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Copied from Debian.
Description: fix multiple integer overflows in the XML_GetBuffer function
Multiple integer overflows in the XML_GetBuffer function in Expat through
2.1.0, as used in Google Chrome before 44.0.2403.89 and other products,
allow remote attackers to cause a denial of service (heap-based buffer
overflow) or possibly have unspecified other impact via crafted XML data,
a related issue to CVE-2015-2716.
Origin: Mozilla, https://hg.mozilla.org/releases/mozilla-esr31/rev/2f3e78643f5c
Author: Eric Rahm <erahm@mozilla.com>
Forwarded: not-needed
Last-Update: 2015-07-24
diff --git a/lib/xmlparse.c b/lib/xmlparse.c
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -1673,29 +1673,40 @@ XML_ParseBuffer(XML_Parser parser, int l
XmlUpdatePosition(encoding, positionPtr, bufferPtr, &position);
positionPtr = bufferPtr;
return result;
}
void * XMLCALL
XML_GetBuffer(XML_Parser parser, int len)
{
+/* BEGIN MOZILLA CHANGE (sanity check len) */
+ if (len < 0) {
+ errorCode = XML_ERROR_NO_MEMORY;
+ return NULL;
+ }
+/* END MOZILLA CHANGE */
switch (ps_parsing) {
case XML_SUSPENDED:
errorCode = XML_ERROR_SUSPENDED;
return NULL;
case XML_FINISHED:
errorCode = XML_ERROR_FINISHED;
return NULL;
default: ;
}
if (len > bufferLim - bufferEnd) {
- /* FIXME avoid integer overflow */
int neededSize = len + (int)(bufferEnd - bufferPtr);
+/* BEGIN MOZILLA CHANGE (sanity check neededSize) */
+ if (neededSize < 0) {
+ errorCode = XML_ERROR_NO_MEMORY;
+ return NULL;
+ }
+/* END MOZILLA CHANGE */
#ifdef XML_CONTEXT_BYTES
int keep = (int)(bufferPtr - buffer);
if (keep > XML_CONTEXT_BYTES)
keep = XML_CONTEXT_BYTES;
neededSize += keep;
#endif /* defined XML_CONTEXT_BYTES */
if (neededSize <= bufferLim - buffer) {
@@ -1714,17 +1725,25 @@ XML_GetBuffer(XML_Parser parser, int len
}
else {
char *newBuf;
int bufferSize = (int)(bufferLim - bufferPtr);
if (bufferSize == 0)
bufferSize = INIT_BUFFER_SIZE;
do {
bufferSize *= 2;
- } while (bufferSize < neededSize);
+/* BEGIN MOZILLA CHANGE (prevent infinite loop on overflow) */
+ } while (bufferSize < neededSize && bufferSize > 0);
+/* END MOZILLA CHANGE */
+/* BEGIN MOZILLA CHANGE (sanity check bufferSize) */
+ if (bufferSize <= 0) {
+ errorCode = XML_ERROR_NO_MEMORY;
+ return NULL;
+ }
+/* END MOZILLA CHANGE */
newBuf = (char *)MALLOC(bufferSize);
if (newBuf == 0) {
errorCode = XML_ERROR_NO_MEMORY;
return NULL;
}
bufferLim = newBuf + bufferSize;
#ifdef XML_CONTEXT_BYTES
if (bufferPtr) {
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