new file mode 100644
@@ -0,0 +1,65 @@
+From 0adcb34c49bee5b19bd29b16a578c510c23597ea Mon Sep 17 00:00:00 2001
+From: Sebastian Pipping <sebastian@pipping.org>
+Date: Mon, 27 Dec 2021 20:15:02 +0100
+Subject: [PATCH] lib: Detect and prevent troublesome left shifts in function
+ storeAtts (CVE-2021-45960)
+
+Upstream-Status: Backport:
+https://github.com/libexpat/libexpat/pull/534/commits/0adcb34c49bee5b19bd29b16a578c510c23597ea
+
+CVE: CVE-2021-45960
+Signed-off-by: Steve Sakoman <steve@sakoman.com>
+
+---
+ expat/lib/xmlparse.c | 31 +++++++++++++++++++++++++++++--
+ 1 file changed, 29 insertions(+), 2 deletions(-)
+
+diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
+index d730f41c3..b47c31b05 100644
+--- a/lib/xmlparse.c
++++ b/lib/xmlparse.c
+@@ -3414,7 +3414,13 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr,
+ 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)
+@@ -3425,7 +3431,28 @@ storeAtts(XML_Parser parser, const ENCODING *enc, const char *attStr,
+ ;
+ 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) {
@@ -8,6 +8,7 @@ LIC_FILES_CHKSUM = "file://COPYING;md5=5b8620d98e49772d95fc1d291c26aa79"
SRC_URI = "git://github.com/libexpat/libexpat.git;protocol=https;branch=master \
file://CVE-2013-0340.patch \
+ file://CVE-2021-45960.patch \
file://CVE-2022-22822-27.patch \
file://libtool-tag.patch \
"
In Expat (aka libexpat) before 2.4.3, a left shift by 29 (or more) places in the storeAtts function in xmlparse.c can lead to realloc misbehavior (e.g., allocating too few bytes, or only freeing memory). Backport patch from: https://github.com/libexpat/libexpat/pull/534/commits/0adcb34c49bee5b19bd29b16a578c510c23597ea CVE: CVE-2021-45960 Signed-off-by: Steve Sakoman <steve@sakoman.com> --- .../expat/expat/CVE-2021-45960.patch | 65 +++++++++++++++++++ meta/recipes-core/expat/expat_2.2.9.bb | 1 + 2 files changed, 66 insertions(+) create mode 100644 meta/recipes-core/expat/expat/CVE-2021-45960.patch