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| author | Andreas Herrmann <andreas.herrmann3@amd.com> | 2012-07-31 15:41:45 +0200 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2012-08-22 16:10:41 -0700 |
| commit | 36bf50d7697be18c6bfd0401e037df10bff1e573 (patch) | |
| tree | e32aeb6e6077c3eecc569f9f2ad4f393ba8b63d8 /arch/x86 | |
| parent | cb09cad44f07044d9810f18f6f9a6a6f3771f979 (diff) | |
| download | linux-36bf50d7697be18c6bfd0401e037df10bff1e573.tar.bz2 | |
x86, microcode, AMD: Fix broken ucode patch size check
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.
Cc: <stable@vger.kernel.org> [3.3+]
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>
Diffstat (limited to 'arch/x86')
| -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; |