libxml2: Fix CVE-2022-40304

Fix dict corruption caused by entity reference cycles

Link: https://gitlab.gnome.org/GNOME/libxml2/-/commit/1b41ec4e9433b05bb0376be4725804c54ef1d80b

Upstream-Status: Pending

Signed-off-by: Bhabu Bindu <bhabu.bindu@kpit.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

2 files changed, 105 insertions, 0 deletions

diff --git a/meta/recipes-core/libxml/libxml2/CVE-2022-40304.patch b/meta/recipes-core/libxml/libxml2/CVE-2022-40304.patch
new file mode 100644
index 0000000000..c19726fe9f
--- /dev/null
+++ b/meta/recipes-core/libxml/libxml2/CVE-2022-40304.patch
@@ -0,0 +1,104 @@
+From 1b41ec4e9433b05bb0376be4725804c54ef1d80b Mon Sep 17 00:00:00 2001
+From: Nick Wellnhofer <wellnhofer@aevum.de>
+Date: Wed, 31 Aug 2022 22:11:25 +0200
+Subject: [PATCH] [CVE-2022-40304] Fix dict corruption caused by entity
+ reference cycles
+
+When an entity reference cycle is detected, the entity content is
+cleared by setting its first byte to zero. But the entity content might
+be allocated from a dict. In this case, the dict entry becomes corrupted
+leading to all kinds of logic errors, including memory errors like
+double-frees.
+
+Stop storing entity content, orig, ExternalID and SystemID in a dict.
+These values are unlikely to occur multiple times in a document, so they
+shouldn't have been stored in a dict in the first place.
+
+Thanks to Ned Williamson and Nathan Wachholz working with Google Project
+Zero for the report!
+
+CVE: CVE-2022-40304
+Upstream-Status: Backport [https://gitlab.gnome.org/GNOME/libxml2/-/commit/1b41ec4e9433b05bb0376be4725804c54ef1d80b]
+Signed-off-by: Bhabu Bindu <bhabu.bindu@kpit.com>
+---
+ entities.c | 55 ++++++++++++++++--------------------------------------
+ 1 file changed, 16 insertions(+), 39 deletions(-)
+
+diff --git a/entities.c b/entities.c
+index 84435515..d4e5412e 100644
+--- a/entities.c
++++ b/entities.c
+@@ -128,36 +128,19 @@ xmlFreeEntity(xmlEntityPtr entity)
+     if ((entity->children) && (entity->owner == 1) &&
+         (entity == (xmlEntityPtr) entity->children->parent))
+         xmlFreeNodeList(entity->children);
+-    if (dict != NULL) {
+-        if ((entity->name != NULL) && (!xmlDictOwns(dict, entity->name)))
+-            xmlFree((char *) entity->name);
+-        if ((entity->ExternalID != NULL) &&
+-	    (!xmlDictOwns(dict, entity->ExternalID)))
+-            xmlFree((char *) entity->ExternalID);
+-        if ((entity->SystemID != NULL) &&
+-	    (!xmlDictOwns(dict, entity->SystemID)))
+-            xmlFree((char *) entity->SystemID);
+-        if ((entity->URI != NULL) && (!xmlDictOwns(dict, entity->URI)))
+-            xmlFree((char *) entity->URI);
+-        if ((entity->content != NULL)
+-            && (!xmlDictOwns(dict, entity->content)))
+-            xmlFree((char *) entity->content);
+-        if ((entity->orig != NULL) && (!xmlDictOwns(dict, entity->orig)))
+-            xmlFree((char *) entity->orig);
+-    } else {
+-        if (entity->name != NULL)
+-            xmlFree((char *) entity->name);
+-        if (entity->ExternalID != NULL)
+-            xmlFree((char *) entity->ExternalID);
+-        if (entity->SystemID != NULL)
+-            xmlFree((char *) entity->SystemID);
+-        if (entity->URI != NULL)
+-            xmlFree((char *) entity->URI);
+-        if (entity->content != NULL)
+-            xmlFree((char *) entity->content);
+-        if (entity->orig != NULL)
+-            xmlFree((char *) entity->orig);
+-    }
++    if ((entity->name != NULL) &&
++        ((dict == NULL) || (!xmlDictOwns(dict, entity->name))))
++        xmlFree((char *) entity->name);
++    if (entity->ExternalID != NULL)
++        xmlFree((char *) entity->ExternalID);
++    if (entity->SystemID != NULL)
++        xmlFree((char *) entity->SystemID);
++    if (entity->URI != NULL)
++        xmlFree((char *) entity->URI);
++    if (entity->content != NULL)
++        xmlFree((char *) entity->content);
++    if (entity->orig != NULL)
++        xmlFree((char *) entity->orig);
+     xmlFree(entity);
+ }
+ 
+@@ -193,18 +176,12 @@ xmlCreateEntity(xmlDictPtr dict, const xmlChar *name, int type,
+ 	    ret->SystemID = xmlStrdup(SystemID);
+     } else {
+         ret->name = xmlDictLookup(dict, name, -1);
+-	if (ExternalID != NULL)
+-	    ret->ExternalID = xmlDictLookup(dict, ExternalID, -1);
+-	if (SystemID != NULL)
+-	    ret->SystemID = xmlDictLookup(dict, SystemID, -1);
++	ret->ExternalID = xmlStrdup(ExternalID);
++	ret->SystemID = xmlStrdup(SystemID);
+     }
+     if (content != NULL) {
+         ret->length = xmlStrlen(content);
+-	if ((dict != NULL) && (ret->length < 5))
+-	    ret->content = (xmlChar *)
+-	                   xmlDictLookup(dict, content, ret->length);
+-	else
+-	    ret->content = xmlStrndup(content, ret->length);
++	ret->content = xmlStrndup(content, ret->length);
+      } else {
+         ret->length = 0;
+         ret->content = NULL;
+-- 
+GitLab
diff --git a/meta/recipes-core/libxml/libxml2_2.9.10.bb b/meta/recipes-core/libxml/libxml2_2.9.10.bb
index 39036f2688..40e3434ead 100644
--- a/meta/recipes-core/libxml/libxml2_2.9.10.bb
+++ b/meta/recipes-core/libxml/libxml2_2.9.10.bb
@@ -35,6 +35,7 @@ SRC_URI += "http://www.w3.org/XML/Test/xmlts20080827.tar.gz;subdir=${BP};name=te
            file://0001-Port-gentest.py-to-Python-3.patch \
            file://CVE-2016-3709.patch \
            file://CVE-2022-40303.patch \
+           file://CVE-2022-40304.patch \
            "
 
 SRC_URI[archive.sha256sum] = "593b7b751dd18c2d6abcd0c4bcb29efc203d0b4373a6df98e3a455ea74ae2813"