From dc8ba239fbc1b8f50f572e84adfcfdf52bd0d0da Mon Sep 17 00:00:00 2001 From: pwpiwi Date: Wed, 24 Jun 2015 07:48:36 +0200 Subject: [PATCH] (implementing suggestion #94) hf mf mifare: gracefully exit if tag isn't vulnerable to this attack hf mf nested: dito --- armsrc/iso14443a.c | 27 ++++++++++++++++++++------- armsrc/mifarecmd.c | 22 +++++++++++++++++----- client/cmdhfmf.c | 39 ++++++++++++++++++++++++++++----------- client/mifarehost.c | 38 ++++++++++++++++++-------------------- 4 files changed, 83 insertions(+), 43 deletions(-) diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c index cf64da2f..2fd568b9 100644 --- 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 939c9002..14d2b68a 100644 --- 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 // statistics on nonce distance + int16_t isOK = 0; + #define NESTED_MAX_TRIES 12 + uint16_t unsuccessfull_tries = 0; if (calibrate) { // for first call only. Otherwise reuse previous calibration LED_B_ON(); WDT_HIT(); @@ -655,6 +658,12 @@ void MifareNested(uint32_t arg0, uint32_t arg1, uint32_t calibrate, uint8_t *dat for (rtr = 0; rtr < 17; rtr++) { + // Test if the action was cancelled + if(BUTTON_PRESS()) { + isOK = -2; + break; + } + // prepare next select. No need to power down the card. if(mifare_classic_halt(pcs, cuid)) { if (MF_DBGLEVEL >= 1) Dbprintf("Nested: Halt error"); @@ -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 } if (MF_DBGLEVEL >= 3) Dbprintf("Nested: calibrating... ntdist=%d", i); + } else { + unsuccessfull_tries++; + if (unsuccessfull_tries > NESTED_MAX_TRIES) { // card isn't vulnerable to nested attack (random numbers are not predictable) + isOK = -3; + } } } - - if (rtr <= 1) return; davg = (davg + (rtr - 1)/2) / (rtr - 1); - if (MF_DBGLEVEL >= 3) Dbprintf("min=%d max=%d avg=%d, delta_time=%d", dmin, dmax, davg, delta_time); + 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); dmin = davg - 2; dmax = davg + 2; @@ -722,7 +734,7 @@ void MifareNested(uint32_t arg0, uint32_t arg1, uint32_t calibrate, uint8_t *dat LED_C_ON(); // get crypted nonces for target sector - for(i=0; i < 2; i++) { // look for exactly two different nonces + for(i=0; i < 2 && !isOK; i++) { // look for exactly two different nonces target_nt[i] = 0; while(target_nt[i] == 0) { // continue until we have an unambiguous nonce @@ -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); LED_B_ON(); - cmd_send(CMD_ACK, 0, 2, targetBlockNo + (targetKeyType * 0x100), buf, sizeof(buf)); + cmd_send(CMD_ACK, isOK, 0, targetBlockNo + (targetKeyType * 0x100), buf, sizeof(buf)); LED_B_OFF(); if (MF_DBGLEVEL >= 3) DbpString("NESTED FINISHED"); diff --git a/client/cmdhfmf.c b/client/cmdhfmf.c index 5abda060..5ef5273a 100644 --- a/client/cmdhfmf.c +++ b/client/cmdhfmf.c @@ -17,7 +17,7 @@ int CmdHF14AMifare(const char *Cmd) uint32_t uid = 0; uint32_t nt = 0, nr = 0; uint64_t par_list = 0, ks_list = 0, r_key = 0; - uint8_t isOK = 0; + int16_t isOK = 0; uint8_t keyBlock[8] = {0}; UsbCommand c = {CMD_READER_MIFARE, {true, 0, 0}}; @@ -25,7 +25,7 @@ int CmdHF14AMifare(const char *Cmd) // message printf("-------------------------------------------------------------------------\n"); printf("Executing command. Expected execution time: 25sec on average :-)\n"); - printf("Press the key on the proxmark3 device to abort both proxmark3 and client.\n"); + printf("Press button on the proxmark3 device to abort both proxmark3 and client.\n"); printf("-------------------------------------------------------------------------\n"); @@ -47,15 +47,20 @@ start: } UsbCommand resp; - if (WaitForResponseTimeout(CMD_ACK,&resp,1000)) { - isOK = resp.arg[0] & 0xff; + if (WaitForResponseTimeout(CMD_ACK, &resp, 1000)) { + isOK = resp.arg[0]; uid = (uint32_t)bytes_to_num(resp.d.asBytes + 0, 4); nt = (uint32_t)bytes_to_num(resp.d.asBytes + 4, 4); par_list = bytes_to_num(resp.d.asBytes + 8, 8); ks_list = bytes_to_num(resp.d.asBytes + 16, 8); nr = bytes_to_num(resp.d.asBytes + 24, 4); printf("\n\n"); - if (!isOK) PrintAndLog("Proxmark can't get statistic info. Execution aborted.\n"); + switch (isOK) { + case -1 : PrintAndLog("Button pressed. Aborted.\n"); break; + case -2 : PrintAndLog("Card is not vulnerable to Darkside attack (doesn't send NACK on authentication requests).\n"); break; + case -3 : PrintAndLog("Card is not vulnerable to Darkside attack (its random number generator is not predictable).\n"); break; + default: ; + } break; } } @@ -622,8 +627,14 @@ int CmdHF14AMfNested(const char *Cmd) if (cmdp == 'o') { PrintAndLog("--target block no:%3d, target key type:%c ", trgBlockNo, trgKeyType?'B':'A'); - if (mfnested(blockNo, keyType, key, trgBlockNo, trgKeyType, keyBlock, true)) { - PrintAndLog("Nested error."); + int16_t isOK = mfnested(blockNo, keyType, key, trgBlockNo, trgKeyType, keyBlock, true); + if (isOK) { + switch (isOK) { + case -1 : PrintAndLog("Error: No response from Proxmark.\n"); break; + case -2 : PrintAndLog("Button pressed. Aborted.\n"); break; + case -3 : PrintAndLog("Tag isn't vulnerable to Nested Attack (random numbers are not predictable).\n"); break; + default : PrintAndLog("Unknown Error.\n"); + } return 2; } key64 = bytes_to_num(keyBlock, 6); @@ -696,11 +707,17 @@ int CmdHF14AMfNested(const char *Cmd) for (trgKeyType = 0; trgKeyType < 2; trgKeyType++) { if (e_sector[sectorNo].foundKey[trgKeyType]) continue; PrintAndLog("-----------------------------------------------"); - if(mfnested(blockNo, keyType, key, FirstBlockOfSector(sectorNo), trgKeyType, keyBlock, calibrate)) { - PrintAndLog("Nested error.\n"); + int16_t isOK = mfnested(blockNo, keyType, key, FirstBlockOfSector(sectorNo), trgKeyType, keyBlock, calibrate); + if(isOK) { + switch (isOK) { + case -1 : PrintAndLog("Error: No response from Proxmark.\n"); break; + case -2 : PrintAndLog("Button pressed. Aborted.\n"); break; + case -3 : PrintAndLog("Tag isn't vulnerable to Nested Attack (random numbers are not predictable).\n"); break; + default : PrintAndLog("Unknown Error.\n"); + } free(e_sector); - return 2; } - else { + return 2; + } else { calibrate = false; } diff --git a/client/mifarehost.c b/client/mifarehost.c index 237979c1..95453ebf 100644 --- a/client/mifarehost.c +++ b/client/mifarehost.c @@ -69,7 +69,7 @@ void* nested_worker_thread(void *arg) int mfnested(uint8_t blockNo, uint8_t keyType, uint8_t * key, uint8_t trgBlockNo, uint8_t trgKeyType, uint8_t * resultKey, bool calibrate) { - uint16_t i, len; + uint16_t i; uint32_t uid; UsbCommand resp; @@ -77,31 +77,29 @@ int mfnested(uint8_t blockNo, uint8_t keyType, uint8_t * key, uint8_t trgBlockNo struct Crypto1State *p1, *p2, *p3, *p4; // flush queue - WaitForResponseTimeout(CMD_ACK,NULL,100); + WaitForResponseTimeout(CMD_ACK, NULL, 100); UsbCommand c = {CMD_MIFARE_NESTED, {blockNo + keyType * 0x100, trgBlockNo + trgKeyType * 0x100, calibrate}}; memcpy(c.d.asBytes, key, 6); SendCommand(&c); - if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) { - len = resp.arg[1]; - if (len == 2) { - memcpy(&uid, resp.d.asBytes, 4); - PrintAndLog("uid:%08x len=%d trgbl=%d trgkey=%x", uid, len, (uint16_t)resp.arg[2] & 0xff, (uint16_t)resp.arg[2] >> 8); - - for (i = 0; i < 2; i++) { - statelists[i].blockNo = resp.arg[2] & 0xff; - statelists[i].keyType = (resp.arg[2] >> 8) & 0xff; - statelists[i].uid = uid; + if (!WaitForResponseTimeout(CMD_ACK, &resp, 1500)) { + return -1; + } - memcpy(&statelists[i].nt, (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4); - memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4); - } - } - else { - PrintAndLog("Got 0 keys from proxmark."); - return 1; - } + if (resp.arg[0]) { + return resp.arg[0]; // error during nested + } + + memcpy(&uid, resp.d.asBytes, 4); + PrintAndLog("uid:%08x trgbl=%d trgkey=%x", uid, (uint16_t)resp.arg[2] & 0xff, (uint16_t)resp.arg[2] >> 8); + + for (i = 0; i < 2; i++) { + statelists[i].blockNo = resp.arg[2] & 0xff; + statelists[i].keyType = (resp.arg[2] >> 8) & 0xff; + statelists[i].uid = uid; + memcpy(&statelists[i].nt, (void *)(resp.d.asBytes + 4 + i * 8 + 0), 4); + memcpy(&statelists[i].ks1, (void *)(resp.d.asBytes + 4 + i * 8 + 4), 4); } // calc keys -- 2.39.2