User:Magicus/Magicus's Tools/Parse-channel.c

Put this file in the same directory as a compiled version of Segher's Wii.git tools, since it depends on them.

// parse-channel.c
// Compile with:
// gcc -g -DLARGE_FILES -D_FILE_OFFSET_BITS=64 -Wall -W -O2   -c -o parse-channel.o parse-channel.c
// gcc -g -lcrypto  parse-channel.o tools.o bn.o ec.o   -o parse-channel
// The other files are from segher's git repository, created by his Makefile.

// Copyright 2008 Magicus <magicus@gmail.com>
// This file is based on tachtig.c, which is
// Copyright 2007,2008  Segher Boessenkool  <segher@kernel.crashing.org>
//
// Licensed under the terms of the GNU GPL, version 2
// http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt

// Version 1.0 Initial release
// Version 1.1 Fixing IV-bug for part B. Adding support for decompressing part B;
// thanks Arcnor <arcnorj@yahoo.es> for the basic LZ77 code!


#include <string.h>
#include <stdlib.h>
#include <stdio.h>

#include "tools.h"

#define ERROR(s) do { fprintf(stderr, s "\n"); exit(1); } while (0)

static u8 sd_key[16];
static u8 sd_iv[16];
static u8 md5_blanker[16];

static FILE *fp;

static char gamename[5];

static size_t partB_size;
static u16 num_contents;
static size_t* content_sizes;

typedef struct {
      u32 title_id_01_code;
      u32 title_id_02_name;
      u32 partB_size;
      u8  md5[0x10];
      u8  data[0x624];
} partA_header_t;

typedef struct {
      u32 imd5_tag; // 0x494D4435 "IMD5";
      u32 size;  // size of the rest of part B, starting from next field.
      u8 zeroes[8];
      u8 crypto[16];
      u32 lz77_tag; // 0x4C5A3737 "LZ77"
      u32 unknown; // padding to 0x40?
}  partB_header_t;

typedef struct {
       u32 sig_type; 
       u8 sig[256];
       u8 fill1[60];
       u8 issuer[64]; // Root-CA%08x-CP%08x
       u8 version;
       u8 ca_crl_version;
       u8 signer_crl_version;
       u8 fill2;
       u64 sys_version;
       u64 title_id;
       u32 title_type;
       u16 group_id; // publisher
       u8 reserved[62];
       u32 access_rights;
       u16 title_version;
       u16 num_contents;
       u16 boot_index;
       u16 fill3;
} tmd_t;

typedef struct {
  u32 cid;		// content id
  u16 index;		// # number of the file
  u16  type;
  u64 size;
  u8  hash [20]; 		//  SHA1 hash content
} content_record_t;

static void write_part(void* data, size_t size, char* name)
{
	FILE *out;
	char filename[128];

  snprintf(filename, sizeof(filename), "%s_%s.bin", gamename, name);
  filename[128] = '\0';
	out = fopen(filename, "wb");
	fwrite(data, 1, size, out);
	fclose(out);	
}

static void do_partA_header(void)
{
  partA_header_t header;
	u8 partA_iv[16];
	u8 md5_file[16];
	u8 md5_calc[16];

	fread(&header, 1, sizeof header, fp);

  // Use a private copy of the sd_iv since we need it again
  // and it will be overwritten otherwise.
	memcpy(partA_iv, sd_iv, 16);
	aes_cbc_dec(sd_key, partA_iv, (u8*) &header, sizeof header, (u8*) &header);

	memcpy(md5_file, header.md5, 16);
	memcpy(header.md5, md5_blanker, 16);
	md5((u8*) &header, sizeof header, md5_calc);

	if (memcmp(md5_file, md5_calc, 0x10)) {
		ERROR("MD5 mismatch");
  }

	// Get the four-letter code of the game, for file naming purposes.
	strncpy(gamename, (char*) &header.title_id_02_name, 4);
	gamename[5] = '\0';
	printf("Game code is: %s\n", gamename);

  partB_size = be32((u8*) &header.partB_size);

  write_part(&header, sizeof(header), "01_header");
}

static u8* decompress_lz77(u8 *data, size_t data_size, size_t* decompressed_size)
{
	u8 *data_end;
	u8 *decompressed_data;
	size_t unpacked_size;
	u8 *in_ptr;
	u8 *out_ptr;
	u8 *out_end;

	in_ptr = data;
	data_end = data + data_size;

	// Assume this for now and grow when needed
	unpacked_size = data_size;

	decompressed_data = malloc(unpacked_size);
	out_end = decompressed_data + unpacked_size;
	
	out_ptr = decompressed_data;
	
	while (in_ptr < data_end) {
	  int bit;
	  u8 bitmask = *in_ptr;

	  in_ptr++;
	  for (bit = 0x80; bit != 0; bit >>= 1) {
	    if (bitmask & bit) {
	      // Next section is compressed
	      u8 rep_length;
	      u16 rep_offset;
	      
	      rep_length = (*in_ptr >> 4) + 3;
	      rep_offset = *in_ptr & 0x0f;
	      in_ptr++;
	      rep_offset = *in_ptr | (rep_offset << 8);
	      in_ptr++;
	      if (out_ptr-decompressed_data < rep_offset) {
	        ERROR("Inconsistency in LZ77 encoding");
	      }

        for ( ; rep_length > 0; rep_length--) {
          *out_ptr = out_ptr[-rep_offset-1];
          out_ptr++;
          if (out_ptr >= out_end) {
            // Need to grow buffer
            decompressed_data = realloc(decompressed_data, unpacked_size*2);
            out_ptr = decompressed_data + unpacked_size;
            unpacked_size *= 2;
            out_end = decompressed_data + unpacked_size;
          }
        }
	    } else {
	      // Just copy byte
        *out_ptr = *in_ptr;
        out_ptr++;
        if (out_ptr >= out_end) {
          // Need to grow buffer
          decompressed_data = realloc(decompressed_data, unpacked_size*2);
          out_ptr = decompressed_data + unpacked_size;
          unpacked_size *= 2;
          out_end = decompressed_data + unpacked_size;
        }
	      in_ptr++;
	    }
	  }
	}

	*decompressed_size = (out_ptr - decompressed_data);
	return decompressed_data;
}

static void do_partB_gameinfo(void)
{
	u8 *data;
	u8 *decompressed_data;
	size_t rounded_size;
	size_t decompressed_size;
	partB_header_t* header;
	u32 tag;
	u32 unknown;
	u32 size;

	rounded_size = (partB_size + 63) & ~63;

	data = malloc(rounded_size);
	fread(data, 1, rounded_size, fp);

	aes_cbc_dec(sd_key, sd_iv, data, rounded_size, data);
	
	header = (partB_header_t*) data;
	
	tag = be32((u8*) &header->imd5_tag);
	if (tag != 0x494D4435) {
	  ERROR("No IMD5 tag");
	}
	size = be32((u8*) &header->size);
	if (size != partB_size - 32) {
	  ERROR("Size mismatch");
	}

	tag = be32((u8*) &header->lz77_tag);
	if (tag != 0x4C5A3737) {
	  ERROR("No LZ77 tag");
	}

	unknown = be32((u8*) &header->unknown);
	printf("Part B unknown field: %x\n", unknown);

	write_part(data, sizeof(partB_header_t), "02a_banner_header");

	decompressed_data = decompress_lz77(data + sizeof(partB_header_t), partB_size - sizeof(partB_header_t), &decompressed_size);
	write_part(decompressed_data, decompressed_size, "02b_banner_decompressed");
  
	free(data);
//  free(decompressed_data);
}

static void do_partC_Bk_header(void)
{
	u8 header[0x80];

	fread(header, 1, sizeof header, fp);

	if (be32(header + 4) != 0x426b0001)
		ERROR("no Bk header");
	if (be32(header) != 0x70)
		ERROR("wrong Bk header size");

	fprintf(stderr, "NG id: %08x\n", be32(header + 8));

	write_part(header, sizeof(header), "03_bk_header");
}

static void do_partD_tmd(void)
{
	tmd_t tmd;
	u8* data;
	size_t tmd_size;
	int i;
	content_record_t* rec;

	fread(&tmd, 1, sizeof tmd, fp);

  num_contents = be16((u8*) &tmd.num_contents);
  printf("Number of content files: %d\n", num_contents);
  
  // Now we can read the rest of the tmd.
  tmd_size = sizeof(tmd) + num_contents*sizeof(content_record_t);
  tmd_size = (tmd_size + 63) & ~63;

  data = malloc(tmd_size);
  memcpy(data, &tmd, sizeof(tmd));
  fread(&data[sizeof(tmd)], 1, tmd_size-sizeof(tmd), fp);

  write_part(data, tmd_size, "04_tmd");

  content_sizes = calloc(1, sizeof (size_t) *  num_contents);
  
  rec = (content_record_t*) &data[sizeof(tmd)];
  for (i = 0; i < num_contents; i++, rec++) {
    u16 type = be16((u8*) &rec->type);

    if (!(type & 0x8000)) {
      content_sizes[i] = (size_t)be64((u8*) &rec->size);
    }
  }
}

static void do_partE_contents(void)
{
  int i;
	
  for (i=0; i < num_contents; i++) {
	  if (content_sizes[i] != 0) {
      char name[128];
      u8 *data;
      size_t rounded_size = (content_sizes[i] + 63) & ~63;
      
      data = malloc(rounded_size);
      fread(data, 1, rounded_size, fp);
	
      snprintf(name, 128, "05_content_%02d", i);
      printf("Writing included content index %d of size: %x\n", i, content_sizes[i]);
      
      write_part(data, rounded_size, name);

      free (data);
    }
  }
}

static void do_partF_cert(void)
{
	u8 cert[0x340];

	fread(cert, 1, sizeof cert, fp);
	
  write_part(cert, sizeof(cert), "06_cert");
}


int main(int argc, char **argv)
{
  if (argc != 2) {
    ERROR("Usage: parse-channel <file>");
  }

	get_key("sd-key", sd_key, 16);
	get_key("sd-iv", sd_iv, 16);
	get_key("md5-blanker", md5_blanker, 16);

	fp = fopen(argv[1], "rb");

  do_partA_header();
	do_partB_gameinfo();
	do_partC_Bk_header();
	do_partD_tmd();
	do_partE_contents();
	do_partF_cert();

	fclose(fp);

	return 0;
}

See Also

LZ77