expat: backport the fix for CVE-2022-43680

(From OE-Core rev: 791fe354e5887af3fa3d3f772fafacc5eaedca21)

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

meta/recipes-core/expat/expat/CVE-2022-43680.patch

@@ -0,0 +1,33 @@
+CVE: CVE-2022-43680
+Upstream-Status: Backport [5290462a7ea1278a8d5c0d5b2860d4e244f997e4]
+Signed-off-by: Ross Burton <ross.burton@arm.com>
+
+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
+
+---
+ expat/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
+@@ -1068,6 +1068,14 @@ parserCreate(const XML_Char *encodingName,
+   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;
+   }

meta/recipes-core/expat/expat_2.4.9.bb

@@ -9,6 +9,7 @@ LIC_FILES_CHKSUM = "file://COPYING;md5=7b3b078238d0901d3b339289117cb7fb"
 VERSION_TAG = "${@d.getVar('PV').replace('.', '_')}"
 
 SRC_URI = "https://github.com/libexpat/libexpat/releases/download/R_${VERSION_TAG}/expat-${PV}.tar.bz2  \
+           file://CVE-2022-43680.patch \
            file://run-ptest \
            "