On 30.10.2015 16:49, Andrei Borzenkov wrote:
> This did not cause real problem but is good for reproducible builds. I hit
> it with recent bootinfoscript that displays embedded config; I was puzzled
> by random garbage at the end.
>
> Also remove redundant zeroing code where we fill in the whole memory block
> anyway.
>
Could we just zero-out the whole block when we allocate it to have an
easier code and avoid it happening again?
> ---
> util/mkimage.c | 29 +++++++++++++----------------
> 1 file changed, 13 insertions(+), 16 deletions(-)
>
> diff --git a/util/mkimage.c b/util/mkimage.c
> index 35df998..1c522fe 100644
> --- a/util/mkimage.c
> +++ b/util/mkimage.c
> @@ -992,7 +992,7 @@ grub_install_generate_image (const char *dir, const char
> *prefix,
> {
> char *kernel_img, *core_img;
> size_t kernel_size, total_module_size, core_size, exec_size;
> - size_t memdisk_size = 0, config_size = 0, config_size_pure = 0;
> + size_t memdisk_size = 0, memdisk_size_pure = 0, config_size = 0,
> config_size_pure = 0;
> size_t prefix_size = 0;
> char *kernel_path;
> size_t offset;
> @@ -1035,7 +1035,8 @@ grub_install_generate_image (const char *dir, const
> char *prefix,
>
> if (memdisk_path)
> {
> - memdisk_size = ALIGN_UP(grub_util_get_image_size (memdisk_path), 512);
> + memdisk_size_pure = grub_util_get_image_size (memdisk_path);
> + memdisk_size = ALIGN_UP(memdisk_size_pure, 512);
> grub_util_info ("the size of memory disk is 0x%"
> GRUB_HOST_PRIxLONG_LONG,
> (unsigned long long) memdisk_size);
> total_module_size += memdisk_size + sizeof (struct grub_module_header);
> @@ -1043,8 +1044,8 @@ grub_install_generate_image (const char *dir, const
> char *prefix,
>
> if (config_path)
> {
> - config_size_pure = grub_util_get_image_size (config_path) + 1;
> - config_size = ALIGN_ADDR (config_size_pure);
> + config_size_pure = grub_util_get_image_size (config_path);
> + config_size = ALIGN_ADDR (config_size_pure + 1);
> grub_util_info ("the size of config file is 0x%"
> GRUB_HOST_PRIxLONG_LONG,
> (unsigned long long) config_size);
> total_module_size += config_size + sizeof (struct grub_module_header);
> @@ -1140,19 +1141,21 @@ grub_install_generate_image (const char *dir, const
> char *prefix,
> size_t i;
> for (i = 0; i < npubkeys; i++)
> {
> - size_t curs;
> struct grub_module_header *header;
> + size_t key_size, orig_size;
>
> - curs = grub_util_get_image_size (pubkey_paths[i]);
> + orig_size = grub_util_get_image_size (pubkey_paths[i]);
> + key_size = ALIGN_ADDR (orig_size);
>
> header = (struct grub_module_header *) (kernel_img + offset);
> memset (header, 0, sizeof (struct grub_module_header));
> header->type = grub_host_to_target32 (OBJ_TYPE_PUBKEY);
> - header->size = grub_host_to_target32 (curs + sizeof (*header));
> + header->size = grub_host_to_target32 (key_size + sizeof (*header));
> offset += sizeof (*header);
>
> grub_util_load_image (pubkey_paths[i], kernel_img + offset);
> - offset += ALIGN_ADDR (curs);
> + memset (kernel_img + offset + orig_size, 0, key_size - orig_size);
> + offset += key_size;
> }
> }
>
> @@ -1167,6 +1170,7 @@ grub_install_generate_image (const char *dir, const
> char *prefix,
> offset += sizeof (*header);
>
> grub_util_load_image (memdisk_path, kernel_img + offset);
> + memset (kernel_img + offset + memdisk_size_pure, 0, memdisk_size -
> memdisk_size_pure);
> offset += memdisk_size;
> }
>
> @@ -1181,7 +1185,7 @@ grub_install_generate_image (const char *dir, const
> char *prefix,
> offset += sizeof (*header);
>
> grub_util_load_image (config_path, kernel_img + offset);
> - *(kernel_img + offset + config_size_pure - 1) = 0;
> + memset (kernel_img + offset + config_size_pure, 0, config_size -
> config_size_pure);
> offset += config_size;
> }
>
> @@ -1267,17 +1271,10 @@ grub_install_generate_image (const char *dir, const
> char *prefix,
> = grub_host_to_target_addr (image_target->link_addr);
> }
> full_size = core_size + decompress_size;
> -
> full_img = xmalloc (full_size);
> - memset (full_img, 0, full_size);
> -
> memcpy (full_img, decompress_img, decompress_size);
> -
> memcpy (full_img + decompress_size, core_img, core_size);
>
> - memset (full_img + decompress_size + core_size, 0,
> - full_size - (decompress_size + core_size));
> -
> free (core_img);
> core_img = full_img;
> core_size = full_size;
> 
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