[xml] Patch: avoid potential double memory free

[Brian Stafford <brian stafford office-logic com>]

Hi all,

the following short patch avoids a potential double free or referencing memory 
after its freed when code like the following, extracted from testC14n.c, is 
called

        xmlXPathRegisterNs(ctx, ns->prefix, ns->href)

ns->href in the above would be freed when the xpath context is destroyed.  
This can cause a SEGV later on when ns->href is referenced or mode likely when 
xmlFreeDoc is called.  The patch duplicates the string to avoid this.  Since 
xpointer.c expects the original semantic, an extra call to xmlFree is added to 
avoid a leak.

Regards
Brian Stafford

Index: xpath.c
===================================================================
RCS file: /cvs/gnome/gnome-xml/xpath.c,v
retrieving revision 1.201
diff -u -r1.201 xpath.c
--- xpath.c     19 Jul 2002 08:32:00 -0000      1.201
+++ xpath.c     26 Jul 2002 14:14:58 -0000
@@ -2825,7 +2825,7 @@
        ctxt->nsHash = xmlHashCreate(10);
     if (ctxt->nsHash == NULL)
        return(-1);
-    return(xmlHashUpdateEntry(ctxt->nsHash, prefix, (void *) ns_uri,
+    return(xmlHashUpdateEntry(ctxt->nsHash, prefix, (void *)xmlStrdup(ns_uri),
                              (xmlHashDeallocator)xmlFree));
 }
 Index: xpointer.c
===================================================================
RCS file: /cvs/gnome/gnome-xml/xpointer.c,v
retrieving revision 1.42
diff -u -r1.42 xpointer.c
--- xpointer.c  18 Mar 2002 19:37:04 -0000      1.42
+++ xpointer.c  26 Jul 2002 14:15:01 -0000
@@ -1020,6 +1020,7 @@
        }
                xmlXPathRegisterNs(ctxt->context, prefix, URI);
+       xmlFree(URI);
        CUR_PTR = left;
 #endif /* XPTR_XMLNS_SCHEME */
     } else {