//----------------------------------------------------------------------------- // Copyright (C) Proxmark3 contributors. See AUTHORS.md for details. // // 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. // // See LICENSE.txt for the text of the license. //----------------------------------------------------------------------------- #include "hitag2.h" #include "hitag2/hitag2_crypto.h" #include "string.h" #include "proxmark3_arm.h" #include "cmd.h" #include "BigBuf.h" #include "fpgaloader.h" #include "ticks.h" #include "dbprint.h" #include "util.h" #include "lfadc.h" #include "lfsampling.h" #include "lfdemod.h" #include "commonutil.h" #include "appmain.h" #include "protocols.h" #define test_bit(data, i) (*(data + (i/8)) >> (7-(i % 8))) & 1 #define set_bit(data, i) *(data + (i/8)) |= (1 << (7-(i % 8))) #define clear_bit(data, i) *(data + (i/8)) &= ~(1 << (7-(i % 8))) #define flip_bit(data, i) *(data + (i/8)) ^= (1 << (7-(i % 8))) // Successful crypto auth static bool bCrypto; // Is in auth stage static bool bAuthenticating; // Successful password auth static bool bSelecting; static bool bCollision; static bool bPwd; static bool bSuccessful; /* Password Mode : 0x06 - 0000 0110 Crypto Mode : 0x0E - 0000 1110 Public Mode A : 0x02 - 0000 0010 Public Mode B : 0x00 - 0000 0000 Public Mode C : 0x04 - 0000 0100 */ static hitag2_t tag = { .state = TAG_STATE_RESET, .sectors = { // Password mode: | Crypto mode: [0] = { 0x02, 0x4e, 0x02, 0x20}, // UID | UID [1] = { 0x4d, 0x49, 0x4b, 0x52}, // Password RWD | 32 bit LSB key [2] = { 0x20, 0xf0, 0x4f, 0x4e}, // Reserved | 16 bit MSB key, 16 bit reserved [3] = { 0x06, 0xaa, 0x48, 0x54}, // Configuration, password TAG | Configuration, password TAG [4] = { 0x46, 0x5f, 0x4f, 0x4b}, // Data: F_OK [5] = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU [6] = { 0xaa, 0xaa, 0xaa, 0xaa}, // Data: .... [7] = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU [8] = { 0x00, 0x00, 0x00, 0x00}, // RSK Low [9] = { 0x00, 0x00, 0x00, 0x00}, // RSK High [10] = { 0x00, 0x00, 0x00, 0x00}, // RCF [11] = { 0x00, 0x00, 0x00, 0x00}, // SYNC // up to index 15 reserved for HITAG 1/HITAG S public data }, }; static enum { WRITE_STATE_START = 0x0, WRITE_STATE_PAGENUM_WRITTEN, WRITE_STATE_PROG } writestate; // ToDo: define a meaningful maximum size for auth_table. The bigger this is, the lower will be the available memory for traces. // Historically it used to be FREE_BUFFER_SIZE, which was 2744. #define AUTH_TABLE_LENGTH 2744 static uint8_t *auth_table; static size_t auth_table_pos = 0; static size_t auth_table_len = AUTH_TABLE_LENGTH; static uint8_t password[4]; static uint8_t NrAr[8]; static uint8_t key[8]; static uint8_t writedata[4]; static uint8_t logdata_0[4], logdata_1[4]; static uint8_t nonce[4]; static uint8_t key_no; static uint64_t cipher_state; static int16_t blocknr; static size_t flipped_bit = 0; static uint32_t byte_value = 0; static void hitag2_reset(void) { tag.state = TAG_STATE_RESET; tag.crypto_active = 0; } static void hitag2_init(void) { hitag2_reset(); } // Sam7s has several timers, we will use the source TIMER_CLOCK1 (aka AT91C_TC_CLKS_TIMER_DIV1_CLOCK) // TIMER_CLOCK1 = MCK/2, MCK is running at 48 MHz, Timer is running at 48/2 = 24 MHz // Hitag units (T0) have duration of 8 microseconds (us), which is 1/125000 per second (carrier) // T0 = TIMER_CLOCK1 / 125000 = 192 #ifndef HITAG_T0 #define HITAG_T0 192 #endif #define HITAG_FRAME_LEN 20 #define HITAG_FRAME_BIT_COUNT (8 * HITAG_FRAME_LEN) #define HITAG_T_STOP 36 /* T_EOF should be > 36 */ #define HITAG_T_LOW 6 /* T_LOW should be 4..10 */ #define HITAG_T_0_MIN 15 /* T[0] should be 18..22 */ #define HITAG_T_0 20 /* T[0] should be 18..22 */ #define HITAG_T_1_MIN 25 /* T[1] should be 26..30 */ #define HITAG_T_1 30 /* T[1] should be 26..30 */ #define HITAG_T_EOF 80 /* T_EOF should be > 36 and must be larger than HITAG_T_TAG_CAPTURE_FOUR_HALF */ #define HITAG_T_WAIT_1_MIN 199 /* T_wresp should be 199..206 */ #define HITAG_T_WAIT_2_MIN 90 /* T_wait2 should be at least 90 */ #define HITAG_T_WAIT_MAX 300 /* bit more than HITAG_T_WAIT_1 + HITAG_T_WAIT_2 */ #define HITAG_T_PROG 614 #define HITAG_T_WAIT_POWERUP 313 /* transponder internal powerup time is 312.5 */ #define HITAG_T_WAIT_START_AUTH_MAX 232 /* transponder waiting time to receive the START_AUTH command is 232.5, then it enters public mode */ #define HITAG_T_TAG_ONE_HALF_PERIOD 10 #define HITAG_T_TAG_TWO_HALF_PERIOD 25 #define HITAG_T_TAG_THREE_HALF_PERIOD 41 #define HITAG_T_TAG_FOUR_HALF_PERIOD 57 #define HITAG_T_TAG_HALF_PERIOD 16 #define HITAG_T_TAG_FULL_PERIOD 32 #define HITAG_T_TAG_CAPTURE_ONE_HALF 13 #define HITAG_T_TAG_CAPTURE_TWO_HALF 25 #define HITAG_T_TAG_CAPTURE_THREE_HALF 41 #define HITAG_T_TAG_CAPTURE_FOUR_HALF 57 #define HT2_MAX_NRSZ ((8 * HITAG_FRAME_LEN + 5) * 2) /* // sim static void hitag_send_bit(int bit, bool ledcontrol) { if (ledcontrol) LED_A_ON(); // Reset clock for the next bit AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG; // Fixed modulation, earlier proxmark version used inverted signal // check datasheet if reader uses BiPhase? if (bit == 0) { // Manchester: Unloaded, then loaded |__--| LOW(GPIO_SSC_DOUT); while (AT91C_BASE_TC0->TC_CV < HITAG_T0 * HITAG_T_TAG_HALF_PERIOD); HIGH(GPIO_SSC_DOUT); while (AT91C_BASE_TC0->TC_CV < HITAG_T0 * HITAG_T_TAG_FULL_PERIOD); } else { // Manchester: Loaded, then unloaded |--__| HIGH(GPIO_SSC_DOUT); while (AT91C_BASE_TC0->TC_CV < HITAG_T0 * HITAG_T_TAG_HALF_PERIOD); LOW(GPIO_SSC_DOUT); while (AT91C_BASE_TC0->TC_CV < HITAG_T0 * HITAG_T_TAG_FULL_PERIOD); } if (ledcontrol) LED_A_OFF(); } // sim static void hitag_send_frame(const uint8_t *frame, size_t frame_len) { // SOF - send start of frame hitag_send_bit(1); hitag_send_bit(1); hitag_send_bit(1); hitag_send_bit(1); hitag_send_bit(1); // Send the content of the frame for (size_t i = 0; i < frame_len; i++) { hitag_send_bit((frame[i / 8] >> (7 - (i % 8))) & 1); } // Drop the modulation LOW(GPIO_SSC_DOUT); } */ // sim static void hitag2_handle_reader_command(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen) { uint8_t rx_air[HITAG_FRAME_LEN]; // Copy the (original) received frame how it is send over the air memcpy(rx_air, rx, nbytes(rxlen)); if (tag.crypto_active) { ht2_hitag2_cipher_transcrypt(&(tag.cs), rx, rxlen / 8, rxlen % 8); } // Reset the transmission frame length *txlen = 0; // Try to find out which command was send by selecting on length (in bits) switch (rxlen) { // Received 11000 from the reader, request for UID, send UID case 5: { // Always send over the air in the clear plaintext mode if (rx_air[0] != HITAG2_START_AUTH) { // Unknown frame ? return; } *txlen = 32; memcpy(tx, tag.sectors[0], 4); tag.crypto_active = 0; } break; // Read/Write command: ..xx x..y yy with yyy == ~xxx, xxx is sector number case 10: { uint16_t sector = (~(((rx[0] << 2) & 0x04) | ((rx[1] >> 6) & 0x03)) & 0x07); // Verify complement of sector index if (sector != ((rx[0] >> 3) & 0x07)) { DBG DbpString("Transmission error (read/write)"); return; } switch (rx[0] & 0xC6) { // Read command: 11xx x00y case HITAG2_READ_PAGE: { memcpy(tx, tag.sectors[sector], 4); *txlen = 32; break; } // Inverted Read command: 01xx x10y case HITAG2_READ_PAGE_INVERTED: { for (size_t i = 0; i < 4; i++) { tx[i] = tag.sectors[sector][i] ^ 0xff; } *txlen = 32; break; } // Write command: 10xx x01y case HITAG2_WRITE_PAGE: { // Prepare write, acknowledge by repeating command memcpy(tx, rx, nbytes(rxlen)); *txlen = rxlen; tag.active_sector = sector; tag.state = TAG_STATE_WRITING; break; } // Unknown command default: { DBG Dbprintf("Unknown command: %02x %02x", rx[0], rx[1]); return; } } } break; // Writing data or Reader password case 32: { if (tag.state == TAG_STATE_WRITING) { // These are the sector contents to be written. We don't have to do anything else. memcpy(tag.sectors[tag.active_sector], rx, nbytes(rxlen)); tag.state = TAG_STATE_RESET; return; } else { // Received RWD password, respond with configuration and our password if (memcmp(rx, tag.sectors[1], 4) != 0) { DBG DbpString("Reader password is wrong"); return; } *txlen = 32; memcpy(tx, tag.sectors[3], 4); } } break; // Received RWD authentication challenge and response case 64: { // Store the authentication attempt if (auth_table_len < (AUTH_TABLE_LENGTH - 8)) { memcpy(auth_table + auth_table_len, rx, 8); auth_table_len += 8; } // Reset the cipher state ht2_hitag2_cipher_reset(&tag, rx); // Check if the authentication was correct if (!ht2_hitag2_cipher_authenticate(&(tag.cs), rx + 4)) { // The reader failed to authenticate, do nothing DBG Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed!", rx[0], rx[1], rx[2], rx[3], rx[4], rx[5], rx[6], rx[7]); return; } // Activate encryption algorithm for all further communication tag.crypto_active = 1; // Use the tag password as response memcpy(tx, tag.sectors[3], 4); *txlen = 32; } break; } // LogTraceBits(rx, rxlen, 0, 0, false); // LogTraceBits(tx, txlen, 0, 0, true); if (tag.crypto_active) { ht2_hitag2_cipher_transcrypt(&(tag.cs), tx, *txlen / 8, *txlen % 8); } } // reader/writer // returns how long it took static uint32_t hitag_reader_send_bit(int bit) { // Binary pulse length modulation (BPLM) is used to encode the data stream // This means that a transmission of a one takes longer than that of a zero // Enable modulation, which means, drop the field lf_modulation(true); // Wait for 4-10 times the carrier period lf_wait_periods(HITAG_T_LOW); // wait for 4-10 times the carrier period uint32_t wait = HITAG_T_LOW; // Disable modulation, just activates the field again lf_modulation(false); if (bit == 0) { // Zero bit: |_-| lf_wait_periods(HITAG_T_0 - HITAG_T_LOW); // wait for 18-22 times the carrier period wait += HITAG_T_0 - HITAG_T_LOW; } else { // One bit: |_--| lf_wait_periods(HITAG_T_1 - HITAG_T_LOW); // wait for 26-32 times the carrier period wait += HITAG_T_1 - HITAG_T_LOW; } return wait; } // reader / writer commands // frame_len is in number of bits? static uint32_t hitag_reader_send_frame(const uint8_t *frame, size_t frame_len) { WDT_HIT(); uint32_t wait = 0; // Send the content of the frame for (size_t i = 0; i < frame_len; i++) { wait += hitag_reader_send_bit((frame[i / 8] >> (7 - (i % 8))) & 1); } // Send EOF // Enable modulation, which means, drop the field lf_modulation(true); // Wait for 4-10 times the carrier period lf_wait_periods(HITAG_T_LOW); wait += HITAG_T_LOW; // Disable modulation, just activates the field again lf_modulation(false); // t_stop, high field for stop condition (> 36) lf_wait_periods(HITAG_T_STOP); wait += HITAG_T_STOP; WDT_HIT(); return wait; } // reader / writer commands // frame_len is in number of bits? static uint32_t hitag_reader_send_framebits(const uint8_t *frame, size_t frame_len) { WDT_HIT(); uint32_t wait = 0; // Send the content of the frame for (size_t i = 0; i < frame_len; i++) { wait += hitag_reader_send_bit(frame[i]); } // Send EOF // Enable modulation, which means, drop the field // set GPIO_SSC_DOUT to HIGH lf_modulation(true); // Wait for 4-10 times the carrier period lf_wait_periods(HITAG_T_LOW); wait += HITAG_T_LOW; // Disable modulation, just activates the field again // set GPIO_SSC_DOUT to LOW lf_modulation(false); // t_stop, high field for stop condition (> 36) lf_wait_periods(HITAG_T_STOP); wait += HITAG_T_STOP; WDT_HIT(); return wait; } static uint8_t hitag_crc(uint8_t *data, size_t n) { uint8_t crc = 0xFF; for (size_t i = 0; i < ((n + 7) / 8); i++) { crc ^= *(data + i); uint8_t bit = n < (8 * (i + 1)) ? (n % 8) : 8; while (bit--) { if (crc & 0x80) { crc <<= 1; crc ^= 0x1D; } else { crc <<= 1; } } } return crc; } /* void fix_ac_decoding(uint8_t *input, size_t len) { // Reader routine tries to decode AC data after Manchester decoding // AC has double the bitrate, extract data from bit-pairs uint8_t temp[len / 16]; memset(temp, 0, sizeof(temp)); for (size_t i = 1; i < len; i += 2) { if (test_bit(input, i) && test_bit(input, (i + 1))) { set_bit(temp, (i / 2)); } } memcpy(input, temp, sizeof(temp)); } */ // looks at number of received bits. // 0 = collision? // 32 = good response static bool hitag1_plain(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen, bool hitag_s) { *txlen = 0; switch (rxlen) { case 0: { // retry waking up card /*tx[0] = 0xb0; // Rev 3.0*/ tx[0] = HITAG1_SET_CC; // Rev 2.0 *txlen = 5; if (!bCollision) blocknr--; if (blocknr < 0) { blocknr = 0; } if (!hitag_s) { if (blocknr > 1 && blocknr < 31) { blocknr = 31; } } bCollision = true; return true; } case 32: { uint8_t crc; if (bCollision) { // Select card by serial from response tx[0] = HITAG1_SELECT | rx[0] >> 5; tx[1] = rx[0] << 3 | rx[1] >> 5; tx[2] = rx[1] << 3 | rx[2] >> 5; tx[3] = rx[2] << 3 | rx[3] >> 5; tx[4] = rx[3] << 3; crc = hitag_crc(tx, 37); tx[4] |= crc >> 5; tx[5] = crc << 3; *txlen = 45; bCollision = false; } else { memcpy(tag.sectors[blocknr], rx, 4); blocknr++; if (!hitag_s) { if (blocknr > 1 && blocknr < 31) { blocknr = 31; } } if (blocknr > 63) { DbpString("Read successful!"); *txlen = 0; bSuccessful = true; return false; } // read next page of card until done Dbprintf("Reading page %02u", blocknr); tx[0] = HITAG1_RDPPAGE | blocknr >> 4; // RDPPAGE tx[1] = blocknr << 4; crc = hitag_crc(tx, 12); tx[1] |= crc >> 4; tx[2] = crc << 4; *txlen = 20; } } break; default: { Dbprintf("Unknown frame length: %d", rxlen); return false; } break; } return true; } static bool hitag1_authenticate(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen) { uint8_t crc; *txlen = 0; switch (rxlen) { case 0: { // retry waking up card /*tx[0] = 0xb0; // Rev 3.0*/ tx[0] = HITAG1_SELECT; // Rev 2.0 *txlen = 5; if (bCrypto && byte_value <= 0xff) { // to retry bCrypto = false; } if (!bCollision) blocknr--; if (blocknr < 0) { blocknr = 0; } bCollision = true; // will receive 32-bit UID } break; case 2: { if (bAuthenticating) { // received Auth init ACK, send nonce // TODO Roel, bit-manipulation goes here /*nonce[0] = 0x2d;*/ /*nonce[1] = 0x74;*/ /*nonce[2] = 0x80;*/ /*nonce[3] = 0xa5;*/ nonce[0] = byte_value; byte_value++; /*set_bit(nonce,flipped_bit);*/ memcpy(tx, nonce, 4); *txlen = 32; // will receive 32 bit encrypted Logdata } else if (bCrypto) { // authed, start reading tx[0] = HITAG1_RDCPAGE | blocknr >> 4; // RDCPAGE tx[1] = blocknr << 4; crc = hitag_crc(tx, 12); tx[1] |= crc >> 4; tx[2] = crc << 4; *txlen = 20; // will receive 32-bit encrypted page } } break; case 32: { if (bCollision) { // Select card by serial from response tx[0] = HITAG1_SELECT | rx[0] >> 5; tx[1] = rx[0] << 3 | rx[1] >> 5; tx[2] = rx[1] << 3 | rx[2] >> 5; tx[3] = rx[2] << 3 | rx[3] >> 5; tx[4] = rx[3] << 3; crc = hitag_crc(tx, 37); tx[4] |= crc >> 5; tx[5] = crc << 3; *txlen = 45; bCollision = false; bSelecting = true; // will receive 32-bit configuration page } else if (bSelecting) { // Initiate auth tx[0] = HITAG1_WRCPAGE | (key_no); // WRCPAGE tx[1] = blocknr << 4; crc = hitag_crc(tx, 12); tx[1] |= crc >> 4; tx[2] = crc << 4; *txlen = 20; bSelecting = false; bAuthenticating = true; // will receive 2-bit ACK } else if (bAuthenticating) { // received 32-bit logdata 0 // TODO decrypt logdata 0, verify against logdata_0 memcpy(tag.sectors[0], rx, 4); memcpy(tag.sectors[1], tx, 4); Dbprintf("%02x%02x%02x%02x %02x%02x%02x%02x", rx[0], rx[1], rx[2], rx[3], tx[0], tx[1], tx[2], tx[3]); // TODO replace with secret data stream // TODO encrypt logdata_1 memcpy(tx, logdata_1, 4); *txlen = 32; bAuthenticating = false; bCrypto = true; // will receive 2-bit ACK } else if (bCrypto) { // received 32-bit encrypted page // TODO decrypt rx memcpy(tag.sectors[blocknr], rx, 4); blocknr++; if (blocknr > 63) { DbpString("Read successful!"); bSuccessful = true; return false; } // TEST Dbprintf("Successfully authenticated with logdata:"); Dbhexdump(4, logdata_1, false); bSuccessful = true; return false; /* // read next page of card until done tx[0] = HITAG1_RDCPAGE | blocknr >> 4; // RDCPAGE tx[1] = blocknr << 4; crc = hitag_crc(tx, 12); tx[1] |= crc >> 4; tx[2] = crc << 4; *txlen = 20; */ } } break; default: { Dbprintf("Unknown frame length: %d", rxlen); return false; } break; } return true; } //----------------------------------------------------------------------------- // Hitag 2 operations //----------------------------------------------------------------------------- static bool hitag2_write_page(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen) { switch (writestate) { case WRITE_STATE_START: { *txlen = 10; tx[0] = HITAG2_WRITE_PAGE | (blocknr << 3) | ((blocknr ^ 7) >> 2); tx[1] = ((blocknr ^ 7) << 6); writestate = WRITE_STATE_PAGENUM_WRITTEN; break; } case WRITE_STATE_PAGENUM_WRITTEN: { // Check if page number was received correctly if ((rxlen == 10) && (rx[0] == (HITAG2_WRITE_PAGE | (blocknr << 3) | ((blocknr ^ 7) >> 2))) && (rx[1] == (((blocknr & 0x3) ^ 0x3) << 6))) { *txlen = 32; memset(tx, 0, HITAG_FRAME_LEN); memcpy(tx, writedata, 4); writestate = WRITE_STATE_PROG; } else { Dbprintf("hitag2_write_page: Page number was not received correctly: rxlen %d rx %02x%02x%02x%02x" , rxlen , rx[0], rx[1], rx[2], rx[3] ); bSuccessful = false; return false; } break; } case WRITE_STATE_PROG: { if (rxlen == 0) { bSuccessful = true; } else { bSuccessful = false; Dbprintf("hitag2_write_page: unexpected rx data (%d) after page write", rxlen); } return false; } default: { Dbprintf("hitag2_write_page: Unknown state " _RED_("%d"), writestate); bSuccessful = false; return false; } } return true; } static bool hitag2_password(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen, bool write) { // Reset the transmission frame length *txlen = 0; if (bPwd && (bAuthenticating == false) && write) { SpinDelay(2); if (hitag2_write_page(rx, rxlen, tx, txlen) == false) { return false; } } else { // Try to find out which command was send by selecting on length (in bits) switch (rxlen) { // No answer, try to resurrect case 0: { // Stop if there is no answer (after sending password) if (bPwd) { DBG DbpString("Password failed!"); return false; } *txlen = 5; memcpy(tx, "\xC0", nbytes(*txlen)); } break; // Received UID, tag password case 32: { // stage 1, got UID if (bPwd == false) { bPwd = true; bAuthenticating = true; memcpy(tx, password, 4); *txlen = 32; } else { // stage 2, got config byte+password TAG, discard as will read later if (bAuthenticating) { bAuthenticating = false; if (write) { if (!hitag2_write_page(rx, rxlen, tx, txlen)) { return false; } break; } } // stage 2+, got data block else { memcpy(tag.sectors[blocknr], rx, 4); blocknr++; } if (blocknr > 7) { bSuccessful = true; return false; } *txlen = 10; tx[0] = HITAG2_READ_PAGE | (blocknr << 3) | ((blocknr ^ 7) >> 2); tx[1] = ((blocknr ^ 7) << 6); } } break; // Unexpected response default: { DBG Dbprintf("Unknown frame length: " _RED_("%d"), rxlen); return false; } break; } } return true; } static bool hitag2_crypto(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen, bool write) { // Reset the transmission frame length *txlen = 0; if (bCrypto) { ht2_hitag2_cipher_transcrypt(&cipher_state, rx, rxlen / 8, rxlen % 8); } if (bCrypto && (bAuthenticating == false) && write) { SpinDelay(2); if (hitag2_write_page(rx, rxlen, tx, txlen) == false) { return false; } } else { // Try to find out which command was send by selecting on length (in bits) switch (rxlen) { // No answer, try to resurrect case 0: { // Stop if there is no answer while we are in crypto mode (after sending NrAr) if (bCrypto) { // Failed during authentication if (bAuthenticating) { DBG DbpString("Authentication failed!"); return false; } else { // Failed reading a block, could be (read/write) locked, skip block and re-authenticate if (blocknr == 1) { // Write the low part of the key in memory memcpy(tag.sectors[1], key + 2, 4); } else if (blocknr == 2) { // Write the high part of the key in memory tag.sectors[2][0] = 0x00; tag.sectors[2][1] = 0x00; tag.sectors[2][2] = key[0]; tag.sectors[2][3] = key[1]; } else { // Just put zero's in the memory (of the unreadable block) memset(tag.sectors[blocknr], 0x00, 4); } blocknr++; bCrypto = false; } } else { *txlen = 5; memcpy(tx, "\xc0", nbytes(*txlen)); } break; } // Received UID, crypto tag answer case 32: { // stage 1, got UID if (bCrypto == false) { DBG Dbprintf("hitag2_crypto: key array "); DBG Dbhexdump(6, key, false); uint64_t ui64key = key[0] | ((uint64_t)key[1]) << 8 | ((uint64_t)key[2]) << 16 | ((uint64_t)key[3]) << 24 | ((uint64_t)key[4]) << 32 | ((uint64_t)key[5]) << 40; uint32_t ui32uid = rx[0] | ((uint32_t)rx[1]) << 8 | ((uint32_t)rx[2]) << 16 | ((uint32_t)rx[3]) << 24; DBG Dbprintf("hitag2_crypto: key=0x%x%x uid=0x%x" , (uint32_t)((REV64(ui64key)) >> 32) , (uint32_t)((REV64(ui64key)) & 0xffffffff) , REV32(ui32uid) ); cipher_state = ht2_hitag2_init(REV64(ui64key), REV32(ui32uid), 0); // PRN 00 00 00 00 memset(tx, 0x00, 4); // Secret data FF FF FF FF memset(tx + 4, 0xff, 4); ht2_hitag2_cipher_transcrypt(&cipher_state, tx + 4, 4, 0); *txlen = 64; bCrypto = true; bAuthenticating = true; } else { // stage 2, got config byte+password TAG, discard as will read later if (bAuthenticating) { bAuthenticating = false; if (write) { if (hitag2_write_page(rx, rxlen, tx, txlen) == false) { return false; } break; } } else { // stage 2+, got data block // Store the received block memcpy(tag.sectors[blocknr], rx, 4); blocknr++; } if (blocknr > 7) { DBG DbpString("Read successful!"); bSuccessful = true; return false; } else { *txlen = 10; tx[0] = HITAG2_READ_PAGE | (blocknr << 3) | ((blocknr ^ 7) >> 2); tx[1] = ((blocknr ^ 7) << 6); } } break; } default: { DBG Dbprintf("Unknown frame length: " _RED_("%d"), rxlen); return false; } } } // try to avoid double encryption calls if (bCrypto && bAuthenticating == false) { ht2_hitag2_cipher_transcrypt(&cipher_state, tx, *txlen / 8, *txlen % 8); } return true; } static bool hitag2_authenticate(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen, bool write) { // Reset the transmission frame length *txlen = 0; // Try to find out which command was send by selecting on length (in bits) switch (rxlen) { case 0: { // No answer, try to resurrect // Stop if there is no answer while we are in crypto mode (after sending NrAr) if (bCrypto) { DBG DbpString("No answer after sending NrAr!"); return false; } else { // Failed during authentication if (bAuthenticating) { DBG DbpString("Authentication - failed!"); return false; } DBG DbpString("Authenticating - send 0xC0"); *txlen = 5; memcpy(tx, "\xC0", nbytes(*txlen)); } break; } case 32: { // Received UID or crypto tag answer if (bCrypto == false) { *txlen = 64; memcpy(tx, NrAr, sizeof(NrAr)); bCrypto = true; bAuthenticating = true; DBG DbpString("Authenticating sending NrAr"); } else { DBG DbpString("Authentication successful!"); // stage 2, got config byte+password TAG, discard as will read later if (bAuthenticating) { bAuthenticating = false; if (write) { if (hitag2_write_page(rx, rxlen, tx, txlen) == false) { return false; } break; } } else { // stage 2+, got data block // Store the received block memcpy(tag.sectors[blocknr], rx, 4); blocknr++; } if (blocknr > 7) { DBG DbpString("Read successful!"); bSuccessful = true; return false; } else { DBG Dbprintf("Sending read block %u", blocknr); *txlen = 10; tx[0] = HITAG2_READ_PAGE | (blocknr << 3) | ((blocknr ^ 7) >> 2); tx[1] = ((blocknr ^ 7) << 6); } } break; } default: { DBG Dbprintf("Unknown frame length: " _RED_("%d"), rxlen); return false; } } return true; } static bool hitag2_test_auth_attempts(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen) { // Reset the transmission frame length *txlen = 0; // Try to find out which command was send by selecting on length (in bits) switch (rxlen) { // No answer, try to resurrect case 0: { // Stop if there is no answer while we are in crypto mode (after sending NrAr) if (bCrypto) { Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed, removed entry!", NrAr[0], NrAr[1], NrAr[2], NrAr[3], NrAr[4], NrAr[5], NrAr[6], NrAr[7]); // Removing failed entry from authentications table memcpy(auth_table + auth_table_pos, auth_table + auth_table_pos + 8, 8); auth_table_len -= 8; // Return if we reached the end of the authentications table bCrypto = false; if (auth_table_pos == auth_table_len) { return false; } // Copy the next authentication attempt in row (at the same position, b/c we removed last failed entry) memcpy(NrAr, auth_table + auth_table_pos, 8); } *txlen = 5; memcpy(tx, "\xc0", nbytes(*txlen)); } break; // Received UID, crypto tag answer, or read block response case 32: { if (bCrypto == false) { *txlen = 64; memcpy(tx, NrAr, 8); bCrypto = true; } else { Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x ( " _GREEN_("ok") " )", NrAr[0], NrAr[1], NrAr[2], NrAr[3], NrAr[4], NrAr[5], NrAr[6], NrAr[7]); bCrypto = false; if ((auth_table_pos + 8) == auth_table_len) { return false; } auth_table_pos += 8; memcpy(NrAr, auth_table + auth_table_pos, 8); } } break; default: { Dbprintf("Unknown frame length: " _RED_("%d"), rxlen); return false; } break; } return true; } // Hitag 2 Sniffing void hitag_sniff(void) { FpgaDownloadAndGo(FPGA_BITSTREAM_LF); BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); set_tracing(true); // Set up eavesdropping mode, frequency divisor which will drive the FPGA // and analog mux selection. FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_TOGGLE_MODE); FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); // 125Khz SetAdcMuxFor(GPIO_MUXSEL_LOPKD); RELAY_OFF(); } // T0 18-22 fc (total time ZERO) // T1 26-32 fc (total time ONE) // Tstop 36 > fc (high field stop limit) // Tlow 4-10 fc (reader field low time) void SniffHitag2(bool ledcontrol) { if (ledcontrol) LED_D_ON(); FpgaDownloadAndGo(FPGA_BITSTREAM_LF); BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); set_tracing(true); /* lf_init(false, false, ledcontrol); // no logging of the raw signal g_logging = true; uint32_t total_count = 0; uint8_t rx[HITAG_FRAME_BIT_COUNT * 2]; while (BUTTON_PRESS() == false) { lf_reset_counter(); WDT_HIT(); size_t periods = 0; uint16_t rxlen = 0; memset(rx, 0x00, sizeof(rx)); // Use the current modulation state as starting point uint8_t mod_state = lf_get_reader_modulation(); while (rxlen < sizeof(rx)) { periods = lf_count_edge_periods(64); // Evaluate the number of periods before the next edge if (periods >= 24 && periods < 64) { // Detected two sequential equal bits and a modulation switch // NRZ modulation: (11 => --|) or (11 __|) rx[rxlen++] = mod_state; if (rxlen < sizeof(rx)) { rx[rxlen++] = mod_state; } // toggle tag modulation state mod_state ^= 1; } else if (periods > 0 && periods < 24) { // Detected one bit and a modulation switch // NRZ modulation: (1 => -|) or (0 _|) rx[rxlen++] = mod_state; mod_state ^= 1; } else { mod_state ^= 1; // The function lf_count_edge_periods() returns > 64 periods, this is not a valid number periods Dbprintf("Detected unexpected period count... " _YELLOW_("%zu"), periods); break; } } if (rxlen < 10) { continue; } // tag sends 11111 + uid, bool got_tag = (memcmp(rx, "\x01\x00\x01\x00\x01\x00\x01\x00\x01\x00", 10) == 0); Dbprintf("periods... %zu rxlen... %u", periods, rxlen); Dbhexdump(rxlen, rx, false); if (got_tag) { bool bad_man = false; uint16_t bitnum = 0; // mqnchester decode for (uint16_t i = 0; i < rxlen; i += 2) { if (rx[i] == 1 && (rx[i + 1] == 0)) { rx[bitnum++] = 0; } else if ((rx[i] == 0) && rx[i + 1] == 1) { rx[bitnum++] = 1; } else { bad_man = true; break; } } // Dbprintf(_YELLOW_("TAG") " rxlen... %u bitnum... %u", rxlen, bitnum); if (bad_man) { Dbprintf("bad manchester ( bitnum %u )", bitnum); continue;; } if (bitnum < 5) { DbpString("too few bits"); continue; } // Pack the response into a byte array, // and skip header 11111 (start at idx 5) rxlen = 0; for (uint16_t i = 5; i < bitnum; i++) { uint8_t b = rx[i]; rx[rxlen >> 3] |= b << (7 - (rxlen % 8)); rxlen++; } // skip spurious bit if (rxlen % 8 == 1) { rxlen--; } // nothing to log if (rxlen == 0) { if (ledcontrol) LED_A_INV(); continue; } LogTraceBits(rx, rxlen, 0, periods, false); total_count += nbytes(rxlen); } else { // nothing to log if (rxlen < 3) { if (ledcontrol) LED_A_INV(); continue; } uint16_t n = 0; for (uint16_t i = 0; i < rxlen; i++) { uint8_t b = rx[i]; rx[n >> 3] |= b << (7 - (n % 8)); n++; } // decode reader comms LogTraceBits(rx, n, 0, periods, true); total_count += nbytes(n); } if (ledcontrol) LED_A_INV(); } lf_finalize(ledcontrol); Dbprintf("Collected %u bytes", total_count); switch_off(); BigBuf_free(); } */ // Set up eavesdropping mode, frequency divisor which will drive the FPGA // and analog mux selection. FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_TOGGLE_MODE); FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); // 125Khz SetAdcMuxFor(GPIO_MUXSEL_LOPKD); RELAY_OFF(); // Configure output pin that is connected to the FPGA (for modulating) // AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT; // AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT; // Disable modulation, we are going to eavesdrop, not modulate ;) // LOW(GPIO_SSC_DOUT); // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the reader frames AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1); AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME; // Disable timer during configuration AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger, // external trigger rising edge, load RA on rising edge of TIOA. AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_BOTH | AT91C_TC_ABETRG | AT91C_TC_LDRA_BOTH; // Enable and reset counter AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; // Assert a sync signal. This sets all timers to 0 on next active clock edge AT91C_BASE_TCB->TCB_BCR = 1; int frame_count = 0, response = 0, lastbit = 1, tag_sof = 4; int overflow = 0; bool rising_edge, reader_frame = false, bSkip = true; // bool exit_due_to_overflow; // HACK -- add one byte to avoid rewriting manchester decoder for edge case uint8_t rx[HITAG_FRAME_LEN + 1]; size_t rxlen = 0; auth_table_len = 0; auth_table_pos = 0; auth_table = (uint8_t *)BigBuf_calloc(AUTH_TABLE_LENGTH); while (BUTTON_PRESS() == false) { WDT_HIT(); // bool exit_due_to_overflow = false; // Receive frame, watch for at most T0 * EOF periods while (AT91C_BASE_TC1->TC_CV < (HITAG_T0 * HITAG_T_EOF)) { // Check if rising edge in modulation is detected if (AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) { // Retrieve the new timing values int ra = (AT91C_BASE_TC1->TC_RA / HITAG_T0) + overflow; overflow = 0; // Find out if we are dealing with a rising or falling edge rising_edge = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME) > 0; // Shorter periods will only happen with reader frames if (reader_frame == false && rising_edge && ra < HITAG_T_TAG_CAPTURE_ONE_HALF) { // Switch from tag to reader capture if (ledcontrol) LED_C_OFF(); reader_frame = true; rxlen = 0; } // Only handle if reader frame and rising edge, or tag frame and falling edge if (reader_frame != rising_edge) { overflow += ra; continue; } // Add the buffered timing values of earlier captured edges which were skipped ra += overflow; overflow = 0; if (reader_frame) { if (ledcontrol) LED_B_ON(); // Capture reader frame if (ra >= HITAG_T_STOP) { // if (rxlen != 0) { //DbpString("wierd0?"); // } // Capture the T0 periods that have passed since last communication or field drop (reset) response = (ra - HITAG_T_LOW); if (rxlen != 0) { Dbprintf("ra - HITAG_T_LOW... %i", response); } } else if (ra >= HITAG_T_1_MIN) { // '1' bit rx[rxlen / 8] |= 1 << (7 - (rxlen % 8)); rxlen++; } else if (ra >= HITAG_T_0_MIN) { // '0' bit rx[rxlen / 8] |= 0 << (7 - (rxlen % 8)); rxlen++; } } else { if (ledcontrol) LED_C_ON(); // Capture tag frame (manchester decoding using only falling edges) if (ra >= HITAG_T_EOF) { // if (rxlen != 0) { //DbpString("wierd1?"); // } // Capture the T0 periods that have passed since last communication or field drop (reset) // We always receive a 'one' first, which has the falling edge after a half period |-_| response = ra - HITAG_T_TAG_HALF_PERIOD; } else if (ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) { // Manchester coding example |-_|_-|-_| (101) rx[rxlen / 8] |= 0 << (7 - (rxlen % 8)); rxlen++; rx[rxlen / 8] |= 1 << (7 - (rxlen % 8)); rxlen++; } else if (ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) { // Manchester coding example |_-|...|_-|-_| (0...01) rx[rxlen / 8] |= 0 << (7 - (rxlen % 8)); rxlen++; // We have to skip this half period at start and add the 'one' the second time if (bSkip == false) { rx[rxlen / 8] |= 1 << (7 - (rxlen % 8)); rxlen++; } lastbit = !lastbit; bSkip = !bSkip; } else if (ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) { // Manchester coding example |_-|_-| (00) or |-_|-_| (11) if (tag_sof) { // Ignore bits that are transmitted during SOF tag_sof--; } else { // bit is same as last bit rx[rxlen / 8] |= lastbit << (7 - (rxlen % 8)); rxlen++; } } } } } // end while // Check if frame was captured if (rxlen) { frame_count++; LogTraceBits(rx, rxlen, response, 0, reader_frame); // Check if we recognize a valid authentication attempt if (rxlen == 64) { // Store the authentication attempt if (auth_table_len < (AUTH_TABLE_LENGTH - 8)) { memcpy(auth_table + auth_table_len, rx, 8); auth_table_len += 8; } } if (ledcontrol) { LED_B_OFF(); LED_C_OFF(); } response = 0; reader_frame = false; lastbit = 1; bSkip = true; tag_sof = 4; overflow = 0; if (ledcontrol) { LED_B_OFF(); LED_C_OFF(); } } else { // Save the timer overflow, will be 0 when frame was received overflow += (AT91C_BASE_TC1->TC_CV / HITAG_T0); } // Reset the frame length rxlen = 0; // Reset the timer to restart while-loop that receives frames AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG; // Assert a sync signal. This sets all timers to 0 on next active clock edge AT91C_BASE_TCB->TCB_BCR = 1; } if (ledcontrol) LEDsoff(); AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; DBG Dbprintf("frames.......... %d", frame_count); Dbprintf("Auth attempts... %d", (auth_table_len / 8)); switch_off(); BigBuf_free(); } // Hitag 2 simulation void SimulateHitag2(bool ledcontrol) { BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); set_tracing(true); // empties bigbuff etc lf_init(false, true, ledcontrol); int response = 0; uint8_t rx[HITAG_FRAME_LEN] = {0}; uint8_t tx[HITAG_FRAME_LEN] = {0}; auth_table_len = 0; auth_table_pos = 0; // auth_table = BigBuf_calloc(AUTH_TABLE_LENGTH); DbpString("Starting Hitag 2 simulation"); // hitag2 state machine? hitag2_init(); // printing uint32_t block = 0; for (size_t i = 0; i < 12; i++) { // num2bytes? for (size_t j = 0; j < 4; j++) { block <<= 8; block |= tag.sectors[i][j]; } Dbprintf("| %d | %08x |", i, block); } size_t max_nrzs = 8 * HITAG_FRAME_LEN + 5; uint8_t nrz_samples[max_nrzs]; // uint32_t command_start = 0, command_duration = 0; // int16_t checked = 0; // SIMULATE uint32_t signal_size = 10000; while (BUTTON_PRESS() == false) { // use malloc initSampleBufferEx(&signal_size, true); if (ledcontrol) { LED_D_ON(); LED_A_OFF(); } // lf_reset_counter(); WDT_HIT(); /* // only every 1000th times, in order to save time when collecting samples. if (checked == 100) { if (data_available()) { checked = -1; break; } else { checked = 0; } } ++checked; */ size_t rxlen = 0, txlen = 0; // Keep administration of the first edge detection bool waiting_for_first_edge = true; // Did we detected any modulaiton at all bool detected_modulation = false; // Use the current modulation state as starting point uint8_t reader_modulation = lf_get_reader_modulation(); // Receive frame, watch for at most max_nrzs periods // Reset the number of NRZ samples and use edge detection to detect them size_t nrzs = 0; while (nrzs < max_nrzs) { // Get the timing of the next edge in number of wave periods size_t periods = lf_count_edge_periods(128); // Just break out of loop after an initial time-out (tag is probably not available) // The function lf_count_edge_periods() returns 0 when a time-out occurs if (periods == 0) { break; } if (ledcontrol) LED_A_ON(); // Are we dealing with the first incoming edge if (waiting_for_first_edge) { // Register the number of periods that have passed response = periods; // Indicate that we have dealt with the first edge waiting_for_first_edge = false; // The first edge is always a single NRZ bit, force periods on 16 periods = 16; // We have received more than 0 periods, so we have detected a tag response detected_modulation = true; } // Evaluate the number of periods before the next edge if (periods > 24 && periods <= 64) { // Detected two sequential equal bits and a modulation switch // NRZ modulation: (11 => --|) or (11 __|) nrz_samples[nrzs++] = reader_modulation; if (nrzs < max_nrzs) { nrz_samples[nrzs++] = reader_modulation; } // Invert tag modulation state reader_modulation ^= 1; } else if (periods > 0 && periods <= 24) { // Detected one bit and a modulation switch // NRZ modulation: (1 => -|) or (0 _|) nrz_samples[nrzs++] = reader_modulation; reader_modulation ^= 1; } else { reader_modulation ^= 1; // The function lf_count_edge_periods() returns > 64 periods, this is not a valid number periods Dbprintf("Detected unexpected period count: %zu", periods); break; } } if (ledcontrol) LED_D_OFF(); // If there is no response, just repeat the loop if (!detected_modulation) continue; if (ledcontrol) LED_A_OFF(); // Make sure we always have an even number of samples. This fixes the problem // of ending the manchester decoding with a zero. See the example below where // the '|' character is end of modulation // One at the end: ..._-|_____... // Zero at the end: ...-_|_____... // The last modulation change of a zero is not detected, but we should take // the half period in account, otherwise the demodulator will fail. if ((nrzs % 2) != 0) { if (nrzs >= max_nrzs) { Dbprintf("max_nrzs (%d) is odd? Must be even!", max_nrzs); // should be a static assert above continue; } nrz_samples[nrzs++] = reader_modulation; } if (ledcontrol) LED_B_ON(); // decode bitstream manrawdecode((uint8_t *)nrz_samples, &nrzs, true, 0); // Verify if the header consists of five consecutive ones if (nrzs < 5) { Dbprintf("Detected unexpected number of manchester decoded samples [%d]", nrzs); continue; } else { for (size_t i = 0; i < 5; i++) { if (nrz_samples[i] != 1) { Dbprintf("Detected incorrect header, the bit [%d] is zero instead of one", i); } } } // Pack the response into a byte array for (size_t i = 5; i < 37; i++) { uint8_t bit = nrz_samples[i]; rx[rxlen / 8] |= bit << (7 - (rxlen % 8)); rxlen++; } // Check if frame was captured if (rxlen > 4) { LogTraceBits(rx, rxlen, response, response, true); // Process the incoming frame (rx) and prepare the outgoing frame (tx) hitag2_handle_reader_command(rx, rxlen, tx, &txlen); // Wait for HITAG_T_WAIT_1 carrier periods after the last reader bit, // not that since the clock counts since the rising edge, but T_Wait1 is // with respect to the falling edge, we need to wait actually (T_Wait1 - T_Low) // periods. The gap time T_Low varies (4..10). All timer values are in // terms of T0 units (HITAG_T_WAIT_1_MIN - HITAG_T_LOW ) lf_wait_periods(HITAG_T_WAIT_1_MIN); // Send and store the tag answer (if there is any) if (txlen) { // Transmit the tag frame //hitag_send_frame(tx, txlen); lf_manchester_send_bytes(tx, txlen, ledcontrol); // Store the frame in the trace LogTraceBits(tx, txlen, 0, 0, false); } // Reset the received frame and response timing info memset(rx, 0x00, sizeof(rx)); response = 0; if (ledcontrol) LED_B_OFF(); } } lf_finalize(ledcontrol); // release allocated memory from BigBuff. BigBuf_free(); DbpString("Sim stopped"); // reply_ng(CMD_LF_HITAG_SIMULATE, (checked == -1) ? PM3_EOPABORTED : PM3_SUCCESS, (uint8_t *)tag.sectors, tag_size); } void ReaderHitag(const lf_hitag_data_t *payload, bool ledcontrol) { uint32_t command_start = 0, command_duration = 0; uint32_t response_start = 0, response_duration = 0; uint8_t rx[HITAG_FRAME_LEN] = {0}; size_t rxlen = 0; uint8_t txbuf[HITAG_FRAME_LEN] = {0}; uint8_t *tx = txbuf; size_t txlen = 0; int t_wait_1 = 204; int t_wait_1_guard = 8; int t_wait_2 = 128; size_t tag_size = 48; bool bStop = false; // Raw demodulation/decoding by sampling edge periods size_t periods = 0; // Reset the return status bSuccessful = false; bCrypto = false; // Clean up trace and prepare it for storing frames set_tracing(true); clear_trace(); // Check configuration switch (payload->cmd) { case HT1F_PLAIN: { DBG Dbprintf("Read public blocks in plain mode"); // this part will be unreadable memset(tag.sectors + 2, 0x0, 30); blocknr = 0; break; } case HT1F_AUTHENTICATE: { DBG Dbprintf("Read all blocks in authed mode"); memcpy(nonce, payload->nonce, 4); memcpy(key, payload->key, 4); memcpy(logdata_0, payload->logdata_0, 4); memcpy(logdata_1, payload->logdata_1, 4); // TEST memset(nonce, 0x0, 4); memset(logdata_1, 0x00, 4); byte_value = 0; key_no = payload->key_no; DBG Dbprintf("Authenticating using key #%u :", key_no); DBG Dbhexdump(4, key, false); DBG DbpString("Nonce:"); DBG Dbhexdump(4, nonce, false); DBG DbpString("Logdata_0:"); DBG Dbhexdump(4, logdata_0, false); DBG DbpString("Logdata_1:"); DBG Dbhexdump(4, logdata_1, false); blocknr = 0; break; } case HT2F_PASSWORD: { DBG Dbprintf("List identifier in password mode"); if (memcmp(payload->pwd, "\x00\x00\x00\x00", 4) == 0) { memcpy(password, tag.sectors[1], sizeof(password)); } else { memcpy(password, payload->pwd, sizeof(password)); } blocknr = 0; bPwd = false; bAuthenticating = false; break; } case HT2F_AUTHENTICATE: { DBG DbpString("Authenticating using NrAr pair:"); memcpy(NrAr, payload->NrAr, 8); DBG Dbhexdump(8, NrAr, false); // We can't read block 0, 1, 2.. blocknr = 3; bCrypto = false; bPwd = false; bAuthenticating = false; break; } case HT2F_CRYPTO: { DBG DbpString("Authenticating using key:"); memcpy(key, payload->key, 6); //HACK; 4 or 6?? I read both in the code. DBG Dbhexdump(6, key, false); DBG DbpString("Nonce:"); DBG Dbhexdump(4, nonce, false); memcpy(nonce, payload->data, 4); blocknr = 0; bCrypto = false; bAuthenticating = false; break; } case HT2F_TEST_AUTH_ATTEMPTS: { DBG Dbprintf("Testing " _YELLOW_("%d") " authentication attempts", (auth_table_len / 8)); auth_table_pos = 0; memcpy(NrAr, auth_table, 8); bCrypto = false; break; } default: { DBG Dbprintf("Error, unknown function: " _RED_("%d"), payload->cmd); set_tracing(false); reply_ng(CMD_LF_HITAG_READER, PM3_ESOFT, NULL, 0); return; } } if (ledcontrol) LED_D_ON(); // hitag 2 state machine? hitag2_init(); // Tag specific configuration settings (sof, timings, etc.) // TODO HTS /* if (payload->cmd <= HTS_LAST_CMD) { // hitag S settings t_wait_1 = 204; t_wait_2 = 128; flipped_bit = 0; tag_size = 8; DBG DbpString("Configured for " _YELLOW_("Hitag S") " reader"); } else */ if (payload->cmd <= HT1_LAST_CMD) { // hitag 1 settings t_wait_1 = 204; t_wait_2 = 128; tag_size = 256; flipped_bit = 0; DBG DbpString("Configured for " _YELLOW_("Hitag 1") " reader"); } else if (payload->cmd <= HT2_LAST_CMD) { // hitag 2 settings t_wait_1 = HITAG_T_WAIT_1_MIN; t_wait_2 = HITAG_T_WAIT_2_MIN; tag_size = 48; DBG DbpString("Configured for " _YELLOW_("Hitag 2") " reader"); } // init as reader lf_init(true, false, ledcontrol); FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); uint8_t tag_modulation; size_t max_nrzs = (8 * HITAG_FRAME_LEN + 5) * 2; // up to 2 nrzs per bit uint8_t nrz_samples[max_nrzs]; bool turn_on = true; size_t nrzs = 0; int16_t checked = 0; uint32_t signal_size = 10000; while (bStop == false && BUTTON_PRESS() == false) { // use malloc initSampleBufferEx(&signal_size, true); WDT_HIT(); // only every 1000th times, in order to save time when collecting samples. if (checked == 4000) { if (data_available()) { checked = -1; break; } else { checked = 0; } } ++checked; // By default reset the transmission buffer tx = txbuf; switch (payload->cmd) { case HT1F_PLAIN: { bStop = !hitag1_plain(rx, rxlen, tx, &txlen, false); break; } case HT1F_AUTHENTICATE: { bStop = !hitag1_authenticate(rx, rxlen, tx, &txlen); break; } case HT2F_PASSWORD: { bStop = !hitag2_password(rx, rxlen, tx, &txlen, false); break; } case HT2F_AUTHENTICATE: { bStop = !hitag2_authenticate(rx, rxlen, tx, &txlen, false); break; } case HT2F_CRYPTO: { bStop = !hitag2_crypto(rx, rxlen, tx, &txlen, false); break; } case HT2F_TEST_AUTH_ATTEMPTS: { bStop = !hitag2_test_auth_attempts(rx, rxlen, tx, &txlen); break; } default: { DBG Dbprintf("Error, unknown function: " _RED_("%d"), payload->cmd); goto out; } } if (bStop) { break; } if (turn_on) { // Wait 50ms with field off to be sure the transponder gets reset SpinDelay(50); FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD); turn_on = false; // Wait with field on to be in "Wait for START_AUTH" timeframe lf_wait_periods(HITAG_T_WAIT_POWERUP + HITAG_T_WAIT_START_AUTH_MAX / 4); command_start += HITAG_T_WAIT_POWERUP + HITAG_T_WAIT_START_AUTH_MAX / 4; } else { // Wait for t_wait_2 carrier periods after the last tag bit before transmitting, lf_wait_periods(t_wait_2); command_start += t_wait_2; } // Transmit the reader frame command_duration = hitag_reader_send_frame(tx, txlen); response_start = command_start + command_duration; // Let the antenna and ADC values settle // And find the position where edge sampling should start lf_wait_periods(t_wait_1 - t_wait_1_guard); response_start += t_wait_1 - t_wait_1_guard; // Keep administration of the first edge detection bool waiting_for_first_edge = true; // Did we detected any modulaiton at all bool detected_tag_modulation = false; // Use the current modulation state as starting point tag_modulation = lf_get_tag_modulation(); // Reset the number of NRZ samples and use edge detection to detect them nrzs = 0; while (nrzs < max_nrzs) { // Get the timing of the next edge in number of wave periods periods = lf_count_edge_periods(128); // Are we dealing with the first incoming edge if (waiting_for_first_edge) { // Just break out of loop after an initial time-out (tag is probably not available) if (periods == 0) { break; } if (tag_modulation == 0) { // hitag replies always start with 11111 == 1010101010, if we see 0 // it means we missed the first period, e.g. if the signal never crossed 0 since reader signal // so let's add it: nrz_samples[nrzs++] = tag_modulation ^ 1; // Register the number of periods that have passed // we missed the begin of response but we know it happened one period of 16 earlier response_start += periods - 16; response_duration = response_start; } else { // Register the number of periods that have passed response_start += periods; response_duration = response_start; } // Indicate that we have dealt with the first edge waiting_for_first_edge = false; // The first edge is always a single NRZ bit, force periods on 16 periods = 16; // We have received more than 0 periods, so we have detected a tag response detected_tag_modulation = true; } else { // The function lf_count_edge_periods() returns 0 when a time-out occurs if (periods == 0) { DBG Dbprintf("Detected timeout after [" _YELLOW_("%zu") "] nrz samples", nrzs); break; } } // Evaluate the number of periods before the next edge if (periods > 24 && periods <= 64) { // Detected two sequential equal bits and a modulation switch // NRZ modulation: (11 => --|) or (11 __|) nrz_samples[nrzs++] = tag_modulation; if (nrzs < max_nrzs) { nrz_samples[nrzs++] = tag_modulation; } response_duration += periods; // Invert tag modulation state tag_modulation ^= 1; } else if (periods > 0 && periods <= 24) { // Detected one bit and a modulation switch // NRZ modulation: (1 => -|) or (0 _|) nrz_samples[nrzs++] = tag_modulation; response_duration += periods; tag_modulation ^= 1; } else { // The function lf_count_edge_periods() returns > 64 periods, this is not a valid number periods DBG Dbprintf("Detected unexpected period count: " _RED_("%zu"), periods); break; } } // Store the TX frame, we do this now at this point, to avoid delay in processing // and to be able to overwrite the first samples with the trace (since they currently // still use the same memory space) LogTraceBits(tx, txlen, command_start, command_start + command_duration, true); // Reset values for receiving frames memset(rx, 0x00, sizeof(rx)); rxlen = 0; // If there is no response if (detected_tag_modulation == false) { checked = -1; goto out; } // Make sure we always have an even number of samples. This fixes the problem // of ending the manchester decoding with a zero. See the example below where // the '|' character is end of modulation // One at the end: ..._-|_____... // Zero at the end: ...-_|_____... // The last modulation change of a zero is not detected, but we should take // the half period in account, otherwise the demodulator will fail. if ((nrzs % 2) != 0) { if (nrzs >= max_nrzs) { DBG Dbprintf("max_nrzs ( " _YELLOW_("%zu") " ) is odd? Must be even!", max_nrzs); continue; } nrz_samples[nrzs++] = tag_modulation; } if (ledcontrol) LED_B_ON(); // decode bitstream manrawdecode((uint8_t *)nrz_samples, &nrzs, true, 0); // decode frame // Verify if the header consists of five consecutive ones if (nrzs < 5) { DBG Dbprintf("Detected unexpected number of manchester decoded samples [%zu]", nrzs); break; } else { size_t i; for (i = 0; i < 5; i++) { if (nrz_samples[i] != 1) { DBG Dbprintf("Detected incorrect header, the bit [%zu] is zero instead of one, abort", i); break; } } if (i < 5) { break; } } // Pack the response into a byte array for (size_t i = 5; i < nrzs && rxlen < (sizeof(rx) << 3); i++) { uint8_t bit = nrz_samples[i]; if (bit > 1) { // When Manchester detects impossible symbol it writes "7" DBG Dbprintf("Error in Manchester decoding, abort"); break; } rx[rxlen >> 3] |= bit << (7 - (rxlen % 8)); rxlen++; } // skip spurious bit if (rxlen % 8 == 1) { rxlen--; } // Check if frame was captured and store it LogTraceBits(rx, rxlen, response_start, response_start + response_duration, false); // TODO when using cumulative time for command_start, pm3 doesn't reply anymore, e.g. on lf hitag reader --23 -k 4F4E4D494B52 // Use delta time? // command_start = response_start + response_duration; command_start = 0; nrzs = 0; } out: lf_finalize(ledcontrol); // release allocated memory from BigBuff. BigBuf_free(); if (checked == -1) { reply_ng(CMD_LF_HITAG_READER, PM3_ESOFT, NULL, 0); } reply_ng(CMD_LF_HITAG_READER , (bSuccessful) ? PM3_SUCCESS : PM3_EFAILED , (uint8_t *)tag.sectors , tag_size ); } void WriterHitag(const lf_hitag_data_t *payload, bool ledcontrol) { uint32_t command_start = 0; uint32_t command_duration = 0; uint32_t response_start = 0; uint32_t response_duration = 0; uint8_t rx[HITAG_FRAME_LEN]; size_t rxlen = 0; uint8_t txbuf[HITAG_FRAME_LEN]; uint8_t *tx = txbuf; size_t txlen = 0; int t_wait_1 = 204; int t_wait_1_guard = 8; int t_wait_2 = 128; size_t tag_size = 48; bool bStop = false; // Raw demodulation/decoding by sampling edge periods size_t periods = 0; // iceman: Hitag2 is filled with static global vars. // these following are globals status indicator :-| // Reset the return status bSuccessful = false; writestate = WRITE_STATE_START; blocknr = 0; // Clean up trace and prepare it for storing frames set_tracing(true); clear_trace(); // Check configuration switch (payload->cmd) { case HT2F_CRYPTO: { DBG DbpString("Authenticating using key:"); memcpy(key, payload->key, 6); //HACK; 4 or 6?? I read both in the code. memcpy(writedata, payload->data, 4); Dbhexdump(6, key, false); blocknr = payload->page; bCrypto = false; bAuthenticating = false; } break; case HT2F_PASSWORD: { DBG DbpString("Authenticating using password:"); if (memcmp(payload->pwd, "\x00\x00\x00\x00", 4) == 0) { memcpy(password, tag.sectors[1], sizeof(password)); } else { memcpy(password, payload->pwd, sizeof(password)); } memcpy(writedata, payload->data, 4); DBG Dbhexdump(4, password, false); blocknr = payload->page; bPwd = false; bAuthenticating = false; } break; default: { DBG Dbprintf("Error, unknown function: " _RED_("%d"), payload->cmd); reply_ng(CMD_LF_HITAG2_WRITE, PM3_ESOFT, NULL, 0); return; } break; } if (ledcontrol) LED_D_ON(); hitag2_init(); // init as reader lf_init(true, false, ledcontrol); FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // Tag specific configuration settings (sof, timings, etc.) // TODO HTS /* if (payload->cmd <= HTS_LAST_CMD) { // hitag S settings t_wait_1 = 204; t_wait_2 = 128; //tag_size = 256; flipped_bit = 0; tag_size = 8; DBG DbpString("Configured for " _YELLOW_("Hitag S") " writer"); } else */ if (payload->cmd <= HT1_LAST_CMD) { // hitag 1 settings t_wait_1 = 204; t_wait_2 = 128; tag_size = 256; flipped_bit = 0; DBG DbpString("Configured for " _YELLOW_("Hitag 1") " writer"); } else if (payload->cmd <= HT2_LAST_CMD) { // hitag 2 settings t_wait_1 = HITAG_T_WAIT_1_MIN; t_wait_2 = HITAG_T_WAIT_2_MIN; tag_size = 48; DBG DbpString("Configured for " _YELLOW_("Hitag 2") " writer"); } uint8_t tag_modulation; size_t max_nrzs = (8 * HITAG_FRAME_LEN + 5) * 2; // up to 2 nrzs per bit uint8_t nrz_samples[max_nrzs]; size_t nrzs = 0; int16_t checked = 0; uint32_t signal_size = 10000; bool turn_on = true; while (bStop == false && BUTTON_PRESS() == false) { // use malloc initSampleBufferEx(&signal_size, true); // only every 4000th times, in order to save time when collecting samples. if (checked == 4000) { if (data_available()) { checked = -1; break; } else { checked = 0; } } ++checked; WDT_HIT(); // By default reset the transmission buffer tx = txbuf; switch (payload->cmd) { case HT2F_CRYPTO: { bStop = !hitag2_crypto(rx, rxlen, tx, &txlen, true); break; } case HT2F_PASSWORD: { bStop = !hitag2_password(rx, rxlen, tx, &txlen, true); break; } default: { goto out; } } if (bStop) { break; } if (turn_on) { // Wait 50ms with field off to be sure the transponder gets reset SpinDelay(50); FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD); turn_on = false; // Wait with field on to be in "Wait for START_AUTH" timeframe lf_wait_periods(HITAG_T_WAIT_POWERUP + HITAG_T_WAIT_START_AUTH_MAX / 4); command_start += HITAG_T_WAIT_POWERUP + HITAG_T_WAIT_START_AUTH_MAX / 4; } else { // Wait for t_wait_2 carrier periods after the last tag bit before transmitting, lf_wait_periods(t_wait_2); command_start += t_wait_2; } // Transmit the reader frame command_duration = hitag_reader_send_frame(tx, txlen); // global write state variable used // tearoff occurred if ((writestate == WRITE_STATE_PROG) && (tearoff_hook() == PM3_ETEAROFF)) { reply_ng(CMD_LF_HITAG2_WRITE, PM3_ETEAROFF, NULL, 0); lf_finalize(ledcontrol); BigBuf_free(); return; } response_start = command_start + command_duration; // Let the antenna and ADC values settle // And find the position where edge sampling should start lf_wait_periods(t_wait_1 - t_wait_1_guard); response_start += t_wait_1 - t_wait_1_guard; // Keep administration of the first edge detection bool waiting_for_first_edge = true; // Did we detected any modulaiton at all bool detected_tag_modulation = false; // Use the current modulation state as starting point tag_modulation = lf_get_tag_modulation(); // Reset the number of NRZ samples and use edge detection to detect them nrzs = 0; while (nrzs < max_nrzs) { // Get the timing of the next edge in number of wave periods periods = lf_count_edge_periods(128); // Are we dealing with the first incoming edge if (waiting_for_first_edge) { // Just break out of loop after an initial time-out (tag is probably not available) if (periods == 0) { break; } if (tag_modulation == 0) { // hitag replies always start with 11111 == 1010101010, if we see 0 // it means we missed the first period, e.g. if the signal never crossed 0 since reader signal // so let's add it: nrz_samples[nrzs++] = tag_modulation ^ 1; // Register the number of periods that have passed // we missed the begin of response but we know it happened one period of 16 earlier response_start += periods - 16; response_duration = response_start; } else { // Register the number of periods that have passed response_start += periods; response_duration = response_start; } // Indicate that we have dealt with the first edge waiting_for_first_edge = false; // The first edge is always a single NRZ bit, force periods on 16 periods = 16; // We have received more than 0 periods, so we have detected a tag response detected_tag_modulation = true; } else { // The function lf_count_edge_periods() returns 0 when a time-out occurs if (periods == 0) { DBG Dbprintf("Detected timeout after [" _YELLOW_("%zu") "] nrz samples", nrzs); break; } } // Evaluate the number of periods before the next edge if (periods > 24 && periods <= 64) { // Detected two sequential equal bits and a modulation switch // NRZ modulation: (11 => --|) or (11 __|) nrz_samples[nrzs++] = tag_modulation; if (nrzs < max_nrzs) { nrz_samples[nrzs++] = tag_modulation; } response_duration += periods; // Invert tag modulation state tag_modulation ^= 1; } else if (periods > 0 && periods <= 24) { // Detected one bit and a modulation switch // NRZ modulation: (1 => -|) or (0 _|) nrz_samples[nrzs++] = tag_modulation; response_duration += periods; tag_modulation ^= 1; } else { // The function lf_count_edge_periods() returns > 64 periods, this is not a valid number periods DBG Dbprintf("Detected unexpected period count: " _RED_("%zu"), periods); break; } } // Wait some extra time for flash to be programmed // Store the TX frame, we do this now at this point, to avoid delay in processing // and to be able to overwrite the first samples with the trace (since they currently // still use the same memory space) LogTraceBits(tx, txlen, command_start, command_start + command_duration, true); // Reset values for receiving frames memset(rx, 0x00, sizeof(rx)); rxlen = 0; // If there is no response, just repeat the loop if (detected_tag_modulation == false) { continue; } // Make sure we always have an even number of samples. This fixes the problem // of ending the manchester decoding with a zero. See the example below where // the '|' character is end of modulation // One at the end: ..._-|_____... // Zero at the end: ...-_|_____... // The last modulation change of a zero is not detected, but we should take // the half period in account, otherwise the demodulator will fail. if ((nrzs % 2) != 0) { if (nrzs >= max_nrzs) { Dbprintf("max_nrzs ( " _YELLOW_("%zu") " ) is odd? Must be even!", max_nrzs); continue; } else { nrz_samples[nrzs++] = tag_modulation; } } if (ledcontrol) LED_B_ON(); // decode bitstream manrawdecode((uint8_t *)nrz_samples, &nrzs, true, 0); // decode frame // Verify if the header consists of five consecutive ones if (nrzs < 5) { DBG Dbprintf("Detected unexpected number of manchester decoded samples [%zu]", nrzs); break; } else { size_t i; for (i = 0; i < 5; i++) { if (nrz_samples[i] != 1) { DBG Dbprintf("Detected incorrect header, the bit " _YELLOW_("%zu") " is zero instead of one, abort", i); break; } } if (i < 5) { break; } } // Pack the response into a byte array for (size_t i = 5; i < nrzs && rxlen < (sizeof(rx) << 3); i++) { uint8_t bit = nrz_samples[i]; // When Manchester detects impossible symbol it writes "7" if (bit > 1) { DBG Dbprintf("Error in Manchester decoding, abort"); break; } // >> 3 instead of div by 8 rx[rxlen >> 3] |= bit << (7 - (rxlen % 8)); rxlen++; } // skip spurious bit if (rxlen % 8 == 1) { rxlen--; } // Check if frame was captured and store it LogTraceBits(rx, rxlen, response_start, response_start + response_duration, false); command_start = 0; nrzs = 0; } out: lf_finalize(ledcontrol); // release allocated memory from BigBuff. BigBuf_free(); if (checked == -1) { reply_ng(CMD_LF_HITAG2_WRITE, PM3_ESOFT, NULL, 0); } reply_ng(CMD_LF_HITAG2_WRITE , (bSuccessful) ? PM3_SUCCESS : PM3_EFAILED , (uint8_t *)tag.sectors , tag_size ); } static void ht2_send(bool turn_on, uint32_t *cmd_start , uint32_t *cmd_duration, uint32_t *resp_start , uint8_t *tx, size_t txlen, bool send_bits) { // Tag specific configuration settings (sof, timings, etc.) HITAG2 Settings #define T_WAIT_1_GUARD 7 if (turn_on) { // Wait 50ms with field off to be sure the transponder gets reset SpinDelay(50); FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD); // Wait with field on to be in "Wait for START_AUTH" timeframe lf_wait_periods(HITAG_T_WAIT_POWERUP + HITAG_T_WAIT_START_AUTH_MAX / 4); *cmd_start += HITAG_T_WAIT_POWERUP + HITAG_T_WAIT_START_AUTH_MAX / 4; } else { // Wait for t_wait_2 carrier periods after the last tag bit before transmitting, lf_wait_periods(HITAG_T_WAIT_2_MIN + HITAG_T_WAIT_2_MIN); *cmd_start += (HITAG_T_WAIT_2_MIN + HITAG_T_WAIT_2_MIN); } // Transmit the reader frame if (send_bits) { *cmd_duration = hitag_reader_send_framebits(tx, txlen); } else { *cmd_duration = hitag_reader_send_frame(tx, txlen); } *resp_start = (*cmd_start + *cmd_duration); *resp_start += (HITAG_T_WAIT_1_MIN - T_WAIT_1_GUARD); // Let the antenna and ADC values settle // And find the position where edge sampling should start lf_wait_periods(HITAG_T_WAIT_1_MIN - T_WAIT_1_GUARD); } static bool ht2_receive(uint32_t *resp_start, uint32_t *resp_duration, uint8_t *nrz_samples, size_t *samples) { // Keep administration of the first edge detection bool waiting_for_first_edge = true; // Did we detected any modulaiton at all bool detected_tag_modulation = false; // Reset the number of NRZ samples and use edge detection to detect them size_t nrzs = 0; // Use the current modulation state as starting point uint8_t tag_modulation = lf_get_tag_modulation(); // Raw demodulation/decoding by sampling edge periods while (nrzs < HT2_MAX_NRSZ) { // Get the timing of the next edge in number of wave periods size_t periods = lf_count_edge_periods(128); // Are we dealing with the first incoming edge if (waiting_for_first_edge) { // Just break out of loop after an initial time-out (tag is probably not available) if (periods == 0) { break; } if (tag_modulation == 0) { // hitag replies always start with 11111 == 1010101010, if we see 0 // it means we missed the first period, e.g. if the signal never crossed 0 since reader signal // so let's add it: nrz_samples[nrzs++] = tag_modulation ^ 1; // Register the number of periods that have passed // we missed the begin of response but we know it happened one period of 16 earlier resp_start += (periods - 16); resp_duration = resp_start; } else { // Register the number of periods that have passed resp_start += periods; resp_duration = resp_start; } // Indicate that we have dealt with the first edge waiting_for_first_edge = false; // The first edge is always a single NRZ bit, force periods on 16 periods = 16; // We have received more than 0 periods, so we have detected a tag response detected_tag_modulation = true; } else { // The function lf_count_edge_periods() returns 0 when a time-out occurs if (periods == 0) { break; } } // Evaluate the number of periods before the next edge if (periods > 24 && periods <= 64) { // Detected two sequential equal bits and a modulation switch // NRZ modulation: (11 => --|) or (11 __|) nrz_samples[nrzs++] = tag_modulation; if (nrzs < HT2_MAX_NRSZ) { nrz_samples[nrzs++] = tag_modulation; } resp_duration += periods; // Invert tag modulation state tag_modulation ^= 1; } else if (periods > 0 && periods <= 24) { // Detected one bit and a modulation switch // NRZ modulation: (1 => -|) or (0 _|) nrz_samples[nrzs++] = tag_modulation; resp_duration += periods; tag_modulation ^= 1; } else { // The function lf_count_edge_periods() returns > 64 periods, this is not a valid number periods break; } } // Make sure we always have an even number of samples. This fixes the problem // of ending the manchester decoding with a zero. See the example below where // the '|' character is end of modulation // One at the end: ..._-|_____... // Zero at the end: ...-_|_____... // The last modulation change of a zero is not detected, but we should take // the half period in account, otherwise the demodulator will fail. if ((nrzs % 2) != 0) { if (nrzs >= HT2_MAX_NRSZ) { return false; } nrz_samples[nrzs++] = tag_modulation; } *samples = nrzs; return detected_tag_modulation; } bool ht2_packbits(uint8_t *nrz_samples, size_t nrzs, uint8_t *rx, size_t *rxlen) { // Verify if the header consists of five consecutive ones if (nrzs < 5) { return false; } // detect hitag 2 header if (memcmp(nrz_samples, "\x01\x01\x01\x01\x01", 5)) { return false; } // Pack the response into a byte array for (size_t i = 5; i < nrzs && *rxlen < (HITAG_FRAME_LEN << 3); i++) { uint8_t bit = nrz_samples[i]; // When Manchester detects impossible symbol it writes "7" if (bit > 1) { break; } rx[*rxlen >> 3] |= bit << (7 - (*rxlen % 8)); *rxlen = *rxlen + 1; } // skip spurious bit if (*rxlen % 8 == 1) { *rxlen = *rxlen - 1; } return true; } int ht2_read_uid(uint8_t *uid, bool ledcontrol, bool send_answer, bool keep_field_up) { g_logging = false; // keep field up indicates there are more traffic to be done. if (keep_field_up == false) { clear_trace(); } // hitag 2 state machine? hitag2_init(); // init as reader lf_init(true, false, true); FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); uint8_t rx[HITAG_FRAME_LEN] = {0}; size_t rxlen = 0; // In number of bits uint8_t nrz_samples[HT2_MAX_NRSZ]; uint8_t attempt_count = 3; int res = PM3_EFAILED; bool turn_on = true; while (attempt_count && BUTTON_PRESS() == false) { attempt_count--; WDT_HIT(); uint32_t command_start = 0, command_duration = 0; uint32_t response_start = 0, response_duration = 0; // start AUTH command size_t txlen = 5; uint8_t tx[] = {HITAG2_START_AUTH}; // Transmit as reader ht2_send(turn_on, &command_start, &command_duration, &response_start, tx, txlen, false); turn_on = false; // Reset the number of NRZ samples and use edge detection to detect them size_t nrzs = 0; // receive raw samples if (ht2_receive(&response_start, &response_duration, nrz_samples, &nrzs) == false) { continue;; } // Store the transmit frame ( TX ), we do this now at this point, to avoid delay in processing // and to be able to overwrite the first samples with the trace (since they currently // still use the same memory space) LogTraceBits(tx, txlen, command_start, command_start + command_duration, true); // decode raw samples from Manchester Encoded to bits manrawdecode(nrz_samples, &nrzs, true, 0); // pack bits to bytes if (ht2_packbits(nrz_samples, nrzs, rx, &rxlen) == false) { continue; } // log Receive data LogTraceBits(rx, rxlen, response_start, response_start + response_duration, false); if (rxlen != 32) { continue; } // Store received UID memcpy(tag.sectors[0], rx, 4); if (uid) { memcpy(uid, rx, 4); } res = PM3_SUCCESS; break; } if (keep_field_up == false) { lf_finalize(false); BigBuf_free_keep_EM(); } if (send_answer) { reply_ng(CMD_LF_HITAG_READER, res, (uint8_t *)tag.sectors, 4); } return res; } // This function assumes you have called hitag2_read_uid before to turn on the field :) // tx = expects bin arrays 0,1 i // txlen = number of bits to send // rx = return bin arrys // rxlen = number of bits returned int ht2_tx_rx(uint8_t *tx, size_t txlen, uint8_t *rx, size_t *rxlen, bool ledcontrol, bool keep_field_up) { int res = PM3_EFAILED; size_t nrzs = 0; uint8_t samples[HT2_MAX_NRSZ] = {0}; uint32_t command_start = 0, command_duration = 0; uint32_t response_start = 0, response_duration = 0; // Transmit as reader ht2_send(false, &command_start, &command_duration, &response_start, tx, txlen, true); // receive raw samples if (ht2_receive(&response_start, &response_duration, samples, &nrzs) == false) { goto out; } // decode raw samples from Manchester Encoded to bits if (manrawdecode(samples, &nrzs, true, 0)) { goto out; } // pack bits to bytes if (rx && (ht2_packbits(samples, nrzs, rx, rxlen) == false)) { goto out; } res = PM3_SUCCESS; out: if (keep_field_up == false) { lf_finalize(false); } return res; }