From 5b5489baf42989b21e0d946aab3f945bc0af0384 Mon Sep 17 00:00:00 2001
From: Michael Farrell <micolous+git@gmail.com>
Date: Thu, 26 Jan 2017 20:27:08 +1100
Subject: [PATCH] hf mf sim: Multiple fixes from review of PR #209.

- Don't increment the nonce when random mode is disabled (this breaks the
  standard attack).

- Don't attempt the standard attack when random mode is enabled (there's no
  point as it won't work, per comments from @pwpiwi).

- Attempt the moebius attack if the standard attack fails.
---
 armsrc/iso14443a.c |  4 +---
 client/cmdhfmf.c   | 40 +++++++++++++++++++++++++++++++++++-----
 2 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index 07bbd37d..83907fce 100644
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -2329,7 +2329,7 @@ typedef struct {
   * FLAG_7B_UID_IN_DATA - means that there is a 7-byte UID in the data-section, we're expected to use that
   * FLAG_10B_UID_IN_DATA	- use 10-byte UID in the data-section not finished
   *	FLAG_NR_AR_ATTACK  - means we should collect NR_AR responses for bruteforcing later
-  * FLAG_RANDOM_NONCE - means we should generate some pseudo-random nonce data
+  * FLAG_RANDOM_NONCE - means we should generate some pseudo-random nonce data (only allows moebius attack)
   *@param exitAfterNReads, exit simulation after n blocks have been read, 0 is infinite ...
   * (unless reader attack mode enabled then it runs util it gets enough nonces to recover all keys attmpted)
   */
@@ -2543,8 +2543,6 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 			cardAUTHKEY = 0xff;
 			if (flags & FLAG_RANDOM_NONCE) {
 				nonce = prand();
-			} else {
-				nonce++;
 			}
 			continue;
 		}
diff --git a/client/cmdhfmf.c b/client/cmdhfmf.c
index 2b14c763..cdac6476 100644
--- a/client/cmdhfmf.c
+++ b/client/cmdhfmf.c
@@ -1016,7 +1016,7 @@ int CmdHF14AMfChk(const char *Cmd)
 	return 0;
 }
 
-void readerAttack(nonces_t ar_resp[], bool setEmulatorMem) {
+void readerAttack(nonces_t ar_resp[], bool setEmulatorMem, bool doStandardAttack) {
 	#define ATTACK_KEY_COUNT 8 // keep same as define in iso14443a.c -> Mifare1ksim()
 	uint64_t key = 0;
 	typedef struct {
@@ -1034,7 +1034,7 @@ void readerAttack(nonces_t ar_resp[], bool setEmulatorMem) {
 	for (uint8_t i = 0; i<ATTACK_KEY_COUNT; i++) {
 		if (ar_resp[i].ar2 > 0) {
 			//PrintAndLog("DEBUG: Trying sector %d, cuid %08x, nt %08x, ar %08x, nr %08x, ar2 %08x, nr2 %08x",ar_resp[i].sector, ar_resp[i].cuid,ar_resp[i].nonce,ar_resp[i].ar,ar_resp[i].nr,ar_resp[i].ar2,ar_resp[i].nr2);
-			if (mfkey32(ar_resp[i], &key)) {
+			if (doStandardAttack && mfkey32(ar_resp[i], &key)) {
 				PrintAndLog("  Found Key%s for sector %02d: [%04x%08x]", (ar_resp[i].keytype) ? "B" : "A", ar_resp[i].sector, (uint32_t) (key>>32), (uint32_t) (key &0xFFFFFFFF));
 
 				for (uint8_t ii = 0; ii<ATTACK_KEY_COUNT; ii++) {
@@ -1054,6 +1054,34 @@ void readerAttack(nonces_t ar_resp[], bool setEmulatorMem) {
 						}
 					}
 				}
+			} else if (tryMfk32_moebius(ar_resp[i+ATTACK_KEY_COUNT], &key)) {
+				uint8_t sectorNum = ar_resp[i+ATTACK_KEY_COUNT].sector;
+				uint8_t keyType = ar_resp[i+ATTACK_KEY_COUNT].keytype;
+
+				PrintAndLog("M-Found Key%s for sector %02d: [%012"llx"]"
+					, keyType ? "B" : "A"
+					, sectorNum
+					, key
+				);
+
+				for (uint8_t ii = 0; ii<ATTACK_KEY_COUNT; ii++) {
+					if (key_cnt[ii]==0 || stSector[ii]==sectorNum) {
+						if (keyType==0) {
+							//keyA
+							sector_trailer[ii].keyA = key;
+							stSector[ii] = sectorNum;
+							key_cnt[ii]++;
+							break;
+						} else {
+							//keyB
+							sector_trailer[ii].keyB = key;
+							stSector[ii] = sectorNum;
+							key_cnt[ii]++;
+							break;
+						}
+					}
+				}
+				continue;
 			}
 		}
 	}
@@ -1100,7 +1128,7 @@ int usage_hf14_mf1ksim(void) {
 	PrintAndLog("      x    (Optional) Crack, performs the 'reader attack', nr/ar attack against a legitimate reader, fishes out the key(s)");
 	PrintAndLog("      e    (Optional) set keys found from 'reader attack' to emulator memory (implies x and i)");
 	PrintAndLog("      f    (Optional) get UIDs to use for 'reader attack' from file 'f <filename.txt>' (implies x and i)");
-	PrintAndLog("      r    (Optional) Generate random nonces instead of sequential nonces.");
+	PrintAndLog("      r    (Optional) Generate random nonces instead of sequential nonces. Standard reader attack won't work with this option, only moebius attack works.");
 	PrintAndLog("samples:");
 	PrintAndLog("           hf mf sim u 0a0a0a0a");
 	PrintAndLog("           hf mf sim u 11223344556677");
@@ -1252,7 +1280,8 @@ int CmdHF14AMf1kSim(const char *Cmd) {
 			//got a response
 			nonces_t ar_resp[ATTACK_KEY_COUNT*2];
 			memcpy(ar_resp, resp.d.asBytes, sizeof(ar_resp));
-			readerAttack(ar_resp, setEmulatorMem);
+			// We can skip the standard attack if we have RANDOM_NONCE set.
+			readerAttack(ar_resp, setEmulatorMem, !(flags & FLAG_RANDOM_NONCE));
 			if ((bool)resp.arg[1]) {
 				PrintAndLog("Device button pressed - quitting");
 				fclose(f);
@@ -1284,7 +1313,8 @@ int CmdHF14AMf1kSim(const char *Cmd) {
 			if (flags & FLAG_NR_AR_ATTACK) {
 				nonces_t ar_resp[ATTACK_KEY_COUNT*2];
 				memcpy(ar_resp, resp.d.asBytes, sizeof(ar_resp));
-				readerAttack(ar_resp, setEmulatorMem);
+				// We can skip the standard attack if we have RANDOM_NONCE set.
+				readerAttack(ar_resp, setEmulatorMem, !(flags & FLAG_RANDOM_NONCE));
 			}
 		}
 	}
-- 
2.39.5