/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * * Copyright (C) 2006 by Barry Wardell * Copyright (C) 2020 by William Wilgus [MULTIBOOT] * * Based on Rockbox iriver bootloader by Linus Nielsen Feltzing * and the ipodlinux bootloader by Daniel Palffy and Bernard Leach * * 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 #include #include "config.h" #include "mi4-loader.h" #include "loader_strerror.h" #include "crc32.h" #include "file.h" #if defined(HAVE_BOOTDATA) #include "multiboot.h" #endif /* HAVE_BOOTDATA */ static inline unsigned 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 struct tea_key tea_keytable[] = { { "default" , { 0x20d36cc0, 0x10e8c07d, 0xc0e7dcaa, 0x107eb080 } }, { "sansa", { 0xe494e96e, 0x3ee32966, 0x6f48512b, 0xa93fbb42 } }, { "sansa_gh", { 0xd7b10538, 0xc662945b, 0x1b3fce68, 0xf389c0e6 } }, { "sansa_103", { 0x1d29ddc0, 0x2579c2cd, 0xce339e1a, 0x75465dfe } }, { "rhapsody", { 0x7aa9c8dc, 0xbed0a82a, 0x16204cc7, 0x5904ef38 } }, { "p610", { 0x950e83dc, 0xec4907f9, 0x023734b9, 0x10cfb7c7 } }, { "p640", { 0x220c5f23, 0xd04df68e, 0x431b5e25, 0x4dcc1fa1 } }, { "virgin", { 0xe83c29a1, 0x04862973, 0xa9b3f0d4, 0x38be2a9c } }, { "20gc_eng", { 0x0240772c, 0x6f3329b5, 0x3ec9a6c5, 0xb0c9e493 } }, { "20gc_fre", { 0xbede8817, 0xb23bfe4f, 0x80aa682d, 0xd13f598c } }, { "elio_p722", { 0x6af3b9f8, 0x777483f5, 0xae8181cc, 0xfa6d8a84 } }, { "c200", { 0xbf2d06fa, 0xf0e23d59, 0x29738132, 0xe2d04ca7 } }, { "c200_103", { 0x2a7968de, 0x15127979, 0x142e60a7, 0xe49c1893 } }, { "c200_106", { 0xa913d139, 0xf842f398, 0x3e03f1a6, 0x060ee012 } }, { "view", { 0x70e19bda, 0x0c69ea7d, 0x2b8b1ad1, 0xe9767ced } }, { "sa9200", { 0x33ea0236, 0x9247bdc5, 0xdfaedf9f, 0xd67c9d30 } }, { "hdd1630/hdd63x0", { 0x04543ced, 0xcebfdbad, 0xf7477872, 0x0d12342e } }, { "vibe500", { 0xe3a66156, 0x77c6b67a, 0xe821dca5, 0xca8ca37c } }, }; /* tea_decrypt() from http://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm "Following is an adaptation of the reference encryption and decryption routines in C, released into the public domain by David Wheeler and Roger Needham:" */ /* NOTE: The mi4 version of TEA uses a different initial value to sum compared to the reference implementation and the main loop is 8 iterations, not 32. */ static void tea_decrypt(uint32_t* v0, uint32_t* v1, uint32_t* k) { uint32_t sum=0xF1BBCDC8, i; /* set up */ uint32_t delta=0x9E3779B9; /* a key schedule constant */ uint32_t k0=k[0], k1=k[1], k2=k[2], k3=k[3]; /* cache key */ for(i=0; i<8; i++) { /* basic cycle start */ *v1 -= ((*v0<<4) + k2) ^ (*v0 + sum) ^ ((*v0>>5) + k3); *v0 -= ((*v1<<4) + k0) ^ (*v1 + sum) ^ ((*v1>>5) + k1); sum -= delta; /* end cycle */ } } /* mi4 files are encrypted in 64-bit blocks (two little-endian 32-bit integers) and the key is incremented after each block */ static void tea_decrypt_buf(unsigned char* src, unsigned char* dest, size_t n, uint32_t * key) { uint32_t v0, v1; unsigned int i; for (i = 0; i < (n / 8); i++) { v0 = le2int(src); v1 = le2int(src+4); tea_decrypt(&v0, &v1, key); int2le(v0, dest); int2le(v1, dest+4); src += 8; dest += 8; /* Now increment the key */ key[0]++; if (key[0]==0) { key[1]++; if (key[1]==0) { key[2]++; if (key[2]==0) { key[3]++; } } } } } static int tea_find_key(struct mi4header_t *mi4header, unsigned char* buf) { unsigned int i; uint32_t key[4]; uint32_t keyinc; unsigned char magic_dec[8]; int key_found = -1; unsigned int magic_location = mi4header->length-4; int unaligned = 0; if ( (magic_location % 8) != 0 ) { unaligned = 1; magic_location -= 4; } for (i=0; i < NUM_KEYS && (key_found<0) ; i++) { key[0] = tea_keytable[i].key[0]; key[1] = tea_keytable[i].key[1]; key[2] = tea_keytable[i].key[2]; key[3] = tea_keytable[i].key[3]; /* Now increment the key */ keyinc = (magic_location-mi4header->plaintext)/8; if ((key[0]+keyinc) < key[0]) key[1]++; key[0] += keyinc; if (key[1]==0) key[2]++; if (key[2]==0) key[3]++; /* Decrypt putative magic */ tea_decrypt_buf(&buf[magic_location], magic_dec, 8, key); if (le2int(&magic_dec[4*unaligned]) == 0xaa55aa55) { key_found = i; } } return key_found; } /* Load mi4 format firmware image from a FULLY QUALIFIED PATH */ static int load_mi4_filename(unsigned char* buf, const char* filename, unsigned int buffer_size) { int fd; struct mi4header_t mi4header; int rc; unsigned long sum; fd = open(filename, O_RDONLY); if(fd < 0) return EFILE_NOT_FOUND; read(fd, &mi4header, MI4_HEADER_SIZE); /* MI4 file size */ if ((mi4header.mi4size-MI4_HEADER_SIZE) > buffer_size) { close(fd); return EFILE_TOO_BIG; } /* Load firmware file */ lseek(fd, MI4_HEADER_SIZE, SEEK_SET); rc = read(fd, buf, mi4header.mi4size-MI4_HEADER_SIZE); close(fd); if(rc < (int)mi4header.mi4size-MI4_HEADER_SIZE) return EREAD_IMAGE_FAILED; /* Check CRC32 to see if we have a valid file */ sum = crc_32r (buf, mi4header.mi4size - MI4_HEADER_SIZE, 0); if(sum != mi4header.crc32) return EBAD_CHKSUM; if( (mi4header.plaintext + MI4_HEADER_SIZE) != mi4header.mi4size) { /* Load encrypted firmware */ int key_index = tea_find_key(&mi4header, buf); if (key_index < 0) return EINVALID_FORMAT; /* Plaintext part is already loaded */ buf += mi4header.plaintext; /* Decrypt in-place */ tea_decrypt_buf(buf, buf, mi4header.mi4size-(mi4header.plaintext+MI4_HEADER_SIZE), tea_keytable[key_index].key); /* Check decryption was successfull */ if(le2int(&buf[mi4header.length-mi4header.plaintext-4]) != 0xaa55aa55) return EREAD_IMAGE_FAILED; } return mi4header.mi4size - MI4_HEADER_SIZE; } /* Load mi4 format firmware image */ int load_mi4(unsigned char* buf, const char* firmware, unsigned int buffer_size) { int ret = EFILE_NOT_FOUND; char filename[MAX_PATH+2]; /* only filename passed */ if (firmware[0] != '/') { #ifdef HAVE_MULTIBOOT /* defined by config.h */ /* checks highest index to lowest for redirect file * 0 is the default boot volume, it is not checked here * if found /rockbox_main. and firmware * has a bootdata region this firmware will be loaded */ for (unsigned int i = NUM_VOLUMES - 1; i > 0 && ret < 0; i--) { if (get_redirect_dir(filename, sizeof(filename), i, BOOTDIR, firmware) > 0) { ret = load_mi4_filename(buf, filename, buffer_size); /* if firmware has no boot_data don't load from external drive */ if (!write_bootdata(buf, ret, i)) ret = EKEY_NOT_FOUND; } /* if ret is valid breaks from loop to continue loading */ } #endif if (ret < 0) /* Check default volume, no valid firmware file loaded yet */ { /* First check in BOOTDIR */ snprintf(filename, sizeof(filename), BOOTDIR "/%s",firmware); ret = load_mi4_filename(buf, filename, buffer_size); if (ret < 0) { /* Check in root dir */ snprintf(filename, sizeof(filename),"/%s",firmware); ret = load_mi4_filename(buf, filename, buffer_size); } #ifdef HAVE_BOOTDATA /* 0 is the default boot volume */ write_bootdata(buf, ret, 0); #endif } } else /* full path passed ROLO etc.*/ ret = load_mi4_filename(buf, firmware, buffer_size); return ret; }