gnu: expat: Add fix for CVE-2015-1283.

* gnu/packages/patches/expat-CVE-2015-1283.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/xml.scm (expat)[source]: Add patch.

gnu-system.am

@@ -432,6 +432,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/elfutils-tests-ptrace.patch		\
   gnu/packages/patches/emacs-exec-path.patch			\
   gnu/packages/patches/eudev-rules-directory.patch		\
+  gnu/packages/patches/expat-CVE-2015-1283.patch		\
   gnu/packages/patches/findutils-absolute-paths.patch		\
   gnu/packages/patches/findutils-localstatedir.patch		\
   gnu/packages/patches/flashrom-use-libftdi1.patch		\

gnu/packages/patches/expat-CVE-2015-1283.patch

+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) {
+
+
+
+

gnu/packages/xml.scm

@@ -4,6 +4,7 @@
 ;;; Copyright © 2015 Eric Bavier <bavier@member.fsf.org>
 ;;; Copyright © 2015 Sou Bunnbu <iyzsong@gmail.com>
 ;;; Copyright © 2015 Ricardo Wurmus <rekado@elephly.net>
+;;; Copyright © 2015 Mark H Weaver <mhw@netris.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -48,7 +49,8 @@ (define-public expat
                                  version "/expat-" version ".tar.gz"))
              (sha256
               (base32
-               "11pblz61zyxh68s5pdcbhc30ha1b2vfjd83aiwfg4vc15x3hadw2"))))
+               "11pblz61zyxh68s5pdcbhc30ha1b2vfjd83aiwfg4vc15x3hadw2"))
+             (patches (list (search-patch "expat-CVE-2015-1283.patch")))))
     (build-system gnu-build-system)
     (home-page "http://www.libexpat.org/")
     (synopsis "Stream-oriented XML parser library written in C")