Parser for Santiago, Chile BIP transit card

applications/main/nfc/application.fam

@@ -128,6 +128,15 @@ App(
     sources=["plugins/supported_cards/aime.c"],
 )
 
+App(
+    appid="bip_parser",
+    apptype=FlipperAppType.PLUGIN,
+    entry_point="bip_plugin_ep",
+    targets=["f7"],
+    requires=["nfc"],
+    sources=["plugins/supported_cards/bip.c"],
+)
+
 App(
     appid="umarsh_parser",
     apptype=FlipperAppType.PLUGIN,

applications/main/nfc/plugins/supported_cards/bip.c

@@ -0,0 +1,372 @@
+#include "nfc_supported_card_plugin.h"
+
+#include <bit_lib/bit_lib.h>
+#include <flipper_application/flipper_application.h>
+#include <nfc/nfc_device.h>
+#include <nfc/protocols/mf_classic/mf_classic_poller_sync.h>
+
+#define TAG "Bip"
+
+#define SECTOR_BLOCK_OFFSET(sector, block) (((sector) * 4) + (block))
+
+static const uint64_t bip_keys_a[] = {
+    0x3a42f33af429,
+    0x6338a371c0ed,
+    0xf124c2578ad0,
+    0x32ac3b90ac13,
+    0x4ad1e273eaf1,
+    0xe2c42591368a,
+    0x2a3c347a1200,
+    0x16f3d5ab1139,
+    0x937a4fff3011,
+    0x35c3d2caee88,
+    0x693143f10368,
+    0xa3f97428dd01,
+    0x63f17a449af0,
+    0xc4652c54261c,
+    0xd49e2826664f,
+    0x3df14c8000a1,
+};
+
+static const uint64_t bip_keys_b[] = {
+    0x1fc235ac1309,
+    0x243f160918d1,
+    0x9afc42372af1,
+    0x682d401abb09,
+    0x067db45454a9,
+    0x15fc4c7613fe,
+    0x68d30288910a,
+    0xf59a36a2546d,
+    0x64e3c10394c2,
+    0xb736412614af,
+    0x324f5df65310,
+    0x643fb6de2217,
+    0x82f435dedf01,
+    0x0263de1278f3,
+    0x51284c3686a6,
+    0x6a470d54127c,
+};
+
+bool bip_verify(Nfc* nfc) {
+    bool verified = true;
+
+    const uint8_t verify_sector = 0;
+    uint8_t block_num = mf_classic_get_first_block_num_of_sector(verify_sector);
+    FURI_LOG_D(TAG, "Verifying sector %u", verify_sector);
+
+    MfClassicKey key_a_0 = {};
+    bit_lib_num_to_bytes_be(bip_keys_a[0], COUNT_OF(key_a_0.data), key_a_0.data);
+
+    MfClassicAuthContext auth_ctx = {};
+    MfClassicError error =
+        mf_classic_poller_sync_auth(nfc, block_num, &key_a_0, MfClassicKeyTypeA, &auth_ctx);
+
+    if(error == MfClassicErrorNotPresent) {
+        FURI_LOG_D(TAG, "Failed to read block %u: %d", block_num, error);
+        verified = false;
+    }
+
+    return verified;
+}
+
+static bool bip_read(Nfc* nfc, NfcDevice* device) {
+    furi_assert(nfc);
+    furi_assert(device);
+
+    bool is_read = false;
+
+    MfClassicData* data = mf_classic_alloc();
+    nfc_device_copy_data(device, NfcProtocolMfClassic, data);
+
+    do {
+        MfClassicType type = MfClassicType1k;
+        MfClassicError error = mf_classic_poller_sync_detect_type(nfc, &type);
+        if(error == MfClassicErrorNotPresent) {
+            FURI_LOG_W(TAG, "Card not MIFARE Classic 1k");
+            break;
+        }
+
+        data->type = type;
+        MfClassicDeviceKeys keys = {};
+        for(size_t i = 0; i < mf_classic_get_total_sectors_num(data->type); i++) {
+            bit_lib_num_to_bytes_be(bip_keys_a[i], sizeof(MfClassicKey), keys.key_a[i].data);
+            FURI_BIT_SET(keys.key_a_mask, i);
+            bit_lib_num_to_bytes_be(bip_keys_b[i], sizeof(MfClassicKey), keys.key_b[i].data);
+            FURI_BIT_SET(keys.key_b_mask, i);
+        }
+
+        error = mf_classic_poller_sync_read(nfc, &keys, data);
+        if(error == MfClassicErrorNotPresent) {
+            FURI_LOG_W(TAG, "Failed to read data. Bad keys?");
+            break;
+        }
+
+        nfc_device_set_data(device, NfcProtocolMfClassic, data);
+
+        is_read = true;
+    } while(false);
+
+    mf_classic_free(data);
+
+    return is_read;
+}
+
+typedef struct {
+    uint16_t year;
+    uint8_t month;
+    uint8_t day;
+    uint8_t hour;
+    uint8_t minute;
+    uint8_t second;
+} BipTimestamp;
+
+static void parse_bip_timestamp(const MfClassicBlock* block, BipTimestamp* timestamp) {
+    furi_assert(block);
+    furi_assert(timestamp);
+
+    timestamp->day = (((block->data[1] << 8) + block->data[0]) >> 6) & 0x1f;
+    timestamp->month = (((block->data[1] << 8) + block->data[0]) >> 11) & 0xf;
+    timestamp->year = 2000 + ((((block->data[2] << 8) + block->data[1]) >> 7) & 0x1f);
+    timestamp->hour = (((block->data[3] << 8) + block->data[2]) >> 4) & 0x1f;
+    timestamp->minute = (((block->data[3] << 8) + block->data[2]) >> 9) & 0x3f;
+    timestamp->second = (((block->data[4] << 8) + block->data[3]) >> 7) & 0x3f;
+}
+
+static int compare_bip_timestamp(const BipTimestamp* t1, const BipTimestamp* t2) {
+    furi_assert(t1);
+    furi_assert(t2);
+    if(t1->year != t2->year) {
+        return t1->year - t2->year;
+    }
+    if(t1->month != t2->month) {
+        return t1->month - t2->month;
+    }
+    if(t1->day != t2->day) {
+        return t1->day - t2->day;
+    }
+    if(t1->hour != t2->hour) {
+        return t1->hour - t2->hour;
+    }
+    if(t1->minute != t2->minute) {
+        return t1->minute - t2->minute;
+    }
+    if(t1->second != t2->second) {
+        return t1->second - t2->second;
+    }
+    return 0;
+}
+
+static void print_bip_timestamp(const BipTimestamp* timestamp, FuriString* str) {
+    furi_assert(timestamp);
+    furi_assert(str);
+    furi_string_cat_printf(
+        str,
+        "%04u-%02u-%02u %02u:%02u:%02u",
+        timestamp->year,
+        timestamp->month,
+        timestamp->day,
+        timestamp->hour,
+        timestamp->minute,
+        timestamp->second);
+}
+
+static bool is_bip_block_empty(const MfClassicBlock* block) {
+    furi_assert(block);
+    // check if all but last byte are zero (last is checksum)
+    for(size_t i = 0; i < sizeof(block->data) - 1; i++) {
+        if(block->data[i] != 0) {
+            return false;
+        }
+    }
+    return true;
+}
+
+static void parse_uint16_le(const uint8_t* data, uint16_t* value) {
+    furi_assert(data);
+    furi_assert(value);
+
+    *value = (data[0]) | (data[1] << 8);
+}
+
+static void parse_uint32_le(const uint8_t* data, uint32_t* value) {
+    furi_assert(data);
+    furi_assert(value);
+
+    *value = (data[0]) | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
+}
+
+static void parse_uint16_txn_amount(const uint8_t* data, uint16_t* value) {
+    furi_assert(data);
+    furi_assert(value);
+
+    parse_uint16_le(data, value);
+    *value = *value >> 2;
+}
+
+typedef struct {
+    BipTimestamp timestamp;
+    uint16_t amount;
+} BipTransaction;
+
+static bool bip_parse(const NfcDevice* device, FuriString* parsed_data) {
+    furi_assert(device);
+    furi_assert(parsed_data);
+
+    bool parsed = true;
+
+    struct {
+        uint32_t card_id;
+        uint16_t balance;
+        uint16_t flags;
+        BipTimestamp trip_time_window;
+        BipTransaction top_ups[3];
+        BipTransaction charges[3];
+    } bip_data = {
+        .card_id = 0,
+        .balance = 0,
+        .flags = 0,
+        .trip_time_window = {0, 0, 0, 0, 0, 0},
+        .top_ups =
+            {
+                {{0, 0, 0, 0, 0, 0}, 0},
+                {{0, 0, 0, 0, 0, 0}, 0},
+                {{0, 0, 0, 0, 0, 0}, 0},
+            },
+        .charges =
+            {
+                {{0, 0, 0, 0, 0, 0}, 0},
+                {{0, 0, 0, 0, 0, 0}, 0},
+                {{0, 0, 0, 0, 0, 0}, 0},
+            },
+    };
+
+    const MfClassicData* data = nfc_device_get_data(device, NfcProtocolMfClassic);
+
+    do {
+        // verify all sectors' keys
+        for(size_t i = 0; i < mf_classic_get_total_sectors_num(data->type); i++) {
+            MfClassicSectorTrailer* sec_tr = mf_classic_get_sector_trailer_by_sector(data, i);
+            uint64_t key = bit_lib_bytes_to_num_be(sec_tr->key_a.data, 6);
+            if(key != bip_keys_a[i]) {
+                parsed = false;
+                break;
+            }
+            key = bit_lib_bytes_to_num_be(sec_tr->key_b.data, 6);
+            if(key != bip_keys_b[i]) {
+                parsed = false;
+                break;
+            }
+        }
+
+        // Get Card ID, little-endian 4 bytes at sector 0 block 1, bytes 4-7
+        parse_uint32_le(&data->block[SECTOR_BLOCK_OFFSET(0, 1)].data[4], &bip_data.card_id);
+
+        // Get balance, little-endian 2 bytes at sector 8 block 1, bytes 0-1
+        parse_uint16_le(&data->block[SECTOR_BLOCK_OFFSET(8, 1)].data[0], &bip_data.balance);
+
+        // Get balance flags (negative balance, etc.), little-endian 2 bytes at sector 8 block 1, bytes 2-3
+        parse_uint16_le(&data->block[SECTOR_BLOCK_OFFSET(8, 1)].data[2], &bip_data.flags);
+
+        // Get trip time window, proprietary format, at sector 5 block 1, bytes 0-7
+        parse_bip_timestamp(&data->block[SECTOR_BLOCK_OFFSET(5, 1)], &bip_data.trip_time_window);
+
+        // Last 3 top-ups: sector 10, ring-buffer of 3 blocks, timestamp in bytes 0-7, amount in bytes 9-10
+        for(size_t i = 0; i < 3; i++) {
+            if(is_bip_block_empty(&data->block[SECTOR_BLOCK_OFFSET(10, i)])) {
+                continue;
+            }
+            BipTransaction* top_up = &bip_data.top_ups[i];
+            parse_bip_timestamp(&data->block[SECTOR_BLOCK_OFFSET(10, i)], &top_up->timestamp);
+            parse_uint16_txn_amount(
+                &data->block[SECTOR_BLOCK_OFFSET(10, i)].data[9], &top_up->amount);
+        }
+
+        // Last 3 charges (i.e. trips), sector 11, ring-buffer of 3 blocks, timestamp in bytes 0-7, amount in bytes 10-11
+        for(size_t i = 0; i < 3; i++) {
+            if(is_bip_block_empty(&data->block[SECTOR_BLOCK_OFFSET(11, i)])) {
+                continue;
+            }
+            BipTransaction* charge = &bip_data.charges[i];
+            parse_bip_timestamp(&data->block[SECTOR_BLOCK_OFFSET(11, i)], &charge->timestamp);
+            parse_uint16_txn_amount(
+                &data->block[SECTOR_BLOCK_OFFSET(11, i)].data[10], &charge->amount);
+        }
+
+        parsed = true;
+    } while(false);
+
+    if(parsed) {
+        // Print basic info
+        furi_string_printf(
+            parsed_data,
+            "\e#Tarjeta Bip!\n"
+            "Card Number: %ld\n"
+            "Balance: $%d (flags %x)\n"
+            "Current Trip Window Ends:\n  @",
+            bip_data.card_id,
+            bip_data.balance,
+            bip_data.flags);
+
+        print_bip_timestamp(&bip_data.trip_time_window, parsed_data);
+
+        // Find newest top-up
+        size_t newest_top_up = 0;
+        for(size_t i = 1; i < 3; i++) {
+            const BipTimestamp* newest = &bip_data.top_ups[newest_top_up].timestamp;
+            const BipTimestamp* current = &bip_data.top_ups[i].timestamp;
+            if(compare_bip_timestamp(current, newest) > 0) {
+                newest_top_up = i;
+            }
+        }
+
+        // Print top-ups, newest first
+        furi_string_cat_printf(parsed_data, "\n\e#Last Top-ups");
+        for(size_t i = 0; i < 3; i++) {
+            const BipTransaction* top_up = &bip_data.top_ups[(3u + newest_top_up - i) % 3];
+            furi_string_cat_printf(parsed_data, "\n+$%d\n  @", top_up->amount);
+            print_bip_timestamp(&top_up->timestamp, parsed_data);
+        }
+
+        // Find newest charge
+        size_t newest_charge = 0;
+        for(size_t i = 1; i < 3; i++) {
+            const BipTimestamp* newest = &bip_data.charges[newest_charge].timestamp;
+            const BipTimestamp* current = &bip_data.charges[i].timestamp;
+            if(compare_bip_timestamp(current, newest) > 0) {
+                newest_charge = i;
+            }
+        }
+
+        // Print charges
+        furi_string_cat_printf(parsed_data, "\n\e#Last Charges (Trips)");
+        for(size_t i = 0; i < 3; i++) {
+            const BipTransaction* charge = &bip_data.charges[(3u + newest_charge - i) % 3];
+            furi_string_cat_printf(parsed_data, "\n-$%d\n  @", charge->amount);
+            print_bip_timestamp(&charge->timestamp, parsed_data);
+        }
+
+        return true;
+    } else {
+        return false;
+    }
+}
+
+/* Actual implementation of app<>plugin interface */
+static const NfcSupportedCardsPlugin bip_plugin = {
+    .protocol = NfcProtocolMfClassic,
+    .verify = bip_verify,
+    .read = bip_read,
+    .parse = bip_parse,
+};
+
+/* Plugin descriptor to comply with basic plugin specification */
+static const FlipperAppPluginDescriptor bip_plugin_descriptor = {
+    .appid = NFC_SUPPORTED_CARD_PLUGIN_APP_ID,
+    .ep_api_version = NFC_SUPPORTED_CARD_PLUGIN_API_VERSION,
+    .entry_point = &bip_plugin,
+};
+
+/* Plugin entry point - must return a pointer to const descriptor  */
+const FlipperAppPluginDescriptor* bip_plugin_ep() {
+    return &bip_plugin_descriptor;
+}