mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-12-24 15:28:10 +00:00
194 lines
6.4 KiB
C
194 lines
6.4 KiB
C
/*
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* Copyright (c) Pavol Rusnak, SatoshiLabs
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*
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* Licensed under TREZOR License
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* see LICENSE file for details
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*/
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#include <string.h>
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#include "blake2s.h"
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#include "ed25519-donna/ed25519.h"
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#include "common.h"
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#include "flash.h"
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#include "image.h"
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static secbool compute_pubkey(uint8_t sig_m, uint8_t sig_n, const uint8_t * const *pub, uint8_t sigmask, ed25519_public_key res)
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{
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if (0 == sig_m || 0 == sig_n) return secfalse;
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if (sig_m > sig_n) return secfalse;
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// discard bits higher than sig_n
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sigmask &= ((1 << sig_n) - 1);
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// remove if number of set bits in sigmask is not equal to sig_m
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if (__builtin_popcount(sigmask) != sig_m) return secfalse;
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ed25519_public_key keys[sig_m];
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int j = 0;
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for (int i = 0; i < sig_n; i++) {
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if ((1 << i) & sigmask) {
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memcpy(keys[j], pub[i], 32);
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j++;
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}
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}
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return sectrue * (0 == ed25519_cosi_combine_publickeys(res, keys, sig_m));
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}
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secbool load_image_header(const uint8_t * const data, const uint32_t magic, const uint32_t maxsize, uint8_t key_m, uint8_t key_n, const uint8_t * const *keys, image_header * const hdr)
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{
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memcpy(&hdr->magic, data, 4);
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if (hdr->magic != magic) return secfalse;
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memcpy(&hdr->hdrlen, data + 4, 4);
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if (hdr->hdrlen != IMAGE_HEADER_SIZE) return secfalse;
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memcpy(&hdr->expiry, data + 8, 4);
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// TODO: expiry mechanism needs to be ironed out before production or those
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// devices won't accept expiring bootloaders (due to boardloader write protection).
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if (hdr->expiry != 0) return secfalse;
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memcpy(&hdr->codelen, data + 12, 4);
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if (hdr->codelen > (maxsize - hdr->hdrlen)) return secfalse;
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if ((hdr->hdrlen + hdr->codelen) < 4 * 1024) return secfalse;
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if ((hdr->hdrlen + hdr->codelen) % 512 != 0) return secfalse;
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memcpy(&hdr->version, data + 16, 4);
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memcpy(&hdr->fix_version, data + 20, 4);
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memcpy(hdr->hashes, data + 32, 512);
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memcpy(&hdr->sigmask, data + IMAGE_HEADER_SIZE - IMAGE_SIG_SIZE, 1);
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memcpy(hdr->sig, data + IMAGE_HEADER_SIZE - IMAGE_SIG_SIZE + 1, IMAGE_SIG_SIZE - 1);
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// check header signature
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BLAKE2S_CTX ctx;
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blake2s_Init(&ctx, BLAKE2S_DIGEST_LENGTH);
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blake2s_Update(&ctx, data, IMAGE_HEADER_SIZE - IMAGE_SIG_SIZE);
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for (int i = 0; i < IMAGE_SIG_SIZE; i++) {
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blake2s_Update(&ctx, (const uint8_t *)"\x00", 1);
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}
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blake2s_Final(&ctx, hdr->fingerprint, BLAKE2S_DIGEST_LENGTH);
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ed25519_public_key pub;
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if (sectrue != compute_pubkey(key_m, key_n, keys, hdr->sigmask, pub)) return secfalse;
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return sectrue * (0 == ed25519_sign_open(hdr->fingerprint, BLAKE2S_DIGEST_LENGTH, pub, *(const ed25519_signature *)hdr->sig));
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}
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secbool load_vendor_header(const uint8_t * const data, uint8_t key_m, uint8_t key_n, const uint8_t * const *keys, vendor_header * const vhdr)
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{
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memcpy(&vhdr->magic, data, 4);
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if (vhdr->magic != 0x565A5254) return secfalse; // TRZV
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memcpy(&vhdr->hdrlen, data + 4, 4);
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if (vhdr->hdrlen > 64 * 1024) return secfalse;
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memcpy(&vhdr->expiry, data + 8, 4);
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if (vhdr->expiry != 0) return secfalse;
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memcpy(&vhdr->version, data + 12, 2);
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memcpy(&vhdr->vsig_m, data + 14, 1);
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memcpy(&vhdr->vsig_n, data + 15, 1);
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memcpy(&vhdr->vtrust, data + 16, 2);
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if (vhdr->vsig_n > MAX_VENDOR_PUBLIC_KEYS) {
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return secfalse;
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}
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for (int i = 0; i < vhdr->vsig_n; i++) {
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vhdr->vpub[i] = data + 32 + i * 32;
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}
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for (int i = vhdr->vsig_n; i < MAX_VENDOR_PUBLIC_KEYS; i++) {
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vhdr->vpub[i] = 0;
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}
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memcpy(&vhdr->vstr_len, data + 32 + vhdr->vsig_n * 32, 1);
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vhdr->vstr = (const char *)(data + 32 + vhdr->vsig_n * 32 + 1);
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vhdr->vimg = data + 32 + vhdr->vsig_n * 32 + 1 + vhdr->vstr_len;
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// align to 4 bytes
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vhdr->vimg += (-(uintptr_t)vhdr->vimg) & 3;
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memcpy(&vhdr->sigmask, data + vhdr->hdrlen - IMAGE_SIG_SIZE, 1);
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memcpy(vhdr->sig, data + vhdr->hdrlen - IMAGE_SIG_SIZE + 1, IMAGE_SIG_SIZE - 1);
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// check header signature
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uint8_t hash[BLAKE2S_DIGEST_LENGTH];
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BLAKE2S_CTX ctx;
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blake2s_Init(&ctx, BLAKE2S_DIGEST_LENGTH);
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blake2s_Update(&ctx, data, vhdr->hdrlen - IMAGE_SIG_SIZE);
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for (int i = 0; i < IMAGE_SIG_SIZE; i++) {
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blake2s_Update(&ctx, (const uint8_t *)"\x00", 1);
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}
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blake2s_Final(&ctx, hash, BLAKE2S_DIGEST_LENGTH);
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ed25519_public_key pub;
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if (sectrue != compute_pubkey(key_m, key_n, keys, vhdr->sigmask, pub)) return secfalse;
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return sectrue * (0 == ed25519_sign_open(hash, BLAKE2S_DIGEST_LENGTH, pub, *(const ed25519_signature *)vhdr->sig));
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}
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void vendor_keys_hash(const vendor_header * const vhdr, uint8_t *hash)
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{
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BLAKE2S_CTX ctx;
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blake2s_Init(&ctx, BLAKE2S_DIGEST_LENGTH);
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blake2s_Update(&ctx, &(vhdr->vsig_m), sizeof(vhdr->vsig_m));
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blake2s_Update(&ctx, &(vhdr->vsig_n), sizeof(vhdr->vsig_n));
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for (int i = 0; i < MAX_VENDOR_PUBLIC_KEYS; i++) {
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if (vhdr->vpub[i] != 0) {
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blake2s_Update(&ctx, vhdr->vpub[i], 32);
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} else {
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blake2s_Update(&ctx, "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 32);
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}
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}
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blake2s_Final(&ctx, hash, BLAKE2S_DIGEST_LENGTH);
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}
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secbool check_single_hash(const uint8_t * const hash, const uint8_t * const data, int len)
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{
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uint8_t h[BLAKE2S_DIGEST_LENGTH];
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blake2s(data, len, h, BLAKE2S_DIGEST_LENGTH);
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return sectrue * (0 == memcmp(h, hash, BLAKE2S_DIGEST_LENGTH));
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}
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secbool check_image_contents(const image_header * const hdr, uint32_t firstskip, const uint8_t *sectors, int blocks)
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{
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if (0 == sectors || blocks < 1) {
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return secfalse;
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}
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const void *data = flash_get_address(sectors[0], firstskip, IMAGE_CHUNK_SIZE - firstskip);
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if (!data) {
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return secfalse;
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}
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int remaining = hdr->codelen;
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if (sectrue != check_single_hash(hdr->hashes, data, MIN(remaining, IMAGE_CHUNK_SIZE - firstskip))) {
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return secfalse;
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}
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int block = 1;
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remaining -= IMAGE_CHUNK_SIZE - firstskip;
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while (remaining > 0) {
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if (block >= blocks) {
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return secfalse;
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}
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data = flash_get_address(sectors[block], 0, IMAGE_CHUNK_SIZE);
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if (!data) {
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return secfalse;
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}
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if (sectrue != check_single_hash(hdr->hashes + block * 32, data, MIN(remaining, IMAGE_CHUNK_SIZE))) {
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return secfalse;
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}
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block++;
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remaining -= IMAGE_CHUNK_SIZE;
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}
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return sectrue;
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}
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