// mifare commands\r
//-----------------------------------------------------------------------------\r
\r
+#include "mifarehost.h"\r
+\r
#include <stdio.h>\r
-#include <stdlib.h> \r
+#include <stdlib.h>\r
#include <string.h>\r
#include <pthread.h>\r
-#include "mifarehost.h"\r
-#include "proxmark3.h"\r
\r
-// MIFARE\r
-int compar_int(const void * a, const void * b) {\r
+#include "crapto1/crapto1.h"\r
+#include "comms.h"\r
+#include "usb_cmd.h"\r
+#include "cmdmain.h"\r
+#include "ui.h"\r
+#include "parity.h"\r
+#include "util.h"\r
+#include "iso14443crc.h"\r
+\r
+#include "mifare.h"\r
+\r
+// mifare tracer flags used in mfTraceDecode()\r
+#define TRACE_IDLE 0x00\r
+#define TRACE_AUTH1 0x01\r
+#define TRACE_AUTH2 0x02\r
+#define TRACE_AUTH_OK 0x03\r
+#define TRACE_READ_DATA 0x04\r
+#define TRACE_WRITE_OK 0x05\r
+#define TRACE_WRITE_DATA 0x06\r
+#define TRACE_ERROR 0xFF\r
+\r
+\r
+static int compare_uint64(const void *a, const void *b) {\r
// didn't work: (the result is truncated to 32 bits)\r
- //return (*(uint64_t*)b - *(uint64_t*)a);\r
+ //return (*(int64_t*)b - *(int64_t*)a);\r
\r
// better:\r
if (*(uint64_t*)b == *(uint64_t*)a) return 0;\r
- else if (*(uint64_t*)b > *(uint64_t*)a) return 1;\r
+ else if (*(uint64_t*)b < *(uint64_t*)a) return 1;\r
else return -1;\r
}\r
\r
+\r
+// create the intersection (common members) of two sorted lists. Lists are terminated by -1. Result will be in list1. Number of elements is returned.\r
+static uint32_t intersection(uint64_t *list1, uint64_t *list2)\r
+{\r
+ if (list1 == NULL || list2 == NULL) {\r
+ return 0;\r
+ }\r
+ uint64_t *p1, *p2, *p3;\r
+ p1 = p3 = list1;\r
+ p2 = list2;\r
+\r
+ while ( *p1 != -1 && *p2 != -1 ) {\r
+ if (compare_uint64(p1, p2) == 0) {\r
+ *p3++ = *p1++;\r
+ p2++;\r
+ }\r
+ else {\r
+ while (compare_uint64(p1, p2) < 0) ++p1;\r
+ while (compare_uint64(p1, p2) > 0) ++p2;\r
+ }\r
+ }\r
+ *p3 = -1;\r
+ return p3 - list1;\r
+}\r
+\r
+\r
+// Darkside attack (hf mf mifare)\r
+static uint32_t nonce2key(uint32_t uid, uint32_t nt, uint32_t nr, uint32_t ar, uint64_t par_info, uint64_t ks_info, uint64_t **keys) {\r
+ struct Crypto1State *states;\r
+ uint32_t i, pos;\r
+ uint8_t bt, ks3x[8], par[8][8];\r
+ uint64_t key_recovered;\r
+ uint64_t *keylist;\r
+\r
+ // Reset the last three significant bits of the reader nonce\r
+ nr &= 0xffffff1f;\r
+\r
+ for (pos=0; pos<8; pos++) {\r
+ ks3x[7-pos] = (ks_info >> (pos*8)) & 0x0f;\r
+ bt = (par_info >> (pos*8)) & 0xff;\r
+ for (i=0; i<8; i++) {\r
+ par[7-pos][i] = (bt >> i) & 0x01;\r
+ }\r
+ }\r
+\r
+ states = lfsr_common_prefix(nr, ar, ks3x, par, (par_info == 0));\r
+\r
+ if (states == NULL) {\r
+ *keys = NULL;\r
+ return 0;\r
+ }\r
+\r
+ keylist = (uint64_t*)states;\r
+\r
+ for (i = 0; keylist[i]; i++) {\r
+ lfsr_rollback_word(states+i, uid^nt, 0);\r
+ crypto1_get_lfsr(states+i, &key_recovered);\r
+ keylist[i] = key_recovered;\r
+ }\r
+ keylist[i] = -1;\r
+\r
+ *keys = keylist;\r
+ return i;\r
+}\r
+\r
+\r
+int mfDarkside(uint64_t *key)\r
+{\r
+ uint32_t uid = 0;\r
+ uint32_t nt = 0, nr = 0, ar = 0;\r
+ uint64_t par_list = 0, ks_list = 0;\r
+ uint64_t *keylist = NULL, *last_keylist = NULL;\r
+ uint32_t keycount = 0;\r
+ int16_t isOK = 0;\r
+\r
+ UsbCommand c = {CMD_READER_MIFARE, {true, 0, 0}};\r
+\r
+ // message\r
+ printf("-------------------------------------------------------------------------\n");\r
+ printf("Executing command. Expected execution time: 25sec on average\n");\r
+ printf("Press button on the proxmark3 device to abort both proxmark3 and client.\n");\r
+ printf("-------------------------------------------------------------------------\n");\r
+\r
+\r
+ while (true) {\r
+ clearCommandBuffer();\r
+ SendCommand(&c);\r
+\r
+ //flush queue\r
+ while (ukbhit()) {\r
+ int c = getchar(); (void) c;\r
+ }\r
+\r
+ // wait cycle\r
+ while (true) {\r
+ printf(".");\r
+ fflush(stdout);\r
+ if (ukbhit()) {\r
+ return -5;\r
+ break;\r
+ }\r
+\r
+ UsbCommand resp;\r
+ if (WaitForResponseTimeout(CMD_ACK, &resp, 1000)) {\r
+ isOK = resp.arg[0];\r
+ if (isOK < 0) {\r
+ return isOK;\r
+ }\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 = (uint32_t)bytes_to_num(resp.d.asBytes + 24, 4);\r
+ ar = (uint32_t)bytes_to_num(resp.d.asBytes + 28, 4);\r
+ break;\r
+ }\r
+ }\r
+\r
+ if (par_list == 0 && c.arg[0] == true) {\r
+ PrintAndLog("Parity is all zero. Most likely this card sends NACK on every failed authentication.");\r
+ }\r
+ c.arg[0] = false;\r
+\r
+ keycount = nonce2key(uid, nt, nr, ar, par_list, ks_list, &keylist);\r
+\r
+ if (keycount == 0) {\r
+ PrintAndLog("Key not found (lfsr_common_prefix list is null). Nt=%08x", nt);\r
+ PrintAndLog("This is expected to happen in 25%% of all cases. Trying again with a different reader nonce...");\r
+ continue;\r
+ }\r
+\r
+ if (par_list == 0) {\r
+ qsort(keylist, keycount, sizeof(*keylist), compare_uint64);\r
+ keycount = intersection(last_keylist, keylist);\r
+ if (keycount == 0) {\r
+ free(last_keylist);\r
+ last_keylist = keylist;\r
+ continue;\r
+ }\r
+ }\r
+\r
+ if (keycount > 1) {\r
+ PrintAndLog("Found %u possible keys. Trying to authenticate with each of them ...\n", keycount);\r
+ } else {\r
+ PrintAndLog("Found a possible key. Trying to authenticate...\n");\r
+ }\r
+\r
+ *key = -1;\r
+ uint8_t keyBlock[USB_CMD_DATA_SIZE];\r
+ int max_keys = USB_CMD_DATA_SIZE/6;\r
+ for (int i = 0; i < keycount; i += max_keys) {\r
+ int size = keycount - i > max_keys ? max_keys : keycount - i;\r
+ for (int j = 0; j < size; j++) {\r
+ if (par_list == 0) {\r
+ num_to_bytes(last_keylist[i*max_keys + j], 6, keyBlock+(j*6));\r
+ } else {\r
+ num_to_bytes(keylist[i*max_keys + j], 6, keyBlock+(j*6));\r
+ }\r
+ }\r
+ if (!mfCheckKeys(0, 0, false, size, keyBlock, key)) {\r
+ break;\r
+ }\r
+ }\r
+\r
+ if (*key != -1) {\r
+ free(last_keylist);\r
+ free(keylist);\r
+ break;\r
+ } else {\r
+ PrintAndLog("Authentication failed. Trying again...");\r
+ free(last_keylist);\r
+ last_keylist = keylist;\r
+ }\r
+ }\r
+\r
+ return 0;\r
+}\r
+\r
+\r
+int mfCheckKeys (uint8_t blockNo, uint8_t keyType, bool clear_trace, uint8_t keycnt, uint8_t * keyBlock, uint64_t * key){\r
+\r
+ *key = -1;\r
+\r
+ UsbCommand c = {CMD_MIFARE_CHKKEYS, {((blockNo & 0xff) | ((keyType & 0xff) << 8)), clear_trace, keycnt}}; \r
+ memcpy(c.d.asBytes, keyBlock, 6 * keycnt);\r
+ SendCommand(&c);\r
+\r
+ UsbCommand resp;\r
+ if (!WaitForResponseTimeout(CMD_ACK,&resp,3000)) return 1; \r
+ if ((resp.arg[0] & 0xff) != 0x01) return 2;\r
+ *key = bytes_to_num(resp.d.asBytes, 6);\r
+ return 0;\r
+}\r
+\r
+int mfCheckKeysSec(uint8_t sectorCnt, uint8_t keyType, uint8_t timeout14a, bool clear_trace, uint8_t keycnt, uint8_t * keyBlock, sector_t * e_sector){\r
+\r
+ uint8_t keyPtr = 0;\r
+\r
+ if (e_sector == NULL)\r
+ return -1;\r
+\r
+ UsbCommand c = {CMD_MIFARE_CHKKEYS, {((sectorCnt & 0xff) | ((keyType & 0xff) << 8)), (clear_trace | 0x02)|((timeout14a & 0xff) << 8), keycnt}}; \r
+ memcpy(c.d.asBytes, keyBlock, 6 * keycnt);\r
+ SendCommand(&c);\r
+\r
+ UsbCommand resp;\r
+ if (!WaitForResponseTimeoutW(CMD_ACK, &resp, MAX(3000, 1000 + 13 * sectorCnt * keycnt * (keyType == 2 ? 2 : 1)), false)) return 1; // timeout: 13 ms / fail auth\r
+ if ((resp.arg[0] & 0xff) != 0x01) return 2;\r
+ \r
+ bool foundAKey = false;\r
+ for(int sec = 0; sec < sectorCnt; sec++){\r
+ for(int keyAB = 0; keyAB < 2; keyAB++){\r
+ keyPtr = *(resp.d.asBytes + keyAB * 40 + sec);\r
+ if (keyPtr){\r
+ e_sector[sec].foundKey[keyAB] = true;\r
+ e_sector[sec].Key[keyAB] = bytes_to_num(keyBlock + (keyPtr - 1) * 6, 6);\r
+ foundAKey = true;\r
+ }\r
+ }\r
+ }\r
+ return foundAKey ? 0 : 3;\r
+}\r
+\r
// Compare 16 Bits out of cryptostate\r
int Compare16Bits(const void * a, const void * b) {\r
if ((*(uint64_t*)b & 0x00ff000000ff0000) == (*(uint64_t*)a & 0x00ff000000ff0000)) return 0;\r
else return -1;\r
}\r
\r
-typedef \r
+typedef\r
struct {\r
union {\r
struct Crypto1State *slhead;\r
\r
\r
// wrapper function for multi-threaded lfsr_recovery32\r
-void* nested_worker_thread(void *arg)\r
+void\r
+#ifdef __has_attribute\r
+#if __has_attribute(force_align_arg_pointer)\r
+__attribute__((force_align_arg_pointer)) \r
+#endif\r
+#endif\r
+*nested_worker_thread(void *arg)\r
{\r
struct Crypto1State *p1;\r
StateList_t *statelist = arg;\r
statelist->len = p1 - statelist->head.slhead;\r
statelist->tail.sltail = --p1;\r
qsort(statelist->head.slhead, statelist->len, sizeof(uint64_t), Compare16Bits);\r
- \r
+\r
return statelist->head.slhead;\r
}\r
\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
+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
StateList_t statelists[2];\r
struct Crypto1State *p1, *p2, *p3, *p4;\r
- \r
+\r
// flush queue\r
- WaitForResponseTimeout(CMD_ACK,NULL,100);\r
- \r
+ (void)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
-\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 (!WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {\r
+ return -1;\r
}\r
- \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
- \r
+\r
pthread_t thread_id[2];\r
- \r
+\r
// create and run worker threads\r
for (i = 0; i < 2; i++) {\r
pthread_create(thread_id + i, NULL, nested_worker_thread, &statelists[i]);\r
}\r
- \r
+\r
// wait for threads to terminate:\r
for (i = 0; i < 2; i++) {\r
pthread_join(thread_id[i], (void*)&statelists[i].head.slhead);\r
// the first 16 Bits of the cryptostate already contain part of our key.\r
// Create the intersection of the two lists based on these 16 Bits and\r
// roll back the cryptostate\r
- p1 = p3 = statelists[0].head.slhead; \r
+ p1 = p3 = statelists[0].head.slhead;\r
p2 = p4 = statelists[1].head.slhead;\r
while (p1 <= statelists[0].tail.sltail && p2 <= statelists[1].tail.sltail) {\r
if (Compare16Bits(p1, p2) == 0) {\r
while (Compare16Bits(p1, p2) == 1) p2++;\r
}\r
}\r
- p3->even = 0; p3->odd = 0;\r
- p4->even = 0; p4->odd = 0;\r
+ *(uint64_t*)p3 = -1;\r
+ *(uint64_t*)p4 = -1;\r
statelists[0].len = p3 - statelists[0].head.slhead;\r
statelists[1].len = p4 - statelists[1].head.slhead;\r
statelists[0].tail.sltail=--p3;\r
\r
// the statelists now contain possible keys. The key we are searching for must be in the\r
// intersection of both lists. Create the intersection:\r
- qsort(statelists[0].head.keyhead, statelists[0].len, sizeof(uint64_t), compar_int);\r
- qsort(statelists[1].head.keyhead, statelists[1].len, sizeof(uint64_t), compar_int);\r
-\r
- uint64_t *p5, *p6, *p7;\r
- p5 = p7 = statelists[0].head.keyhead; \r
- p6 = statelists[1].head.keyhead;\r
- while (p5 <= statelists[0].tail.keytail && p6 <= statelists[1].tail.keytail) {\r
- if (compar_int(p5, p6) == 0) {\r
- *p7++ = *p5++;\r
- p6++;\r
- }\r
- else {\r
- while (compar_int(p5, p6) == -1) p5++;\r
- while (compar_int(p5, p6) == 1) p6++;\r
- }\r
- }\r
- statelists[0].len = p7 - statelists[0].head.keyhead;\r
- statelists[0].tail.keytail=--p7;\r
+ qsort(statelists[0].head.keyhead, statelists[0].len, sizeof(uint64_t), compare_uint64);\r
+ qsort(statelists[1].head.keyhead, statelists[1].len, sizeof(uint64_t), compare_uint64);\r
+ statelists[0].len = intersection(statelists[0].head.keyhead, statelists[1].head.keyhead);\r
\r
memset(resultKey, 0, 6);\r
// The list may still contain several key candidates. Test each of them with mfCheckKeys\r
crypto1_get_lfsr(statelists[0].head.slhead + i, &key64);\r
num_to_bytes(key64, 6, keyBlock);\r
key64 = 0;\r
- if (!mfCheckKeys(statelists[0].blockNo, statelists[0].keyType, 1, keyBlock, &key64)) {\r
+ if (!mfCheckKeys(statelists[0].blockNo, statelists[0].keyType, false, 1, keyBlock, &key64)) {\r
num_to_bytes(key64, 6, resultKey);\r
break;\r
}\r
}\r
- \r
+\r
free(statelists[0].head.slhead);\r
free(statelists[1].head.slhead);\r
- \r
- return 0;\r
-}\r
-\r
-int mfCheckKeys (uint8_t blockNo, uint8_t keyType, uint8_t keycnt, uint8_t * keyBlock, uint64_t * key){\r
-\r
- *key = 0;\r
\r
- UsbCommand c = {CMD_MIFARE_CHKKEYS, {blockNo, keyType, keycnt}};\r
- memcpy(c.d.asBytes, keyBlock, 6 * keycnt);\r
- SendCommand(&c);\r
-\r
- UsbCommand resp;\r
- if (!WaitForResponseTimeout(CMD_ACK,&resp,3000)) return 1;\r
- if ((resp.arg[0] & 0xff) != 0x01) return 2;\r
- *key = bytes_to_num(resp.d.asBytes, 6);\r
return 0;\r
}\r
\r
\r
int mfEmlSetMem(uint8_t *data, int blockNum, int blocksCount) {\r
UsbCommand c = {CMD_MIFARE_EML_MEMSET, {blockNum, blocksCount, 0}};\r
- memcpy(c.d.asBytes, data, blocksCount * 16); \r
+ memcpy(c.d.asBytes, data, blocksCount * 16);\r
SendCommand(&c);\r
return 0;\r
}\r
\r
// "MAGIC" CARD\r
\r
-int mfCSetUID(uint8_t *uid, uint8_t *oldUID, bool wantWipe) {\r
- \r
- uint8_t oldblock0[16] = {0x00};\r
- uint8_t block0[16] = {0x00};\r
- memcpy(block0, uid, 4); \r
- block0[4] = block0[0]^block0[1]^block0[2]^block0[3]; // Mifare UID BCC\r
- // mifare classic SAK(byte 5) and ATQA(byte 6 and 7)\r
- //block0[5] = 0x08;\r
- //block0[6] = 0x04;\r
- //block0[7] = 0x00;\r
- \r
- block0[5] = 0x01; //sak\r
- block0[6] = 0x01;\r
- block0[7] = 0x0f;\r
- \r
- int old = mfCGetBlock(0, oldblock0, CSETBLOCK_SINGLE_OPER);\r
- if ( old == 0) {\r
- memcpy(block0+8, oldblock0+8, 8);\r
- PrintAndLog("block 0: %s", sprint_hex(block0,16));\r
+int mfCGetBlock(uint8_t blockNo, uint8_t *data, uint8_t params) {\r
+ uint8_t isOK = 0;\r
+\r
+ UsbCommand c = {CMD_MIFARE_CGETBLOCK, {params, 0, blockNo}};\r
+ SendCommand(&c);\r
+\r
+ UsbCommand resp;\r
+ if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {\r
+ isOK = resp.arg[0] & 0xff;\r
+ memcpy(data, resp.d.asBytes, 16);\r
+ if (!isOK) return 2;\r
} else {\r
- PrintAndLog("Couldn't get olddata. Will write over the last bytes of Block 0.");\r
+ PrintAndLog("Command execute timeout");\r
+ return 1;\r
}\r
- return mfCSetBlock(0, block0, oldUID, wantWipe, CSETBLOCK_SINGLE_OPER);\r
+ return 0;\r
}\r
\r
int mfCSetBlock(uint8_t blockNo, uint8_t *data, uint8_t *uid, bool wantWipe, uint8_t params) {\r
\r
uint8_t isOK = 0;\r
UsbCommand c = {CMD_MIFARE_CSETBLOCK, {wantWipe, params & (0xFE | (uid == NULL ? 0:1)), blockNo}};\r
- memcpy(c.d.asBytes, data, 16); \r
+ memcpy(c.d.asBytes, data, 16);\r
SendCommand(&c);\r
\r
- UsbCommand resp;\r
- if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {\r
+ UsbCommand resp;\r
+ if (WaitForResponseTimeout(CMD_ACK, &resp, 1500)) {\r
isOK = resp.arg[0] & 0xff;\r
- if (uid != NULL) \r
+ if (uid != NULL)\r
memcpy(uid, resp.d.asBytes, 4);\r
- if (!isOK) \r
+ if (!isOK)\r
return 2;\r
} else {\r
PrintAndLog("Command execute timeout");\r
return 1;\r
}\r
+\r
return 0;\r
}\r
\r
-int mfCGetBlock(uint8_t blockNo, uint8_t *data, uint8_t params) {\r
+int mfCWipe(uint32_t numSectors, bool gen1b, bool wantWipe, bool wantFill) {\r
uint8_t isOK = 0;\r
-\r
- UsbCommand c = {CMD_MIFARE_CGETBLOCK, {params, 0, blockNo}};\r
+ uint8_t cmdParams = wantWipe + wantFill * 0x02 + gen1b * 0x04;\r
+ UsbCommand c = {CMD_MIFARE_CWIPE, {numSectors, cmdParams, 0}};\r
SendCommand(&c);\r
\r
- UsbCommand resp;\r
- if (WaitForResponseTimeout(CMD_ACK,&resp,1500)) {\r
- isOK = resp.arg[0] & 0xff;\r
- memcpy(data, resp.d.asBytes, 16);\r
- if (!isOK) return 2;\r
+ UsbCommand resp;\r
+ WaitForResponse(CMD_ACK,&resp);\r
+ isOK = resp.arg[0] & 0xff;\r
+ \r
+ return isOK;\r
+}\r
+\r
+int mfCSetUID(uint8_t *uid, uint8_t *atqa, uint8_t *sak, uint8_t *oldUID) {\r
+ uint8_t oldblock0[16] = {0x00};\r
+ uint8_t block0[16] = {0x00};\r
+ int gen = 0, res;\r
+\r
+ gen = mfCIdentify();\r
+\r
+ /* generation 1a magic card by default */\r
+ uint8_t cmdParams = CSETBLOCK_SINGLE_OPER;\r
+ if (gen == 2) {\r
+ /* generation 1b magic card */\r
+ cmdParams = CSETBLOCK_SINGLE_OPER | CSETBLOCK_MAGIC_1B;\r
+ }\r
+ \r
+ res = mfCGetBlock(0, oldblock0, cmdParams);\r
+\r
+ if (res == 0) {\r
+ memcpy(block0, oldblock0, 16);\r
+ PrintAndLog("old block 0: %s", sprint_hex(block0,16));\r
} else {\r
- PrintAndLog("Command execute timeout");\r
- return 1;\r
+ PrintAndLog("Couldn't get old data. Will write over the last bytes of Block 0.");\r
}\r
+\r
+ // fill in the new values\r
+ // UID\r
+ memcpy(block0, uid, 4);\r
+ // Mifare UID BCC\r
+ block0[4] = block0[0] ^ block0[1] ^ block0[2] ^ block0[3];\r
+ // mifare classic SAK(byte 5) and ATQA(byte 6 and 7, reversed)\r
+ if (sak != NULL)\r
+ block0[5] = sak[0];\r
+ if (atqa != NULL) {\r
+ block0[6] = atqa[1];\r
+ block0[7] = atqa[0];\r
+ }\r
+ PrintAndLog("new block 0: %s", sprint_hex(block0, 16));\r
+\r
+ res = mfCSetBlock(0, block0, oldUID, false, cmdParams);\r
+ if (res) {\r
+ PrintAndLog("Can't set block 0. Error: %d", res);\r
+ return res;\r
+ }\r
+ \r
return 0;\r
}\r
\r
+int mfCIdentify() {\r
+ UsbCommand c = {CMD_MIFARE_CIDENT, {0, 0, 0}};\r
+ SendCommand(&c);\r
+ UsbCommand resp;\r
+ WaitForResponse(CMD_ACK,&resp);\r
+\r
+ uint8_t isGeneration = resp.arg[0] & 0xff;\r
+ switch( isGeneration ){\r
+ case 1: PrintAndLog("Chinese magic backdoor commands (GEN 1a) detected"); break;\r
+ case 2: PrintAndLog("Chinese magic backdoor command (GEN 1b) detected"); break;\r
+ default: PrintAndLog("No chinese magic backdoor command detected"); break;\r
+ }\r
+\r
+ return (int) isGeneration;\r
+}\r
+\r
+\r
// SNIFFER\r
\r
// constants\r
static uint8_t trailerAccessBytes[4] = {0x08, 0x77, 0x8F, 0x00};\r
\r
// variables\r
-char logHexFileName[200] = {0x00};\r
+char logHexFileName[FILE_PATH_SIZE] = {0x00};\r
static uint8_t traceCard[4096] = {0x00};\r
-static char traceFileName[200] = {0x00};\r
+static char traceFileName[FILE_PATH_SIZE] = {0x00};\r
static int traceState = TRACE_IDLE;\r
static uint8_t traceCurBlock = 0;\r
static uint8_t traceCurKey = 0;\r
\r
struct Crypto1State *revstate;\r
uint64_t lfsr;\r
+uint64_t ui64Key;\r
uint32_t ks2;\r
uint32_t ks3;\r
\r
-uint32_t uid; // serial number\r
-uint32_t nt; // tag challenge\r
-uint32_t nr_enc; // encrypted reader challenge\r
-uint32_t ar_enc; // encrypted reader response\r
-uint32_t at_enc; // encrypted tag response\r
+uint32_t uid; // serial number\r
+uint32_t nt; // tag challenge\r
+uint32_t nt_enc; // encrypted tag challenge\r
+uint8_t nt_enc_par; // encrypted tag challenge parity\r
+uint32_t nr_enc; // encrypted reader challenge\r
+uint32_t ar_enc; // encrypted reader response\r
+uint8_t ar_enc_par; // encrypted reader response parity\r
+uint32_t at_enc; // encrypted tag response\r
+uint8_t at_enc_par; // encrypted tag response parity\r
\r
int isTraceCardEmpty(void) {\r
return ((traceCard[0] == 0) && (traceCard[1] == 0) && (traceCard[2] == 0) && (traceCard[3] == 0));\r
}\r
\r
int isBlockEmpty(int blockN) {\r
- for (int i = 0; i < 16; i++) \r
+ for (int i = 0; i < 16; i++)\r
if (traceCard[blockN * 16 + i] != 0) return 0;\r
\r
return 1;\r
return ((blockN & 0x03) == 0x03);\r
}\r
\r
+int saveTraceCard(void) {\r
+ FILE * f;\r
+\r
+ if ((!strlen(traceFileName)) || (isTraceCardEmpty())) return 0;\r
+\r
+ f = fopen(traceFileName, "w+");\r
+ if ( !f ) return 1;\r
+\r
+ for (int i = 0; i < 64; i++) { // blocks\r
+ for (int j = 0; j < 16; j++) // bytes\r
+ fprintf(f, "%02x", *(traceCard + i * 16 + j));\r
+ if (i < 63)\r
+ fprintf(f,"\n");\r
+ }\r
+ fclose(f);\r
+ return 0;\r
+}\r
+\r
int loadTraceCard(uint8_t *tuid) {\r
FILE * f;\r
char buf[64] = {0x00};\r
uint8_t buf8[64] = {0x00};\r
int i, blockNum;\r
- \r
- if (!isTraceCardEmpty()) \r
+\r
+ if (!isTraceCardEmpty())\r
saveTraceCard();\r
- \r
+\r
memset(traceCard, 0x00, 4096);\r
memcpy(traceCard, tuid + 3, 4);\r
\r
\r
f = fopen(traceFileName, "r");\r
if (!f) return 1;\r
- \r
+\r
blockNum = 0;\r
+\r
while(!feof(f)){\r
+\r
memset(buf, 0, sizeof(buf));\r
if (fgets(buf, sizeof(buf), f) == NULL) {\r
PrintAndLog("File reading error.");\r
return 0;\r
}\r
\r
-int saveTraceCard(void) {\r
- FILE * f;\r
- \r
- if ((!strlen(traceFileName)) || (isTraceCardEmpty())) return 0;\r
- \r
- f = fopen(traceFileName, "w+");\r
- for (int i = 0; i < 64; i++) { // blocks\r
- for (int j = 0; j < 16; j++) // bytes\r
- fprintf(f, "%02x", *(traceCard + i * 16 + j)); \r
- fprintf(f,"\n");\r
- }\r
- fclose(f);\r
-\r
- return 0;\r
-}\r
-\r
int mfTraceInit(uint8_t *tuid, uint8_t *atqa, uint8_t sak, bool wantSaveToEmlFile) {\r
\r
- if (traceCrypto1) \r
+ if (traceCrypto1)\r
crypto1_destroy(traceCrypto1);\r
\r
traceCrypto1 = NULL;\r
\r
- if (wantSaveToEmlFile) \r
+ if (wantSaveToEmlFile)\r
loadTraceCard(tuid);\r
- \r
+\r
traceCard[4] = traceCard[0] ^ traceCard[1] ^ traceCard[2] ^ traceCard[3];\r
traceCard[5] = sak;\r
memcpy(&traceCard[6], atqa, 2);\r
traceCurBlock = 0;\r
uid = bytes_to_num(tuid + 3, 4);\r
- \r
+\r
traceState = TRACE_IDLE;\r
\r
return 0;\r
void mf_crypto1_decrypt(struct Crypto1State *pcs, uint8_t *data, int len, bool isEncrypted){\r
uint8_t bt = 0;\r
int i;\r
- \r
+\r
if (len != 1) {\r
for (i = 0; i < len; i++)\r
data[i] = crypto1_byte(pcs, 0x00, isEncrypted) ^ data[i];\r
bt = 0;\r
for (i = 0; i < 4; i++)\r
bt |= (crypto1_bit(pcs, 0, isEncrypted) ^ BIT(data[0], i)) << i;\r
- \r
+\r
data[0] = bt;\r
}\r
return;\r
}\r
\r
+bool NTParityCheck(uint32_t ntx) {\r
+ if (\r
+ (oddparity8(ntx >> 8 & 0xff) ^ (ntx & 0x01) ^ ((nt_enc_par >> 5) & 0x01) ^ (nt_enc & 0x01)) ||\r
+ (oddparity8(ntx >> 16 & 0xff) ^ (ntx >> 8 & 0x01) ^ ((nt_enc_par >> 6) & 0x01) ^ (nt_enc >> 8 & 0x01)) ||\r
+ (oddparity8(ntx >> 24 & 0xff) ^ (ntx >> 16 & 0x01) ^ ((nt_enc_par >> 7) & 0x01) ^ (nt_enc >> 16 & 0x01))\r
+ )\r
+ return false;\r
+ \r
+ uint32_t ar = prng_successor(ntx, 64);\r
+ if (\r
+ (oddparity8(ar >> 8 & 0xff) ^ (ar & 0x01) ^ ((ar_enc_par >> 5) & 0x01) ^ (ar_enc & 0x01)) ||\r
+ (oddparity8(ar >> 16 & 0xff) ^ (ar >> 8 & 0x01) ^ ((ar_enc_par >> 6) & 0x01) ^ (ar_enc >> 8 & 0x01)) ||\r
+ (oddparity8(ar >> 24 & 0xff) ^ (ar >> 16 & 0x01) ^ ((ar_enc_par >> 7) & 0x01) ^ (ar_enc >> 16 & 0x01))\r
+ )\r
+ return false;\r
+\r
+ uint32_t at = prng_successor(ntx, 96);\r
+ if (\r
+ (oddparity8(ar & 0xff) ^ (at >> 24 & 0x01) ^ ((ar_enc_par >> 4) & 0x01) ^ (at_enc >> 24 & 0x01)) ||\r
+ (oddparity8(at >> 8 & 0xff) ^ (at & 0x01) ^ ((at_enc_par >> 5) & 0x01) ^ (at_enc & 0x01)) ||\r
+ (oddparity8(at >> 16 & 0xff) ^ (at >> 8 & 0x01) ^ ((at_enc_par >> 6) & 0x01) ^ (at_enc >> 8 & 0x01)) ||\r
+ (oddparity8(at >> 24 & 0xff) ^ (at >> 16 & 0x01) ^ ((at_enc_par >> 7) & 0x01) ^ (at_enc >> 16 & 0x01))\r
+ )\r
+ return false;\r
+ \r
+ return true;\r
+}\r
+\r
\r
-int mfTraceDecode(uint8_t *data_src, int len, bool wantSaveToEmlFile) {\r
+int mfTraceDecode(uint8_t *data_src, int len, uint8_t parity, bool wantSaveToEmlFile) {\r
uint8_t data[64];\r
\r
if (traceState == TRACE_ERROR) return 1;\r
traceState = TRACE_ERROR;\r
return 1;\r
}\r
- \r
+\r
memcpy(data, data_src, len);\r
if ((traceCrypto1) && ((traceState == TRACE_IDLE) || (traceState > TRACE_AUTH_OK))) {\r
mf_crypto1_decrypt(traceCrypto1, data, len, 0);\r
- PrintAndLog("dec> %s", sprint_hex(data, len));\r
- AddLogHex(logHexFileName, "dec> ", data, len); \r
+ uint8_t parity[16];\r
+ oddparitybuf(data, len, parity);\r
+ PrintAndLog("dec> %s [%s]", sprint_hex(data, len), printBitsPar(parity, len));\r
+ AddLogHex(logHexFileName, "dec> ", data, len);\r
}\r
- \r
+\r
switch (traceState) {\r
- case TRACE_IDLE: \r
+ case TRACE_IDLE:\r
// check packet crc16!\r
if ((len >= 4) && (!CheckCrc14443(CRC_14443_A, data, len))) {\r
PrintAndLog("dec> CRC ERROR!!!");\r
- AddLogLine(logHexFileName, "dec> ", "CRC ERROR!!!"); \r
+ AddLogLine(logHexFileName, "dec> ", "CRC ERROR!!!");\r
traceState = TRACE_ERROR; // do not decrypt the next commands\r
return 1;\r
}\r
- \r
+\r
// AUTHENTICATION\r
if ((len ==4) && ((data[0] == 0x60) || (data[0] == 0x61))) {\r
traceState = TRACE_AUTH1;\r
traceState = TRACE_ERROR; // do not decrypt the next commands\r
return 0;\r
}\r
- \r
+\r
return 0;\r
break;\r
- \r
- case TRACE_READ_DATA: \r
+\r
+ case TRACE_READ_DATA:\r
if (len == 18) {\r
traceState = TRACE_IDLE;\r
\r
}\r
break;\r
\r
- case TRACE_WRITE_OK: \r
+ case TRACE_WRITE_OK:\r
if ((len == 1) && (data[0] == 0x0a)) {\r
traceState = TRACE_WRITE_DATA;\r
\r
}\r
break;\r
\r
- case TRACE_WRITE_DATA: \r
+ case TRACE_WRITE_DATA:\r
if (len == 18) {\r
traceState = TRACE_IDLE;\r
\r
}\r
break;\r
\r
- case TRACE_AUTH1: \r
+ case TRACE_AUTH1:\r
if (len == 4) {\r
traceState = TRACE_AUTH2;\r
- nt = bytes_to_num(data, 4);\r
+ if (!traceCrypto1) {\r
+ nt = bytes_to_num(data, 4);\r
+ } else {\r
+ nt_enc = bytes_to_num(data, 4);\r
+ nt_enc_par = parity;\r
+ }\r
return 0;\r
} else {\r
traceState = TRACE_ERROR;\r
}\r
break;\r
\r
- case TRACE_AUTH2: \r
+ case TRACE_AUTH2:\r
if (len == 8) {\r
traceState = TRACE_AUTH_OK;\r
\r
nr_enc = bytes_to_num(data, 4);\r
ar_enc = bytes_to_num(data + 4, 4);\r
+ ar_enc_par = parity << 4;\r
return 0;\r
} else {\r
traceState = TRACE_ERROR;\r
}\r
break;\r
\r
- case TRACE_AUTH_OK: \r
+ case TRACE_AUTH_OK:\r
if (len ==4) {\r
traceState = TRACE_IDLE;\r
\r
at_enc = bytes_to_num(data, 4);\r
- \r
- // decode key here)\r
- ks2 = ar_enc ^ prng_successor(nt, 64);\r
- ks3 = at_enc ^ prng_successor(nt, 96);\r
- revstate = lfsr_recovery64(ks2, ks3);\r
- lfsr_rollback_word(revstate, 0, 0);\r
- lfsr_rollback_word(revstate, 0, 0);\r
- lfsr_rollback_word(revstate, nr_enc, 1);\r
- lfsr_rollback_word(revstate, uid ^ nt, 0);\r
-\r
- crypto1_get_lfsr(revstate, &lfsr);\r
- printf("key> %x%x\n", (unsigned int)((lfsr & 0xFFFFFFFF00000000) >> 32), (unsigned int)(lfsr & 0xFFFFFFFF));\r
- AddLogUint64(logHexFileName, "key> ", lfsr); \r
- \r
+ at_enc_par = parity;\r
+ if (!traceCrypto1) {\r
+\r
+ // decode key here)\r
+ ks2 = ar_enc ^ prng_successor(nt, 64);\r
+ ks3 = at_enc ^ prng_successor(nt, 96);\r
+ revstate = lfsr_recovery64(ks2, ks3);\r
+ lfsr_rollback_word(revstate, 0, 0);\r
+ lfsr_rollback_word(revstate, 0, 0);\r
+ lfsr_rollback_word(revstate, nr_enc, 1);\r
+ lfsr_rollback_word(revstate, uid ^ nt, 0);\r
+\r
+ crypto1_get_lfsr(revstate, &lfsr);\r
+ crypto1_destroy(revstate);\r
+ ui64Key = lfsr;\r
+ printf("key> probable key:%x%x Prng:%s ks2:%08x ks3:%08x\n", \r
+ (unsigned int)((lfsr & 0xFFFFFFFF00000000) >> 32), (unsigned int)(lfsr & 0xFFFFFFFF), \r
+ validate_prng_nonce(nt) ? "WEAK": "HARDEND",\r
+ ks2,\r
+ ks3);\r
+ AddLogUint64(logHexFileName, "key> ", lfsr);\r
+ } else {\r
+ if (validate_prng_nonce(nt)) {\r
+ struct Crypto1State *pcs;\r
+ pcs = crypto1_create(ui64Key);\r
+ uint32_t nt1 = crypto1_word(pcs, nt_enc ^ uid, 1) ^ nt_enc;\r
+ uint32_t ar = prng_successor(nt1, 64);\r
+ uint32_t at = prng_successor(nt1, 96);\r
+ printf("key> nested auth uid: %08x nt: %08x nt_parity: %s ar: %08x at: %08x\n", uid, nt1, printBitsPar(&nt_enc_par, 4), ar, at);\r
+ uint32_t nr1 = crypto1_word(pcs, nr_enc, 1) ^ nr_enc;\r
+ uint32_t ar1 = crypto1_word(pcs, 0, 0) ^ ar_enc;\r
+ uint32_t at1 = crypto1_word(pcs, 0, 0) ^ at_enc;\r
+ crypto1_destroy(pcs);\r
+ printf("key> the same key test. nr1: %08x ar1: %08x at1: %08x \n", nr1, ar1, at1);\r
+\r
+ if (NTParityCheck(nt1))\r
+ printf("key> the same key test OK. key=%x%x\n", (unsigned int)((ui64Key & 0xFFFFFFFF00000000) >> 32), (unsigned int)(ui64Key & 0xFFFFFFFF));\r
+ else\r
+ printf("key> the same key test. check nt parity error.\n");\r
+ \r
+ uint32_t ntc = prng_successor(nt, 90);\r
+ uint32_t ntx = 0;\r
+ int ntcnt = 0;\r
+ for (int i = 0; i < 16383; i++) {\r
+ ntc = prng_successor(ntc, 1);\r
+ if (NTParityCheck(ntc)){\r
+ if (!ntcnt)\r
+ ntx = ntc;\r
+ ntcnt++;\r
+ } \r
+ }\r
+ if (ntcnt)\r
+ printf("key> nt candidate=%08x nonce distance=%d candidates count=%d\n", ntx, nonce_distance(nt, ntx), ntcnt);\r
+ else\r
+ printf("key> don't have any nt candidate( \n");\r
+\r
+ nt = ntx;\r
+ ks2 = ar_enc ^ prng_successor(ntx, 64);\r
+ ks3 = at_enc ^ prng_successor(ntx, 96);\r
+\r
+ // decode key\r
+ revstate = lfsr_recovery64(ks2, ks3);\r
+ lfsr_rollback_word(revstate, 0, 0);\r
+ lfsr_rollback_word(revstate, 0, 0);\r
+ lfsr_rollback_word(revstate, nr_enc, 1);\r
+ lfsr_rollback_word(revstate, uid ^ nt, 0);\r
+\r
+ crypto1_get_lfsr(revstate, &lfsr);\r
+ crypto1_destroy(revstate);\r
+ ui64Key = lfsr;\r
+ printf("key> probable key:%x%x ks2:%08x ks3:%08x\n", \r
+ (unsigned int)((lfsr & 0xFFFFFFFF00000000) >> 32), (unsigned int)(lfsr & 0xFFFFFFFF),\r
+ ks2,\r
+ ks3);\r
+ AddLogUint64(logHexFileName, "key> ", lfsr);\r
+ } else { \r
+ printf("key> hardnested not implemented!\n");\r
+ \r
+ crypto1_destroy(traceCrypto1);\r
+\r
+ // not implemented\r
+ traceState = TRACE_ERROR;\r
+ }\r
+ }\r
+\r
int blockShift = ((traceCurBlock & 0xFC) + 3) * 16;\r
if (isBlockEmpty((traceCurBlock & 0xFC) + 3)) memcpy(traceCard + blockShift + 6, trailerAccessBytes, 4);\r
- \r
+\r
if (traceCurKey) {\r
num_to_bytes(lfsr, 6, traceCard + blockShift + 10);\r
} else {\r
if (traceCrypto1) {\r
crypto1_destroy(traceCrypto1);\r
}\r
- \r
+\r
// set cryptosystem state\r
traceCrypto1 = lfsr_recovery64(ks2, ks3);\r
- \r
-// nt = crypto1_word(traceCrypto1, nt ^ uid, 1) ^ nt;\r
-\r
- /* traceCrypto1 = crypto1_create(lfsr); // key in lfsr\r
- crypto1_word(traceCrypto1, nt ^ uid, 0);\r
- crypto1_word(traceCrypto1, ar, 1);\r
- crypto1_word(traceCrypto1, 0, 0);\r
- crypto1_word(traceCrypto1, 0, 0);*/\r
- \r
return 0;\r
} else {\r
traceState = TRACE_ERROR;\r
}\r
break;\r
\r
- default: \r
+ default:\r
traceState = TRACE_ERROR;\r
return 1;\r
}\r
\r
return 0;\r
}\r
+\r
+// DECODING\r
+\r
+int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data, int len){\r
+ /*\r
+ uint32_t nt; // tag challenge\r
+ uint32_t ar_enc; // encrypted reader response\r
+ uint32_t at_enc; // encrypted tag response\r
+ */\r
+ if (traceCrypto1) {\r
+ crypto1_destroy(traceCrypto1);\r
+ }\r
+ ks2 = ar_enc ^ prng_successor(nt, 64);\r
+ ks3 = at_enc ^ prng_successor(nt, 96);\r
+ traceCrypto1 = lfsr_recovery64(ks2, ks3);\r
+\r
+ mf_crypto1_decrypt(traceCrypto1, data, len, 0);\r
+\r
+ PrintAndLog("Decrypted data: [%s]", sprint_hex(data,len) );\r
+ crypto1_destroy(traceCrypto1);\r
+ return 0;\r
+}\r
+\r
+/** validate_prng_nonce\r
+ * Determine if nonce is deterministic. ie: Suspectable to Darkside attack.\r
+ * returns\r
+ * true = weak prng\r
+ * false = hardend prng\r
+ */\r
+bool validate_prng_nonce(uint32_t nonce) {\r
+ uint16_t *dist = 0;\r
+ uint16_t x, i;\r
+\r
+ dist = malloc(2 << 16);\r
+ if(!dist)\r
+ return -1;\r
+\r
+ // init prng table:\r
+ for (x = i = 1; i; ++i) {\r
+ dist[(x & 0xff) << 8 | x >> 8] = i;\r
+ x = x >> 1 | (x ^ x >> 2 ^ x >> 3 ^ x >> 5) << 15;\r
+ }\r
+ \r
+ uint32_t res = (65535 - dist[nonce >> 16] + dist[nonce & 0xffff]) % 65535;\r
+ \r
+ free(dist); \r
+ return (res == 16);\r
+}\r
+\r
+/* Detect Tag Prng, \r
+* function performs a partial AUTH, where it tries to authenticate against block0, key A, but only collects tag nonce.\r
+* the tag nonce is check to see if it has a predictable PRNG.\r
+* @returns \r
+* TRUE if tag uses WEAK prng (ie Now the NACK bug also needs to be present for Darkside attack)\r
+* FALSE is tag uses HARDEND prng (ie hardnested attack possible, with known key)\r
+*/\r
+int DetectClassicPrng(void){\r
+\r
+ UsbCommand resp, respA; \r
+ uint8_t cmd[] = {0x60, 0x00}; // MIFARE_AUTH_KEYA\r
+ uint32_t flags = ISO14A_CONNECT | ISO14A_RAW | ISO14A_APPEND_CRC | ISO14A_NO_RATS;\r
+ \r
+ UsbCommand c = {CMD_READER_ISO_14443a, {flags, sizeof(cmd), 0}};\r
+ memcpy(c.d.asBytes, cmd, sizeof(cmd));\r
+\r
+ clearCommandBuffer();\r
+ SendCommand(&c);\r
+ if (!WaitForResponseTimeout(CMD_ACK, &resp, 2000)) {\r
+ PrintAndLog("PRNG UID: Reply timeout.");\r
+ return -1;\r
+ }\r
+ \r
+ // if select tag failed.\r
+ if (resp.arg[0] == 0) {\r
+ PrintAndLog("PRNG error: selecting tag failed, can't detect prng.");\r
+ return -1;\r
+ }\r
+ \r
+ if (!WaitForResponseTimeout(CMD_ACK, &respA, 5000)) {\r
+ PrintAndLog("PRNG data: Reply timeout.");\r
+ return -1;\r
+ }\r
+\r
+ // check respA\r
+ if (respA.arg[0] != 4) {\r
+ PrintAndLog("PRNG data error: Wrong length: %d", respA.arg[0]);\r
+ return -1;\r
+ }\r
+\r
+ uint32_t nonce = bytes_to_num(respA.d.asBytes, respA.arg[0]);\r
+ return validate_prng_nonce(nonce);\r
+}\r
projects / proxmark3-svn / blobdiff