diff options
| author | Andreas Herrmann <andreas.herrmann3@amd.com> | 2012-07-31 15:41:45 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-09-14 09:59:55 -0700 |
| commit | 3a392aa579df87e3be160947758428681fbe2611 (patch) | |
| tree | 2e4766ad30732ce4b87a12444b2ed38512348abe | |
| parent | a1ee34a43130fd31d7d0990695115a8e099b5ae6 (diff) | |
x86, microcode, AMD: Fix broken ucode patch size check
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 <andreas.herrmann3@amd.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/1344361461-10076-1-git-send-email-bp@amd64.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/kernel/microcode_amd.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/kernel/microcode_amd.c b/arch/x86/kernel/microcode_amd.c index 8a2ce8fd41c0..82746f942cd8 100644 --- a/arch/x86/kernel/microcode_amd.c +++ b/arch/x86/kernel/microcode_amd.c @@ -143,11 +143,12 @@ static int get_matching_microcode(int cpu, const u8 *ucode_ptr, 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 cpu, const u8 *ucode_ptr, /* * 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; |