gnu: grub: Add fix for CVE-2015-8730.

* gnu/packages/patches/grub-CVE-2015-8370.patch: New file.
* gnu-system.am (dist_patch_DATA): Register patch.
* gnu/packages/grub.scm: Apply patch.

gnu-system.am

@@ -497,6 +497,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/gobject-introspection-cc.patch		\
   gnu/packages/patches/gobject-introspection-girepository.patch	\
   gnu/packages/patches/grep-CVE-2015-1345.patch			\
+  gnu/packages/patches/grub-CVE-2015-8370.patch			\
   gnu/packages/patches/grub-gets-undeclared.patch		\
   gnu/packages/patches/grub-freetype.patch			\
   gnu/packages/patches/guile-1.8-cpp-4.5.patch			\

gnu/packages/grub.scm

@@ -1,6 +1,7 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2015 Mark H Weaver <mhw@netris.org>
+;;; Copyright © 2015 Leo Famulari <leo@famulari.name>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -83,7 +84,8 @@
               (base32
                "0n64hpmsccvicagvr0c6v0kgp2yw0kgnd3jvsyd26cnwgs7c6kkq"))
              (patches (list (search-patch "grub-gets-undeclared.patch")
-                            (search-patch "grub-freetype.patch")))))
+                            (search-patch "grub-freetype.patch")
+                            (search-patch "grub-CVE-2015-8370.patch")))))
     (build-system gnu-build-system)
     (arguments
      '(#:configure-flags '("--disable-werror")

gnu/packages/patches/grub-CVE-2015-8370.patch

@@ -0,0 +1,45 @@
+From 88c9657960a6c5d3673a25c266781e876c181add Mon Sep 17 00:00:00 2001
+From: Hector Marco-Gisbert <hecmargi@upv.es>
+Date: Fri, 13 Nov 2015 16:21:09 +0100
+Subject: [PATCH] Fix security issue when reading username and password
+
+  This patch fixes two integer underflows at:
+    * grub-core/lib/crypto.c
+    * grub-core/normal/auth.c
+
+Signed-off-by: Hector Marco-Gisbert <hecmargi@upv.es>
+Signed-off-by: Ismael Ripoll-Ripoll <iripoll@disca.upv.es>
+---
+ grub-core/lib/crypto.c  | 2 +-
+ grub-core/normal/auth.c | 2 +-
+ 2 files changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/grub-core/lib/crypto.c b/grub-core/lib/crypto.c
+index 010e550..524a3d8 100644
+--- a/grub-core/lib/crypto.c
++++ b/grub-core/lib/crypto.c
+@@ -468,7 +468,7 @@ grub_password_get (char buf[], unsigned buf_size)
+ 	  break;
+ 	}
+ 
+-      if (key == '\b')
++      if (key == '\b' && cur_len)
+ 	{
+ 	  cur_len--;
+ 	  continue;
+diff --git a/grub-core/normal/auth.c b/grub-core/normal/auth.c
+index c6bd96e..5782ec5 100644
+--- a/grub-core/normal/auth.c
++++ b/grub-core/normal/auth.c
+@@ -172,7 +172,7 @@ grub_username_get (char buf[], unsigned buf_size)
+ 	  break;
+ 	}
+ 
+-      if (key == '\b')
++      if (key == '\b' && cur_len)
+ 	{
+ 	  cur_len--;
+ 	  grub_printf ("\b");
+-- 
+1.9.1
+