From b07eb7c5771baf65021c48f7648d3e05c665ce1f Mon Sep 17 00:00:00 2001
From: schneider <schneider@blinkenlichts.net>
Date: Wed, 3 Aug 2011 08:59:55 +0200
Subject: [PATCH] executor: made encryption work

---
 firmware/basic/xxtea.c        |  4 ++--
 firmware/filesystem/execute.c | 30 +++++++++++++++++++++++-------
 2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/firmware/basic/xxtea.c b/firmware/basic/xxtea.c
index 9ae81f8..fb7278c 100644
--- a/firmware/basic/xxtea.c
+++ b/firmware/basic/xxtea.c
@@ -57,7 +57,7 @@ void xxtea_cbcmac(uint32_t mac[4], uint32_t *data,
 
 void xxtea_encode_words(uint32_t *v, int n, uint32_t const k[4])
 {
-    if(k[0] == 0 && k[1] == 0 && k[2] == 0 && k[3] == 0) return;
+    //if(k[0] == 0 && k[1] == 0 && k[2] == 0 && k[3] == 0) return;
     uint32_t y, z, sum;
     unsigned p, rounds, e;
 
@@ -80,7 +80,7 @@ void xxtea_encode_words(uint32_t *v, int n, uint32_t const k[4])
 
 void xxtea_decode_words(uint32_t *v, int n, uint32_t const k[4])
 {
-    if(k[0] == 0 && k[1] == 0 && k[2] == 0 && k[3] == 0) return;
+    //if(k[0] == 0 && k[1] == 0 && k[2] == 0 && k[3] == 0) return;
     uint32_t y, z, sum;
     unsigned p, rounds, e;
     htonlp(v ,n);
diff --git a/firmware/filesystem/execute.c b/firmware/filesystem/execute.c
index ee387b0..9b0aa91 100644
--- a/firmware/filesystem/execute.c
+++ b/firmware/filesystem/execute.c
@@ -12,8 +12,9 @@
 
 #include "basic/xxtea.h"
 
-const uint32_t signature_key[4] = {0,0,0,0};
-const uint32_t decode_key[4] = {0,0,0,0};
+const uint32_t signature_key[4] = {0x123456,0,0,0x234567};
+const uint32_t decode_key[4] = {0x123456,0,0,0x234567};
+//const uint32_t decode_key[4] = {0,0,0,0};
 
 extern void * sram_top;
 
@@ -39,7 +40,7 @@ void execute_file (const char * fname, uint8_t checksignature, uint8_t decode){
     if(res){
         return;
     };
-
+    
     res = f_read(&file, (char *)dst, RAMCODE, &readbytes);
     //lcdPrint("read: ");
     //lcdPrintln(f_get_rc_string(res));
@@ -47,11 +48,15 @@ void execute_file (const char * fname, uint8_t checksignature, uint8_t decode){
     if(res){
         return;
     };
-
     if( decode || checksignature )
-        if( readbytes & 0x03 )
+        //only accept files with fixed length
+        //if( readbytes != 2048 )
+        if( readbytes & 0x3 ){
+            lcdPrint("readbytes&3");
+            lcdRefresh();
+            while(1);
             return;
-    
+        }
     if( checksignature ){
         uint32_t mac[4];
         uint32_t *data = (uint32_t*)dst;
@@ -59,14 +64,25 @@ void execute_file (const char * fname, uint8_t checksignature, uint8_t decode){
         xxtea_cbcmac(mac, (uint32_t*)dst, len-4, signature_key);
         if( data[len-4] != mac[0] || data[len-3] != mac[1]
             || data[len-2] != mac[2] || data[len-1] != mac[3] ){
+            lcdClear();
+            lcdPrint("mac wrong");lcdNl();
+            lcdPrintIntHex(mac[0]); lcdNl();
+            lcdPrintIntHex(mac[1]); lcdNl();
+            lcdPrintIntHex(mac[2]); lcdNl();
+            lcdPrintIntHex(mac[3]); lcdNl();
+            lcdRefresh();
+            while(1); 
             return;
         }
+        //lcdPrint("macok");
+        //lcdRefresh();
+        //while(1);
     }
 
     if( decode ){
         uint32_t *data = (uint32_t*)dst;
         uint32_t len = readbytes/4;
-        xxtea_decode_words(data, len, decode_key);
+        xxtea_decode_words(data, len-4, decode_key);
     }
     //lcdPrintInt(readbytes);
     //lcdPrintln(" bytes");