libxml2: fix CVE-2016-4658 Disallow namespace nodes in XPointer points and ranges

Namespace nodes must be copied to avoid use-after-free errors.
But they don't necessarily have a physical representation in a
document, so simply disallow them in XPointer ranges.

Signed-off-by: Andrej Valek <andrej.valek@siemens.com>
Signed-off-by: Pascal Bach <pascal.bach@siemens.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>

2 files changed, 270 insertions, 0 deletions

diff --git a/meta/recipes-core/libxml/libxml2/libxml2-CVE-2016-4658.patch b/meta/recipes-core/libxml/libxml2/libxml2-CVE-2016-4658.patch
new file mode 100644
index 0000000000..5412e8c02a
--- /dev/null
+++ b/meta/recipes-core/libxml/libxml2/libxml2-CVE-2016-4658.patch
@@ -0,0 +1,269 @@
+libxml2-2.9.4: Fix CVE-2016-4658
+
+[No upstream tracking] -- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2016-4658
+
+xpointer: Disallow namespace nodes in XPointer points and ranges
+
+Namespace nodes must be copied to avoid use-after-free errors.
+But they don't necessarily have a physical representation in a
+document, so simply disallow them in XPointer ranges.
+
+Upstream-Status: Backported 
+ - [https://git.gnome.org/browse/libxml2/commit/?id=c1d1f7121194036608bf555f08d3062a36fd344b]
+ - [https://git.gnome.org/browse/libxml2/commit/?id=3f8a91036d338e51c059d54397a42d645f019c65]
+CVE: CVE-2016-4658
+Signed-off-by: Andrej Valek <andrej.valek@siemens.com>
+Signed-off-by: Pascal Bach <pascal.bach@siemens.com>
+
+diff --git a/xpointer.c b/xpointer.c
+index 676c510..911680d 100644
+--- a/xpointer.c
++++ b/xpointer.c
+@@ -320,6 +320,45 @@ xmlXPtrRangesEqual(xmlXPathObjectPtr range1, xmlXPathObjectPtr range2) {
+ }
+ 
+ /**
++ * xmlXPtrNewRangeInternal:
++ * @start:  the starting node
++ * @startindex:  the start index
++ * @end:  the ending point
++ * @endindex:  the ending index
++ *
++ * Internal function to create a new xmlXPathObjectPtr of type range
++ *
++ * Returns the newly created object.
++ */
++static xmlXPathObjectPtr
++xmlXPtrNewRangeInternal(xmlNodePtr start, int startindex,
++                        xmlNodePtr end, int endindex) {
++    xmlXPathObjectPtr ret;
++
++    /*
++     * Namespace nodes must be copied (see xmlXPathNodeSetDupNs).
++     * Disallow them for now.
++     */
++    if ((start != NULL) && (start->type == XML_NAMESPACE_DECL))
++	return(NULL);
++    if ((end != NULL) && (end->type == XML_NAMESPACE_DECL))
++	return(NULL);
++
++    ret = (xmlXPathObjectPtr) xmlMalloc(sizeof(xmlXPathObject));
++    if (ret == NULL) {
++        xmlXPtrErrMemory("allocating range");
++	return(NULL);
++    }
++    memset(ret, 0, sizeof(xmlXPathObject));
++    ret->type = XPATH_RANGE;
++    ret->user = start;
++    ret->index = startindex;
++    ret->user2 = end;
++    ret->index2 = endindex;
++    return(ret);
++}
++
++/**
+  * xmlXPtrNewRange:
+  * @start:  the starting node
+  * @startindex:  the start index
+@@ -344,17 +383,7 @@ xmlXPtrNewRange(xmlNodePtr start, int startindex,
+     if (endindex < 0)
+ 	return(NULL);
+ 
+-    ret = (xmlXPathObjectPtr) xmlMalloc(sizeof(xmlXPathObject));
+-    if (ret == NULL) {
+-        xmlXPtrErrMemory("allocating range");
+-	return(NULL);
+-    }
+-    memset(ret, 0 , (size_t) sizeof(xmlXPathObject));
+-    ret->type = XPATH_RANGE;
+-    ret->user = start;
+-    ret->index = startindex;
+-    ret->user2 = end;
+-    ret->index2 = endindex;
++    ret = xmlXPtrNewRangeInternal(start, startindex, end, endindex);
+     xmlXPtrRangeCheckOrder(ret);
+     return(ret);
+ }
+@@ -381,17 +410,8 @@ xmlXPtrNewRangePoints(xmlXPathObjectPtr start, xmlXPathObjectPtr end) {
+     if (end->type != XPATH_POINT)
+ 	return(NULL);
+ 
+-    ret = (xmlXPathObjectPtr) xmlMalloc(sizeof(xmlXPathObject));
+-    if (ret == NULL) {
+-        xmlXPtrErrMemory("allocating range");
+-	return(NULL);
+-    }
+-    memset(ret, 0 , (size_t) sizeof(xmlXPathObject));
+-    ret->type = XPATH_RANGE;
+-    ret->user = start->user;
+-    ret->index = start->index;
+-    ret->user2 = end->user;
+-    ret->index2 = end->index;
++    ret = xmlXPtrNewRangeInternal(start->user, start->index, end->user,
++				  end->index);
+     xmlXPtrRangeCheckOrder(ret);
+     return(ret);
+ }
+@@ -416,17 +436,7 @@ xmlXPtrNewRangePointNode(xmlXPathObjectPtr start, xmlNodePtr end) {
+     if (start->type != XPATH_POINT)
+ 	return(NULL);
+ 
+-    ret = (xmlXPathObjectPtr) xmlMalloc(sizeof(xmlXPathObject));
+-    if (ret == NULL) {
+-        xmlXPtrErrMemory("allocating range");
+-	return(NULL);
+-    }
+-    memset(ret, 0 , (size_t) sizeof(xmlXPathObject));
+-    ret->type = XPATH_RANGE;
+-    ret->user = start->user;
+-    ret->index = start->index;
+-    ret->user2 = end;
+-    ret->index2 = -1;
++    ret = xmlXPtrNewRangeInternal(start->user, start->index, end, -1);
+     xmlXPtrRangeCheckOrder(ret);
+     return(ret);
+ }
+@@ -453,17 +463,7 @@ xmlXPtrNewRangeNodePoint(xmlNodePtr start, xmlXPathObjectPtr end) {
+     if (end->type != XPATH_POINT)
+ 	return(NULL);
+ 
+-    ret = (xmlXPathObjectPtr) xmlMalloc(sizeof(xmlXPathObject));
+-    if (ret == NULL) {
+-        xmlXPtrErrMemory("allocating range");
+-	return(NULL);
+-    }
+-    memset(ret, 0 , (size_t) sizeof(xmlXPathObject));
+-    ret->type = XPATH_RANGE;
+-    ret->user = start;
+-    ret->index = -1;
+-    ret->user2 = end->user;
+-    ret->index2 = end->index;
++    ret = xmlXPtrNewRangeInternal(start, -1, end->user, end->index);
+     xmlXPtrRangeCheckOrder(ret);
+     return(ret);
+ }
+@@ -486,17 +486,7 @@ xmlXPtrNewRangeNodes(xmlNodePtr start, xmlNodePtr end) {
+     if (end == NULL)
+ 	return(NULL);
+ 
+-    ret = (xmlXPathObjectPtr) xmlMalloc(sizeof(xmlXPathObject));
+-    if (ret == NULL) {
+-        xmlXPtrErrMemory("allocating range");
+-	return(NULL);
+-    }
+-    memset(ret, 0 , (size_t) sizeof(xmlXPathObject));
+-    ret->type = XPATH_RANGE;
+-    ret->user = start;
+-    ret->index = -1;
+-    ret->user2 = end;
+-    ret->index2 = -1;
++    ret = xmlXPtrNewRangeInternal(start, -1, end, -1);
+     xmlXPtrRangeCheckOrder(ret);
+     return(ret);
+ }
+@@ -516,17 +506,7 @@ xmlXPtrNewCollapsedRange(xmlNodePtr start) {
+     if (start == NULL)
+ 	return(NULL);
+ 
+-    ret = (xmlXPathObjectPtr) xmlMalloc(sizeof(xmlXPathObject));
+-    if (ret == NULL) {
+-        xmlXPtrErrMemory("allocating range");
+-	return(NULL);
+-    }
+-    memset(ret, 0 , (size_t) sizeof(xmlXPathObject));
+-    ret->type = XPATH_RANGE;
+-    ret->user = start;
+-    ret->index = -1;
+-    ret->user2 = NULL;
+-    ret->index2 = -1;
++    ret = xmlXPtrNewRangeInternal(start, -1, NULL, -1);
+     return(ret);
+ }
+ 
+@@ -541,6 +521,8 @@ xmlXPtrNewCollapsedRange(xmlNodePtr start) {
+  */
+ xmlXPathObjectPtr
+ xmlXPtrNewRangeNodeObject(xmlNodePtr start, xmlXPathObjectPtr end) {
++    xmlNodePtr endNode;
++    int endIndex;
+     xmlXPathObjectPtr ret;
+ 
+     if (start == NULL)
+@@ -549,7 +531,12 @@ xmlXPtrNewRangeNodeObject(xmlNodePtr start, xmlXPathObjectPtr end) {
+ 	return(NULL);
+     switch (end->type) {
+ 	case XPATH_POINT:
++	    endNode = end->user;
++	    endIndex = end->index;
++	    break;
+ 	case XPATH_RANGE:
++	    endNode = end->user2;
++	    endIndex = end->index2;
+ 	    break;
+ 	case XPATH_NODESET:
+ 	    /*
+@@ -557,39 +544,15 @@ xmlXPtrNewRangeNodeObject(xmlNodePtr start, xmlXPathObjectPtr end) {
+ 	     */
+ 	    if (end->nodesetval->nodeNr <= 0)
+ 		return(NULL);
++	    endNode = end->nodesetval->nodeTab[end->nodesetval->nodeNr - 1];
++	    endIndex = -1;
+ 	    break;
+ 	default:
+ 	    /* TODO */
+ 	    return(NULL);
+     }
+ 
+-    ret = (xmlXPathObjectPtr) xmlMalloc(sizeof(xmlXPathObject));
+-    if (ret == NULL) {
+-        xmlXPtrErrMemory("allocating range");
+-	return(NULL);
+-    }
+-    memset(ret, 0 , (size_t) sizeof(xmlXPathObject));
+-    ret->type = XPATH_RANGE;
+-    ret->user = start;
+-    ret->index = -1;
+-    switch (end->type) {
+-	case XPATH_POINT:
+-	    ret->user2 = end->user;
+-	    ret->index2 = end->index;
+-	    break;
+-	case XPATH_RANGE:
+-	    ret->user2 = end->user2;
+-	    ret->index2 = end->index2;
+-	    break;
+-	case XPATH_NODESET: {
+-	    ret->user2 = end->nodesetval->nodeTab[end->nodesetval->nodeNr - 1];
+-	    ret->index2 = -1;
+-	    break;
+-	}
+-	default:
+-	    STRANGE
+-	    return(NULL);
+-    }
++    ret = xmlXPtrNewRangeInternal(start, -1, endNode, endIndex);
+     xmlXPtrRangeCheckOrder(ret);
+     return(ret);
+ }
+@@ -1835,8 +1798,8 @@ xmlXPtrStartPointFunction(xmlXPathParserContextPtr ctxt, int nargs) {
+ 		case XPATH_RANGE: {
+ 		    xmlNodePtr node = tmp->user;
+ 		    if (node != NULL) {
+-			if (node->type == XML_ATTRIBUTE_NODE) {
+-			    /* TODO: Namespace Nodes ??? */
++			if ((node->type == XML_ATTRIBUTE_NODE) ||
++			     (node->type == XML_NAMESPACE_DECL)) {
+ 			    xmlXPathFreeObject(obj);
+ 			    xmlXPtrFreeLocationSet(newset);
+ 			    XP_ERROR(XPTR_SYNTAX_ERROR);
+@@ -1931,8 +1894,8 @@ xmlXPtrEndPointFunction(xmlXPathParserContextPtr ctxt, int nargs) {
+ 		case XPATH_RANGE: {
+ 		    xmlNodePtr node = tmp->user2;
+ 		    if (node != NULL) {
+-			if (node->type == XML_ATTRIBUTE_NODE) {
+-			    /* TODO: Namespace Nodes ??? */
++			if ((node->type == XML_ATTRIBUTE_NODE) ||
++			     (node->type == XML_NAMESPACE_DECL)) {
+ 			    xmlXPathFreeObject(obj);
+ 			    xmlXPtrFreeLocationSet(newset);
+ 			    XP_ERROR(XPTR_SYNTAX_ERROR);
diff --git a/meta/recipes-core/libxml/libxml2_2.9.4.bb b/meta/recipes-core/libxml/libxml2_2.9.4.bb
index 66a89400e5..a1d1e9e12d 100644
--- a/meta/recipes-core/libxml/libxml2_2.9.4.bb
+++ b/meta/recipes-core/libxml/libxml2_2.9.4.bb
@@ -21,6 +21,7 @@ SRC_URI = "ftp://xmlsoft.org/libxml2/libxml2-${PV}.tar.gz;name=libtar \
            file://libxml-m4-use-pkgconfig.patch \
            file://libxml2-fix_node_comparison.patch \
            file://libxml2-CVE-2016-5131.patch \
+           file://libxml2-CVE-2016-4658.patch \
           "
 
 SRC_URI[libtar.md5sum] = "ae249165c173b1ff386ee8ad676815f5"