gnu: libxslt: Fix CVE-2016-4738.

* gnu/packages/patches/libxslt-CVE-2016-4738.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/xml.scm (libxslt)[replacement]: New field.
(libxslt/fixed): New variable.

gnu/local.mk

@@ -692,6 +692,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/libxv-CVE-2016-5407.patch		\
   %D%/packages/patches/libxvmc-CVE-2016-7953.patch		\
   %D%/packages/patches/libxslt-generated-ids.patch		\
+  %D%/packages/patches/libxslt-CVE-2016-4738.patch		\
   %D%/packages/patches/lirc-localstatedir.patch			\
   %D%/packages/patches/llvm-for-extempore.patch			\
   %D%/packages/patches/lm-sensors-hwmon-attrs.patch		\

gnu/packages/patches/libxslt-CVE-2016-4738.patch

@@ -0,0 +1,39 @@
+Fix CVE-2016-4738:
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-4738
+https://bugs.chromium.org/p/chromium/issues/detail?id=619006
+
+Patch copied from upstream source repository:
+https://git.gnome.org/browse/libxslt/commit/?id=eb1030de31165b68487f288308f9d1810fed6880
+
+From eb1030de31165b68487f288308f9d1810fed6880 Mon Sep 17 00:00:00 2001
+From: Nick Wellnhofer <wellnhofer@aevum.de>
+Date: Fri, 10 Jun 2016 14:23:58 +0200
+Subject: [PATCH] Fix heap overread in xsltFormatNumberConversion
+
+An empty decimal-separator could cause a heap overread. This can be
+exploited to leak a couple of bytes after the buffer that holds the
+pattern string.
+
+Found with afl-fuzz and ASan.
+---
+ libxslt/numbers.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/libxslt/numbers.c b/libxslt/numbers.c
+index d1549b4..e78c46b 100644
+--- a/libxslt/numbers.c
++++ b/libxslt/numbers.c
+@@ -1090,7 +1090,8 @@ xsltFormatNumberConversion(xsltDecimalFormatPtr self,
+     }
+ 
+     /* We have finished the integer part, now work on fraction */
+-    if (xsltUTF8Charcmp(the_format, self->decimalPoint) == 0) {
++    if ( (*the_format != 0) &&
++         (xsltUTF8Charcmp(the_format, self->decimalPoint) == 0) ) {
+         format_info.add_decimal = TRUE;
+ 	the_format += xsltUTF8Size(the_format);	/* Skip over the decimal */
+     }
+-- 
+2.10.2
+

gnu/packages/xml.scm

@@ -147,6 +147,7 @@ project (but it is usable outside of the Gnome platform).")
 (define-public libxslt
   (package
     (name "libxslt")
+    (replacement libxslt/fixed)
     (version "1.1.29")
     (source (origin
              (method url-fetch)
@@ -168,6 +169,14 @@ project (but it is usable outside of the Gnome platform).")
 based on libxml for XML parsing, tree manipulation and XPath support.")
     (license license:x11)))
 
+(define libxslt/fixed
+  (package
+    (inherit libxslt)
+    (name "libxslt")
+    (source (origin
+              (inherit (package-source libxslt))
+              (patches (search-patches "libxslt-CVE-2016-4738.patch"))))))
+
 (define-public perl-graph-readwrite
   (package
     (name "perl-graph-readwrite")