expat: fix CVE-2022-23990

Expat (aka libexpat) before 2.4.4 has an integer overflow in the
doProlog function.

Backport patch from:

https://github.com/libexpat/libexpat/pull/551/commits/ede41d1e186ed2aba88a06e84cac839b770af3a1

CVE: CVE-2021-23990
(From OE-Core rev: 6a0c9607656970c669ff12cdafd39f4fb7082f6c)

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

2 files changed, 50 insertions, 0 deletions

diff --git a/meta/recipes-core/expat/expat/CVE-2022-23990.patch b/meta/recipes-core/expat/expat/CVE-2022-23990.patch
new file mode 100644
index 0000000000..c599517b3e
--- /dev/null
+++ b/meta/recipes-core/expat/expat/CVE-2022-23990.patch
@@ -0,0 +1,49 @@
+From ede41d1e186ed2aba88a06e84cac839b770af3a1 Mon Sep 17 00:00:00 2001
+From: Sebastian Pipping <sebastian@pipping.org>
+Date: Wed, 26 Jan 2022 02:36:43 +0100
+Subject: [PATCH] lib: Prevent integer overflow in doProlog (CVE-2022-23990)
+
+The change from "int nameLen" to "size_t nameLen"
+addresses the overflow on "nameLen++" in code
+"for (; name[nameLen++];)" right above the second
+change in the patch.
+
+Upstream-Status: Backport:
+https://github.com/libexpat/libexpat/pull/551/commits/ede41d1e186ed2aba88a06e84cac839b770af3a1
+
+CVE: CVE-2022-23990
+
+Signed-off-by: Steve Sakoman <steve@sakoman.com>
+
+---
+ lib/xmlparse.c | 10 ++++++++--
+ 1 file changed, 8 insertions(+), 2 deletions(-)
+
+diff --git a/lib/xmlparse.c b/expat/lib/xmlparse.c
+index 5ce31402..d1d17005 100644
+--- a/lib/xmlparse.c
++++ b/lib/xmlparse.c
+@@ -5372,7 +5372,7 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
+       if (dtd->in_eldecl) {
+         ELEMENT_TYPE *el;
+         const XML_Char *name;
+-        int nameLen;
++        size_t nameLen;
+         const char *nxt
+             = (quant == XML_CQUANT_NONE ? next : next - enc->minBytesPerChar);
+         int myindex = nextScaffoldPart(parser);
+@@ -5388,7 +5388,13 @@ doProlog(XML_Parser parser, const ENCODING *enc, const char *s, const char *end,
+         nameLen = 0;
+         for (; name[nameLen++];)
+           ;
+-        dtd->contentStringLen += nameLen;
++
++        /* Detect and prevent integer overflow */
++        if (nameLen > UINT_MAX - dtd->contentStringLen) {
++          return XML_ERROR_NO_MEMORY;
++        }
++
++        dtd->contentStringLen += (unsigned)nameLen;
+         if (parser->m_elementDeclHandler)
+           handleDefault = XML_FALSE;
+       }
diff --git a/meta/recipes-core/expat/expat_2.2.9.bb b/meta/recipes-core/expat/expat_2.2.9.bb
index 6a6d5c066f..4c86f90ef1 100644
--- a/meta/recipes-core/expat/expat_2.2.9.bb
+++ b/meta/recipes-core/expat/expat_2.2.9.bb
@@ -12,6 +12,7 @@ SRC_URI = "git://github.com/libexpat/libexpat.git;protocol=https;branch=master \
            file://CVE-2021-46143.patch \
            file://CVE-2022-22822-27.patch \
            file://CVE-2022-23852.patch \
+           file://CVE-2022-23990.patch \
            file://libtool-tag.patch \
          "