---
 xpath.c |   40 +++++++++++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 11 deletions(-)

Index: libxml2-2.13.5/xpath.c
===================================================================
--- libxml2-2.13.5.orig/xpath.c
+++ libxml2-2.13.5/xpath.c
@@ -25,6 +25,7 @@
 #include <limits.h>
 #include <string.h>
 #include <stddef.h>
+#include <stdlib.h>
 #include <math.h>
 #include <float.h>
 #include <ctype.h>
@@ -104,14 +105,32 @@
 #define XPATH_MAX_STACK_DEPTH 1000000
 
 /*
- * XPATH_MAX_NODESET_LENGTH:
+ * XPATH_DEFAULT_MAX_NODESET_LENGTH:
  * when evaluating an XPath expression nodesets are created and we
- * arbitrary limit the maximum length of those node set. 10000000 is
- * an insanely large value which should never be reached under normal
- * circumstances, one would first need to construct an in memory tree
+ * arbitrary limit the maximum length of those node set. Default value is
+ * 10000000, an insanely large value which should never be reached under
+ * normal circumstances, one would first need to construct an in memory tree
  * with more than 10 millions nodes.
+ *
+ * Adjustable via LIBXML_MAX_NODESET_LENGTH env variable.
+ * Absolute maximum is INT_MAX.
  */
-#define XPATH_MAX_NODESET_LENGTH 10000000
+#define XPATH_DEFAULT_MAX_NODESET_LENGTH 10000000
+
+int
+get_max_nodeset_len() {
+    const char *max_nodeset_len_str = getenv("LIBXML_MAX_NODESET_LENGTH");
+    int max_nodeset_len = XPATH_DEFAULT_MAX_NODESET_LENGTH;
+
+    if (max_nodeset_len_str != NULL) {
+        max_nodeset_len = strtol(max_nodeset_len_str, NULL, 10);
+
+        if (max_nodeset_len <= 0 || max_nodeset_len > INT_MAX)
+            max_nodeset_len = XPATH_DEFAULT_MAX_NODESET_LENGTH;
+    }
+
+    return max_nodeset_len;
+}
 
 /*
  * XPATH_MAX_RECRUSION_DEPTH:
@@ -2881,7 +2900,7 @@ xmlXPathNodeSetAddNs(xmlNodeSetPtr cur,
     } else if (cur->nodeNr == cur->nodeMax) {
         xmlNodePtr *temp;
 
-        if (cur->nodeMax >= XPATH_MAX_NODESET_LENGTH)
+        if (cur->nodeMax >= get_max_nodeset_len())
             return(-1);
 	temp = (xmlNodePtr *) xmlRealloc(cur->nodeTab, cur->nodeMax * 2 *
 				      sizeof(xmlNodePtr));
@@ -2933,7 +2952,7 @@ xmlXPathNodeSetAdd(xmlNodeSetPtr cur, xm
     } else if (cur->nodeNr == cur->nodeMax) {
         xmlNodePtr *temp;
 
-        if (cur->nodeMax >= XPATH_MAX_NODESET_LENGTH)
+        if (cur->nodeMax >= get_max_nodeset_len())
             return(-1);
 	temp = (xmlNodePtr *) xmlRealloc(cur->nodeTab, cur->nodeMax * 2 *
 				      sizeof(xmlNodePtr));
@@ -2983,7 +3002,7 @@ xmlXPathNodeSetAddUnique(xmlNodeSetPtr c
     } else if (cur->nodeNr == cur->nodeMax) {
         xmlNodePtr *temp;
 
-        if (cur->nodeMax >= XPATH_MAX_NODESET_LENGTH)
+        if (cur->nodeMax >= get_max_nodeset_len())
             return(-1);
 	temp = (xmlNodePtr *) xmlRealloc(cur->nodeTab, cur->nodeMax * 2 *
 				      sizeof(xmlNodePtr));
@@ -3071,7 +3090,7 @@ xmlXPathNodeSetMerge(xmlNodeSetPtr val1,
 	} else if (val1->nodeNr == val1->nodeMax) {
 	    xmlNodePtr *temp;
 
-            if (val1->nodeMax >= XPATH_MAX_NODESET_LENGTH)
+            if (val1->nodeMax >= get_max_nodeset_len())
                 goto error;
 	    temp = (xmlNodePtr *) xmlRealloc(val1->nodeTab, val1->nodeMax * 2 *
 					     sizeof(xmlNodePtr));
@@ -3157,7 +3176,7 @@ xmlXPathNodeSetMergeAndClear(xmlNodeSetP
 	    } else if (set1->nodeNr >= set1->nodeMax) {
 		xmlNodePtr *temp;
 
-                if (set1->nodeMax >= XPATH_MAX_NODESET_LENGTH)
+                if (set1->nodeMax >= get_max_nodeset_len())
                     goto error;
 		temp = (xmlNodePtr *) xmlRealloc(
 		    set1->nodeTab, set1->nodeMax * 2 * sizeof(xmlNodePtr));
@@ -3212,7 +3231,7 @@ xmlXPathNodeSetMergeAndClearNoDupls(xmlN
 	    } else if (set1->nodeNr >= set1->nodeMax) {
 		xmlNodePtr *temp;
 
-                if (set1->nodeMax >= XPATH_MAX_NODESET_LENGTH)
+                if (set1->nodeMax >= get_max_nodeset_len())
                     goto error;
 		temp = (xmlNodePtr *) xmlRealloc(
 		    set1->nodeTab, set1->nodeMax * 2 * sizeof(xmlNodePtr));
