OpenWrt – Rev 1
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/*
* Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/stat.h>
#include "buffalo-lib.h"
static uint32_t crc32_table[256] =
{
0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9,
0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9,
0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011,
0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81,
0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49,
0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae,
0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066,
0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e,
0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686,
0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f,
0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47,
0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7,
0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f,
0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f,
0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30,
0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088,
0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0,
0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
};
int bcrypt_init(struct bcrypt_ctx *ctx, void *key, int keylen,
unsigned long state_len)
{
unsigned char *state;
unsigned char *p = key;
unsigned long i, j;
unsigned long k = 0;
state = malloc(state_len);
if (state == NULL)
return -1;
ctx->i = 0;
ctx->j = 0;
ctx->state = state;
ctx->state_len = state_len;
for (i = 0; i < state_len; i++)
state[i] = i;
for(i = 0, j = 0; i < state_len; i++, j = (j + 1) % keylen) {
unsigned char t;
t = state[i];
k = (k + p[j] + t) % state_len;
state[i] = state[k];
state[k] = t;
}
return 0;
}
int bcrypt_process(struct bcrypt_ctx *ctx, unsigned char *src,
unsigned char *dst, unsigned long len)
{
unsigned char *state = ctx->state;
unsigned long state_len = ctx->state_len;
unsigned char i, j;
unsigned long k;
i = ctx->i;
j = ctx->j;
for (k = 0; k < len; k++) {
unsigned char t;
i = (i + 1) % state_len;
j = (j + state[i]) % state_len;
t = state[j];
state[j] = state[i];
state[i] = t;
dst[k] = src[k] ^ state[(state[i] + state[j]) % state_len];
}
ctx->i = i;
ctx->j = j;
return len;
}
void bcrypt_finish(struct bcrypt_ctx *ctx)
{
if (ctx->state)
free(ctx->state);
}
int bcrypt_buf(unsigned char seed, unsigned char *key, unsigned char *src,
unsigned char *dst, unsigned long len, int longstate)
{
unsigned char bckey[BCRYPT_MAX_KEYLEN + 1];
unsigned int keylen;
struct bcrypt_ctx ctx;
int ret;
/* setup decryption key */
keylen = strlen((char *) key);
bckey[0] = seed;
memcpy(&bckey[1], key, keylen);
keylen++;
ret = bcrypt_init(&ctx, bckey, keylen,
(longstate) ? len : BCRYPT_DEFAULT_STATE_LEN);
if (ret)
return ret;
bcrypt_process(&ctx, src, dst, len);
bcrypt_finish(&ctx);
return 0;
}
uint32_t buffalo_csum(uint32_t csum, void *buf, unsigned long len)
{
signed char *p = buf;
while (len--) {
int i;
csum ^= *p++;
for (i = 0; i < 8; i++)
csum = (csum >> 1) ^ ((csum & 1) ? 0xedb88320ul : 0);
}
return csum;
}
uint32_t buffalo_crc(void *buf, unsigned long len)
{
unsigned char *p = buf;
unsigned long t = len;
uint32_t crc = 0;
while (len--)
crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ *p++) & 0xFF];
while (t) {
crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ t) & 0xFF];
t >>= 8;
}
return ~crc;
}
unsigned long enc_compute_header_len(char *product, char *version)
{
return ENC_MAGIC_LEN + 1 + strlen(product) + 1 +
strlen(version) + 1 + 3 * sizeof(uint32_t);
}
unsigned long enc_compute_buf_len(char *product, char *version,
unsigned long datalen)
{
unsigned long ret;
ret = enc_compute_header_len(product, version);
ret += datalen + sizeof(uint32_t);
ret += (4 - ret % 4);
return ret;
}
static void put_be32(void *data, uint32_t val)
{
unsigned char *p = data;
p[0] = (val >> 24) & 0xff;
p[1] = (val >> 16) & 0xff;
p[2] = (val >> 8) & 0xff;
p[3] = val & 0xff;
}
static uint32_t get_be32(void *data)
{
unsigned char *p = data;
return (((uint32_t)p[0]) << 24) |
(((uint32_t)p[1]) << 16) |
(((uint32_t)p[2]) << 8) |
((uint32_t)p[3]);
}
static int check_magic(void *magic)
{
if (!memcmp("start", magic, ENC_MAGIC_LEN))
return 0;
if (!memcmp("asar1", magic, ENC_MAGIC_LEN))
return 0;
return -1;
}
int encrypt_buf(struct enc_param *ep, unsigned char *hdr,
unsigned char *data)
{
unsigned char *p;
uint32_t len;
int err;
int ret = -1;
unsigned char s;
p = (unsigned char *) hdr;
/* setup magic */
len = strlen((char *) ep->magic) + 1;
memcpy(p, ep->magic, len);
p += len;
/* setup seed */
*p++ = ep->seed;
/* put product len */
len = strlen((char *) ep->product) + 1;
put_be32(p, len);
p += sizeof(uint32_t);
/* copy and crypt product name */
memcpy(p, ep->product, len);
err = bcrypt_buf(ep->seed, ep->key, p, p, len, ep->longstate);
if (err)
goto out;
s = *p;
p += len;
/* put version length */
len = strlen((char *) ep->version) + 1;
put_be32(p, len);
p += sizeof(uint32_t);
/* copy and crypt version */
memcpy(p, ep->version, len);
err = bcrypt_buf(s, ep->key, p, p, len, ep->longstate);
if (err)
goto out;
s = *p;
p += len;
/* put data length */
put_be32(p, ep->datalen);
/* encrypt data */
err = bcrypt_buf(s, ep->key, data, data, ep->datalen, ep->longstate);
if (err)
goto out;
/* put checksum */
put_be32(&data[ep->datalen], ep->csum);
ret = 0;
out:
return ret;
}
int decrypt_buf(struct enc_param *ep, unsigned char *data,
unsigned long datalen)
{
unsigned char *p;
uint32_t prod_len;
uint32_t ver_len;
uint32_t len;
uint32_t csum;
ssize_t remain;
int err;
int ret = -1;
#define CHECKLEN(_l) do { \
len = (_l); \
if (remain < len) { \
goto out; \
} \
} while (0)
#define INCP() do { \
p += len; \
remain -= len; \
} while (0)
remain = datalen;
p = data;
CHECKLEN(ENC_MAGIC_LEN);
err = check_magic(p);
if (err)
goto out;
memcpy(ep->magic, p, ENC_MAGIC_LEN);
INCP();
CHECKLEN(1);
ep->seed = *p;
INCP();
CHECKLEN(sizeof(uint32_t));
prod_len = get_be32(p);
if (prod_len > ENC_PRODUCT_LEN)
goto out;
INCP();
CHECKLEN(prod_len);
memcpy(ep->product, p, prod_len);
INCP();
CHECKLEN(sizeof(uint32_t));
ver_len = get_be32(p);
if (ver_len > ENC_VERSION_LEN)
goto out;
INCP();
CHECKLEN(ver_len);
memcpy(ep->version, p, ver_len);
INCP();
CHECKLEN(sizeof(uint32_t));
ep->datalen = get_be32(p);
INCP();
/* decrypt data */
CHECKLEN(ep->datalen);
err = bcrypt_buf(ep->version[0], ep->key, p, data, ep->datalen,
ep->longstate);
if (err)
goto out;
INCP();
CHECKLEN(sizeof(uint32_t));
ep->csum = get_be32(p);
INCP();
csum = buffalo_csum(ep->datalen, data, ep->datalen);
if (csum != ep->csum)
goto out;
/* decrypt product name */
err = bcrypt_buf(ep->product[0], ep->key, ep->version, ep->version,
ver_len, ep->longstate);
if (err)
goto out;
/* decrypt version */
err = bcrypt_buf(ep->seed, ep->key, ep->product, ep->product, prod_len,
ep->longstate);
if (err)
goto out;
ret = 0;
out:
return ret;
#undef CHECKLEN
#undef INCP
}
ssize_t get_file_size(char *name)
{
struct stat st;
int err;
err = stat(name, &st);
if (err)
return -1;
return st.st_size;
}
int read_file_to_buf(char *name, void *buf, ssize_t buflen)
{
FILE *f;
size_t done;
int ret = -1;
f = fopen(name, "r");
if (f == NULL)
goto out;
errno = 0;
done = fread(buf, buflen, 1, f);
if (done != 1)
goto close;
ret = 0;
close:
fclose(f);
out:
return ret;
}
int write_buf_to_file(char *name, void *buf, ssize_t buflen)
{
FILE *f;
size_t done;
int ret = -1;
f = fopen(name, "w");
if (f == NULL)
goto out;
errno = 0;
done = fwrite(buf, buflen, 1, f);
if (done != 1)
goto close;
ret = 0;
close:
fflush(f);
fclose(f);
if (ret)
unlink(name);
out:
return ret;
}