From b5be31f9967700a184adce27d2eb172d5cc89989 Mon Sep 17 00:00:00 2001
From: iceman1001 <iceman@iuse.se>
Date: Wed, 7 Jan 2015 22:56:20 +0100
Subject: [PATCH] FIX: The input handling for "hf 14b write" is now correct.
 Thanks Asper for spotting the fault. ADD: crc32.c functionality

---
 client/cmdhf14b.c | 28 ++++++++++++++++++----------
 common/crc32.c    | 35 +++++++++++++++++++++++++++++++++++
 common/crc32.h    | 15 +++++++++++++++
 3 files changed, 68 insertions(+), 10 deletions(-)
 create mode 100644 common/crc32.c
 create mode 100644 common/crc32.h

diff --git a/client/cmdhf14b.c b/client/cmdhf14b.c
index 713959f2..e3d0fc23 100644
--- a/client/cmdhf14b.c
+++ b/client/cmdhf14b.c
@@ -404,20 +404,27 @@ int CmdHF14BWrite( const char *Cmd){
 	bool isSrix4k = true;
 	char str[20];	
 
-	if (cmdp == 'h' || cmdp == 'H') {
+	if (strlen(Cmd) < 1 || cmdp == 'h' || cmdp == 'H') {
 		PrintAndLog("Usage:  hf 14b write <1|2> <BLOCK> <DATA>");
-		PrintAndLog("");
-		PrintAndLog("     sample: hf 14b write 1 127 11223344");
-		PrintAndLog("     sample: hf 14b write 1 255 11223344");
-		PrintAndLog("     sample: hf 14b write 2 15 11223344");
-		PrintAndLog("     sample: hf 14b write 2 255 11223344");
+		PrintAndLog("    [1 = SRIX4K]");
+		PrintAndLog("    [2 = SRI512]");
+		PrintAndLog("    [BLOCK number depends on tag, special block == FF]");
+		PrintAndLog("     sample: hf 14b write 1 7F 11223344");
+		PrintAndLog("           : hf 14b write 1 FF 11223344");
+		PrintAndLog("           : hf 14b write 2 15 11223344");
+		PrintAndLog("           : hf 14b write 2 FF 11223344");
 		return 0;
 	}
 
-	if ( param_getchar(Cmd, 0) == '2' )
+	if ( cmdp == '2' )
 		isSrix4k = false;
 	
-	blockno = param_get8(Cmd, 1);
+	//blockno = param_get8(Cmd, 1);
+	
+	if ( param_gethex(Cmd,1, &blockno, 2) ) {
+		PrintAndLog("Block number must include 2 HEX symbols");
+		return 0;
+	}
 	
 	if ( isSrix4k ){
 		if ( blockno > 0x7f && blockno != 0xff ){
@@ -437,11 +444,12 @@ int CmdHF14BWrite( const char *Cmd){
 	}
  
 	if ( blockno == 0xff)
-		PrintAndLog("Writing to special block %02X [ %s]", blockno,  sprint_hex(data,4) );
+		PrintAndLog("[%s] Write special block %02X [ %s ]", (isSrix4k)?"SRIX4K":"SRI512" , blockno,  sprint_hex(data,4) );
 	else
-		PrintAndLog("Writing to block %02X [ %s]", blockno,  sprint_hex(data,4) );
+		PrintAndLog("[%s] Write block %02X [ %s ]", (isSrix4k)?"SRIX4K":"SRI512", blockno,  sprint_hex(data,4) );
  
 	sprintf(str, "-c -p 09 %02x %02x%02x%02x%02x", blockno, data[0], data[1], data[2], data[3]);
+
 	CmdHF14BCmdRaw(str);
 	return 0;
 }
diff --git a/common/crc32.c b/common/crc32.c
new file mode 100644
index 00000000..69d770f4
--- /dev/null
+++ b/common/crc32.c
@@ -0,0 +1,35 @@
+#include <stdint.h>
+#include <stddef.h>
+#include "crc32.h"
+
+#define htole32(x) (x)
+#define CRC32_PRESET 0xFFFFFFFF
+
+
+static void crc32_byte (uint32_t *crc, const uint8_t value);
+
+static void crc32_byte (uint32_t *crc, const uint8_t value) {
+    /* x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x + 1 */
+    const uint32_t poly = 0xEDB88320;
+
+    *crc ^= value;
+    for (int current_bit = 7; current_bit >= 0; current_bit--) {
+        int bit_out = (*crc) & 0x00000001;
+        *crc >>= 1;
+        if (bit_out)
+            *crc ^= poly;
+    }
+}
+
+void crc32 (const uint8_t *data, const size_t len, uint8_t *crc) {
+    uint32_t desfire_crc = CRC32_PRESET;
+    for (size_t i = 0; i < len; i++) {
+        crc32_byte (&desfire_crc, data[i]);
+    }
+
+    *((uint32_t *)(crc)) = htole32 (desfire_crc);
+}
+
+void crc32_append (uint8_t *data, const size_t len) {
+    crc32 (data, len, data + len);
+}
diff --git a/common/crc32.h b/common/crc32.h
new file mode 100644
index 00000000..0dd2a328
--- /dev/null
+++ b/common/crc32.h
@@ -0,0 +1,15 @@
+//-----------------------------------------------------------------------------
+// This code is licensed to you under the terms of the GNU GPL, version 2 or,
+// at your option, any later version. See the LICENSE.txt file for the text of
+// the license.
+//-----------------------------------------------------------------------------
+// CRC32
+//-----------------------------------------------------------------------------
+
+#ifndef __CRC32_H
+#define __CRC32_H
+
+void             	crc32 (const uint8_t *data, const size_t len, uint8_t *crc);
+void             	crc32_append (uint8_t *data, const size_t len);
+
+#endif
-- 
2.39.2