Go ahead
Le 31 oct. 2015 9:39 AM, "Andrei Borzenkov" <[email protected]> a écrit :
> 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.
>
> Prezero memory buffer used to assemble core.img. This makes individual
> memset redundant. Also ensure buffer is filled with zeroes in several other
> places.
>
> Also remove redundant zeroing code where we fill in the whole memory block
> anyway.
>
> ---
> util/grub-mkimagexx.c | 3 ++-
> util/mkimage.c | 30 +++++++++---------------------
> 2 files changed, 11 insertions(+), 22 deletions(-)
>
> diff --git a/util/grub-mkimagexx.c b/util/grub-mkimagexx.c
> index 3c76d07..a1ddc62 100644
> --- a/util/grub-mkimagexx.c
> +++ b/util/grub-mkimagexx.c
> @@ -101,7 +101,7 @@ SUFFIX (generate_elf) (const struct
> grub_install_image_target_desc *image_target
> program_size = ALIGN_ADDR (*core_size);
>
> elf_img = xmalloc (program_size + header_size + footer_size);
> - memset (elf_img, 0, program_size + header_size);
> + memset (elf_img, 0, program_size + header_size + footer_size);
> memcpy (elf_img + header_size, *core_img, *core_size);
> ehdr = (void *) elf_img;
> phdr = (void *) (elf_img + sizeof (*ehdr));
> @@ -1587,6 +1587,7 @@ SUFFIX (load_image) (const char *kernel_path, size_t
> *exec_size,
> }
>
> out_img = xmalloc (*kernel_sz + total_module_size);
> + memset (out_img, 0, *kernel_sz + total_module_size);
>
> if (image_target->id == IMAGE_EFI)
> {
> diff --git a/util/mkimage.c b/util/mkimage.c
> index 35df998..dc40461 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, config_size = 0;
> size_t prefix_size = 0;
> char *kernel_path;
> size_t offset;
> @@ -1043,8 +1043,7 @@ 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 = ALIGN_ADDR (grub_util_get_image_size (config_path) +
> 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);
> @@ -1080,7 +1079,10 @@ grub_install_generate_image (const char *dir, const
> char *prefix,
> = grub_host_to_target32 (total_module_size);
>
> if (image_target->flags & PLATFORM_FLAGS_MODULES_BEFORE_KERNEL)
> - memmove (kernel_img + total_module_size, kernel_img, kernel_size);
> + {
> + memmove (kernel_img + total_module_size, kernel_img, kernel_size);
> + memset (kernel_img, 0, total_module_size);
> + }
>
> if (image_target->voidp_sizeof == 8)
> {
> @@ -1090,7 +1092,6 @@ grub_install_generate_image (const char *dir, const
> char *prefix,
> modinfo = (struct grub_module_info64 *) kernel_img;
> else
> modinfo = (struct grub_module_info64 *) (kernel_img + kernel_size);
> - memset (modinfo, 0, sizeof (struct grub_module_info64));
> modinfo->magic = grub_host_to_target32 (GRUB_MODULE_MAGIC);
> modinfo->offset = grub_host_to_target_addr (sizeof (struct
> grub_module_info64));
> modinfo->size = grub_host_to_target_addr (total_module_size);
> @@ -1107,7 +1108,6 @@ grub_install_generate_image (const char *dir, const
> char *prefix,
> modinfo = (struct grub_module_info32 *) kernel_img;
> else
> modinfo = (struct grub_module_info32 *) (kernel_img + kernel_size);
> - memset (modinfo, 0, sizeof (struct grub_module_info32));
> modinfo->magic = grub_host_to_target32 (GRUB_MODULE_MAGIC);
> modinfo->offset = grub_host_to_target_addr (sizeof (struct
> grub_module_info32));
> modinfo->size = grub_host_to_target_addr (total_module_size);
> @@ -1120,17 +1120,14 @@ grub_install_generate_image (const char *dir,
> const char *prefix,
> for (p = path_list; p; p = p->next)
> {
> struct grub_module_header *header;
> - size_t mod_size, orig_size;
> + size_t mod_size;
>
> - orig_size = grub_util_get_image_size (p->name);
> - mod_size = ALIGN_ADDR (orig_size);
> + mod_size = ALIGN_ADDR (grub_util_get_image_size (p->name));
>
> header = (struct grub_module_header *) (kernel_img + offset);
> - memset (header, 0, sizeof (struct grub_module_header));
> header->type = grub_host_to_target32 (OBJ_TYPE_ELF);
> header->size = grub_host_to_target32 (mod_size + sizeof (*header));
> offset += sizeof (*header);
> - memset (kernel_img + offset + orig_size, 0, mod_size - orig_size);
>
> grub_util_load_image (p->name, kernel_img + offset);
> offset += mod_size;
> @@ -1146,7 +1143,6 @@ grub_install_generate_image (const char *dir, const
> char *prefix,
> curs = grub_util_get_image_size (pubkey_paths[i]);
>
> 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));
> offset += sizeof (*header);
> @@ -1161,7 +1157,6 @@ grub_install_generate_image (const char *dir, const
> char *prefix,
> struct grub_module_header *header;
>
> header = (struct grub_module_header *) (kernel_img + offset);
> - memset (header, 0, sizeof (struct grub_module_header));
> header->type = grub_host_to_target32 (OBJ_TYPE_MEMDISK);
> header->size = grub_host_to_target32 (memdisk_size + sizeof
> (*header));
> offset += sizeof (*header);
> @@ -1175,13 +1170,11 @@ grub_install_generate_image (const char *dir,
> const char *prefix,
> struct grub_module_header *header;
>
> header = (struct grub_module_header *) (kernel_img + offset);
> - memset (header, 0, sizeof (struct grub_module_header));
> header->type = grub_host_to_target32 (OBJ_TYPE_CONFIG);
> header->size = grub_host_to_target32 (config_size + sizeof
> (*header));
> offset += sizeof (*header);
>
> grub_util_load_image (config_path, kernel_img + offset);
> - *(kernel_img + offset + config_size_pure - 1) = 0;
> offset += config_size;
> }
>
> @@ -1190,12 +1183,10 @@ grub_install_generate_image (const char *dir,
> const char *prefix,
> struct grub_module_header *header;
>
> header = (struct grub_module_header *) (kernel_img + offset);
> - memset (header, 0, sizeof (struct grub_module_header));
> header->type = grub_host_to_target32 (OBJ_TYPE_PREFIX);
> header->size = grub_host_to_target32 (prefix_size + sizeof
> (*header));
> offset += sizeof (*header);
>
> - grub_memset (kernel_img + offset, 0, prefix_size);
> grub_strcpy (kernel_img + offset, prefix);
> offset += prefix_size;
> }
> @@ -1269,15 +1260,11 @@ grub_install_generate_image (const char *dir,
> const char *prefix,
> 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;
> @@ -1428,6 +1415,7 @@ grub_install_generate_image (const char *dir, const
> char *prefix,
> pe_img = xmalloc (reloc_addr + reloc_size);
> memset (pe_img, 0, header_size);
> memcpy ((char *) pe_img + header_size, core_img, core_size);
> + memset ((char *) pe_img + header_size + core_size, 0, reloc_addr -
> (header_size + core_size));
> memcpy ((char *) pe_img + reloc_addr, rel_section, reloc_size);
> header = pe_img;
>
> --
> tg: (2066766..) u/mkimage-zero-pad (depends on: master)
>
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>
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