
|
|
463a2a |
+ nsAttsSize = 1u << parser->m_nsAttsPower;
|
|
|
463a2a |
+
|
|
|
463a2a |
+ /* Detect and prevent integer overflow.
|
|
|
463a2a |
+ * The preprocessor guard addresses the "always false" warning
|
|
|
463a2a |
+ * from -Wtype-limits on platforms where
|
|
|
463a2a |
+ * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
|
|
|
463a2a |
+#if UINT_MAX >= SIZE_MAX
|
|
|
463a2a |
+ if (nsAttsSize > (size_t)(-1) / sizeof(NS_ATT)) {
|
|
|
463a2a |
+ /* Restore actual size of memory in m_nsAtts */
|
|
|
463a2a |
+ parser->m_nsAttsPower = oldNsAttsPower;
|
|
|
463a2a |
+ return XML_ERROR_NO_MEMORY;
|
|
|
463a2a |
+ }
|
|
|
463a2a |
+#endif
|
|
|
463a2a |
+
|
|
|
463a2a |
temp = (NS_ATT *)REALLOC(parser, parser->m_nsAtts,
|
|
|
463a2a |
nsAttsSize * sizeof(NS_ATT));
|
|
|
463a2a |
if (! temp) {
|