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rockbox/utils/ipodpatcher/ipodpatcher-aupd.c
Dominik Riebeling 748b00a7fc ipodpatcher: Split executable only parts out. 
Allow building both as library and executable at the same time.

Change-Id: Idc40354fdedaeace727043936352fc17232bf16e
2022-03-12 20:40:08 +01:00

398 lines
10 KiB
C
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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2006-2007 Dave Chapman
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <inttypes.h>
#include <stdbool.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "ipodpatcher.h"
#include "arc4.h"
static inline int le2int(unsigned char* buf)
{
int32_t res = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
return res;
}
static inline void int2le(unsigned int val, unsigned char* addr)
{
addr[0] = val & 0xFF;
addr[1] = (val >> 8) & 0xff;
addr[2] = (val >> 16) & 0xff;
addr[3] = (val >> 24) & 0xff;
}
static inline uint32_t getuint32le(unsigned char* buf)
{
int32_t res = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
return res;
}
/* testMarker and GetSecurityBlockKey based on code from BadBlocks and
Kingstone, posted at http://ipodlinux.org/Flash_Decryption
*/
static bool testMarker(int marker)
{
int mask, decrypt, temp1, temp2;
mask = (marker&0xff)|((marker&0xff)<<8)|((marker&0xff)<<16)|((marker&0xff)<<24);
decrypt = marker ^ mask;
temp1=(int)((unsigned int)decrypt>>24);
temp2=decrypt<<8;
if (temp1==0)
return false;
temp2=(int)((unsigned int)temp2>>24);
decrypt=decrypt<<16;
decrypt=(int)((unsigned int)decrypt>>24);
if ((temp1 < temp2) && (temp2 < decrypt))
{
temp1 = temp1 & 0xf;
temp2 = temp2 & 0xf;
decrypt = decrypt & 0xf;
if ((temp1 > temp2) && (temp2 > decrypt) && (decrypt != 0))
{
return true;
}
}
return false;
}
static int GetSecurityBlockKey(unsigned char *data, unsigned char* this_key)
{
int constant = 0x54c3a298;
int key=0;
int nkeys = 0;
int aMarker=0;
int pos=0;
int c, count;
int temp1;
static const int offset[8]={0x5,0x25,0x6f,0x69,0x15,0x4d,0x40,0x34};
for (c = 0; c < 8; c++)
{
pos = offset[c]*4;
aMarker = getuint32le(data + pos);
if (testMarker(aMarker))
{
if (c<7)
pos =(offset[c+1]*4)+4;
else
pos =(offset[0]*4)+4;
key=0;
temp1=aMarker;
for (count=0;count<2;count++){
int word = getuint32le(data + pos);
temp1 = aMarker;
temp1 = temp1^word;
temp1 = temp1^constant;
key = temp1;
pos = pos+4;
}
int r1=0x6f;
int r2=0;
int r12;
int r14;
unsigned int r_tmp;
for (count=2;count<128;count=count+2){
r2=getuint32le(data+count*4);
r12=getuint32le(data+(count*4)+4);
r_tmp=(unsigned int)r12>>16;
r14=r2 | ((int)r_tmp);
r2=r2&0xffff;
r2=r2 | r12;
r1=r1^r14;
r1=r1+r2;
}
key=key^r1;
// Invert key, little endian
this_key[0] = key & 0xff;
this_key[1] = (key >> 8) & 0xff;
this_key[2] = (key >> 16) & 0xff;
this_key[3] = (key >> 24) & 0xff;
nkeys++;
}
}
return nkeys;
}
static int find_key(struct ipod_t* ipod, int aupd, unsigned char* key)
{
int n;
/* Firstly read the security block and find the RC4 key. This is
in the sector preceeding the AUPD image. */
if(ipod->sectorbuf == NULL) {
fprintf(stderr,"[ERR] Buffer not initialized.");
return -1;
}
fprintf(stderr, "[INFO] Reading security block at offset 0x%08x\n",ipod->ipod_directory[aupd].devOffset-ipod->sector_size);
if (ipod_seek(ipod, ipod->fwoffset+ipod->ipod_directory[aupd].devOffset-ipod->sector_size) < 0) {
return -1;
}
if ((n = ipod_read(ipod, 512)) < 0) {
return -1;
}
n = GetSecurityBlockKey(ipod->sectorbuf, key);
if (n != 1)
{
fprintf(stderr, "[ERR] %d keys found in security block, can not continue\n",n);
return -1;
}
return 0;
}
int read_aupd(struct ipod_t* ipod, char* filename)
{
int length;
int i;
int outfile;
int n;
int aupd;
struct rc4_key_t rc4;
unsigned char key[4];
unsigned long chksum=0;
if(ipod->sectorbuf == NULL) {
fprintf(stderr,"[ERR] Buffer not initialized.");
return -1;
}
aupd = 0;
while ((aupd < ipod->nimages) && (ipod->ipod_directory[aupd].ftype != FTYPE_AUPD))
{
aupd++;
}
if (aupd == ipod->nimages)
{
fprintf(stderr,"[ERR] No AUPD image in firmware partition.\n");
return -1;
}
length = ipod->ipod_directory[aupd].len;
fprintf(stderr,"[INFO] Reading firmware (%d bytes)\n",length);
if (find_key(ipod, aupd, key) < 0)
{
return -1;
}
fprintf(stderr, "[INFO] Decrypting AUPD image with key %02x%02x%02x%02x\n",key[0],key[1],key[2],key[3]);
if (ipod_seek(ipod, ipod->fwoffset+ipod->ipod_directory[aupd].devOffset) < 0) {
return -1;
}
i = (length+ipod->sector_size-1) & ~(ipod->sector_size-1);
if ((n = ipod_read(ipod,i)) < 0) {
return -1;
}
if (n < i) {
fprintf(stderr,"[ERR] Short read - requested %d bytes, received %d\n",
i,n);
return -1;
}
/* Perform the decryption - this is standard (A)RC4 */
matrixArc4Init(&rc4, key, 4);
matrixArc4(&rc4, ipod->sectorbuf, ipod->sectorbuf, length);
chksum = 0;
for (i = 0; i < (int)length; i++) {
/* add 8 unsigned bits but keep a 32 bit sum */
chksum += ipod->sectorbuf[i];
}
if (chksum != ipod->ipod_directory[aupd].chksum)
{
fprintf(stderr,"[ERR] Decryption failed - checksum error\n");
return -1;
}
fprintf(stderr,"[INFO] Decrypted OK (checksum matches header)\n");
outfile = open(filename,O_CREAT|O_TRUNC|O_WRONLY|O_BINARY,0666);
if (outfile < 0) {
fprintf(stderr,"[ERR] Couldn't open file %s\n",filename);
return -1;
}
n = write(outfile,ipod->sectorbuf,length);
if (n != length) {
fprintf(stderr,"[ERR] Write error - %d\n",n);
}
close(outfile);
return 0;
}
int write_aupd(struct ipod_t* ipod, char* filename)
{
unsigned int length;
int i;
int x;
int n;
int infile;
int newsize;
int aupd;
unsigned long chksum=0;
struct rc4_key_t rc4;
unsigned char key[4];
if(ipod->sectorbuf == NULL) {
fprintf(stderr,"[ERR] Buffer not initialized.");
return -1;
}
/* First check that the input file is the correct type for this ipod. */
infile=open(filename,O_RDONLY);
if (infile < 0) {
fprintf(stderr,"[ERR] Couldn't open input file %s\n",filename);
return -1;
}
length = filesize(infile);
newsize=(length+ipod->sector_size-1)&~(ipod->sector_size-1);
fprintf(stderr,"[INFO] Padding input file from 0x%08x to 0x%08x bytes\n",
length,newsize);
if (newsize > BUFFER_SIZE) {
fprintf(stderr,"[ERR] Input file too big for buffer\n");
if (infile >= 0) close(infile);
return -1;
}
/* Find aupd image number */
aupd = 0;
while ((aupd < ipod->nimages) && (ipod->ipod_directory[aupd].ftype != FTYPE_AUPD))
{
aupd++;
}
if (aupd == ipod->nimages)
{
fprintf(stderr,"[ERR] No AUPD image in firmware partition.\n");
return -1;
}
if (length != ipod->ipod_directory[aupd].len)
{
fprintf(stderr,"[ERR] AUPD image (%d bytes) differs in size to %s (%d bytes).\n",
ipod->ipod_directory[aupd].len, filename, length);
return -1;
}
if (find_key(ipod, aupd, key) < 0)
{
return -1;
}
fprintf(stderr, "[INFO] Encrypting AUPD image with key %02x%02x%02x%02x\n",key[0],key[1],key[2],key[3]);
/* We now know we have enough space, so write it. */
fprintf(stderr,"[INFO] Reading input file...\n");
n = read(infile,ipod->sectorbuf,length);
if (n < 0) {
fprintf(stderr,"[ERR] Couldn't read input file\n");
close(infile);
return -1;
}
close(infile);
/* Pad the data with zeros */
memset(ipod->sectorbuf+length,0,newsize-length);
/* Calculate the new checksum (before we encrypt) */
chksum = 0;
for (i = 0; i < (int)length; i++) {
/* add 8 unsigned bits but keep a 32 bit sum */
chksum += ipod->sectorbuf[i];
}
/* Perform the encryption - this is standard (A)RC4 */
matrixArc4Init(&rc4, key, 4);
matrixArc4(&rc4, ipod->sectorbuf, ipod->sectorbuf, length);
if (ipod_seek(ipod, ipod->fwoffset+ipod->ipod_directory[aupd].devOffset) < 0) {
fprintf(stderr,"[ERR] Seek failed\n");
return -1;
}
if ((n = ipod_write(ipod,newsize)) < 0) {
perror("[ERR] Write failed\n");
return -1;
}
if (n < newsize) {
fprintf(stderr,"[ERR] Short write - requested %d bytes, received %d\n"
,newsize,n);
return -1;
}
fprintf(stderr,"[INFO] Wrote %d bytes to firmware partition\n",n);
x = ipod->diroffset % ipod->sector_size;
/* Read directory */
if (ipod_seek(ipod, ipod->start + ipod->diroffset - x) < 0) { return -1; }
n=ipod_read(ipod, ipod->sector_size);
if (n < 0) { return -1; }
/* Update checksum */
fprintf(stderr,"[INFO] Updating checksum to 0x%08x (was 0x%08x)\n",(unsigned int)chksum,le2int(ipod->sectorbuf + x + aupd*40 + 28));
int2le(chksum,ipod->sectorbuf+x+aupd*40+28);
/* Write directory */
if (ipod_seek(ipod, ipod->start + ipod->diroffset - x) < 0) { return -1; }
n=ipod_write(ipod, ipod->sector_size);
if (n < 0) { return -1; }
return 0;
}
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