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expat/SOURCES/expat-2.2.5-Detect-and-prev...

55 lines
2.1 KiB

commit dbac77ddbccb23d507758c591fad622e2b6e6324
Author: Tomas Korbar <tkorbar@redhat.com>
Date: Mon Feb 14 12:20:25 2022 +0100
CVE-2021-45960
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index 2821c6f..c45be0c 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -3341,7 +3341,12 @@ storeAtts(XML_Parser parser, const ENCODING *enc,
if (nPrefixes) {
int j; /* hash table index */
unsigned long version = parser->m_nsAttsVersion;
- int nsAttsSize = (int)1 << parser->m_nsAttsPower;
+ /* Detect and prevent invalid shift */
+ if (parser->m_nsAttsPower >= sizeof(unsigned int) * 8 /* bits per byte */) {
+ return XML_ERROR_NO_MEMORY;
+ }
+
+ unsigned int nsAttsSize = 1u << parser->m_nsAttsPower;
unsigned char oldNsAttsPower = parser->m_nsAttsPower;
/* size of hash table must be at least 2 * (# of prefixed attributes) */
if ((nPrefixes << 1) >> parser->m_nsAttsPower) { /* true for m_nsAttsPower = 0 */
@@ -3350,7 +3355,28 @@ storeAtts(XML_Parser parser, const ENCODING *enc,
while (nPrefixes >> parser->m_nsAttsPower++);
if (parser->m_nsAttsPower < 3)
parser->m_nsAttsPower = 3;
- nsAttsSize = (int)1 << parser->m_nsAttsPower;
+
+ /* Detect and prevent invalid shift */
+ if (parser->m_nsAttsPower >= sizeof(nsAttsSize) * 8 /* bits per byte */) {
+ /* Restore actual size of memory in m_nsAtts */
+ parser->m_nsAttsPower = oldNsAttsPower;
+ return XML_ERROR_NO_MEMORY;
+ }
+
+ nsAttsSize = 1u << parser->m_nsAttsPower;
+
+ /* 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 (nsAttsSize > (size_t)(-1) / sizeof(NS_ATT)) {
+ /* Restore actual size of memory in m_nsAtts */
+ parser->m_nsAttsPower = oldNsAttsPower;
+ return XML_ERROR_NO_MEMORY;
+ }
+#endif
+
temp = (NS_ATT *)REALLOC(parser, parser->m_nsAtts, nsAttsSize * sizeof(NS_ATT));
if (!temp) {
/* Restore actual size of memory in m_nsAtts */