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diff -pruN libxml2-2.6.31.cve-2008-3281/entities.c libxml2-2.6.31/entities.c
--- libxml2-2.6.31.cve-2008-3281/entities.c 2007-01-03 08:07:52.000000000 -0500
+++ entities.c 2008-09-11 16:08:42.000000000 -0400
@@ -102,7 +102,7 @@ xmlFreeEntity(xmlEntityPtr entity)
dict = entity->doc->dict;
- if ((entity->children) && (entity->owner == 1) &&
+ if ((entity->children) && (entity->owner != 0) &&
(entity == (xmlEntityPtr) entity->children->parent))
xmlFreeNodeList(entity->children);
if (dict != NULL) {
diff -pruN libxml2-2.6.31.cve-2008-3281/include/libxml/parser.h libxml2-2.6.31/include/libxml/parser.h
--- libxml2-2.6.31.cve-2008-3281/include/libxml/parser.h 2007-01-03 08:07:30.000000000 -0500
+++ include/libxml/parser.h 2008-09-11 16:08:42.000000000 -0400
@@ -297,6 +297,8 @@ struct _xmlParserCtxt {
*/
xmlError lastError;
xmlParserMode parseMode; /* the parser mode */
+ unsigned long nbentities; /* number of entities references */
+ unsigned long sizeentities; /* size of parsed entities */
};
/**
diff -pruN libxml2-2.6.31.cve-2008-3281/parser.c libxml2-2.6.31/parser.c
--- libxml2-2.6.31.cve-2008-3281/parser.c 2008-01-11 01:36:20.000000000 -0500
+++ parser.c 2008-09-11 16:10:45.000000000 -0400
@@ -80,6 +80,95 @@
#include <zlib.h>
#endif
+static void
+xmlFatalErr(xmlParserCtxtPtr ctxt, xmlParserErrors error, const char *info);
+
+/************************************************************************
+ * *
+ * Arbitrary limits set in the parser. *
+ * *
+ ************************************************************************/
+
+#define XML_PARSER_BIG_ENTITY 1000
+#define XML_PARSER_LOT_ENTITY 5000
+
+/*
+ * XML_PARSER_NON_LINEAR is the threshold where the ratio of parsed entity
+ * replacement over the size in byte of the input indicates that you have
+ * and eponential behaviour. A value of 10 correspond to at least 3 entity
+ * replacement per byte of input.
+ */
+#define XML_PARSER_NON_LINEAR 10
+
+/*
+ * xmlParserEntityCheck
+ *
+ * Function to check non-linear entity expansion behaviour
+ * This is here to detect and stop exponential linear entity expansion
+ * This is not a limitation of the parser but a safety
+ * boundary feature.
+ */
+static int
+xmlParserEntityCheck(xmlParserCtxtPtr ctxt, unsigned long size,
+ xmlEntityPtr ent)
+{
+ unsigned long consumed = 0;
+
+ if (ctxt == NULL)
+ return (0);
+ if (ctxt->lastError.code == XML_ERR_ENTITY_LOOP)
+ return (1);
+ if (size != 0) {
+ /*
+ * Do the check based on the replacement size of the entity
+ */
+ if (size < XML_PARSER_BIG_ENTITY)
+ return(0);
+
+ /*
+ * A limit on the amount of text data reasonably used
+ */
+ if (ctxt->input != NULL) {
+ consumed = ctxt->input->consumed +
+ (ctxt->input->cur - ctxt->input->base);
+ }
+ consumed += ctxt->sizeentities;
+
+ if ((size < XML_PARSER_NON_LINEAR * consumed) &&
+ (ctxt->nbentities * 3 < XML_PARSER_NON_LINEAR * consumed))
+ return (0);
+ } else if (ent != NULL) {
+ /*
+ * use the number of parsed entities in the replacement
+ */
+ size = ent->owner;
+
+ /*
+ * The amount of data parsed counting entities size only once
+ */
+ if (ctxt->input != NULL) {
+ consumed = ctxt->input->consumed +
+ (ctxt->input->cur - ctxt->input->base);
+ }
+ consumed += ctxt->sizeentities;
+
+ /*
+ * Check the density of entities for the amount of data
+ * knowing an entity reference will take at least 3 bytes
+ */
+ if (size * 3 < consumed * XML_PARSER_NON_LINEAR)
+ return (0);
+ } else {
+ /*
+ * strange we got no data for checking just return
+ */
+ return (0);
+ }
+
+ xmlFatalErr(ctxt, XML_ERR_ENTITY_LOOP, NULL);
+ return (1);
+}
+
/**
* xmlParserMaxDepth:
*
@@ -2260,6 +2349,10 @@ xmlStringLenDecodeEntities(xmlParserCtxt
"String decoding Entity Reference: %.30s\n",
str);
ent = xmlParseStringEntityRef(ctxt, &str);
+ if (ctxt->lastError.code == XML_ERR_ENTITY_LOOP)
+ goto int_error;
+ if (ent != NULL)
+ ctxt->nbentities += ent->owner;
if ((ent != NULL) &&
(ent->etype == XML_INTERNAL_PREDEFINED_ENTITY)) {
if (ent->content != NULL) {
@@ -2284,6 +2377,10 @@ xmlStringLenDecodeEntities(xmlParserCtxt
buffer[nbchars++] = *current++;
if (nbchars >
buffer_size - XML_PARSER_BUFFER_SIZE) {
+ if (xmlParserEntityCheck(ctxt, nbchars, ent)) {
+ xmlFree(rep);
+ goto int_error;
+ }
growBuffer(buffer);
}
}
@@ -2306,6 +2403,10 @@ xmlStringLenDecodeEntities(xmlParserCtxt
xmlGenericError(xmlGenericErrorContext,
"String decoding PE Reference: %.30s\n", str);
ent = xmlParseStringPEReference(ctxt, &str);
+ if (ctxt->lastError.code == XML_ERR_ENTITY_LOOP)
+ goto int_error;
+ if (ent != NULL)
+ ctxt->nbentities += ent->owner;
if (ent != NULL) {
xmlChar *rep;
@@ -2319,6 +2420,10 @@ xmlStringLenDecodeEntities(xmlParserCtxt
buffer[nbchars++] = *current++;
if (nbchars >
buffer_size - XML_PARSER_BUFFER_SIZE) {
+ if (xmlParserEntityCheck(ctxt, nbchars, ent)) {
+ xmlFree(rep);
+ goto int_error;
+ }
growBuffer(buffer);
}
}
@@ -2466,6 +2571,7 @@ xmlStringLenDecodeEntities(xmlParserCtxt
mem_error:
xmlErrMemory(ctxt, NULL);
+int_error:
if (rep != NULL)
xmlFree(rep);
if (buffer != NULL)
@@ -3151,6 +3259,9 @@ xmlParseAttValueComplex(xmlParserCtxtPtr
}
} else {
ent = xmlParseEntityRef(ctxt);
+ ctxt->nbentities++;
+ if (ent != NULL)
+ ctxt->nbentities += ent->owner;
if ((ent != NULL) &&
(ent->etype == XML_INTERNAL_PREDEFINED_ENTITY)) {
if (len > buf_size - 10) {
@@ -4433,6 +4544,7 @@ xmlParseEntityDecl(xmlParserCtxtPtr ctxt
int isParameter = 0;
xmlChar *orig = NULL;
int skipped;
+ unsigned long oldnbent = ctxt->nbentities;
/* GROW; done in the caller */
if (CMP8(CUR_PTR, '<', '!', 'E', 'N', 'T', 'I', 'T', 'Y')) {
@@ -4642,6 +4754,11 @@ xmlParseEntityDecl(xmlParserCtxtPtr ctxt
}
}
if (cur != NULL) {
+ if ((cur->owner != 0) || (cur->children == NULL)) {
+ cur->owner = ctxt->nbentities - oldnbent;
+ if (cur->owner == 0)
+ cur->owner = 1;
+ }
if (cur->orig != NULL)
xmlFree(orig);
else
@@ -6071,7 +6188,8 @@ xmlParseReference(xmlParserCtxtPtr ctxt)
(ent->children == NULL)) {
ent->children = list;
ent->last = list;
- ent->owner = 1;
+ if (ent->owner == 0)
+ ent->owner = 1;
list->parent = (xmlNodePtr) ent;
} else {
xmlFreeNodeList(list);
@@ -6080,6 +6198,7 @@ xmlParseReference(xmlParserCtxtPtr ctxt)
xmlFreeNodeList(list);
}
} else {
+ unsigned long oldnbent = ctxt->nbentities;
/*
* 4.3.2: An internal general parsed entity is well-formed
* if its replacement text matches the production labeled
@@ -6102,6 +6221,7 @@ xmlParseReference(xmlParserCtxtPtr ctxt)
ret = xmlParseBalancedChunkMemoryInternal(ctxt,
value, user_data, &list);
ctxt->depth--;
+
} else if (ent->etype ==
XML_EXTERNAL_GENERAL_PARSED_ENTITY) {
ctxt->depth++;
@@ -6114,6 +6234,24 @@ xmlParseReference(xmlParserCtxtPtr ctxt)
xmlErrMsgStr(ctxt, XML_ERR_INTERNAL_ERROR,
"invalid entity type found\n", NULL);
}
+ /*
+ * Store the number of entities needing parsing for entity
+ * content and do checkings
+ */
+ if ((ent->owner != 0) || (ent->children == NULL)) {
+ ent->owner = ctxt->nbentities - oldnbent;
+ if (ent->owner == 0)
+ ent->owner = 1;
+ }
+ if (ret == XML_ERR_ENTITY_LOOP) {
+ xmlFatalErr(ctxt, XML_ERR_ENTITY_LOOP, NULL);
+ xmlFreeNodeList(list);
+ return;
+ }
+ if (xmlParserEntityCheck(ctxt, 0, ent)) {
+ xmlFreeNodeList(list);
+ return;
+ }
if (ret == XML_ERR_ENTITY_LOOP) {
xmlFatalErr(ctxt, XML_ERR_ENTITY_LOOP, NULL);
return;
@@ -6132,7 +6270,8 @@ xmlParseReference(xmlParserCtxtPtr ctxt)
(ctxt->parseMode == XML_PARSE_READER)) {
list->parent = (xmlNodePtr) ent;
list = NULL;
- ent->owner = 1;
+ if (ent->owner == 0)
+ ent->owner = 1;
} else {
ent->owner = 0;
while (list != NULL) {
@@ -6149,7 +6288,8 @@ xmlParseReference(xmlParserCtxtPtr ctxt)
#endif /* LIBXML_LEGACY_ENABLED */
}
} else {
- ent->owner = 1;
+ if (ent->owner == 0)
+ ent->owner = 1;
while (list != NULL) {
list->parent = (xmlNodePtr) ent;
if (list->next == NULL)
@@ -6326,7 +6466,8 @@ xmlParseReference(xmlParserCtxtPtr ctxt)
break;
cur = next;
}
- ent->owner = 1;
+ if (ent->owner == 0)
+ ent->owner = 1;
#ifdef LIBXML_LEGACY_ENABLED
if (ent->etype == XML_EXTERNAL_GENERAL_PARSED_ENTITY)
xmlAddEntityReference(ent, firstChild, nw);
@@ -6357,6 +6498,8 @@ xmlParseReference(xmlParserCtxtPtr ctxt)
ctxt->nodelen = 0;
return;
}
+ } else if (ent->owner != 1) {
+ ctxt->nbentities += ent->owner;
}
} else {
val = ent->content;
@@ -6416,6 +6559,11 @@ xmlParseEntityRef(xmlParserCtxtPtr ctxt)
if (RAW == ';') {
NEXT;
/*
+ * Increase the number of entity references parsed
+ */
+ ctxt->nbentities++;
+
+ /*
* Ask first SAX for entity resolution, otherwise try the
* predefined set.
*/
@@ -6587,6 +6735,10 @@ xmlParseStringEntityRef(xmlParserCtxtPtr
if (*ptr == ';') {
ptr++;
/*
+ * Increase the number of entity references parsed
+ */
+ ctxt->nbentities++;
+ /*
* Ask first SAX for entity resolution, otherwise try the
* predefined set.
*/
@@ -6748,6 +6900,11 @@ xmlParsePEReference(xmlParserCtxtPtr ctx
} else {
if (RAW == ';') {
NEXT;
+ /*
+ * Increase the number of entity references parsed
+ */
+ ctxt->nbentities++;
+
if ((ctxt->sax != NULL) &&
(ctxt->sax->getParameterEntity != NULL))
entity = ctxt->sax->getParameterEntity(ctxt->userData,
@@ -6878,6 +7035,11 @@ xmlParseStringPEReference(xmlParserCtxtP
if (cur == ';') {
ptr++;
cur = *ptr;
+ /*
+ * Increase the number of entity references parsed
+ */
+ ctxt->nbentities++;
+
if ((ctxt->sax != NULL) &&
(ctxt->sax->getParameterEntity != NULL))
entity = ctxt->sax->getParameterEntity(ctxt->userData,
@@ -11537,11 +11699,31 @@ xmlParseExternalEntityPrivate(xmlDocPtr
}
ret = XML_ERR_OK;
}
+
+ /*
+ * Record in the parent context the number of entities replacement
+ * done when parsing that reference.
+ */
+ oldctxt->nbentities += ctxt->nbentities;
+ /*
+ * Also record the size of the entity parsed
+ */
+ if (ctxt->input != NULL) {
+ oldctxt->sizeentities += ctxt->input->consumed;
+ oldctxt->sizeentities += (ctxt->input->cur - ctxt->input->base);
+ }
+ /*
+ * And record the last error if any
+ */
+ if (ctxt->lastError.code != XML_ERR_OK)
+ xmlCopyError(&ctxt->lastError, &oldctxt->lastError);
+
if (sax != NULL)
ctxt->sax = oldsax;
oldctxt->node_seq.maximum = ctxt->node_seq.maximum;
oldctxt->node_seq.length = ctxt->node_seq.length;
oldctxt->node_seq.buffer = ctxt->node_seq.buffer;
+ oldctxt->nbentities += ctxt->nbentities;
ctxt->node_seq.maximum = 0;
ctxt->node_seq.length = 0;
ctxt->node_seq.buffer = NULL;
@@ -11766,6 +11948,17 @@ xmlParseBalancedChunkMemoryInternal(xmlP
ctxt->myDoc->last = last;
}
+ /*
+ * Record in the parent context the number of entities replacement
+ * done when parsing that reference.
+ */
+ oldctxt->nbentities += ctxt->nbentities;
+ /*
+ * Also record the last error if any
+ */
+ if (ctxt->lastError.code != XML_ERR_OK)
+ xmlCopyError(&ctxt->lastError, &oldctxt->lastError);
+
ctxt->sax = oldsax;
ctxt->dict = NULL;
ctxt->attsDefault = NULL;
@@ -13077,6 +13270,8 @@ xmlCtxtReset(xmlParserCtxtPtr ctxt)
ctxt->depth = 0;
ctxt->charset = XML_CHAR_ENCODING_UTF8;
ctxt->catalogs = NULL;
+ ctxt->nbentities = 0;
+ ctxt->sizeentities = 0;
xmlInitNodeInfoSeq(&ctxt->node_seq);
if (ctxt->attsDefault != NULL) {
diff -pruN libxml2-2.6.31.cve-2008-3281/parserInternals.c libxml2-2.6.31/parserInternals.c
--- libxml2-2.6.31.cve-2008-3281/parserInternals.c 2007-12-14 06:17:14.000000000 -0500
+++ parserInternals.c 2008-09-11 16:08:42.000000000 -0400
@@ -1669,6 +1669,7 @@ xmlInitParserCtxt(xmlParserCtxtPtr ctxt)
ctxt->depth = 0;
ctxt->charset = XML_CHAR_ENCODING_UTF8;
ctxt->catalogs = NULL;
+ ctxt->nbentities = 0;
xmlInitNodeInfoSeq(&ctxt->node_seq);
return(0);
}
|
