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SubjectRe: [PATCH -v2] x86, microcode, AMD: Sanity-check initrd image
On 02/03/2014 02:52 PM, Borislav Petkov wrote:
> On Mon, Feb 03, 2014 at 02:37:34PM -0500, Boris Ostrovsky wrote:
>> It exploded when 'if (!container)' check was done *after* relocation,
>> which made container non-zero. If you do the check *before* then I
>> think you will catch the fact that container is empty.
> Ah, right, this was it.
>
> Ok, just remove the signature check then and give it a try pls:

Yes, this fixes the bug. And it loads microcode for a good binary.

For these two patches:
Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

(You might want to rename the final patch to something else since you
are not checking the blob anymore).

Thanks.

-boris



>
> --
> diff --git a/arch/x86/kernel/cpu/microcode/amd_early.c b/arch/x86/kernel/cpu/microcode/amd_early.c
> index 41537ae7c31d..362994511be1 100644
> --- a/arch/x86/kernel/cpu/microcode/amd_early.c
> +++ b/arch/x86/kernel/cpu/microcode/amd_early.c
> @@ -37,12 +37,10 @@ static __initdata char ucode_path[] = "kernel/x86/microcode/AuthenticAMD.bin";
>
> static struct cpio_data __init find_ucode_in_initrd(void)
> {
> - struct cpio_data ret;
> long offset = 0;
> char *path;
> void *start;
> size_t size;
> - u32 *hdr;
>
> #ifdef CONFIG_X86_32
> struct boot_params *p;
> @@ -60,21 +58,7 @@ static struct cpio_data __init find_ucode_in_initrd(void)
> start = (void *)(boot_params.hdr.ramdisk_image + PAGE_OFFSET);
> size = boot_params.hdr.ramdisk_size;
> #endif
> -
> - ret = find_cpio_data(path, start, size, &offset);
> - if (!ret.data)
> - return ret;
> -
> - /* Verify we didn't get some garbage from the initrd. */
> - hdr = (u32 *)ret.data;
> -
> - if (hdr[0] != UCODE_MAGIC ||
> - hdr[1] != UCODE_EQUIV_CPU_TABLE_TYPE ||
> - hdr[2] == 0) {
> - ret.data = NULL;
> - ret.size = 0;
> - }
> - return ret;
> + return find_cpio_data(path, start, size, &offset);
> }
>
> static size_t compute_container_size(u8 *data, u32 total_size)
> --
>



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