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mirror of https://github.com/trezor/trezor-firmware.git synced 2024-12-25 07:48:10 +00:00
trezor-firmware/core/embed/firmware/bl_check.c
2024-08-29 12:47:24 +02:00

185 lines
6.3 KiB
C

/*
* This file is part of the Trezor project, https://trezor.io/
*
* Copyright (c) SatoshiLabs
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdint.h>
#include <string.h>
#include "blake2s.h"
#include "board_capabilities.h"
#include "common.h"
#include "flash.h"
#include "image.h"
#include "memzero.h"
#include "model.h"
#include "uzlib.h"
// symbols from bootloader.bin => bootloader.o
extern const void
_binary_embed_firmware_bootloaders_bootloader_bin_deflated_start;
extern const void
_binary_embed_firmware_bootloaders_bootloader_bin_deflated_size;
#define CONCAT_NAME_HELPER(prefix, name, suffix) prefix##name##suffix
#define CONCAT_NAME(name, var) CONCAT_NAME_HELPER(BOOTLOADER_, name, var)
#if BOOTLOADER_QA
// QA bootloaders
#define BOOTLOADER_00 CONCAT_NAME(MODEL_INTERNAL_NAME_TOKEN, _QA_00)
#define BOOTLOADER_FF CONCAT_NAME(MODEL_INTERNAL_NAME_TOKEN, _QA_FF)
#else
// normal bootloaders
#define BOOTLOADER_00 CONCAT_NAME(MODEL_INTERNAL_NAME_TOKEN, _00)
#define BOOTLOADER_FF CONCAT_NAME(MODEL_INTERNAL_NAME_TOKEN, _FF)
#endif
// clang-format on
#if PRODUCTION || BOOTLOADER_QA
static secbool latest_bootloader(const uint8_t *hash, int len) {
if (len != 32) return secfalse;
uint8_t hash_00[] = BOOTLOADER_00;
uint8_t hash_FF[] = BOOTLOADER_FF;
if (0 == memcmp(hash, hash_00, 32)) return sectrue;
if (0 == memcmp(hash, hash_FF, 32)) return sectrue;
return secfalse;
}
#endif
#define UZLIB_WINDOW_SIZE (1 << 10)
#if PRODUCTION || BOOTLOADER_QA
static void uzlib_prepare(struct uzlib_uncomp *decomp, uint8_t *window,
const void *src, uint32_t srcsize, void *dest,
uint32_t destsize) {
memzero(decomp, sizeof(struct uzlib_uncomp));
if (window) {
memzero(window, UZLIB_WINDOW_SIZE);
}
memzero(dest, destsize);
decomp->source = (const uint8_t *)src;
decomp->source_limit = decomp->source + srcsize;
decomp->dest = (uint8_t *)dest;
decomp->dest_limit = decomp->dest + destsize;
uzlib_uncompress_init(decomp, window, window ? UZLIB_WINDOW_SIZE : 0);
}
#endif
void check_and_replace_bootloader(void) {
#if PRODUCTION || BOOTLOADER_QA
// compute current bootloader hash
uint8_t hash[BLAKE2S_DIGEST_LENGTH];
const uint32_t bl_len = flash_area_get_size(&BOOTLOADER_AREA);
const void *bl_data = flash_area_get_address(&BOOTLOADER_AREA, 0, bl_len);
blake2s(bl_data, bl_len, hash, BLAKE2S_DIGEST_LENGTH);
// don't whitelist the valid bootloaders for now
// ensure(known_bootloader(hash, BLAKE2S_DIGEST_LENGTH), "Unknown bootloader
// detected");
// do we have the latest bootloader?
if (sectrue == latest_bootloader(hash, BLAKE2S_DIGEST_LENGTH)) {
return;
}
// replace bootloader with the latest one
const uint32_t *data =
(const uint32_t
*)&_binary_embed_firmware_bootloaders_bootloader_bin_deflated_start;
const uint32_t len =
(const uint32_t)&_binary_embed_firmware_bootloaders_bootloader_bin_deflated_size;
struct uzlib_uncomp decomp = {0};
uint8_t decomp_window[UZLIB_WINDOW_SIZE] = {0};
uint32_t decomp_out[IMAGE_HEADER_SIZE / sizeof(uint32_t)] = {0};
uzlib_prepare(&decomp, decomp_window, data, len, decomp_out,
sizeof(decomp_out));
ensure((uzlib_uncompress(&decomp) == TINF_OK) ? sectrue : secfalse,
"Bootloader header decompression failed");
const image_header *new_bld_hdr = read_image_header(
(uint8_t *)decomp_out, BOOTLOADER_IMAGE_MAGIC, BOOTLOADER_IMAGE_MAXSIZE);
ensure(new_bld_hdr == (const image_header *)decomp_out ? sectrue : secfalse,
"Invalid embedded bootloader");
ensure(check_image_model(new_bld_hdr), "Incompatible embedded bootloader");
const image_header *current_bld_hdr = read_image_header(
bl_data, BOOTLOADER_IMAGE_MAGIC, BOOTLOADER_IMAGE_MAXSIZE);
// cannot find valid header for current bootloader, something is wrong
ensure(current_bld_hdr == (const image_header *)bl_data ? sectrue : secfalse,
"Invalid bootloader header");
ensure(check_image_model(current_bld_hdr), "Incompatible bootloader found");
if (new_bld_hdr->monotonic < current_bld_hdr->monotonic) {
// reject downgrade
return;
}
uint32_t board_name = get_board_name();
if (board_name == 0 || strncmp((const char *)&board_name, "T2T1", 4) == 0) {
// no board capabilities, assume Model T
if ((strncmp((const char *)&new_bld_hdr->hw_model, "T2T1", 4) != 0) &&
(new_bld_hdr->hw_model != 0)) {
// reject non-model T bootloader
// 0 represents pre-model check bootloader
error_shutdown("Incompatible embedded bootloader");
}
}
// at this point, due to the previous check_image_model call, we know that the
// new_bld_hdr is
// meant for the same model as this firmware, so we can check the board name
// against the firmware hw_model.
else if (board_name != HW_MODEL) {
// reject incompatible bootloader
error_shutdown("Incompatible embedded bootloader");
}
ensure(flash_area_erase(&BOOTLOADER_AREA, NULL), NULL);
ensure(flash_unlock_write(), NULL);
uint32_t offset = 0;
do {
uint32_t *p = decomp_out;
uint32_t size = decomp.dest - (uint8_t *)decomp_out;
uint32_t size_padded = FLASH_ALIGN(size);
ensure(flash_area_write_data_padded(&BOOTLOADER_AREA, offset, p, size, 0,
size_padded),
NULL);
offset += size_padded;
decomp.dest = (uint8_t *)decomp_out;
} while (uzlib_uncompress(&decomp) >= 0);
if (offset < bl_len) {
// fill the rest of the bootloader area with 0x00
ensure(flash_area_write_data_padded(&BOOTLOADER_AREA, offset, NULL, 0, 0,
bl_len - offset),
NULL);
}
ensure(flash_lock_write(), NULL);
#endif
}