Root/tools/firmware-utils/src/buffalo-lib.c

1/*
2 * Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 as published
6 * by the Free Software Foundation.
7 *
8 */
9
10#include <stdio.h>
11#include <stdlib.h>
12#include <string.h>
13#include <errno.h>
14#include <unistd.h>
15#include <sys/stat.h>
16
17#include "buffalo-lib.h"
18
19static uint32_t crc32_table[256] =
20{
21    0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9,
22    0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
23    0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
24    0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
25    0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9,
26    0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
27    0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011,
28    0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
29    0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
30    0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
31    0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81,
32    0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
33    0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49,
34    0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
35    0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
36    0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
37    0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae,
38    0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
39    0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
40    0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
41    0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
42    0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
43    0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066,
44    0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
45    0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e,
46    0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
47    0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
48    0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
49    0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
50    0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
51    0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686,
52    0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
53    0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
54    0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
55    0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f,
56    0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
57    0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47,
58    0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
59    0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
60    0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
61    0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7,
62    0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
63    0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f,
64    0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
65    0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
66    0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
67    0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f,
68    0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
69    0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
70    0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
71    0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
72    0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
73    0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30,
74    0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
75    0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088,
76    0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
77    0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
78    0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
79    0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
80    0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
81    0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0,
82    0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
83    0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
84    0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
85};
86
87int bcrypt_init(struct bcrypt_ctx *ctx, void *key, int keylen,
88        unsigned long state_len)
89{
90    unsigned char *state;
91    unsigned char *p = key;
92    unsigned long i, j;
93    unsigned long k = 0;
94
95    state = malloc(state_len);
96    if (state == NULL)
97        return -1;
98
99    ctx->i = 0;
100    ctx->j = 0;
101    ctx->state = state;
102    ctx->state_len = state_len;
103
104    for (i = 0; i < state_len; i++)
105        state[i] = i;
106
107    for(i = 0, j = 0; i < state_len; i++, j = (j + 1) % keylen) {
108        unsigned char t;
109
110        t = state[i];
111        k = (k + p[j] + t) % state_len;
112        state[i] = state[k];
113        state[k] = t;
114    }
115
116    return 0;
117}
118
119int bcrypt_process(struct bcrypt_ctx *ctx, unsigned char *src,
120           unsigned char *dst, unsigned long len)
121{
122    unsigned char *state = ctx->state;
123    unsigned long state_len = ctx->state_len;
124    unsigned char i, j;
125    unsigned long k;
126
127    i = ctx->i;
128    j = ctx->j;
129
130    for (k = 0; k < len; k++) {
131        unsigned char t;
132
133        i = (i + 1) % state_len;
134        j = (j + state[i]) % state_len;
135        t = state[j];
136        state[j] = state[i];
137        state[i] = t;
138
139        dst[k] = src[k] ^ state[(state[i] + state[j]) % state_len];
140    }
141
142    ctx->i = i;
143    ctx->j = j;
144
145    return len;
146}
147
148void bcrypt_finish(struct bcrypt_ctx *ctx)
149{
150    if (ctx->state)
151        free(ctx->state);
152}
153
154int bcrypt_buf(unsigned char seed, unsigned char *key, unsigned char *src,
155           unsigned char *dst, unsigned long len, int longstate)
156{
157    unsigned char bckey[BCRYPT_MAX_KEYLEN + 1];
158    unsigned int keylen;
159    struct bcrypt_ctx ctx;
160    int ret;
161
162    /* setup decryption key */
163    keylen = strlen((char *) key);
164    bckey[0] = seed;
165    memcpy(&bckey[1], key, keylen);
166
167    keylen++;
168
169    ret = bcrypt_init(&ctx, bckey, keylen,
170              (longstate) ? len : BCRYPT_DEFAULT_STATE_LEN);
171    if (ret)
172        return ret;
173
174    bcrypt_process(&ctx, src, dst, len);
175    bcrypt_finish(&ctx);
176
177    return 0;
178}
179
180uint32_t buffalo_csum(uint32_t csum, void *buf, unsigned long len)
181{
182    char *p = buf;
183
184    while (len--) {
185        int i;
186
187        csum ^= *p++;
188        for (i = 0; i < 8; i++)
189            csum = (csum >> 1) ^ ((csum & 1) ? 0xedb88320ul : 0);
190    }
191
192    return csum;
193}
194
195uint32_t buffalo_crc(void *buf, unsigned long len)
196{
197    unsigned char *p = buf;
198    unsigned long t = len;
199    uint32_t crc = 0;
200
201    while (len--)
202        crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ *p++) & 0xFF];
203
204    while (t) {
205        crc = (crc << 8) ^ crc32_table[((crc >> 24) ^ t) & 0xFF];
206        t >>= 8;
207    }
208
209    return ~crc;
210}
211
212unsigned long enc_compute_header_len(char *product, char *version)
213{
214    return ENC_MAGIC_LEN + 1 + strlen(product) + 1 +
215           strlen(version) + 1 + 3 * sizeof(uint32_t);
216}
217
218unsigned long enc_compute_buf_len(char *product, char *version,
219                  unsigned long datalen)
220{
221    unsigned long ret;
222
223    ret = enc_compute_header_len(product, version);
224    ret += datalen + sizeof(uint32_t);
225    ret += (4 - ret % 4);
226
227    return ret;
228}
229
230static void put_be32(void *data, uint32_t val)
231{
232    unsigned char *p = data;
233
234    p[0] = (val >> 24) & 0xff;
235    p[1] = (val >> 16) & 0xff;
236    p[2] = (val >> 8) & 0xff;
237    p[3] = val & 0xff;
238}
239
240static uint32_t get_be32(void *data)
241{
242    unsigned char *p = data;
243
244    return (((uint32_t)p[0]) << 24) |
245           (((uint32_t)p[1]) << 16) |
246           (((uint32_t)p[2]) << 8) |
247           ((uint32_t)p[3]);
248}
249
250static int check_magic(void *magic)
251{
252    if (!memcmp("start", magic, ENC_MAGIC_LEN));
253        return 0;
254
255    if (!memcmp("asar1", magic, ENC_MAGIC_LEN));
256        return 0;
257
258    return -1;
259}
260
261int encrypt_buf(struct enc_param *ep, unsigned char *hdr,
262        unsigned char *data)
263{
264    unsigned char *p;
265    uint32_t len;
266    int err;
267    int ret = -1;
268    unsigned char s;
269
270    p = (unsigned char *) hdr;
271
272    /* setup magic */
273    len = strlen((char *) ep->magic) + 1;
274    memcpy(p, ep->magic, len);
275    p += len;
276
277    /* setup seed */
278    *p++ = ep->seed;
279
280    /* put product len */
281    len = strlen((char *) ep->product) + 1;
282    put_be32(p, len);
283    p += sizeof(uint32_t);
284
285    /* copy and crypt product name */
286    memcpy(p, ep->product, len);
287    err = bcrypt_buf(ep->seed, ep->key, p, p, len, ep->longstate);
288    if (err)
289        goto out;
290    s = *p;
291    p += len;
292
293    /* put version length */
294    len = strlen((char *) ep->version) + 1;
295    put_be32(p, len);
296    p += sizeof(uint32_t);
297
298    /* copy and crypt version */
299    memcpy(p, ep->version, len);
300    err = bcrypt_buf(s, ep->key, p, p, len, ep->longstate);
301    if (err)
302        goto out;
303    s = *p;
304    p += len;
305
306    /* put data length */
307    put_be32(p, ep->datalen);
308
309    /* encrypt data */
310    err = bcrypt_buf(s, ep->key, data, data, ep->datalen, ep->longstate);
311    if (err)
312        goto out;
313
314    /* put checksum */
315    put_be32(&data[ep->datalen], ep->csum);
316
317    ret = 0;
318
319out:
320    return ret;
321}
322
323int decrypt_buf(struct enc_param *ep, unsigned char *data,
324        unsigned long datalen)
325{
326    unsigned char *p;
327    uint32_t prod_len;
328    uint32_t ver_len;
329    uint32_t len;
330    uint32_t csum;
331    ssize_t remain;
332    int err;
333    int ret = -1;
334
335#define CHECKLEN(_l) do { \
336    len = (_l); \
337    if (remain < len) { \
338        goto out; \
339    } \
340} while (0)
341
342#define INCP() do { \
343    p += len; \
344    remain -= len; \
345} while (0)
346
347    remain = datalen;
348    p = data;
349
350    CHECKLEN(ENC_MAGIC_LEN);
351    err = check_magic(p);
352    if (err)
353        goto out;
354    memcpy(ep->magic, p, ENC_MAGIC_LEN);
355    INCP();
356
357    CHECKLEN(1);
358    ep->seed = *p;
359    INCP();
360
361    CHECKLEN(sizeof(uint32_t));
362    prod_len = get_be32(p);
363    if (prod_len > ENC_PRODUCT_LEN)
364        goto out;
365    INCP();
366
367    CHECKLEN(prod_len);
368    memcpy(ep->product, p, prod_len);
369    INCP();
370
371    CHECKLEN(sizeof(uint32_t));
372    ver_len = get_be32(p);
373    if (ver_len > ENC_VERSION_LEN)
374        goto out;
375    INCP();
376
377    CHECKLEN(ver_len);
378    memcpy(ep->version, p, ver_len);
379    INCP();
380
381    CHECKLEN(sizeof(uint32_t));
382    ep->datalen = get_be32(p);
383    INCP();
384
385    /* decrypt data */
386    CHECKLEN(ep->datalen);
387    err = bcrypt_buf(ep->version[0], ep->key, p, data, ep->datalen,
388             ep->longstate);
389    if (err)
390        goto out;
391    INCP();
392
393    CHECKLEN(sizeof(uint32_t));
394    ep->csum = get_be32(p);
395    INCP();
396
397    csum = buffalo_csum(ep->datalen, data, ep->datalen);
398    if (csum != ep->csum)
399        goto out;
400
401    /* decrypt product name */
402    err = bcrypt_buf(ep->product[0], ep->key, ep->version, ep->version,
403             ver_len, ep->longstate);
404    if (err)
405        goto out;
406
407    /* decrypt version */
408    err = bcrypt_buf(ep->seed, ep->key, ep->product, ep->product, prod_len,
409             ep->longstate);
410    if (err)
411        goto out;
412
413    ret = 0;
414out:
415    return ret;
416
417#undef CHECKLEN
418#undef INCP
419}
420
421ssize_t get_file_size(char *name)
422{
423    struct stat st;
424    int err;
425
426    err = stat(name, &st);
427    if (err)
428        return -1;
429
430    return st.st_size;
431}
432
433int read_file_to_buf(char *name, void *buf, ssize_t buflen)
434{
435    FILE *f;
436    size_t done;
437    int ret = -1;
438
439    f = fopen(name, "r");
440    if (f == NULL)
441        goto out;
442
443    errno = 0;
444    done = fread(buf, buflen, 1, f);
445    if (done != 1)
446        goto close;
447
448    ret = 0;
449
450close:
451    fclose(f);
452out:
453    return ret;
454}
455
456int write_buf_to_file(char *name, void *buf, ssize_t buflen)
457{
458    FILE *f;
459    size_t done;
460    int ret = -1;
461
462    f = fopen(name, "w");
463    if (f == NULL)
464        goto out;
465
466    errno = 0;
467    done = fwrite(buf, buflen, 1, f);
468    if (done != 1)
469        goto close;
470
471    ret = 0;
472
473close:
474    fflush(f);
475    fclose(f);
476    if (ret)
477        unlink(name);
478out:
479    return ret;
480}
481

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