[x86] efi: Fix dummy variable buffer allocation

svn path=/dists/sid/linux/; revision=20284

debian/changelog

@@ -22,6 +22,7 @@ linux (3.9.7-1) UNRELEASED; urgency=low
   [ Ben Hutchings ]
   * yama: Disable ptrace restrictions by default, and change boot message
     to indicate this (Closes: #712740)
+  * [x86] efi: Fix dummy variable buffer allocation
 
  -- Ben Hutchings <ben@decadent.org.uk>  Wed, 19 Jun 2013 04:30:59 +0100
 

debian/patches/bugfix/x86/x86-efi-Fix-dummy-variable-buffer-allocation.patch

@@ -0,0 +1,43 @@
+From: Ben Hutchings <ben@decadent.org.uk>
+Date: Sun, 16 Jun 2013 21:27:12 +0100
+Subject: x86/efi: Fix dummy variable buffer allocation
+
+commit b8cb62f82103083a6e8fa5470bfe634a2c06514d upstream.
+
+1. Check for allocation failure
+2. Clear the buffer contents, as they may actually be written to flash
+3. Don't leak the buffer
+
+Compile-tested only.
+
+[ Tested successfully on my buggy ASUS machine - Matt ]
+
+Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
+Signed-off-by: Matt Fleming <matt.fleming@intel.com>
+---
+ arch/x86/platform/efi/efi.c |    7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
+
+--- a/arch/x86/platform/efi/efi.c
++++ b/arch/x86/platform/efi/efi.c
+@@ -1074,7 +1074,10 @@ efi_status_t efi_query_variable_store(u3
+ 		 * that by attempting to use more space than is available.
+ 		 */
+ 		unsigned long dummy_size = remaining_size + 1024;
+-		void *dummy = kmalloc(dummy_size, GFP_ATOMIC);
++		void *dummy = kzalloc(dummy_size, GFP_ATOMIC);
++
++		if (!dummy)
++			return EFI_OUT_OF_RESOURCES;
+ 
+ 		status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
+ 					  EFI_VARIABLE_NON_VOLATILE |
+@@ -1094,6 +1097,8 @@ efi_status_t efi_query_variable_store(u3
+ 					 0, dummy);
+ 		}
+ 
++		kfree(dummy);
++
+ 		/*
+ 		 * The runtime code may now have triggered a garbage collection
+ 		 * run, so check the variable info again

debian/patches/series

@@ -107,3 +107,4 @@ features/arm/0001-ARM-mvebu-Add-thermal-support-to-Armada-XP-device-tr.patch
 bugfix/x86/viafb-autoload-on-olpc-xo1.5-only.patch
 debian/powerpc-machdep-avoid-abi-change-in-3.9.6.patch
 debian/yama-disable-by-default.patch
+bugfix/x86/x86-efi-Fix-dummy-variable-buffer-allocation.patch