Rewrite

Makefile

@@ -1,8 +1,9 @@
 VERSION ?= $(shell git rev-parse --short HEAD)
+PKG_CONFIG ?= pkg-config
 
 all: poll_desfire
 
-poll_desfire: poll_desfire.o
+poll_desfire: poll_desfire.o nfc_init.o
 	$(CC) $(LDFLAGS) $(shell $(PKG_CONFIG) --libs libfreefare) $^ -o $@
 
 %.o: %.c

nfc_init.c

@@ -0,0 +1,35 @@
+#include <err.h>
+#include <errno.h>
+#include <stdlib.h>
+#include "poll_desfire.h"
+
+int init(nfc_context **context, nfc_device **device) {
+  nfc_connstring devices[8];
+  size_t device_count;
+
+  nfc_init(context);
+  if (context == NULL) {
+    errx(EXIT_FAILURE, "Unable to init libnfc (malloc)");
+  }
+
+  device_count = nfc_list_devices(*context, devices, sizeof(devices) / sizeof(devices[0]));
+  if (device_count <= 0) {
+    errx(EXIT_FAILURE, "No NFC device found.");
+  }
+  
+  if (device_count > 1) {
+    printf("More than 1 device available. Using %s\n", devices[0]);
+  }
+
+  *device = nfc_open(*context, devices[0]);
+  if (!device) {
+    errx(EXIT_FAILURE, "nfc_open() failed.");
+  }
+  
+  if (nfc_initiator_init(*device) < 0) {
+    errx(EXIT_FAILURE, "Initiator failed.");
+  }
+
+  return 0;
+}
+void poll_target(nfc_device *device);

poll_desfire.c

@@ -1,32 +1,21 @@
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
 #include <err.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
+#include "poll_desfire.h"
 
-#include <nfc/nfc.h>
+#define AID 0x22eaa0
-#include <freefare.h>
+#define RANDOM_UID_SIZE 8
-
-int main(int argc, char **argv) {
-  int error = EXIT_SUCCESS;
-
-  nfc_device *device = NULL;
-  FreefareTag *tags  = NULL;
-
-  nfc_connstring devices[8];
-  size_t device_count;
-
-  nfc_context *context;
-  nfc_init(&context);
-  if (context == NULL) {
-    errx(EXIT_FAILURE, "Unable to init libnfc (malloc)");
-  }
 
+void init_keys(MifareDESFireKey *null_key, MifareDESFireKey *master_key, char const *name) {
   uint8_t const key_data_null[8]  = {0, 0, 0, 0, 0, 0, 0, 0};
-  MifareDESFireKey key_null = mifare_desfire_des_key_new_with_version(key_data_null);
+  *null_key = mifare_desfire_des_key_new_with_version(key_data_null);
   
   uint8_t key_data_real[16] = {0};
   {
-    char const *name = (argc > 1) ? argv[1] : "key";
     FILE *f = fopen(name, "rb");
     if (!f) {
       errx(EXIT_FAILURE, "error opening key file: %s", name);
@@ -36,95 +25,165 @@ int main(int argc, char **argv) {
     }
     fclose(f);
   }
-  MifareDESFireKey key_real = mifare_desfire_aes_key_new(key_data_real);
+  *master_key = mifare_desfire_aes_key_new(key_data_real);
+}
+
+int main(int argc, char **argv) {
+  int error = EXIT_SUCCESS;
+
+  nfc_context *context = NULL;
+  nfc_device *device = NULL;
+  FreefareTag *tags  = NULL;
+  MifareDESFireKey key_null, key_master;
+  MifareDESFireAID aid = mifare_desfire_aid_new(AID);
+
+  error = init(&context, &device);
+  init_keys(&key_null, &key_master, (argc > 1) ? argv[1] : "key");
 
   FILE *out = argc > 2 ? fopen(argv[2], "w") : stdout;
 
-  device_count = nfc_list_devices(context, devices, sizeof(devices) / sizeof(devices[0]));
-  if (device_count <= 0) {
-    errx(EXIT_FAILURE, "No NFC device found.");
-  }
-
-  if (device_count > 1) {
-    printf("More than 1 device available. Using %s\n", devices[0]);
-  }
-
-  device = nfc_open(context, devices[0]);
-  if (!device) {
-    errx(EXIT_FAILURE, "nfc_open() failed.");
-  }
-
-  if (nfc_initiator_init(device) < 0) {
-    errx(EXIT_FAILURE, "Initiator failed.");
-  }
-
   while (true) {
-    /* Poll for targets */
-    const nfc_modulation nmModulations = {.nmt = NMT_ISO14443A, .nbr = NBR_106};
-    nfc_target target;
-    nfc_initiator_poll_target(device, &nmModulations, 1, 10, 1, &target);
-
-    /* Got at least one, read tag list */
     tags = freefare_get_tags(device);
     if (!tags) {
       nfc_close(device);
       errx(EXIT_FAILURE, "Error listing tags.");
     }
 
-    if (!tags[0]) {
+    for (int id = 0; tags[id]; id++) {
-      goto free_tags;
+      FreefareTag tag = tags[id];
-    }
+      if (MIFARE_DESFIRE != freefare_get_tag_type(tag))
+        continue;
       
-    FreefareTag tag = tags[0];
+      char *tag_uid = freefare_get_tag_uid(tag);
-    if (MIFARE_DESFIRE != freefare_get_tag_type(tag))
+      /* Result of various operations */
-      goto free_tags;
+      int res;
-
-    char *tag_uid = freefare_get_tag_uid(tag);
-
-    /* Result of various operations */
-    int res;
-
-    res = mifare_desfire_connect(tag);
-    if (res < 0) {
-      warnx("Can't connect to Mifare DESFire target.");
-      goto free_tag;
-    }
-
-    res = mifare_desfire_authenticate(tag, 0, key_null);
-    if (res >= 0) {
-      // Default key still active, create new key
-      res = mifare_desfire_change_key(tag, 0, key_real, key_null);
       
+      res = mifare_desfire_connect(tag);
       if (res < 0) {
-        warnx("Error changing key");
+        warnx("Can't connect to Mifare DESFire target.");
-        goto free_tag;
+        goto next_tag;
       }
-    }
 
-    res = mifare_desfire_authenticate_aes(tag, 0, key_real);
+      if (mifare_desfire_select_application(tag, aid) != 0) {
-    if (res < 0) {
+        // Check for old card with our key as master key
-      warnx("Authentication on master application failed");
+        res = mifare_desfire_authenticate(tag, 0, key_master);
-      goto free_tag;
+        if (res >= 0) {
-    } else {
+          warnx("Old tag detected: %s", tag_uid);
-      fprintf(out, "%s\n", tag_uid);
+          res = mifare_desfire_change_key(tag, 0, key_master, key_null);
+        }
+        
+        // Card needs to have default null key as master
+        res = mifare_desfire_authenticate(tag, 0, key_null);
+        if (res < 0) {
+          warnx("Could not authenticate: %d", res);
+          goto next_tag;
+        }
+
+        // create application
+        res = mifare_desfire_create_application_aes(tag, aid, MDAPP_SETTINGS(0, 1, 0, 0, 1), 1);
+        if (res < 0) {
+          warnx("Could not create application: %d", res);
+          goto next_tag;
+        }
+
+        // Select it
+        res = mifare_desfire_select_application(tag, aid);
+        if (res < 0) {
+          warnx("Application not selectable after creation: %d", res);
+          goto next_tag;
+        }
+
+        // Key should be null
+        res = mifare_desfire_authenticate_aes(tag, 0, key_null);
+        if (res < 0) {
+          warnx("Could not authenticate new application with default key: %d", res);
+          goto next_tag;
+        }
+
+        // Update to our key
+        res = mifare_desfire_change_key(tag, 0, key_master, key_null);
+        if (res < 0) {
+          warnx("Could not change key of new application to master key: %d", res);
+          goto next_tag;
+        }
+      
+        // Authenticate with new key
+        res = mifare_desfire_authenticate_aes(tag, 0, key_master);
+        if (res < 0) {
+          warnx("Could not authenticate new application with our key: %d", res);
+          goto next_tag;
+        }
+
+        // Create file
+        res = mifare_desfire_create_std_data_file(tag, 0, 0, MDAR(0, 0, 0, 0), RANDOM_UID_SIZE);
+        if (res < 0) {
+          warnx("Could not create data file: %d", res);
+          goto next_tag;
+        }
+
+        // Grab random data for it
+        unsigned char uid_data[RANDOM_UID_SIZE];
+        {
+          int fd = open("/dev/urandom", O_RDONLY);
+          if (fd < 0) {
+            warnx("Could not open /dev/urandom");
+            goto next_tag;
+          }
+
+          if (RANDOM_UID_SIZE != read(fd, &uid_data[0], RANDOM_UID_SIZE)) {
+            warnx("Could not read data from /dev/random");
+            goto next_tag;
+          }
+          close(fd);
+        }
+
+        // Write data
+        res = mifare_desfire_write_data(tag, 0, 0, RANDOM_UID_SIZE, &uid_data[0]);
+        if (res < 0) {
+          warnx("Could not write UID data to tag: %d", res);
+          goto next_tag;
+        }
+      }
+
+      // Authenticate with our key
+      res = mifare_desfire_authenticate_aes(tag, 0, key_master);
+      if (res < 0) {
+        warnx("Authentication on application failed: %d", res);
+        goto next_tag;
+      }
+
+      // Grab UID
+      uint8_t data[RANDOM_UID_SIZE];
+      res = mifare_desfire_read_data(tag, 0, 0, RANDOM_UID_SIZE, &data[0]);
+      if (res != RANDOM_UID_SIZE) {
+        warnx("Could not read all bytes from tag: %d", res);
+        goto next_tag;
+      }
+
+      // Print out key ID and UID
+      fprintf(out, "%s:", tag_uid);
+      for (int j = 0; j < RANDOM_UID_SIZE; j++) {
+        fprintf(out, "%02x", data[j]);
+      }
+      fprintf(out, "\n");
       fflush(out);
+
+next_tag:
+      free(tag_uid);
+      
+      mifare_desfire_disconnect(tag);
     }
 
-  wait_disconnect:
+    while (freefare_selected_tag_is_present(device))
-    while (0 == nfc_initiator_target_is_present(device, 0))
       ;
-    mifare_desfire_disconnect(tag);
       
-  free_tag:
-    free(tag_uid);
-  free_tags:
     freefare_free_tags(tags);
     fflush(stdout);
     fflush(stderr);
   }
 
   mifare_desfire_key_free(key_null);
-  mifare_desfire_key_free(key_real);
+  mifare_desfire_key_free(key_master);
 
   nfc_close(device);
   nfc_exit(context);

poll_desfire.h

@@ -0,0 +1,6 @@
+#include <nfc/nfc.h>
+#include <freefare.h>
+
+int init(nfc_context **context, nfc_device **device);
+void poll_target(nfc_device *device);
+