Fixes error handling when performing MIFARE commands:

Before this commit, MFOC was considering any errors as authentication error (AUTH command) or permission error (READ/WRITE commands);
With this patch, any error which is not a tag-related error will produce a program exit (with EXIT_FAILURE flag).

Plus, this commit silents MIFARE authentication error while MFOC try some default keys...

src/mfoc.c

@@ -277,9 +277,12 @@ int main(int argc, char *const argv[])
       if (trailer_block(block)) {
         if (!t.sectors[i].foundKeyA) {
           mc = MC_AUTH_A;
-          if (!nfc_initiator_mifare_cmd(r.pdi, mc, block, &mp)) {
+          int res;
-            // fprintf(stdout, "!!Error: AUTH [Key A:%012llx] sector %02x t_block %02x\n",
+          if ((res = nfc_initiator_mifare_cmd(r.pdi, mc, block, &mp)) < 0) {
-            // 	bytes_to_num(mp.mpa.abtKey, 6), i, block);
+            if (res != NFC_EMFCAUTHFAIL) {
+              nfc_perror (r.pdi, "nfc_initiator_mifare_cmd");
+              goto error;
+            }
             mf_anticollision(t, r);
           } else {
             // Save all information about successfull keyA authentization
@@ -289,9 +292,12 @@ int main(int argc, char *const argv[])
         }
         if (!t.sectors[i].foundKeyB) {
           mc = MC_AUTH_B;
-          if (!nfc_initiator_mifare_cmd(r.pdi, mc, block, &mp)) {
+          int res;
-            // fprintf(stdout, "!!Error: AUTH [Key B:%012llx] sector %02x t_block %02x\n",
+          if ((res = nfc_initiator_mifare_cmd(r.pdi, mc, block, &mp)) < 0) {
-            //	bytes_to_num(mp.mpa.abtKey, 6), i, block);
+            if (res != NFC_EMFCAUTHFAIL) {
+              nfc_perror (r.pdi, "nfc_initiator_mifare_cmd");
+              goto error;
+            }
             mf_anticollision(t, r);
             // No success, try next block
             t.sectors[i].trailer = block;
@@ -310,8 +316,6 @@ int main(int argc, char *const argv[])
           fprintf(stdout, ".");
         }
         fflush(stdout);
-        // fprintf(stdout, "\nSuccess: AUTH [Key %c:%012llx] sector %02x t_block %02x\n",
-        // 	(mc == MC_AUTH_A ? 'A' :'B'), bytes_to_num(mp.mpa.abtKey, 6), i, block);
         // Save position of a trailer block to sector struct
         t.sectors[i++].trailer = block;
       }
@@ -343,9 +347,12 @@ int main(int argc, char *const argv[])
         for (uint32_t o = 0; o < bk->size; o++) {
           num_to_bytes(bk->brokenKeys[o], 6, mp.mpa.abtKey);
           mc = dumpKeysA ? MC_AUTH_A : MC_AUTH_B;
-          if (!nfc_initiator_mifare_cmd(r.pdi, mc, t.sectors[j].trailer, &mp)) {
+          int res;
-            //	fprintf(stdout, "!!Error: AUTH [Key A:%012llx] sector %02x t_block %02x, key %d\n",
+          if ((res = nfc_initiator_mifare_cmd(r.pdi, mc, t.sectors[j].trailer, &mp)) < 0) {
-            //			bytes_to_num(mp.mpa.abtKey, 6), j, t.sectors[j].trailer, o);
+            if (res != NFC_EMFCAUTHFAIL) {
+              nfc_perror (r.pdi, "nfc_initiator_mifare_cmd");
+              goto error;
+            }
             mf_anticollision(t, r);
           } else {
             // Save all information about successfull authentization
@@ -398,9 +405,12 @@ int main(int argc, char *const argv[])
               // Set required authetication method
               num_to_bytes(ck[i].key, 6, mp.mpa.abtKey);
               mc = dumpKeysA ? MC_AUTH_A : MC_AUTH_B;
-              if (!nfc_initiator_mifare_cmd(r.pdi, mc, t.sectors[j].trailer, &mp)) {
+              int res;
-                // fprintf(stdout, "!!Error: AUTH [Key A:%llx] sector %02x t_block %02x\n",
+              if ((res = nfc_initiator_mifare_cmd(r.pdi, mc, t.sectors[j].trailer, &mp)) < 0) {
-                // 	bytes_to_num(mp.mpa.abtKey, 6), j, t.sectors[j].trailer);
+                if (res != NFC_EMFCAUTHFAIL) {
+                  nfc_perror (r.pdi, "nfc_initiator_mifare_cmd");
+                  goto error;
+                 }
                 mf_anticollision(t, r);
               } else {
                 // Save all information about successfull authentization
@@ -457,12 +467,16 @@ int main(int argc, char *const argv[])
 
       // Try A key, auth() + read()
       memcpy(mp.mpa.abtKey, t.sectors[i].KeyA, sizeof(t.sectors[i].KeyA));
-      if (!nfc_initiator_mifare_cmd(r.pdi, MC_AUTH_A, block, &mp)) {
+      int res;
-        // ERR ("Error: Auth A");
+      if ((res = nfc_initiator_mifare_cmd(r.pdi, MC_AUTH_A, block, &mp)) < 0) {
+        if (res != NFC_EMFCAUTHFAIL) {
+          nfc_perror (r.pdi, "nfc_initiator_mifare_cmd");
+          goto error;
+        }
         mf_configure(r.pdi);
         mf_anticollision(t, r);
       } else { // and Read
-        if (nfc_initiator_mifare_cmd(r.pdi, MC_READ, block, &mp)) {
+        if ((res = nfc_initiator_mifare_cmd(r.pdi, MC_READ, block, &mp)) >= 0) {
           fprintf(stdout, "Block %02d, type %c, key %012llx :", block, 'A', bytes_to_num(t.sectors[i].KeyA, 6));
           print_hex(mp.mpd.abtData, 16);
           mf_configure(r.pdi);
@@ -470,22 +484,32 @@ int main(int argc, char *const argv[])
           failure = false;
         } else {
           // Error, now try read() with B key
-          // ERR ("Error: Read A");
+          if (res != NFC_ERFTRANS) {
+            nfc_perror (r.pdi, "nfc_initiator_mifare_cmd");
+            goto error;
+          }
           mf_configure(r.pdi);
           mf_anticollision(t, r);
           memcpy(mp.mpa.abtKey, t.sectors[i].KeyB, sizeof(t.sectors[i].KeyB));
-          if (!nfc_initiator_mifare_cmd(r.pdi, MC_AUTH_B, block, &mp)) {
+          if ((res = nfc_initiator_mifare_cmd(r.pdi, MC_AUTH_B, block, &mp)) < 0) {
-            // ERR ("Error: Auth B");
+            if (res != NFC_EMFCAUTHFAIL) {
+              nfc_perror (r.pdi, "nfc_initiator_mifare_cmd");
+              goto error;
+            }
             mf_configure(r.pdi);
             mf_anticollision(t, r);
           } else { // and Read
-            if (nfc_initiator_mifare_cmd(r.pdi, MC_READ, block, &mp)) {
+            if ((res = nfc_initiator_mifare_cmd(r.pdi, MC_READ, block, &mp)) >= 0) {
               fprintf(stdout, "Block %02d, type %c, key %012llx :", block, 'B', bytes_to_num(t.sectors[i].KeyB, 6));
               print_hex(mp.mpd.abtData, 16);
               mf_configure(r.pdi);
               mf_select_tag(r.pdi, &(t.nt));
               failure = false;
             } else {
+              if (res != NFC_ERFTRANS) {
+                nfc_perror (r.pdi, "nfc_initiator_mifare_cmd");
+                goto error;
+              }
               mf_configure(r.pdi);
               mf_anticollision(t, r);
               // ERR ("Error: Read B");

src/mifare.c

@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2009 Roel Verdult
  * Copyright (C) 2010 Romain Tartière
- * Copyright (C) 2010, 2011 Romuald Conty
+ * Copyright (C) 2010, 2011, 2013 Romuald Conty
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -28,10 +28,23 @@
  * Note that this license only applies on the examples, NFC library itself is under LGPL
  *
  */
+
 /**
  * @file mifare.c
  * @brief provide samples structs and functions to manipulate MIFARE Classic and Ultralight tags using libnfc
  */
+
+/*
+ * This implementation was written based on information provided by the
+ * following document:
+ *
+ * MIFARE Classic Specification
+ *  MF1ICS50
+ *  Functional specification
+ *  Rev. 5.3 - 29 January 2008
+ *  http://www.nxp.com/acrobat/other/identification/M001053_MF1ICS50_rev5_3.pdf
+ */
+
 #include "mifare.h"
 
 #include <string.h>
@@ -39,25 +52,33 @@
 #include <nfc/nfc.h>
 
 /**
- * @brief Execute a MIFARE Classic Command
+ * @brief Execute a MIFARE Classic command
- * @return Returns true if action was successfully performed; otherwise returns false.
+ * @return Returns NFC_SUCCESS if action was successfully performed; otherwise returns error code (negative value).
  * @param pmp Some commands need additional information. This information should be supplied in the mifare_param union.
  *
- * The specified MIFARE command will be executed on the tag. There are different commands possible, they all require the destination block number.
+ * The specified MIFARE command will be executed on the tag. There are
+ * different commands possible, they all require the destination block number.
+ *
  * @note There are three different types of information (Authenticate, Data and Value).
  *
  * First an authentication must take place using Key A or B. It requires a 48 bit Key (6 bytes) and the UID.
- * They are both used to initialize the internal cipher-state of the PN53X chip (http://libnfc.org/hardware/pn53x-chip).
  * After a successful authentication it will be possible to execute other commands (e.g. Read/Write).
- * The MIFARE Classic Specification (http://www.nxp.com/acrobat/other/identification/M001053_MF1ICS50_rev5_3.pdf) explains more about this process.
+ *
+ * Like libnfc's functions, this one returns negative value on error (libnfc's
+ * error code) but two of them need a special attention in this context (MIFARE
+ * Classic):
+ *  - NFC_EMFCAUTHFAIL, "MIFARE authentication failed", means key is not valid
+ *  on specified sector.
+ *  - NFC_ERFTRANS, "Invalid received frame", when occurs on MIFARE command
+ *  read or write after a successful authentication, means permissions allowed
+ *  by current acces bytes are not sufficient to process the command.
  */
-bool
+int
 nfc_initiator_mifare_cmd(nfc_device *pnd, const mifare_cmd mc, const uint8_t ui8Block, mifare_param *pmp)
 {
   uint8_t  abtRx[265];
   size_t  szParamLen;
   uint8_t  abtCmd[265];
-  //bool    bEasyFraming;
 
   abtCmd[0] = mc;               // The MIFARE Classic command
   abtCmd[1] = ui8Block;         // The block address (1K=0x00..0x39, 4K=0x00..0xff)
@@ -89,7 +110,7 @@ nfc_initiator_mifare_cmd(nfc_device *pnd, const mifare_cmd mc, const uint8_t ui8
 
       // Please fix your code, you never should reach this statement
     default:
-      return false;
+      return NFC_EINVARG;
       break;
   }
 
@@ -98,40 +119,23 @@ nfc_initiator_mifare_cmd(nfc_device *pnd, const mifare_cmd mc, const uint8_t ui8
     memcpy(abtCmd + 2, (uint8_t *) pmp, szParamLen);
 
   // FIXME: Save and restore bEasyFraming
-  // bEasyFraming = nfc_device_get_property_bool (pnd, NP_EASY_FRAMING, &bEasyFraming);
+  int res;
-  if (nfc_device_set_property_bool(pnd, NP_EASY_FRAMING, true) < 0) {
+  if ((res = nfc_device_set_property_bool(pnd, NP_EASY_FRAMING, true)) < 0) {
-    nfc_perror(pnd, "nfc_device_set_property_bool");
+    return res;
-    return false;
   }
   // Fire the mifare command
-  int res;
   if ((res = nfc_initiator_transceive_bytes(pnd, abtCmd, 2 + szParamLen, abtRx, sizeof(abtRx), -1))  < 0) {
-    if (res == NFC_ERFTRANS) {
+    return res;
-      // "Invalid received frame",  usual means we are
-      // authenticated on a sector but the requested MIFARE cmd (read, write)
-      // is not permitted by current acces bytes;
-      // So there is nothing to do here.
-    } else {
-      nfc_perror(pnd, "nfc_initiator_transceive_bytes");
   }
-    // XXX nfc_device_set_property_bool (pnd, NP_EASY_FRAMING, bEasyFraming);
-    return false;
-  }
-  /* XXX
-  if (nfc_device_set_property_bool (pnd, NP_EASY_FRAMING, bEasyFraming) < 0) {
-    nfc_perror (pnd, "nfc_device_set_property_bool");
-    return false;
-  }
-  */
 
   // When we have executed a read command, copy the received bytes into the param
   if (mc == MC_READ) {
     if (res == 16) {
       memcpy(pmp->mpd.abtData, abtRx, 16);
     } else {
-      return false;
+      return NFC_EINVARG;
     }
   }
   // Command succesfully executed
-  return true;
+  return NFC_SUCCESS;
 }

src/mifare.h

@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2009 Roel Verdult
  * Copyright (C) 2010 Romain Tartière
- * Copyright (C) 2010, 2011 Romuald Conty
+ * Copyright (C) 2010, 2011, 2013 Romuald Conty
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -76,7 +76,7 @@ typedef union {
 // Reset struct alignment to default
 #  pragma pack()
 
-bool    nfc_initiator_mifare_cmd(nfc_device *pnd, const mifare_cmd mc, const uint8_t ui8Block, mifare_param *pmp);
+int    nfc_initiator_mifare_cmd(nfc_device *pnd, const mifare_cmd mc, const uint8_t ui8Block, mifare_param *pmp);
 
 // Compiler directive, set struct alignment to 1 uint8_t for compatibility
 #  pragma pack(1)