(implementing suggestion #94)

hf mf mifare: gracefully exit if tag isn't vulnerable to this attack
hf mf nested: dito

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index cf64da2fbcdb3b8c3f6790cabac7429eef89d74f..2fd568b9e78b4cbd374ffe3836f2d06e775634d0 100644 (file)
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -1971,7 +1971,7 @@ int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
                nttmp1 = prng_successor(nttmp1, 1);
                if (nttmp1 == nt2) return i;
                nttmp2 = prng_successor(nttmp2, 1);
-                       if (nttmp2 == nt1) return -i;
+               if (nttmp2 == nt1) return -i;
                }
        
        return(-99999); // either nt1 or nt2 are invalid nonces
@@ -2040,18 +2040,21 @@ void ReaderMifare(bool first_try)
        LED_B_OFF();
        LED_C_OFF();
        
-  
+
+       #define DARKSIDE_MAX_TRIES      32              // number of tries to sync on PRNG cycle. Then give up.
+       uint16_t unsuccessfull_tries = 0;
+       
        for(uint16_t i = 0; TRUE; i++) {
                
+               LED_C_ON();
                WDT_HIT();
 
                // Test if the action was cancelled
                if(BUTTON_PRESS()) {
+                       isOK = -1;
                        break;
                }
                
-               LED_C_ON();
-
                if(!iso14443a_select_card(uid, NULL, &cuid)) {
                        if (MF_DBGLEVEL >= 1)   Dbprintf("Mifare: Can't select card");
                        continue;
@@ -2086,8 +2089,14 @@ void ReaderMifare(bool first_try)
                                nt_attacked = nt;
                        }
                        else {
-                               if (nt_distance == -99999) { // invalid nonce received, try again
-                                       continue;
+                               if (nt_distance == -99999) { // invalid nonce received
+                                       unsuccessfull_tries++;
+                                       if (!nt_attacked && unsuccessfull_tries > DARKSIDE_MAX_TRIES) {
+                                               isOK = -3;              // Card has an unpredictable PRNG. Give up      
+                                               break;
+                                       } else {
+                                               continue;               // continue trying...
+                                       }
                                }
                                sync_cycles = (sync_cycles - nt_distance);
                                if (MF_DBGLEVEL >= 3) Dbprintf("calibrating in cycle %d. nt_distance=%d, Sync_cycles: %d\n", i, nt_distance, sync_cycles);
@@ -2149,6 +2158,10 @@ void ReaderMifare(bool first_try)
                        if (nt_diff == 0 && first_try)
                        {
                                par[0]++;
+                               if (par[0] == 0x00) {           // tried all 256 possible parities without success. Card doesn't send NACK.
+                                       isOK = -2;
+                                       break;
+                               }
                        } else {
                                par[0] = ((par[0] & 0x1F) + 1) | par_low;
                        }
@@ -2165,7 +2178,7 @@ void ReaderMifare(bool first_try)
        memcpy(buf + 16, ks_list, 8);
        memcpy(buf + 24, mf_nr_ar, 4);
                
-       cmd_send(CMD_ACK,isOK,0,0,buf,28);
+       cmd_send(CMD_ACK, isOK, 0, 0, buf, 28);
 
        // Thats it...
        FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);

diff --git a/armsrc/mifarecmd.c b/armsrc/mifarecmd.c
index 939c90028796ef823e0e0c3d5acfbd841cf4f48f..14d2b68a10ac578121e3a66d590c2733405d2439 100644 (file)
--- a/armsrc/mifarecmd.c
+++ b/armsrc/mifarecmd.c
@@ -645,6 +645,9 @@ void MifareNested(uint32_t arg0, uint32_t arg1, uint32_t calibrate, uint8_t *dat
 \r
 \r
        // statistics on nonce distance\r
+       int16_t isOK = 0;\r
+       #define NESTED_MAX_TRIES 12\r
+       uint16_t unsuccessfull_tries = 0;\r
        if (calibrate) {        // for first call only. Otherwise reuse previous calibration\r
                LED_B_ON();\r
                WDT_HIT();\r
@@ -655,6 +658,12 @@ void MifareNested(uint32_t arg0, uint32_t arg1, uint32_t calibrate, uint8_t *dat
                \r
                for (rtr = 0; rtr < 17; rtr++) {\r
 \r
+                       // Test if the action was cancelled\r
+                       if(BUTTON_PRESS()) {\r
+                               isOK = -2;\r
+                               break;\r
+                       }\r
+\r
                        // prepare next select. No need to power down the card.\r
                        if(mifare_classic_halt(pcs, cuid)) {\r
                                if (MF_DBGLEVEL >= 1)   Dbprintf("Nested: Halt error");\r
@@ -702,14 +711,17 @@ void MifareNested(uint32_t arg0, uint32_t arg1, uint32_t calibrate, uint8_t *dat
                                        delta_time = auth2_time - auth1_time + 32;  // allow some slack for proper timing\r
                                }\r
                                if (MF_DBGLEVEL >= 3) Dbprintf("Nested: calibrating... ntdist=%d", i);\r
+                       } else {\r
+                               unsuccessfull_tries++;\r
+                               if (unsuccessfull_tries > NESTED_MAX_TRIES) {   // card isn't vulnerable to nested attack (random numbers are not predictable)\r
+                                       isOK = -3;\r
+                               }\r
                        }\r
                }\r
-               \r
-               if (rtr <= 1)   return;\r
 \r
                davg = (davg + (rtr - 1)/2) / (rtr - 1);\r
                \r
-               if (MF_DBGLEVEL >= 3) Dbprintf("min=%d max=%d avg=%d, delta_time=%d", dmin, dmax, davg, delta_time);\r
+               if (MF_DBGLEVEL >= 3) Dbprintf("rtr=%d isOK=%d min=%d max=%d avg=%d, delta_time=%d", rtr, isOK, dmin, dmax, davg, delta_time);\r
 \r
                dmin = davg - 2;\r
                dmax = davg + 2;\r
@@ -722,7 +734,7 @@ void MifareNested(uint32_t arg0, uint32_t arg1, uint32_t calibrate, uint8_t *dat
        LED_C_ON();\r
 \r
        //  get crypted nonces for target sector\r
-       for(i=0; i < 2; i++) { // look for exactly two different nonces\r
+       for(i=0; i < 2 && !isOK; i++) { // look for exactly two different nonces\r
 \r
                target_nt[i] = 0;\r
                while(target_nt[i] == 0) { // continue until we have an unambiguous nonce\r
@@ -800,7 +812,7 @@ void MifareNested(uint32_t arg0, uint32_t arg1, uint32_t calibrate, uint8_t *dat
        memcpy(buf+16, &target_ks[1], 4);\r
        \r
        LED_B_ON();\r
-       cmd_send(CMD_ACK, 0, 2, targetBlockNo + (targetKeyType * 0x100), buf, sizeof(buf));\r
+       cmd_send(CMD_ACK, isOK, 0, targetBlockNo + (targetKeyType * 0x100), buf, sizeof(buf));\r
        LED_B_OFF();\r
 \r
        if (MF_DBGLEVEL >= 3)   DbpString("NESTED FINISHED");\r

diff --git a/client/cmdhfmf.c b/client/cmdhfmf.c
index 5abda060d8e4e40ae83f71977e4d864ad39dfaff..5ef5273a4013aa759905c16ded2df9c57dcbfc20 100644 (file)
--- a/client/cmdhfmf.c
+++ b/client/cmdhfmf.c
@@ -17,7 +17,7 @@ int CmdHF14AMifare(const char *Cmd)
        uint32_t uid = 0;\r
        uint32_t nt = 0, nr = 0;\r
        uint64_t par_list = 0, ks_list = 0, r_key = 0;\r
-       uint8_t isOK = 0;\r
+       int16_t isOK = 0;\r
        uint8_t keyBlock[8] = {0};\r
 \r
        UsbCommand c = {CMD_READER_MIFARE, {true, 0, 0}};\r
@@ -25,7 +25,7 @@ int CmdHF14AMifare(const char *Cmd)
        // message\r
        printf("-------------------------------------------------------------------------\n");\r
        printf("Executing command. Expected execution time: 25sec on average  :-)\n");\r
-       printf("Press the key on the proxmark3 device to abort both proxmark3 and client.\n");\r
+       printf("Press button on the proxmark3 device to abort both proxmark3 and client.\n");\r
        printf("-------------------------------------------------------------------------\n");\r
 \r
        \r
@@ -47,15 +47,20 @@ start:
                }\r
                \r
                UsbCommand resp;\r
-               if (WaitForResponseTimeout(CMD_ACK,&resp,1000)) {\r
-                       isOK  = resp.arg[0] & 0xff;\r
+               if (WaitForResponseTimeout(CMD_ACK, &resp, 1000)) {\r
+                       isOK  = resp.arg[0];\r
                        uid = (uint32_t)bytes_to_num(resp.d.asBytes +  0, 4);\r
                        nt =  (uint32_t)bytes_to_num(resp.d.asBytes +  4, 4);\r
                        par_list = bytes_to_num(resp.d.asBytes +  8, 8);\r
                        ks_list = bytes_to_num(resp.d.asBytes +  16, 8);\r
                        nr = bytes_to_num(resp.d.asBytes + 24, 4);\r
                        printf("\n\n");\r
-                       if (!isOK) PrintAndLog("Proxmark can't get statistic info. Execution aborted.\n");\r
+                       switch (isOK) {\r
+                               case -1 : PrintAndLog("Button pressed. Aborted.\n"); break;\r
+                               case -2 : PrintAndLog("Card is not vulnerable to Darkside attack (doesn't send NACK on authentication requests).\n"); break;\r
+                               case -3 : PrintAndLog("Card is not vulnerable to Darkside attack (its random number generator is not predictable).\n"); break;\r
+                               default: ;\r
+                       }\r
                        break;\r
                }\r
        }       \r
@@ -622,8 +627,14 @@ int CmdHF14AMfNested(const char *Cmd)
        \r
        if (cmdp == 'o') {\r
                PrintAndLog("--target block no:%3d, target key type:%c ", trgBlockNo, trgKeyType?'B':'A');\r
-               if (mfnested(blockNo, keyType, key, trgBlockNo, trgKeyType, keyBlock, true)) {\r
-                       PrintAndLog("Nested error.");\r
+               int16_t isOK = mfnested(blockNo, keyType, key, trgBlockNo, trgKeyType, keyBlock, true);\r
+               if (isOK) {\r
+                       switch (isOK) {\r
+                               case -1 : PrintAndLog("Error: No response from Proxmark.\n"); break;\r
+                               case -2 : PrintAndLog("Button pressed. Aborted.\n"); break;\r
+                               case -3 : PrintAndLog("Tag isn't vulnerable to Nested Attack (random numbers are not predictable).\n"); break;\r
+                               default : PrintAndLog("Unknown Error.\n");\r
+                       }\r
                        return 2;\r
                }\r
                key64 = bytes_to_num(keyBlock, 6);\r
@@ -696,11 +707,17 @@ int CmdHF14AMfNested(const char *Cmd)
                                for (trgKeyType = 0; trgKeyType < 2; trgKeyType++) { \r
                                        if (e_sector[sectorNo].foundKey[trgKeyType]) continue;\r
                                        PrintAndLog("-----------------------------------------------");\r
-                                       if(mfnested(blockNo, keyType, key, FirstBlockOfSector(sectorNo), trgKeyType, keyBlock, calibrate)) {\r
-                                               PrintAndLog("Nested error.\n");\r
+                                       int16_t isOK = mfnested(blockNo, keyType, key, FirstBlockOfSector(sectorNo), trgKeyType, keyBlock, calibrate);\r
+                                       if(isOK) {\r
+                                               switch (isOK) {\r
+                                                       case -1 : PrintAndLog("Error: No response from Proxmark.\n"); break;\r
+                                                       case -2 : PrintAndLog("Button pressed. Aborted.\n"); break;\r
+                                                       case -3 : PrintAndLog("Tag isn't vulnerable to Nested Attack (random numbers are not predictable).\n"); break;\r
+                                                       default : PrintAndLog("Unknown Error.\n");\r
+                                               }\r
                                                free(e_sector);\r
-                                               return 2;                                       }\r
-                                       else {\r
+                                               return 2;\r
+                                       } else {\r
                                                calibrate = false;\r
                                        }\r
                                        \r

diff --git a/client/mifarehost.c b/client/mifarehost.c
index 237979c1bfaaefc13ca0940093c2a47d5b954f40..95453ebfd9b5e6ab270df7696985a32232ce7e40 100644 (file)
--- a/client/mifarehost.c
+++ b/client/mifarehost.c
@@ -69,7 +69,7 @@ void* nested_worker_thread(void *arg)
 \r
 int mfnested(uint8_t blockNo, uint8_t keyType, uint8_t * key, uint8_t trgBlockNo, uint8_t trgKeyType, uint8_t * resultKey, bool calibrate) \r
 {\r
-       uint16_t i, len;\r
+       uint16_t i;\r
        uint32_t uid;\r
        UsbCommand resp;\r
 \r
@@ -77,31 +77,29 @@ int mfnested(uint8_t blockNo, uint8_t keyType, uint8_t * key, uint8_t trgBlockNo
        struct Crypto1State *p1, *p2, *p3, *p4;\r
        \r
        // flush queue\r
-       WaitForResponseTimeout(CMD_ACK,NULL,100);\r
+       WaitForResponseTimeout(CMD_ACK, NULL, 100);\r
        \r
        UsbCommand c = {CMD_MIFARE_NESTED, {blockNo + keyType * 0x100, trgBlockNo + trgKeyType * 0x100, calibrate}};\r
        memcpy(c.d.asBytes, key, 6);\r
        SendCommand(&c);\r
 \r
-       if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {\r
-               len = resp.arg[1];\r
-               if (len == 2) { \r
-                       memcpy(&uid, resp.d.asBytes, 4);\r
-                       PrintAndLog("uid:%08x len=%d trgbl=%d trgkey=%x", uid, len, (uint16_t)resp.arg[2] & 0xff, (uint16_t)resp.arg[2] >> 8);\r
-                       \r
-                       for (i = 0; i < 2; i++) {\r
-                               statelists[i].blockNo = resp.arg[2] & 0xff;\r
-                               statelists[i].keyType = (resp.arg[2] >> 8) & 0xff;\r
-                               statelists[i].uid = uid;\r
+       if (!WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {\r
+               return -1;\r
+       }\r
 \r
-                               memcpy(&statelists[i].nt,  (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4);\r
-                               memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4);\r
-                       }\r
-               }\r
-               else {\r
-                       PrintAndLog("Got 0 keys from proxmark."); \r
-                       return 1;\r
-               }\r
+       if (resp.arg[0]) {\r
+               return resp.arg[0];  // error during nested\r
+       }\r
+               \r
+       memcpy(&uid, resp.d.asBytes, 4);\r
+       PrintAndLog("uid:%08x trgbl=%d trgkey=%x", uid, (uint16_t)resp.arg[2] & 0xff, (uint16_t)resp.arg[2] >> 8);\r
+       \r
+       for (i = 0; i < 2; i++) {\r
+               statelists[i].blockNo = resp.arg[2] & 0xff;\r
+               statelists[i].keyType = (resp.arg[2] >> 8) & 0xff;\r
+               statelists[i].uid = uid;\r
+               memcpy(&statelists[i].nt,  (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4);\r
+               memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4);\r
        }\r
        \r
        // calc keys\r