expat: fix CVE-2022-23852

Expat (aka libexpat) before 2.4.4 has a signed integer overflow in XML_GetBuffer
for configurations with a nonzero XML_CONTEXT_BYTES.

Backport patch from:
https://github.com/libexpat/libexpat/commit/847a645152f5ebc10ac63b74b604d0c1a79fae40

CVE: CVE-2022-23852
(From OE-Core rev: 37b618d44ebd965ba17bb61ddf6428cdaea876e5)

Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 34 insertions, 0 deletions

diff --git a/meta/recipes-core/expat/expat/CVE-2022-23852.patch b/meta/recipes-core/expat/expat/CVE-2022-23852.patch
new file mode 100644
index 0000000000..41425c108b
--- /dev/null
+++ b/meta/recipes-core/expat/expat/CVE-2022-23852.patch
@@ -0,0 +1,33 @@
+From 847a645152f5ebc10ac63b74b604d0c1a79fae40 Mon Sep 17 00:00:00 2001
+From: Samanta Navarro <ferivoz@riseup.net>
+Date: Sat, 22 Jan 2022 17:48:00 +0100
+Subject: [PATCH] lib: Detect and prevent integer overflow in XML_GetBuffer
+ (CVE-2022-23852)
+
+Upstream-Status: Backport:
+https://github.com/libexpat/libexpat/commit/847a645152f5ebc10ac63b74b604d0c1a79fae40
+
+CVE: CVE-2022-23852
+
+Signed-off-by: Steve Sakoman <steve@sakoman.com>
+
+---
+ expat/lib/xmlparse.c | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
+index d54af683..5ce31402 100644
+--- a/lib/xmlparse.c
++++ b/lib/xmlparse.c
+@@ -2067,6 +2067,11 @@ XML_GetBuffer(XML_Parser parser, int len) {
+     keep = (int)EXPAT_SAFE_PTR_DIFF(parser->m_bufferPtr, parser->m_buffer);
+     if (keep > XML_CONTEXT_BYTES)
+       keep = XML_CONTEXT_BYTES;
++    /* Detect and prevent integer overflow */
++    if (keep > INT_MAX - neededSize) {
++      parser->m_errorCode = XML_ERROR_NO_MEMORY;
++      return NULL;
++    }
+     neededSize += keep;
+ #endif /* defined XML_CONTEXT_BYTES */
+     if (neededSize
diff --git a/meta/recipes-core/expat/expat_2.2.9.bb b/meta/recipes-core/expat/expat_2.2.9.bb
index 757c18c5fa..6a6d5c066f 100644
--- a/meta/recipes-core/expat/expat_2.2.9.bb
+++ b/meta/recipes-core/expat/expat_2.2.9.bb
@@ -11,6 +11,7 @@ SRC_URI = "git://github.com/libexpat/libexpat.git;protocol=https;branch=master \
            file://CVE-2021-45960.patch \
            file://CVE-2021-46143.patch \
            file://CVE-2022-22822-27.patch \
+           file://CVE-2022-23852.patch \
            file://libtool-tag.patch \
          "