This is a note to let you know that I've just added the patch titled
x86, microcode, AMD: Fix broken ucode patch size check
to the 3.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-microcode-amd-fix-broken-ucode-patch-size-check.patch
and it can be found in the queue-3.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 36bf50d7697be18c6bfd0401e037df10bff1e573 Mon Sep 17 00:00:00 2001
From: Andreas Herrmann <[email protected]>
Date: Tue, 31 Jul 2012 15:41:45 +0200
Subject: x86, microcode, AMD: Fix broken ucode patch size check
From: Andreas Herrmann <[email protected]>
commit 36bf50d7697be18c6bfd0401e037df10bff1e573 upstream.
This issue was recently observed on an AMD C-50 CPU where a patch of
maximum size was applied.
Commit be62adb49294 ("x86, microcode, AMD: Simplify ucode verification")
added current_size in get_matching_microcode(). This is calculated as
size of the ucode patch + 8 (ie. size of the header). Later this is
compared against the maximum possible ucode patch size for a CPU family.
And of course this fails if the patch has already maximum size.
Signed-off-by: Andreas Herrmann <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: H. Peter Anvin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kernel/microcode_amd.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/arch/x86/kernel/microcode_amd.c
+++ b/arch/x86/kernel/microcode_amd.c
@@ -143,11 +143,12 @@ static int get_matching_microcode(int cp
unsigned int *current_size)
{
struct microcode_header_amd *mc_hdr;
- unsigned int actual_size;
+ unsigned int actual_size, patch_size;
u16 equiv_cpu_id;
/* size of the current patch we're staring at */
- *current_size = *(u32 *)(ucode_ptr + 4) + SECTION_HDR_SIZE;
+ patch_size = *(u32 *)(ucode_ptr + 4);
+ *current_size = patch_size + SECTION_HDR_SIZE;
equiv_cpu_id = find_equiv_id();
if (!equiv_cpu_id)
@@ -174,7 +175,7 @@ static int get_matching_microcode(int cp
/*
* now that the header looks sane, verify its size
*/
- actual_size = verify_ucode_size(cpu, *current_size, leftover_size);
+ actual_size = verify_ucode_size(cpu, patch_size, leftover_size);
if (!actual_size)
return 0;
Patches currently in stable-queue which might be from [email protected]
are
queue-3.5/x86-microcode-amd-fix-broken-ucode-patch-size-check.patch
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