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trezor-core
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bootloader: don't downgrade firmware below fix_version in the current firmware

This commit is contained in:
Pavol Rusnak 2017-12-14 21:58:32 +01:00
parent 965aa73b63
commit b4933f969e
No known key found for this signature in database
GPG Key ID: 91F3B339B9A02A3D
1 changed files with 32 additions and 5 deletions
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37
embed/bootloader/messages.c
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@ -317,11 +317,26 @@ static bool _read_payload(pb_istream_t *stream, const pb_field_t *field, void **
return true;
}
static image_header hdr;
secbool load_vendor_header_keys(const uint8_t * const data, vendor_header * const vhdr);
secbool compare_to_current_vendor_header(const vendor_header * const new_vhdr)
static int version_compare(uint32_t vera, uint32_t verb)
{
int a, b;
a = vera & 0xFF;
b = verb & 0xFF;
if (a != b) return a - b;
a = (vera >> 8) & 0xFF;
b = (verb >> 8) & 0xFF;
if (a != b) return a - b;
a = (vera >> 16) & 0xFF;
b = (verb >> 16) & 0xFF;
if (a != b) return a - b;
a = (vera >> 24) & 0xFF;
b = (verb >> 24) & 0xFF;
return a - b;
}
static secbool is_legit_upgrade(const vendor_header * const new_vhdr, const image_header * const new_hdr)
{
vendor_header current_vhdr;
if (sectrue != load_vendor_header_keys((const uint8_t *)FIRMWARE_START, &current_vhdr)) {
@ -330,7 +345,17 @@ secbool compare_to_current_vendor_header(const vendor_header * const new_vhdr)
uint8_t hash1[32], hash2[32];
vendor_keys_hash(new_vhdr, hash1);
vendor_keys_hash(&current_vhdr, hash2);
return sectrue * (0 == memcmp(hash1, hash2, 32));
if (0 != memcmp(hash1, hash2, 32)) {
return secfalse;
}
image_header current_hdr;
if (sectrue != load_image_header((const uint8_t *)FIRMWARE_START + current_vhdr.hdrlen, FIRMWARE_IMAGE_MAGIC, FIRMWARE_IMAGE_MAXSIZE, current_vhdr.vsig_m, current_vhdr.vsig_n, current_vhdr.vpub, &current_hdr)) {
return secfalse;
}
if (version_compare(new_hdr->version, current_hdr.fix_version) < 0) {
return secfalse;
}
return sectrue;
}
int process_msg_FirmwareUpload(uint8_t iface_num, uint32_t msg_size, uint8_t *buf)
@ -347,6 +372,8 @@ int process_msg_FirmwareUpload(uint8_t iface_num, uint32_t msg_size, uint8_t *bu
return -1;
}
static image_header hdr;
uint32_t firstskip = 0;
if (firmware_block == 0) {
vendor_header vhdr;
@ -365,7 +392,7 @@ int process_msg_FirmwareUpload(uint8_t iface_num, uint32_t msg_size, uint8_t *bu
return -3;
}
if (sectrue != compare_to_current_vendor_header(&vhdr)) {
if (sectrue != is_legit_upgrade(&vhdr, &hdr)) {
const uint8_t sectors_storage[] = {
FLASH_SECTOR_STORAGE_1,
FLASH_SECTOR_STORAGE_2,