MirrorBackup/GodMode9
1
0
Fork 0
forked from Mirror/GodMode9
Code Pull Requests Activity

On-the-fly decryption for DSiWare Exports

Browse Source
This commit is contained in:
d0k3 2017-11-10 04:14:38 +01:00
parent 83b2fba142
commit fc97df6466
6 changed files with 208 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arm9/source/filesys/filetype.c
View File

@ -128,6 +128,9 @@ u64 IdentifyFileType(const char* path) {
if (fsize < TEMP_BUFFER_SIZE) type |= TXT_GENERIC;
return type;
} else if ((strnlen(fname, 16) == 8) && (sscanf(fname, "%08lx", &id) == 1)) {
if (strncmp(path + 2, "/Nintendo DSiWare/", 18) == 0)
return GAME_DSIWE;
char path_cdn[256];
char* name_cdn = path_cdn + (fname - path);
strncpy(path_cdn, path, 256);

23
arm9/source/filesys/filetype.h
View File

@ -17,17 +17,18 @@
#define GAME_3DSX (1ULL<<12)
#define GAME_NDS (1ULL<<13)
#define GAME_GBA (1ULL<<14)
#define SYS_FIRM (1ULL<<15)
#define SYS_AGBSAVE (1ULL<<16)
#define SYS_TICKDB (1ULL<<17)
#define BIN_NCCHNFO (1ULL<<18)
#define BIN_TIKDB (1ULL<<19)
#define BIN_KEYDB (1ULL<<20)
#define BIN_LEGKEY (1ULL<<21)
#define TXT_SCRIPT (1ULL<<22)
#define TXT_GENERIC (1ULL<<23)
#define NOIMG_NAND (1ULL<<24)
#define HDR_NAND (1ULL<<25)
#define GAME_DSIWE (1ULL<<15)
#define SYS_FIRM (1ULL<<16)
#define SYS_AGBSAVE (1ULL<<17)
#define SYS_TICKDB (1ULL<<18)
#define BIN_NCCHNFO (1ULL<<19)
#define BIN_TIKDB (1ULL<<20)
#define BIN_KEYDB (1ULL<<21)
#define BIN_LEGKEY (1ULL<<22)
#define TXT_SCRIPT (1ULL<<23)
#define TXT_GENERIC (1ULL<<24)
#define NOIMG_NAND (1ULL<<25)
#define HDR_NAND (1ULL<<26)
#define TYPE_BASE 0xFFFFFFFFULL // 32 bit reserved for base types
// #define FLAG_FIRM (1ULL<<58) // <--- for CXIs containing FIRMs

125
arm9/source/filesys/sddata.c
View File

@ -1,7 +1,9 @@
#include "sddata.h"
#include "dsiwareexp.h"
#include "aes.h"
#include "sha.h"
#define DSIWARE_MAGIC "Nintendo DSiWare" // must be exactly 16 chars
#define NUM_ALIAS_DRV 2
#define NUM_FILCRYPTINFO 16
@ -52,28 +54,117 @@ FilCryptInfo* fx_find_cryptinfo(FIL* fptr) {
return info;
}
FRESULT fx_decrypt_dsiware (FIL* fp, void* buff, FSIZE_t ofs, UINT len) {
const u32 mode = AES_CNT_TITLEKEY_DECRYPT_MODE;
const u32 num_tbl = sizeof(DsiWareExpContentTable) / sizeof(u32);
const FSIZE_t ofs0 = f_tell(fp);
u8 __attribute__((aligned(16))) iv[AES_BLOCK_SIZE];
u32 tbl[num_tbl];
u8 hdr[DSIWEXP_HEADER_LEN];
FRESULT res;
UINT br;
// read and decrypt header
if ((res = f_lseek(fp, DSIWEXP_HEADER_OFFSET)) != FR_OK) return res;
if ((res = f_read(fp, hdr, DSIWEXP_HEADER_LEN, &br)) != FR_OK) return res;
if (br != DSIWEXP_HEADER_LEN) return FR_DENIED;
memcpy(iv, hdr + DSIWEXP_HEADER_LEN - AES_BLOCK_SIZE, AES_BLOCK_SIZE);
cbc_decrypt(hdr, hdr, sizeof(DsiWareExpHeader) / AES_BLOCK_SIZE, mode, iv);
// setup the table
if (BuildDsiWareExportContentTable(tbl, hdr) != 0) return FR_DENIED;
if (tbl[num_tbl-1] > f_size(fp)) return FR_DENIED; // obviously missing data
// process sections
u32 sct_start = 0;
u32 sct_end = 0;
for (u32 i = 0; i < num_tbl; i++, sct_start = sct_end) {
sct_end = tbl[i];
if (sct_start == sct_end) continue; // nothing in section
if ((ofs + len <= sct_start) || (ofs >= sct_end)) continue; // section not in data
const u32 crypt_end = sct_end - (AES_BLOCK_SIZE * 2);
const u32 data_end = min(crypt_end, ofs + len);
u32 data_pos = max(ofs, sct_start);
if (ofs >= crypt_end) continue; // nothing to do
if ((sct_start < ofs) || (sct_end > ofs + len)) { // incomplete section, ugh
u8 __attribute__((aligned(16))) block[AES_BLOCK_SIZE];
// load iv0
FSIZE_t block0_ofs = data_pos - (data_pos % AES_BLOCK_SIZE);
FSIZE_t iv0_ofs = ((block0_ofs > sct_start) ? block0_ofs : sct_end) - AES_BLOCK_SIZE;
if ((res = f_lseek(fp, iv0_ofs)) != FR_OK) return res;
if ((res = f_read(fp, iv, AES_BLOCK_SIZE, &br)) != FR_OK) return res;
// load and decrypt block0 (if misaligned)
if (data_pos % AES_BLOCK_SIZE) {
if ((res = f_lseek(fp, block0_ofs)) != FR_OK) return res;
if ((res = f_read(fp, block, AES_BLOCK_SIZE, &br)) != FR_OK) return res;
cbc_decrypt(block, block, 1, mode, iv);
data_pos = min(block0_ofs + AES_BLOCK_SIZE, data_end);
memcpy(buff, block + (ofs - block0_ofs), data_pos - ofs);
}
// decrypt blocks in between
u32 num_blocks = (data_end - data_pos) / AES_BLOCK_SIZE;
if (num_blocks) {
u8* blocks = (u8*) buff + (data_pos - ofs);
cbc_decrypt(blocks, blocks, num_blocks, mode, iv);
data_pos += num_blocks * AES_BLOCK_SIZE;
}
// decrypt last block
if (data_pos < data_end) {
u8* lbuff = (u8*) buff + (data_pos - ofs);
memcpy(block, lbuff, data_end - data_pos);
cbc_decrypt(block, block, 1, mode, iv);
memcpy(lbuff, block, data_end - data_pos);
data_pos = data_end;
}
} else { // complete section (thank god for these!)
u8* blocks = (u8*) buff + (sct_start - ofs);
u8* iv0 = (u8*) buff + (sct_end - ofs) - AES_BLOCK_SIZE;
u32 num_blocks = (crypt_end - sct_start) / AES_BLOCK_SIZE;
memcpy(iv, iv0, AES_BLOCK_SIZE);
cbc_decrypt(blocks, blocks, num_blocks, mode, iv);
}
}
return f_lseek(fp, ofs0);
}
FRESULT fx_open (FIL* fp, const TCHAR* path, BYTE mode) {
int num = alias_num(path);
FilCryptInfo* info = fx_find_cryptinfo(fp);
if (info) info->fptr = NULL;
if (info && (num >= 0)) {
// get AES counter, see: http://www.3dbrew.org/wiki/Extdata#Encryption
// path is the part of the full path after //Nintendo 3DS/<ID0>/<ID1>
u8 hashstr[256];
u8 sha256sum[32];
u32 plen = 0;
// poor man's UTF-8 -> UTF-16 / uppercase -> lowercase
for (plen = 0; plen < 128; plen++) {
u8 symbol = path[2 + plen];
if ((symbol >= 'A') && (symbol <= 'Z')) symbol += ('a' - 'A');
hashstr[2*plen] = symbol;
hashstr[2*plen+1] = 0;
if (symbol == 0) break;
// DSIWare Export, mark with the magic number
if (strncmp(path + 2, "/" DSIWARE_MAGIC, 1 + 16) == 0) {
memcpy(info->ctr, DSIWARE_MAGIC, 16);
} else {
// get AES counter, see: http://www.3dbrew.org/wiki/Extdata#Encryption
// path is the part of the full path after //Nintendo 3DS/<ID0>/<ID1>
u8 hashstr[256];
u8 sha256sum[32];
u32 plen = 0;
// poor man's UTF-8 -> UTF-16 / uppercase -> lowercase
for (plen = 0; plen < 128; plen++) {
u8 symbol = path[2 + plen];
if ((symbol >= 'A') && (symbol <= 'Z')) symbol += ('a' - 'A');
hashstr[2*plen] = symbol;
hashstr[2*plen+1] = 0;
if (symbol == 0) break;
}
sha_quick(sha256sum, hashstr, (plen + 1) * 2, SHA256_MODE);
for (u32 i = 0; i < 16; i++)
info->ctr[i] = sha256sum[i] ^ sha256sum[i+16];
}
sha_quick(sha256sum, hashstr, (plen + 1) * 2, SHA256_MODE);
for (u32 i = 0; i < 16; i++)
info->ctr[i] = sha256sum[i] ^ sha256sum[i+16];
// copy over key, FIL pointer
memcpy(info->keyy, sd_keyy[num], 16);
info->fptr = fp;
@ -89,7 +180,8 @@ FRESULT fx_read (FIL* fp, void* buff, UINT btr, UINT* br) {
if (info && info->fptr) {
setup_aeskeyY(0x34, info->keyy);
use_aeskey(0x34);
ctr_decrypt_byte(buff, buff, btr, off, AES_CNT_CTRNAND_MODE, info->ctr);
if (memcmp(info->ctr, DSIWARE_MAGIC, 16) == 0) fx_decrypt_dsiware(fp, buff, off, btr);
else ctr_decrypt_byte(buff, buff, btr, off, AES_CNT_CTRNAND_MODE, info->ctr);
}
return res;
}
@ -99,6 +191,7 @@ FRESULT fx_write (FIL* fp, const void* buff, UINT btw, UINT* bw) {
FSIZE_t off = f_tell(fp);
FRESULT res = FR_OK;
if (info && info->fptr) {
if (memcmp(info->ctr, DSIWARE_MAGIC, 16) == 0) return FR_DENIED;
setup_aeskeyY(0x34, info->keyy);
use_aeskey(0x34);
*bw = 0;

24
arm9/source/game/dsiwareexp.c Normal file
View File

@ -0,0 +1,24 @@
#include "dsiwareexp.h"
u32 BuildDsiWareExportContentTable(void* table, void* header) {
DsiWareExpHeader* hdr = (DsiWareExpHeader*) header;
DsiWareExpContentTable* tbl = (DsiWareExpContentTable*) table;
if (strncmp(hdr->magic, DSIWEXP_HEADER_MAGIC, strlen(DSIWEXP_HEADER_MAGIC)) != 0)
return 1;
tbl->banner_end = 0 + sizeof(DsiWareExpBanner) + sizeof(DsiWareExpBlockMetaData);
tbl->header_end = tbl->banner_end + sizeof(DsiWareExpHeader) + sizeof(DsiWareExpBlockMetaData);
tbl->footer_end = tbl->header_end + sizeof(DsiWareExpFooter) + sizeof(DsiWareExpBlockMetaData);
u32 content_end_last = tbl->footer_end;
for (u32 i = 0; i < DSIWEXP_NUM_CONTENT; i++) {
tbl->content_end[i] = content_end_last;
if (!hdr->content_size[i]) continue; // non-existant section
tbl->content_end[i] += align(hdr->content_size[i], 0x10) + sizeof(DsiWareExpBlockMetaData);
content_end_last = tbl->content_end[i];
}
return 0;
}

59
arm9/source/game/dsiwareexp.h Normal file
View File

@ -0,0 +1,59 @@
#pragma once
#include "common.h"
#include "nds.h"
#define DSIWEXP_NUM_CONTENT 11
#define DSIWEXP_HEADER_MAGIC "3FDT"
#define DSIWEXP_BANNER_OFFSET 0
#define DSIWEXP_BANNER_LEN (sizeof(DsiWareExpBanner) + sizeof(DsiWareExpBlockMetaData))
#define DSIWEXP_HEADER_OFFSET (DSIWEXP_BANNER_OFFSET + DSIWEXP_BANNER_LEN)
#define DSIWEXP_HEADER_LEN (sizeof(DsiWareExpHeader) + sizeof(DsiWareExpBlockMetaData))
typedef struct {
u32 banner_end;
u32 header_end;
u32 footer_end;
u32 content_end[DSIWEXP_NUM_CONTENT];
} __attribute__((packed)) DsiWareExpContentTable;
// see: https://www.3dbrew.org/wiki/DSiWare_Exports#Block_Metadata
typedef struct {
u8 cmac[16];
u8 iv0[16];
} __attribute__((packed)) DsiWareExpBlockMetaData;
// see: https://www.3dbrew.org/wiki/DSiWare_Exports#File_Structure_v2
typedef struct {
TwlIconData icon_data;
u8 unknown[0x4000 - sizeof(TwlIconData)];
} __attribute__((packed)) DsiWareExpBanner;
// see: https://www.3dbrew.org/wiki/DSiWare_Exports#Header_2
typedef struct {
char magic[4]; // "3FDT"
u16 group_id;
u16 title_version;
u8 movable_enc_sha256[0x20];
u8 cbc_test_block[0x10];
u64 title_id;
u64 unknown0;
u32 content_size[DSIWEXP_NUM_CONTENT];
u8 unknown1[0x30];
u8 tmd_reserved[0x3E];
u8 padding[0x0E];
} __attribute__((packed)) DsiWareExpHeader;
// see: https://www.3dbrew.org/wiki/DSiWare_Exports#Footer
typedef struct {
u8 banner_sha256[0x20];
u8 header_sha256[0x20];
u8 content_sha256[DSIWEXP_NUM_CONTENT][0x20];
u8 ecdsa_signature[0x3C];
u8 ecdsa_apcert[0x180];
u8 ecdsa_ctcert[0x180];
u8 padding[0x4];
} __attribute__((packed)) DsiWareExpFooter;
u32 BuildDsiWareExportContentTable(void* table, void* header);

1
arm9/source/game/game.h
View File

@ -11,5 +11,6 @@
#include "codelzss.h"
#include "nds.h"
#include "gba.h"
#include "dsiwareexp.h"
#include "3dsx.h"
#include "ncchinfo.h"