[libxml2] Fix memory leaks in XPointer error paths

[Nick Wellnhofer <nwellnhof src gnome org>]

commit bd1571cdc56b40638d0aa431ff436e478139a0b8
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Mon May 22 00:33:12 2017 +0200

    Fix memory leaks in XPointer error paths
    
    Found with libFuzzer and ASan.

 xpointer.c |   11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletions(-)
---
diff --git a/xpointer.c b/xpointer.c
index e643ee9..1413868 100644
--- a/xpointer.c
+++ b/xpointer.c
@@ -99,6 +99,10 @@ xmlXPtrErr(xmlXPathParserContextPtr ctxt, int error,
                        msg, extra);
        return;
     }
+
+    /* cleanup current last error */
+    xmlResetError(&ctxt->context->lastError);
+
     ctxt->context->lastError.domain = XML_FROM_XPOINTER;
     ctxt->context->lastError.code = error;
     ctxt->context->lastError.level = XML_ERR_ERROR;
@@ -949,8 +953,10 @@ xmlXPtrEvalXPtrPart(xmlXPathParserContextPtr ctxt, xmlChar *name) {
     if (name == NULL)
        XP_ERROR(XPATH_EXPR_ERROR);
 
-    if (CUR != '(')
+    if (CUR != '(') {
+        xmlFree(name);
        XP_ERROR(XPATH_EXPR_ERROR);
+    }
     NEXT;
     level = 1;
 
@@ -959,6 +965,7 @@ xmlXPtrEvalXPtrPart(xmlXPathParserContextPtr ctxt, xmlChar *name) {
     buffer = (xmlChar *) xmlMallocAtomic(len * sizeof (xmlChar));
     if (buffer == NULL) {
         xmlXPtrErrMemory("allocating buffer");
+        xmlFree(name);
        return;
     }
 
@@ -983,6 +990,7 @@ xmlXPtrEvalXPtrPart(xmlXPathParserContextPtr ctxt, xmlChar *name) {
     *cur = 0;
 
     if ((level != 0) && (CUR == 0)) {
+        xmlFree(name);
        xmlFree(buffer);
        XP_ERROR(XPTR_SYNTAX_ERROR);
     }
@@ -1015,6 +1023,7 @@ xmlXPtrEvalXPtrPart(xmlXPathParserContextPtr ctxt, xmlChar *name) {
            if (name2 == NULL) {
                CUR_PTR = left;
                xmlFree(buffer);
+                xmlFree(name);
                XP_ERROR(XPATH_EXPR_ERROR);
            }
            xmlXPtrEvalChildSeq(ctxt, name2);