Re: [PATCH] use stock embedded timestamp 2015-01-01T0000+0000

["Vladimir 'φ-coder/phcoder' Serbinenko" <phcoder@gmail.com>]

On 22.03.2015 20:33, Daniel Kahn Gillmor wrote:
> Variant timestamps make some grub platforms produce non-deterministic
> core images.  This makes it difficult to use simple tools to audit the
> stability of a system with grub installed.
>
> This patch selects a single timestamp to use for these embedded
> timestamps so that the core images will be replicable.
> ---
>   util/mkimage.c | 9 ++++++---
>   1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/util/mkimage.c b/util/mkimage.c
> index 7821dc5..adc1706 100644
> --- a/util/mkimage.c
> +++ b/util/mkimage.c
> @@ -55,6 +55,9 @@
>
>   #define TARGET_NO_FIELD 0xffffffff
>
> +/* use 2015-01-01T00:00:00+0000 as a stock timestamp */
> +#define STABLE_EMBEDDING_TIMESTAMP 1420070400
> +
>   struct grub_install_image_target_desc
>   {
>     const char *dirname;
> @@ -1439,7 +1442,7 @@ grub_install_generate_image (const char *dir, const char *prefix,
>   	c->machine = grub_host_to_target16 (image_target->pe_target);
>
>   	c->num_sections = grub_host_to_target16 (4);
> -	c->time = grub_host_to_target32 (time (0));
> +	c->time = grub_host_to_target32 (STABLE_EMBEDDING_TIMESTAMP);
>   	c->characteristics = grub_host_to_target16 (GRUB_PE32_EXECUTABLE_IMAGE
>   						    | GRUB_PE32_LINE_NUMS_STRIPPED
>   						    | ((image_target->voidp_sizeof == 4)
> @@ -1782,7 +1785,7 @@ grub_install_generate_image (const char *dir, const char *prefix,
>
>         memset (hdr, 0, sizeof (*hdr));
>         hdr->ih_magic = grub_cpu_to_be32_compile_time (GRUB_UBOOT_IH_MAGIC);
> -      hdr->ih_time = grub_cpu_to_be32 (time (0));
> +      hdr->ih_time = grub_cpu_to_be32 (STABLE_EMBEDDING_TIMESTAMP);
>         hdr->ih_size = grub_cpu_to_be32 (core_size);
>         hdr->ih_load = grub_cpu_to_be32 (image_target->link_addr);
>         hdr->ih_ep = grub_cpu_to_be32 (image_target->link_addr);
> @@ -1856,7 +1859,7 @@ grub_install_generate_image (const char *dir, const char *prefix,
>   	head->magic = image_target->bigendian ? grub_host_to_target16 (0x160)
>   	  : grub_host_to_target16 (0x166);
>   	head->nsec = grub_host_to_target16 (1);
> -	head->time = grub_host_to_target32 (0);
> +	head->time = grub_host_to_target32 (STABLE_EMBEDDING_TIMESTAMP);
I dropped this hunk as it's just changing one const to another.
>   	head->opt = grub_host_to_target16 (0x38);
>   	head->flags = image_target->bigendian
>   	  ? grub_host_to_target16 (0x207)
>