expat: Fix CVE-2022-43680 for expat

Add a patch to fix CVE-2022-43680 issue where use-after free caused by
overeager destruction of a shared DTD in XML_ExternalEntityParserCreate
in out-of-memory situations
Link: https://nvd.nist.gov/vuln/detail/CVE-2022-43680

(From OE-Core rev: ac4476e6594417b14bfb05a110009ef245f419b0)

Signed-off-by: Ranjitsinh Rathod <ranjitsinh.rathod@kpit.com>
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-2022-43680.patch b/meta/recipes-core/expat/expat/CVE-2022-43680.patch
new file mode 100644
index 0000000000..6f93bc3ed7
--- /dev/null
+++ b/meta/recipes-core/expat/expat/CVE-2022-43680.patch
@@ -0,0 +1,33 @@
+From 5290462a7ea1278a8d5c0d5b2860d4e244f997e4 Mon Sep 17 00:00:00 2001
+From: Sebastian Pipping <sebastian@pipping.org>
+Date: Tue, 20 Sep 2022 02:44:34 +0200
+Subject: [PATCH] lib: Fix overeager DTD destruction in
+ XML_ExternalEntityParserCreate
+
+CVE: CVE-2022-43680
+Upstream-Status: Backport [https://github.com/libexpat/libexpat/commit/5290462a7ea1278a8d5c0d5b2860d4e244f997e4.patch]
+Signed-off-by: Ranjitsinh Rathod <ranjitsinh.rathod@kpit.com>
+Comments: Hunk refreshed
+---
+ lib/xmlparse.c | 8 ++++++++
+ 1 file changed, 8 insertions(+)
+
+diff --git a/lib/xmlparse.c b/lib/xmlparse.c
+index aacd6e7fc..57bf103cc 100644
+--- a/lib/xmlparse.c
++++ b/lib/xmlparse.c
+@@ -1035,6 +1035,14 @@ parserCreate(const XML_Char *encodingNam
+   parserInit(parser, encodingName);
+ 
+   if (encodingName && ! parser->m_protocolEncodingName) {
++    if (dtd) {
++      // We need to stop the upcoming call to XML_ParserFree from happily
++      // destroying parser->m_dtd because the DTD is shared with the parent
++      // parser and the only guard that keeps XML_ParserFree from destroying
++      // parser->m_dtd is parser->m_isParamEntity but it will be set to
++      // XML_TRUE only later in XML_ExternalEntityParserCreate (or not at all).
++      parser->m_dtd = NULL;
++    }
+     XML_ParserFree(parser);
+     return NULL;
+   }
diff --git a/meta/recipes-core/expat/expat_2.2.9.bb b/meta/recipes-core/expat/expat_2.2.9.bb
index 578edfcbff..8a5006e59a 100644
--- a/meta/recipes-core/expat/expat_2.2.9.bb
+++ b/meta/recipes-core/expat/expat_2.2.9.bb
@@ -21,6 +21,7 @@ SRC_URI = "git://github.com/libexpat/libexpat.git;protocol=https;branch=master \
            file://CVE-2022-25315.patch \
            file://libtool-tag.patch \
            file://CVE-2022-40674.patch \
+           file://CVE-2022-43680.patch \
          "
 
 SRCREV = "a7bc26b69768f7fb24f0c7976fae24b157b85b13"