gnu: cpio: Add fix for CVE-2016-2037.

* gnu/packages/patches/cpio-CVE-2016-2037.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/cpio.scm (cpio)[source]: Add patch.

gnu-system.am

@@ -437,6 +437,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/clucene-pkgconfig.patch			\
   gnu/packages/patches/cmake-fix-tests.patch			\
   gnu/packages/patches/cpio-gets-undeclared.patch		\
+  gnu/packages/patches/cpio-CVE-2016-2037.patch			\
   gnu/packages/patches/cpufrequtils-fix-aclocal.patch		\
   gnu/packages/patches/crda-optional-gcrypt.patch		\
   gnu/packages/patches/crossmap-allow-system-pysam.patch	\

gnu/packages/cpio.scm

@@ -35,7 +35,8 @@ (define-public cpio
                                  version ".tar.bz2"))
              (sha256
               (base32
-               "0vi9q475h1rki53100zml75vxsykzyhrn70hidy41s5c2rc8r6bh"))))
+               "0vi9q475h1rki53100zml75vxsykzyhrn70hidy41s5c2rc8r6bh"))
+             (patches (list (search-patch "cpio-CVE-2016-2037.patch")))))
     (build-system gnu-build-system)
     (home-page "https://www.gnu.org/software/cpio/")
     (synopsis "Manage cpio and tar file archives")

gnu/packages/patches/cpio-CVE-2016-2037.patch

@@ -0,0 +1,49 @@
+Fix CVE-2016-2037 (out of bounds write in process_copy_in()).
+
+Copied from upstream mailing list:
+https://lists.gnu.org/archive/html/bug-cpio/2016-01/msg00005.html
+
+---
+
+ Other calls to cpio_safer_name_suffix seem to be safe.
+ .
+ * src/copyin.c (process_copy_in):  Make sure that file_hdr.c_name
+ has at least two bytes allocated.
+ * src/util.c (cpio_safer_name_suffix): Document that use of this
+ function requires to be careful.
+Author: Pavel Raiskup <praiskup@redhat.com>
+
+---
+ src/copyin.c | 2 ++
+ src/util.c   | 5 ++++-
+ 2 files changed, 6 insertions(+), 1 deletion(-)
+
+Index: cpio-2.11+dfsg/src/copyin.c
+===================================================================
+--- cpio-2.11+dfsg.orig/src/copyin.c
++++ cpio-2.11+dfsg/src/copyin.c
+@@ -1433,6 +1433,8 @@ process_copy_in ()
+ 	  break;
+ 	}
+ 
++      if (file_hdr.c_namesize <= 1)
++        file_hdr.c_name = xrealloc(file_hdr.c_name, 2);
+       cpio_safer_name_suffix (file_hdr.c_name, false, !no_abs_paths_flag,
+ 			      false);
+       
+Index: cpio-2.11+dfsg/src/util.c
+===================================================================
+--- cpio-2.11+dfsg.orig/src/util.c
++++ cpio-2.11+dfsg/src/util.c
+@@ -1374,7 +1374,10 @@ set_file_times (int fd,
+ }
+ 
+ /* Do we have to ignore absolute paths, and if so, does the filename
+-   have an absolute path?  */
++   have an absolute path?
++   Before calling this function make sure that the allocated NAME buffer has
++   capacity at least 2 bytes to allow us to store the "." string inside.  */
++
+ void
+ cpio_safer_name_suffix (char *name, bool link_target, bool absolute_names,
+ 			bool strip_leading_dots)