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276 lines
11 KiB
276 lines
11 KiB
/*
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* This file is part of the Trezor project, https://trezor.io/
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*
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* Copyright (C) 2014 Pavol Rusnak <stick@satoshilabs.com>
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*
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* This library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <string.h>
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#include "ecdsa.h"
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#include "fw_signatures.h"
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#include "memory.h"
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#include "memzero.h"
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#include "secbool.h"
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#include "secp256k1.h"
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#include "sha2.h"
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const uint32_t FIRMWARE_MAGIC_NEW = 0x465a5254; // TRZF
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/*
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* There are 3 schemes in history of T1, for clarity naming:
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*
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* - v1 - previously called "old" with TRZR magic header (no longer here)
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* - v2 - previously called "new" with TRZF magic header
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* - v3 - the latest scheme using Trezor's SignMessage and VerifyMessage
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* style signatures
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*
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* See `debug_signing/README.md` and the scripts there for signatures debug.
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*
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* Latest scheme v3 ref: https://github.com/trezor/trezor-firmware/issues/2513
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*/
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#define PUBKEYS_V3 3
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#define PUBKEYS_V2 5
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#if DEBUG_T1_SIGNATURES || BOOTLOADER_QA
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// Make build explode if combining debug sigs with production
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#if PRODUCTION
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#error "Can't have production device with debug keys! Build aborted"
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#endif
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// These are **only** for debugging signatures with SignMessage
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// Use this mnemonic for testing signing:
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// "table table table table table table table table table table table advance"
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// the "SignMessage"-style public keys, third signing scheme
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// See legacy/debug_signing/README.md
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static const uint8_t * const pubkey_v3[PUBKEYS_V3] = {
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(const uint8_t *)"\x03\x73\x08\xe1\x40\x77\x16\x1c\x36\x5d\xea\x0f\x5c\x80\xaa\x6c\x5d\xba\x34\x71\x9e\x82\x5b\xd2\x3a\xe5\xf7\xe7\xd2\x98\x8a\xdb\x0f",
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(const uint8_t *)"\x03\x9c\x1b\x24\x60\xe3\x43\x71\x2e\x98\x2e\x07\x32\xe7\xed\x17\xf6\x0d\xe4\xc9\x33\x06\x5b\x71\x70\xd9\x9c\x6e\x7f\xe7\xcc\x7f\x4b",
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(const uint8_t *)"\x03\x15\x2b\x37\xfd\xf1\x26\x11\x12\x74\xc8\x94\xc3\x48\xdc\xc9\x75\xb5\x7c\x11\x5e\xe2\x4c\xeb\x19\xb5\x19\x0a\xc7\xf7\xb6\x51\x73",
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};
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// the "new", or second signing scheme keys
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/*
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Debug private keys for v2 (previously called "new") scheme
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corresponding to pubkeys below as python hexstring array:
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['4444444444444444444444444444444444444444444444444444444444444444',
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'4545454545454545454545454545454545454545454545454545454545454545',
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'bfc4bca9c9c228a16639d3503d999a733a439210b64cebe757a4fd03ca46a5c8',
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'5518381d95e93e8eb68a294354989906e3828f36b4556a2ad85d8333294eb1b7',
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'1d1d34168760dec092c9ff89377d8659076d2dfd95e0281719c15f90d067e211']
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*/
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static const uint8_t * const pubkey_v2[PUBKEYS_V2] = {
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(const uint8_t *)"\x03\x2c\x0b\x7c\xf9\x53\x24\xa0\x7d\x05\x39\x8b\x24\x01\x74\xdc\x0c\x2b\xe4\x44\xd9\x6b\x15\x9a\xa6\xc7\xf7\xb1\xe6\x68\x68\x09\x91",
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(const uint8_t *)"\x02\xed\xab\xbd\x16\xb4\x1c\x83\x71\xb9\x2e\xf2\xf0\x4c\x11\x85\xb4\xf0\x3b\x6d\xcd\x52\xba\x9b\x78\xd9\xd7\xc8\x9c\x8f\x22\x11\x45",
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(const uint8_t *)"\x03\x66\x5f\x66\x0a\x50\x52\xbe\x7a\x95\x54\x6a\x02\x17\x90\x58\xd9\x3d\x3e\x08\xa7\x79\x73\x49\x14\x59\x43\x46\x07\x5b\xb0\xaf\xd4",
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(const uint8_t *)"\x03\x66\x63\x5d\x99\x94\x17\xb6\x55\x66\x86\x6c\x65\x63\x0d\x97\x7a\x7a\xe7\x23\xfe\x5f\x6c\x4c\xd1\x7f\xa0\x0f\x08\x8b\xa1\x84\xc1",
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(const uint8_t *)"\x03\xf3\x6c\x7d\x0f\xb6\x15\xad\xa4\x3d\x71\x88\x58\x0f\x15\xeb\xda\x22\xd6\xf6\xb9\xb1\xa9\x2b\xff\x16\xc6\x93\x77\x99\xdc\xbc\x66"
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};
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#else // DEBUG_T1_SIGNATURES is now 0
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// These public keys are production keys
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// - used in production devices
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// the "SignMessage"-style public keys, third signing scheme
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static const uint8_t * const pubkey_v3[PUBKEYS_V3] = {
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(const uint8_t *)"\x03\x23\x00\xc1\xbb\x45\x39\xfc\xbf\xca\x25\x90\xbd\xa3\xdd\x20\x93\x82\x6f\x4a\xe4\x37\xbd\xde\xcc\x1a\x2e\x72\x52\x07\x64\xff\x7a",
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(const uint8_t *)"\x02\x33\xba\xea\xeb\xc9\x4a\x2a\x3e\x8b\x11\xf3\x9a\x71\x33\xdb\xf4\x27\xbe\x29\x2f\xcb\xce\xb8\x87\xd7\x1e\xf5\x1e\x85\x39\x5a\x19",
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(const uint8_t *)"\x03\x57\x09\x1f\xa2\x54\xb5\x52\x33\xd0\xbb\x4c\x48\xe1\x06\xc9\x1b\x92\xfd\x07\x88\xeb\xed\x9d\x3a\x91\x67\x19\xf4\x4c\x76\xc0\x15"
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};
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// the "new", or second signing scheme keys
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static const uint8_t * const pubkey_v2[PUBKEYS_V2] = {
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(const uint8_t *)"\x02\xd5\x71\xb7\xf1\x48\xc5\xe4\x23\x2c\x38\x14\xf7\x77\xd8\xfa\xea\xf1\xa8\x42\x16\xc7\x8d\x56\x9b\x71\x04\x1f\xfc\x76\x8a\x5b\x2d",
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(const uint8_t *)"\x03\x63\x27\x9c\x0c\x08\x66\xe5\x0c\x05\xc7\x99\xd3\x2b\xd6\xba\xb0\x18\x8b\x6d\xe0\x65\x36\xd1\x10\x9d\x2e\xd9\xce\x76\xcb\x33\x5c",
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(const uint8_t *)"\x02\x43\xae\xdb\xb6\xf7\xe7\x1c\x56\x3f\x8e\xd2\xef\x64\xec\x99\x81\x48\x25\x19\xe7\xef\x4f\x4a\xa9\x8b\x27\x85\x4e\x8c\x49\x12\x6d",
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(const uint8_t *)"\x02\x87\x7c\x39\xfd\x7c\x62\x23\x7e\x03\x82\x35\xe9\xc0\x75\xda\xb2\x61\x63\x0f\x78\xee\xb8\xed\xb9\x24\x87\x15\x9f\xff\xed\xfd\xf6",
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(const uint8_t *)"\x03\x73\x84\xc5\x1a\xe8\x1a\xdd\x0a\x52\x3a\xdb\xb1\x86\xc9\x1b\x90\x6f\xfb\x64\xc2\xc7\x65\x80\x2b\xf2\x6d\xbd\x13\xbd\xf1\x2c\x31"
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};
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#endif
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#define FLASH_META_START 0x08008000
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#define FLASH_META_CODELEN (FLASH_META_START + 0x0004)
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#define FLASH_META_SIGINDEX1 (FLASH_META_START + 0x0008)
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#define FLASH_META_SIGINDEX2 (FLASH_META_START + 0x0009)
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#define FLASH_META_SIGINDEX3 (FLASH_META_START + 0x000A)
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#define FLASH_OLD_APP_START 0x08010000
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#define FLASH_META_SIG1 (FLASH_META_START + 0x0040)
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#define FLASH_META_SIG2 (FLASH_META_START + 0x0080)
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#define FLASH_META_SIG3 (FLASH_META_START + 0x00C0)
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/*
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* 0x18 in message prefix is coin info, 0x20 is the length of hash
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* that follows.
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* See `core/src/apps/bitcoin/sign_message.py`.
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*/
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#define VERIFYMESSAGE_PREFIX \
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("\x18" \
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"Bitcoin Signed Message:\n\x20")
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#define PREFIX_LENGTH (sizeof(VERIFYMESSAGE_PREFIX) - 1)
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#define SIGNED_LENGTH (PREFIX_LENGTH + 32)
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void compute_firmware_fingerprint(const image_header *hdr, uint8_t hash[32]) {
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image_header copy = {0};
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memcpy(©, hdr, sizeof(image_header));
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memzero(copy.sig1, sizeof(copy.sig1));
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memzero(copy.sig2, sizeof(copy.sig2));
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memzero(copy.sig3, sizeof(copy.sig3));
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copy.sigindex1 = 0;
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copy.sigindex2 = 0;
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copy.sigindex3 = 0;
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sha256_Raw((const uint8_t *)©, sizeof(image_header), hash);
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}
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void compute_firmware_fingerprint_for_verifymessage(const image_header *hdr,
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uint8_t hash[32]) {
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uint8_t prefixed_header[SIGNED_LENGTH] = VERIFYMESSAGE_PREFIX;
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uint8_t header_hash[32];
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uint8_t hash_before_double_hashing[32];
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compute_firmware_fingerprint(hdr, header_hash);
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memcpy(prefixed_header + PREFIX_LENGTH, header_hash, sizeof(header_hash));
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sha256_Raw(prefixed_header, sizeof(prefixed_header),
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hash_before_double_hashing);
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// We need to do hash the previous result again because SignMessage
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// computes it this way, see `core/src/apps/bitcoin/sign_message.py`
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sha256_Raw(hash_before_double_hashing, sizeof(hash_before_double_hashing),
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hash);
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}
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bool firmware_present_new(void) {
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const image_header *hdr =
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(const image_header *)FLASH_PTR(FLASH_FWHEADER_START);
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if (hdr->magic != FIRMWARE_MAGIC_NEW) return false;
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// we need to ignore hdrlen for now
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// because we keep reset_handler ptr there
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// for compatibility with older bootloaders
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// after this is no longer necessary, let's uncomment the line below:
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// if (hdr->hdrlen != FLASH_FWHEADER_LEN) return false;
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if (hdr->codelen > FLASH_APP_LEN) return false;
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if (hdr->codelen < 4096) return false;
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return true;
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}
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int signatures_ok(const image_header *hdr, uint8_t store_fingerprint[32],
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secbool use_verifymessage) {
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uint8_t hash[32] = {0};
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// which set of public keys depend on scheme
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const uint8_t *const *pubkey_ptr = NULL;
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uint8_t pubkeys = 0;
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if (use_verifymessage == sectrue) {
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pubkey_ptr = pubkey_v3;
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compute_firmware_fingerprint_for_verifymessage(hdr, hash);
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pubkeys = PUBKEYS_V3;
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} else {
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pubkey_ptr = pubkey_v2;
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compute_firmware_fingerprint(hdr, hash);
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pubkeys = PUBKEYS_V2;
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}
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if (store_fingerprint) {
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memcpy(store_fingerprint, hash, 32);
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}
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if (hdr->sigindex1 < 1 || hdr->sigindex1 > pubkeys)
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return SIG_FAIL; // invalid index
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if (hdr->sigindex2 < 1 || hdr->sigindex2 > pubkeys)
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return SIG_FAIL; // invalid index
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if (use_verifymessage != sectrue) {
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if (hdr->sigindex3 < 1 || hdr->sigindex3 > pubkeys) {
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return SIG_FAIL; // invalid index
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}
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} else if (hdr->sigindex3 != 0) {
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return SIG_FAIL;
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}
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if (hdr->sigindex1 == hdr->sigindex2) return SIG_FAIL; // duplicate use
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if (hdr->sigindex1 == hdr->sigindex3) return SIG_FAIL; // duplicate use
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if (hdr->sigindex2 == hdr->sigindex3) return SIG_FAIL; // duplicate use
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if (0 != ecdsa_verify_digest(&secp256k1, pubkey_ptr[hdr->sigindex1 - 1],
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hdr->sig1, hash)) { // failure
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return SIG_FAIL;
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}
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if (0 != ecdsa_verify_digest(&secp256k1, pubkey_ptr[hdr->sigindex2 - 1],
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hdr->sig2, hash)) { // failure
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return SIG_FAIL;
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}
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if (use_verifymessage != sectrue) {
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if (0 != ecdsa_verify_digest(&secp256k1, pubkey_ptr[hdr->sigindex3 - 1],
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hdr->sig3, hash)) // failure
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{
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return SIG_FAIL;
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}
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} else {
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for (unsigned int i = 0; i < sizeof(hdr->sig3); i++) {
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if (hdr->sig3[i] != 0) {
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return SIG_FAIL;
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}
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}
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}
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return SIG_OK;
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}
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int signatures_match(const image_header *hdr, uint8_t store_fingerprint[32]) {
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int result = 0;
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// Return success if v3 ("verify message") or the v2 ("new") style matches.
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// Use XOR to always force computing both signatures to avoid potential
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// timing side channels.
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// Return only the hash for the v2 computation so that it is
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// the same shown in previous bootloader.
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result ^= signatures_ok(hdr, store_fingerprint, secfalse);
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result ^= signatures_ok(hdr, NULL, sectrue);
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if (result != SIG_OK) {
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return SIG_FAIL;
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}
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return SIG_OK;
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}
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int mem_is_empty(const uint8_t *src, uint32_t len) {
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for (uint32_t i = 0; i < len; i++) {
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if (src[i]) return 0;
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}
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return 1;
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}
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int check_firmware_hashes(const image_header *hdr) {
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uint8_t hash[32] = {0};
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// check hash of the first code chunk
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sha256_Raw(FLASH_PTR(FLASH_APP_START), (64 - 1) * 1024, hash);
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if (0 != memcmp(hash, hdr->hashes, 32)) return SIG_FAIL;
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// check remaining used chunks
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uint32_t total_len = FLASH_FWHEADER_LEN + hdr->codelen;
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int used_chunks = total_len / FW_CHUNK_SIZE;
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if (total_len % FW_CHUNK_SIZE > 0) {
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used_chunks++;
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}
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for (int i = 1; i < used_chunks; i++) {
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sha256_Raw(FLASH_PTR(FLASH_FWHEADER_START + (64 * i) * 1024), 64 * 1024,
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hash);
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if (0 != memcmp(hdr->hashes + 32 * i, hash, 32)) return SIG_FAIL;
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}
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// check unused chunks
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for (int i = used_chunks; i < 16; i++) {
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if (!mem_is_empty(hdr->hashes + 32 * i, 32)) return SIG_FAIL;
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}
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// all OK
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return SIG_OK;
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}
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