mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-12-05 22:18:16 +00:00
88 lines
1.9 KiB
C
88 lines
1.9 KiB
C
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#if FLASH_BLOCK_WORDS <= 1
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#error "FLASH_BLOCK_WORDS must be at least 2 to fit the counter and header"
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#endif
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#define PIN_LOG_HALFWORDS (((FLASH_BLOCK_WORDS - 1) * sizeof(uint32_t)) / 2)
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static uint16_t expand_counter(uint16_t c) {
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c = ((c << 4) | c) & 0x0f0f;
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c = ((c << 2) | c) & 0x3333;
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c = ((c << 1) | c) & 0x5555;
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c = ((c << 1) | c) ^ 0xaaaa;
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return c;
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}
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static uint16_t compress_counter(uint16_t c) {
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if (((c ^ (c << 1)) & 0xAAAA) != 0xAAAA) {
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handle_fault("ill-formed counter");
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}
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c = c & 0x5555;
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c = ((c >> 1) | c) & 0x3333;
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c = ((c >> 2) | c) & 0x0f0f;
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c = ((c >> 4) | c) & 0x00ff;
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return c;
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}
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static secbool pin_get_fails(uint32_t *ctr) {
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const void *logs = NULL;
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uint16_t len = 0;
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wait_random();
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if (sectrue != norcow_get(PIN_LOGS_KEY, &logs, &len) ||
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len != PIN_LOG_HALFWORDS * sizeof(uint16_t)) {
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handle_fault("no PIN logs");
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return secfalse;
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}
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uint16_t c = compress_counter(((uint16_t *)logs)[0]);
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uint16_t correct_bytes_cnt = 0;
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for (uint8_t i = 0; i < PIN_LOG_HALFWORDS; i++) {
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wait_random();
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correct_bytes_cnt += compress_counter(((uint16_t *)logs)[i]) == c;
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*ctr = c;
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}
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if (correct_bytes_cnt != PIN_LOG_HALFWORDS) {
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handle_fault("PIN logs corrupted");
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return secfalse;
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}
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return sectrue * (correct_bytes_cnt == PIN_LOG_HALFWORDS);
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}
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static secbool pin_logs_init(uint32_t fails) {
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wait_random();
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uint16_t logs[PIN_LOG_HALFWORDS];
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uint16_t ctr = expand_counter(fails);
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for (uint8_t i = 0; i < PIN_LOG_HALFWORDS; i++) {
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logs[i] = ctr;
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}
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if (fails != compress_counter(ctr)) {
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handle_fault("PIN logs increase failed");
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return secfalse;
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}
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return norcow_set(PIN_LOGS_KEY, logs, sizeof(logs));
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}
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static secbool pin_fails_reset(void) { return pin_logs_init(0); }
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secbool pin_fails_increase(void) {
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uint32_t fails;
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if (sectrue != pin_get_fails(&fails)) {
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return secfalse;
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}
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fails++;
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return pin_logs_init(fails);
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}
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