expat: CVE-2015-1283

Add CVE-2015-1283 patch for fixing integer overflow bug in expat.

Details are at below link:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1283

Patch comes from:
https://hg.mozilla.org/releases/mozilla-esr31/rev/2f3e78643f5c
https://codereview.chromium.org/1224303003

(From OE-Core rev: c89c5383e304a52b604a3672ac93fd88b5eb8b41)

Signed-off-by: Zhixiong Chi <Zhixiong.Chi@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/expat/expat-2.1.0/expat-CVE-2015-1283.patch

@@ -0,0 +1,62 @@
+Multiple integer overflows in the XML_GetBuffer function in Expat 
+through 2.1.0, allow remote attackers to cause a denial of service 
+(heap-based buffer overflow) or possibly have unspecified other 
+impact via crafted XML data.
+
+CVSSv2:  (AV:N/AC:M/Au:N/C:P/I:P/A:P)
+
+CVE: CVE-2015-1283
+Upstream-Status: Backport
+
+Signed-off-by: Eric Rahm <erahm@mozilla.com>
+Signed-off-by: Zhixiong Chi <zhixiong.chi@windirver.com>
+
+Index: expat-2.1.0/lib/xmlparse.c
+===================================================================
+--- expat-2.1.0.orig/lib/xmlparse.c	2012-03-11 13:13:12.000000000 +0800
++++ expat-2.1.0/lib/xmlparse.c	2015-12-23 10:29:07.347361329 +0800
+@@ -1678,6 +1678,12 @@
+ 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;
+@@ -1689,8 +1695,13 @@
+   }
+ 
+   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);
+ 
+@@ -1719,7 +1730,15 @@
+         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;

meta/recipes-core/expat/expat.inc

@@ -5,7 +5,9 @@ SECTION = "libs"
 LICENSE = "MIT"
 
 SRC_URI = "${SOURCEFORGE_MIRROR}/expat/expat-${PV}.tar.gz \
-           file://autotools.patch"
+           file://autotools.patch \
+           file://expat-CVE-2015-1283.patch \
+	  "
 
 inherit autotools lib_package gzipnative