mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-12-20 21:38:26 +00:00
349 lines
11 KiB
C
349 lines
11 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 <string.h>
|
|
|
|
#include "blake2s.h"
|
|
#include "ed25519-donna/ed25519.h"
|
|
|
|
#include "common.h"
|
|
#include "flash.h"
|
|
#include "image.h"
|
|
#include "model.h"
|
|
|
|
const uint8_t BOOTLOADER_KEY_M = 2;
|
|
const uint8_t BOOTLOADER_KEY_N = 3;
|
|
static const uint8_t * const BOOTLOADER_KEYS[] = {
|
|
#if !PRODUCTION
|
|
/*** DEVEL/QA KEYS ***/
|
|
(const uint8_t *)"\xd7\x59\x79\x3b\xbc\x13\xa2\x81\x9a\x82\x7c\x76\xad\xb6\xfb\xa8\xa4\x9a\xee\x00\x7f\x49\xf2\xd0\x99\x2d\x99\xb8\x25\xad\x2c\x48",
|
|
(const uint8_t *)"\x63\x55\x69\x1c\x17\x8a\x8f\xf9\x10\x07\xa7\x47\x8a\xfb\x95\x5e\xf7\x35\x2c\x63\xe7\xb2\x57\x03\x98\x4c\xf7\x8b\x26\xe2\x1a\x56",
|
|
(const uint8_t *)"\xee\x93\xa4\xf6\x6f\x8d\x16\xb8\x19\xbb\x9b\xeb\x9f\xfc\xcd\xfc\xdc\x14\x12\xe8\x7f\xee\x6a\x32\x4c\x2a\x99\xa1\xe0\xe6\x71\x48",
|
|
#else
|
|
MODEL_BOOTLOADER_KEYS
|
|
#endif
|
|
};
|
|
|
|
static secbool compute_pubkey(uint8_t sig_m, uint8_t sig_n,
|
|
const uint8_t *const *pub, uint8_t sigmask,
|
|
ed25519_public_key res) {
|
|
if (0 == sig_m || 0 == sig_n) return secfalse;
|
|
if (sig_m > sig_n) return secfalse;
|
|
|
|
// discard bits higher than sig_n
|
|
sigmask &= ((1 << sig_n) - 1);
|
|
|
|
// remove if number of set bits in sigmask is not equal to sig_m
|
|
if (__builtin_popcount(sigmask) != sig_m) return secfalse;
|
|
|
|
ed25519_public_key keys[sig_m];
|
|
int j = 0;
|
|
for (int i = 0; i < sig_n; i++) {
|
|
if ((1 << i) & sigmask) {
|
|
memcpy(keys[j], pub[i], 32);
|
|
j++;
|
|
}
|
|
}
|
|
|
|
return sectrue * (0 == ed25519_cosi_combine_publickeys(res, keys, sig_m));
|
|
}
|
|
|
|
const image_header *read_image_header(const uint8_t *const data,
|
|
const uint32_t magic,
|
|
const uint32_t maxsize) {
|
|
const image_header *hdr = (const image_header *)data;
|
|
|
|
if (hdr->magic != magic) {
|
|
return NULL;
|
|
}
|
|
if (hdr->hdrlen != IMAGE_HEADER_SIZE) {
|
|
return NULL;
|
|
}
|
|
|
|
// TODO: expiry mechanism needs to be ironed out before production or those
|
|
// devices won't accept expiring bootloaders (due to boardloader write
|
|
// protection).
|
|
// lowest bit is used for breaking compatibility between old TT bootloaders
|
|
// and non TT images
|
|
// which is evaluated in check_image_model function
|
|
if ((hdr->expiry & 0xFFFFFFFE) != 0) return secfalse;
|
|
|
|
if (hdr->codelen > (maxsize - hdr->hdrlen)) return secfalse;
|
|
if ((hdr->hdrlen + hdr->codelen) < 4 * 1024) return secfalse;
|
|
if ((hdr->hdrlen + hdr->codelen) % 512 != 0) return secfalse;
|
|
|
|
return hdr;
|
|
}
|
|
|
|
secbool check_image_model(const image_header *const hdr) {
|
|
// abusing expiry field to break compatibility of non-TT images with existing
|
|
// bootloaders/boardloaders
|
|
#ifdef TREZOR_MODEL_T
|
|
if (hdr->expiry == 0 && hdr->hw_model == 0 && hdr->hw_revision == 0) {
|
|
// images for model TT older than this check
|
|
return sectrue;
|
|
}
|
|
#else
|
|
if ((hdr->expiry & 0x01) == 0) {
|
|
// for models other than TT, expiry == 0 is unacceptable, as the image will
|
|
// run on bootloaders older that this check
|
|
return secfalse;
|
|
}
|
|
#endif
|
|
|
|
#ifndef TREZOR_EMULATOR
|
|
if (hdr->hw_model != HW_MODEL) {
|
|
return secfalse;
|
|
}
|
|
if (hdr->hw_revision != HW_REVISION) {
|
|
return secfalse;
|
|
}
|
|
#endif
|
|
|
|
return sectrue;
|
|
}
|
|
|
|
void get_image_fingerprint(const image_header *const hdr, uint8_t *const out) {
|
|
BLAKE2S_CTX ctx;
|
|
blake2s_Init(&ctx, BLAKE2S_DIGEST_LENGTH);
|
|
blake2s_Update(&ctx, hdr, IMAGE_HEADER_SIZE - IMAGE_SIG_SIZE);
|
|
for (int i = 0; i < IMAGE_SIG_SIZE; i++) {
|
|
blake2s_Update(&ctx, (const uint8_t *)"\x00", 1);
|
|
}
|
|
blake2s_Final(&ctx, out, BLAKE2S_DIGEST_LENGTH);
|
|
}
|
|
|
|
secbool check_image_header_sig(const image_header *const hdr, uint8_t key_m,
|
|
uint8_t key_n, const uint8_t *const *keys) {
|
|
// check header signature
|
|
|
|
uint8_t fingerprint[32];
|
|
get_image_fingerprint(hdr, fingerprint);
|
|
|
|
ed25519_public_key pub;
|
|
if (sectrue != compute_pubkey(key_m, key_n, keys, hdr->sigmask, pub))
|
|
return secfalse;
|
|
|
|
return sectrue *
|
|
(0 == ed25519_sign_open(fingerprint, BLAKE2S_DIGEST_LENGTH, pub,
|
|
*(const ed25519_signature *)hdr->sig));
|
|
}
|
|
|
|
secbool __wur read_vendor_header(const uint8_t *const data,
|
|
vendor_header *const vhdr) {
|
|
memcpy(&vhdr->magic, data, 4);
|
|
if (vhdr->magic != 0x565A5254) return secfalse; // TRZV
|
|
|
|
memcpy(&vhdr->hdrlen, data + 4, 4);
|
|
if (vhdr->hdrlen > 64 * 1024) return secfalse;
|
|
|
|
memcpy(&vhdr->expiry, data + 8, 4);
|
|
if (vhdr->expiry != 0) return secfalse;
|
|
|
|
vhdr->origin = data;
|
|
|
|
memcpy(&vhdr->version, data + 12, 2);
|
|
|
|
memcpy(&vhdr->vsig_m, data + 14, 1);
|
|
memcpy(&vhdr->vsig_n, data + 15, 1);
|
|
memcpy(&vhdr->vtrust, data + 16, 2);
|
|
|
|
if (vhdr->vsig_n > MAX_VENDOR_PUBLIC_KEYS) {
|
|
return secfalse;
|
|
}
|
|
|
|
for (int i = 0; i < vhdr->vsig_n; i++) {
|
|
vhdr->vpub[i] = data + 32 + i * 32;
|
|
}
|
|
for (int i = vhdr->vsig_n; i < MAX_VENDOR_PUBLIC_KEYS; i++) {
|
|
vhdr->vpub[i] = 0;
|
|
}
|
|
|
|
memcpy(&vhdr->vstr_len, data + 32 + vhdr->vsig_n * 32, 1);
|
|
|
|
vhdr->vstr = (const char *)(data + 32 + vhdr->vsig_n * 32 + 1);
|
|
|
|
vhdr->vimg = data + 32 + vhdr->vsig_n * 32 + 1 + vhdr->vstr_len;
|
|
// align to 4 bytes
|
|
vhdr->vimg += (-(uintptr_t)vhdr->vimg) & 3;
|
|
|
|
memcpy(&vhdr->sigmask, data + vhdr->hdrlen - IMAGE_SIG_SIZE, 1);
|
|
|
|
memcpy(vhdr->sig, data + vhdr->hdrlen - IMAGE_SIG_SIZE + 1,
|
|
IMAGE_SIG_SIZE - 1);
|
|
|
|
return sectrue;
|
|
}
|
|
|
|
secbool check_vendor_header_sig(const vendor_header *const vhdr, uint8_t key_m,
|
|
uint8_t key_n, const uint8_t *const *keys) {
|
|
if (vhdr == NULL) {
|
|
return secfalse;
|
|
}
|
|
|
|
// check header signature
|
|
|
|
uint8_t hash[BLAKE2S_DIGEST_LENGTH];
|
|
BLAKE2S_CTX ctx;
|
|
blake2s_Init(&ctx, BLAKE2S_DIGEST_LENGTH);
|
|
blake2s_Update(&ctx, vhdr->origin, vhdr->hdrlen - IMAGE_SIG_SIZE);
|
|
for (int i = 0; i < IMAGE_SIG_SIZE; i++) {
|
|
blake2s_Update(&ctx, (const uint8_t *)"\x00", 1);
|
|
}
|
|
blake2s_Final(&ctx, hash, BLAKE2S_DIGEST_LENGTH);
|
|
|
|
ed25519_public_key pub;
|
|
if (sectrue != compute_pubkey(key_m, key_n, keys, vhdr->sigmask, pub))
|
|
return secfalse;
|
|
|
|
return sectrue *
|
|
(0 == ed25519_sign_open(hash, BLAKE2S_DIGEST_LENGTH, pub,
|
|
*(const ed25519_signature *)vhdr->sig));
|
|
}
|
|
|
|
secbool check_vendor_header_keys(const vendor_header *const vhdr) {
|
|
return check_vendor_header_sig(vhdr, BOOTLOADER_KEY_M, BOOTLOADER_KEY_N,
|
|
BOOTLOADER_KEYS);
|
|
}
|
|
|
|
void vendor_header_hash(const vendor_header *const vhdr, uint8_t *hash) {
|
|
BLAKE2S_CTX ctx;
|
|
blake2s_Init(&ctx, BLAKE2S_DIGEST_LENGTH);
|
|
blake2s_Update(&ctx, vhdr->vstr, vhdr->vstr_len);
|
|
blake2s_Update(&ctx, "Trezor Vendor Header", 20);
|
|
blake2s_Final(&ctx, hash, BLAKE2S_DIGEST_LENGTH);
|
|
}
|
|
|
|
secbool check_single_hash(const uint8_t *const hash, const uint8_t *const data,
|
|
int len) {
|
|
uint8_t h[BLAKE2S_DIGEST_LENGTH];
|
|
blake2s(data, len, h, BLAKE2S_DIGEST_LENGTH);
|
|
return sectrue * (0 == memcmp(h, hash, BLAKE2S_DIGEST_LENGTH));
|
|
}
|
|
//
|
|
secbool check_image_contents(const image_header *const hdr, uint32_t firstskip,
|
|
const flash_area_t *area) {
|
|
if (0 == area) {
|
|
return secfalse;
|
|
}
|
|
|
|
// Check the firmware integrity, calculate and compare hashes
|
|
size_t offset = firstskip;
|
|
size_t end_offset = offset + hdr->codelen;
|
|
|
|
while (offset < end_offset) {
|
|
size_t bytes_to_check = MIN(IMAGE_CHUNK_SIZE - (offset % IMAGE_CHUNK_SIZE),
|
|
end_offset - offset);
|
|
|
|
const void *data = flash_area_get_address(area, offset, bytes_to_check);
|
|
if (!data) {
|
|
return secfalse;
|
|
}
|
|
|
|
size_t hash_offset = (offset / IMAGE_CHUNK_SIZE) * 32;
|
|
if (sectrue !=
|
|
check_single_hash(hdr->hashes + hash_offset, data, bytes_to_check)) {
|
|
return secfalse;
|
|
}
|
|
|
|
offset += bytes_to_check;
|
|
}
|
|
|
|
// Check the padding to the end of the area
|
|
end_offset = flash_area_get_size(area);
|
|
|
|
if (offset < end_offset) {
|
|
// Use the first byte in the checked area as the expected padding byte
|
|
// Firmware is always padded with 0xFF, while the bootloader might be
|
|
// padded with 0x00 as well
|
|
uint8_t expected_byte = *(
|
|
(const uint8_t *)flash_area_get_address(area, offset, sizeof(uint8_t)));
|
|
|
|
if (expected_byte != 0x00 && expected_byte != 0xFF) {
|
|
return secfalse;
|
|
}
|
|
|
|
while (offset < end_offset) {
|
|
size_t bytes_to_check = MIN(
|
|
IMAGE_CHUNK_SIZE - (offset % IMAGE_CHUNK_SIZE), end_offset - offset);
|
|
|
|
const uint8_t *data =
|
|
(const uint8_t *)flash_area_get_address(area, offset, bytes_to_check);
|
|
if (!data) {
|
|
return secfalse;
|
|
}
|
|
|
|
for (size_t i = 0; i < bytes_to_check; i++) {
|
|
if (data[i] != expected_byte) {
|
|
return secfalse;
|
|
}
|
|
}
|
|
|
|
offset += bytes_to_check;
|
|
}
|
|
}
|
|
|
|
return sectrue;
|
|
}
|
|
|
|
secbool check_firmware_header(const uint8_t *header, size_t header_size,
|
|
firmware_header_info_t *info) {
|
|
// parse and check vendor header
|
|
vendor_header vhdr;
|
|
if (sectrue != read_vendor_header(header, &vhdr)) {
|
|
return secfalse;
|
|
}
|
|
if (sectrue != check_vendor_header_keys(&vhdr)) {
|
|
return secfalse;
|
|
}
|
|
|
|
// parse and check image header
|
|
const image_header *ihdr;
|
|
if ((ihdr = read_image_header(header + vhdr.hdrlen, FIRMWARE_IMAGE_MAGIC,
|
|
FIRMWARE_IMAGE_MAXSIZE)) == NULL) {
|
|
return secfalse;
|
|
}
|
|
if (sectrue !=
|
|
check_image_header_sig(ihdr, vhdr.vsig_m, vhdr.vsig_n, vhdr.vpub)) {
|
|
return secfalse;
|
|
}
|
|
|
|
// copy vendor string
|
|
info->vstr_len = MIN(sizeof(info->vstr), vhdr.vstr_len);
|
|
if (info->vstr_len > 0) {
|
|
memcpy(info->vstr, vhdr.vstr, info->vstr_len);
|
|
}
|
|
|
|
// copy firmware version
|
|
info->ver_major = ihdr->version & 0xFF;
|
|
info->ver_minor = (ihdr->version >> 8) & 0xFF;
|
|
info->ver_patch = (ihdr->version >> 16) & 0xFF;
|
|
|
|
// calculate and copy the image fingerprint
|
|
get_image_fingerprint(ihdr, info->fingerprint);
|
|
|
|
// calculate hash of both vendor and image headers
|
|
BLAKE2S_CTX ctx;
|
|
blake2s_Init(&ctx, BLAKE2S_DIGEST_LENGTH);
|
|
blake2s_Update(&ctx, header, vhdr.hdrlen + ihdr->hdrlen);
|
|
blake2s_Final(&ctx, &info->hash, BLAKE2S_DIGEST_LENGTH);
|
|
|
|
return sectrue;
|
|
}
|