1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138
|
From 9ab01a277d71f54d3143c2cf333c5c2e9aaedd9e Mon Sep 17 00:00:00 2001
From: Nick Wellnhofer <wellnhofer@aevum.de>
Date: Tue, 28 Jun 2016 14:22:23 +0200
Subject: [PATCH] Fix XPointer paths beginning with range-to
The old code would invoke the broken xmlXPtrRangeToFunction. range-to
isn't really a function but a special kind of location step. Remove
this function and always handle range-to in the XPath code.
The old xmlXPtrRangeToFunction could also be abused to trigger a
use-after-free error with the potential for remote code execution.
Found with afl-fuzz.
Fixes CVE-2016-5131.
---
result/XPath/xptr/vidbase | 13 ++++++++
test/XPath/xptr/vidbase | 1 +
xpath.c | 7 ++++-
xpointer.c | 76 ++++-------------------------------------------
4 files changed, 26 insertions(+), 71 deletions(-)
--- a/xpath.c
+++ b/xpath.c
@@ -10691,13 +10691,18 @@ xmlXPathCompPathExpr(xmlXPathParserConte
lc = 1;
break;
} else if ((NXT(len) == '(')) {
- /* Note Type or Function */
+ /* Node Type or Function */
if (xmlXPathIsNodeType(name)) {
#ifdef DEBUG_STEP
xmlGenericError(xmlGenericErrorContext,
"PathExpr: Type search\n");
#endif
lc = 1;
+#ifdef LIBXML_XPTR_ENABLED
+ } else if (ctxt->xptr &&
+ xmlStrEqual(name, BAD_CAST "range-to")) {
+ lc = 1;
+#endif
} else {
#ifdef DEBUG_STEP
xmlGenericError(xmlGenericErrorContext,
--- a/xpointer.c
+++ b/xpointer.c
@@ -1332,8 +1332,6 @@ xmlXPtrNewContext(xmlDocPtr doc, xmlNode
ret->here = here;
ret->origin = origin;
- xmlXPathRegisterFunc(ret, (xmlChar *)"range-to",
- xmlXPtrRangeToFunction);
xmlXPathRegisterFunc(ret, (xmlChar *)"range",
xmlXPtrRangeFunction);
xmlXPathRegisterFunc(ret, (xmlChar *)"range-inside",
@@ -2243,76 +2241,14 @@ xmlXPtrRangeInsideFunction(xmlXPathParse
* @nargs: the number of args
*
* Implement the range-to() XPointer function
+ *
+ * Obsolete. range-to is not a real function but a special type of location
+ * step which is handled in xpath.c.
*/
void
-xmlXPtrRangeToFunction(xmlXPathParserContextPtr ctxt, int nargs) {
- xmlXPathObjectPtr range;
- const xmlChar *cur;
- xmlXPathObjectPtr res, obj;
- xmlXPathObjectPtr tmp;
- xmlLocationSetPtr newset = NULL;
- xmlNodeSetPtr oldset;
- int i;
-
- if (ctxt == NULL) return;
- CHECK_ARITY(1);
- /*
- * Save the expression pointer since we will have to evaluate
- * it multiple times. Initialize the new set.
- */
- CHECK_TYPE(XPATH_NODESET);
- obj = valuePop(ctxt);
- oldset = obj->nodesetval;
- ctxt->context->node = NULL;
-
- cur = ctxt->cur;
- newset = xmlXPtrLocationSetCreate(NULL);
-
- for (i = 0; i < oldset->nodeNr; i++) {
- ctxt->cur = cur;
-
- /*
- * Run the evaluation with a node list made of a single item
- * in the nodeset.
- */
- ctxt->context->node = oldset->nodeTab[i];
- tmp = xmlXPathNewNodeSet(ctxt->context->node);
- valuePush(ctxt, tmp);
-
- xmlXPathEvalExpr(ctxt);
- CHECK_ERROR;
-
- /*
- * The result of the evaluation need to be tested to
- * decided whether the filter succeeded or not
- */
- res = valuePop(ctxt);
- range = xmlXPtrNewRangeNodeObject(oldset->nodeTab[i], res);
- if (range != NULL) {
- xmlXPtrLocationSetAdd(newset, range);
- }
-
- /*
- * Cleanup
- */
- if (res != NULL)
- xmlXPathFreeObject(res);
- if (ctxt->value == tmp) {
- res = valuePop(ctxt);
- xmlXPathFreeObject(res);
- }
-
- ctxt->context->node = NULL;
- }
-
- /*
- * The result is used as the new evaluation set.
- */
- xmlXPathFreeObject(obj);
- ctxt->context->node = NULL;
- ctxt->context->contextSize = -1;
- ctxt->context->proximityPosition = -1;
- valuePush(ctxt, xmlXPtrWrapLocationSet(newset));
+xmlXPtrRangeToFunction(xmlXPathParserContextPtr ctxt,
+ int nargs ATTRIBUTE_UNUSED) {
+ XP_ERROR(XPATH_EXPR_ERROR);
}
/**
|