gnu: expat: Fix regression caused by fix for CVE-2016-0718.

* gnu/packages/xml.scm (expat)[replacement]: New field.
(expat/fixed): New variable.
* gnu/packages/patches/expat-CVE-2016-0718-fix-regression.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.

Signed-off-by: Leo Famulari <leo@famulari.name>

gnu/local.mk

@@ -506,6 +506,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/expat-CVE-2012-6702-and-CVE-2016-5300.patch	\
   %D%/packages/patches/expat-CVE-2015-1283-refix.patch		\
   %D%/packages/patches/expat-CVE-2016-0718.patch		\
+  %D%/packages/patches/expat-CVE-2016-0718-fix-regression.patch	\
   %D%/packages/patches/fastcap-mulGlobal.patch			\
   %D%/packages/patches/fastcap-mulSetup.patch			\
   %D%/packages/patches/fasthenry-spAllocate.patch		\

gnu/packages/patches/expat-CVE-2016-0718-fix-regression.patch

@@ -0,0 +1,35 @@
+Fix regression caused by fix for CVE-2016-0718 when building with -DXML_UNICODE.
+
+Discussion:
+
+https://sourceforge.net/p/expat/bugs/539/
+
+Patch copied from upstream source repository:
+
+https://sourceforge.net/p/expat/code_git/ci/af507cef2c93cb8d40062a0abe43a4f4e9158fb2/
+
+From af507cef2c93cb8d40062a0abe43a4f4e9158fb2 Mon Sep 17 00:00:00 2001
+From: Sebastian Pipping <sebastian@pipping.org>
+Date: Sun, 17 Jul 2016 20:22:29 +0200
+Subject: [PATCH 1/2] Fix regression bug #539 (needs -DXML_UNICODE)
+
+Thanks to Andy Wang and Karl Waclawek!
+---
+ expat/lib/xmlparse.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/expat/lib/xmlparse.c b/expat/lib/xmlparse.c
+index b308e67..0d5dd7b 100644
+--- a/lib/xmlparse.c
++++ b/lib/xmlparse.c
+@@ -2468,7 +2468,7 @@ doContent(XML_Parser parser,
+                        &fromPtr, rawNameEnd,
+                        (ICHAR **)&toPtr, (ICHAR *)tag->bufEnd - 1);
+             convLen = (int)(toPtr - (XML_Char *)tag->buf);
+-            if ((convert_res == XML_CONVERT_COMPLETED) || (convert_res == XML_CONVERT_INPUT_INCOMPLETE)) {
++            if ((fromPtr >= rawNameEnd) || (convert_res == XML_CONVERT_INPUT_INCOMPLETE)) {
+               tag->name.strLen = convLen;
+               break;
+             }
+-- 
+2.10.0

gnu/packages/xml.scm

@@ -52,6 +52,7 @@
 (define-public expat
   (package
     (name "expat")
+    (replacement expat/fixed)
     (version "2.1.1")
     (source (origin
              (method url-fetch)
@@ -72,6 +73,17 @@ stream-oriented parser in which an application registers handlers for
 things the parser might find in the XML document (like start tags).")
     (license license:expat)))
 
+(define expat/fixed
+  (package
+    (inherit expat)
+    (source (origin
+              (inherit (package-source expat))
+              (patches (search-patches
+                         "expat-CVE-2012-6702-and-CVE-2016-5300.patch"
+                         "expat-CVE-2015-1283-refix.patch"
+                         "expat-CVE-2016-0718.patch"
+                         "expat-CVE-2016-0718-fix-regression.patch"))))))
+
 (define-public libxml2
   (package
     (name "libxml2")