summaryrefslogtreecommitdiff
path: root/ccast/axTLS/p12.c
blob: 2bafaf7eaf92d09d1b9c7722a5576a7a47ba250d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
/*
 * Copyright (c) 2007, Cameron Rich
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, 
 *   this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice, 
 *   this list of conditions and the following disclaimer in the documentation 
 *   and/or other materials provided with the distribution.
 * * Neither the name of the axTLS project nor the names of its contributors 
 *   may be used to endorse or promote products derived from this software 
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * Process PKCS#8/PKCS#12 keys.
 *
 * The decoding of a PKCS#12 key is fairly specific - this code was tested on a
 * key generated with:
 *
 * openssl pkcs12 -export -in axTLS.x509_1024.pem -inkey axTLS.key_1024.pem
 * -keypbe PBE-SHA1-RC4-128 -certpbe PBE-SHA1-RC4-128 
 * -name "p12_withoutCA" -out axTLS.withoutCA.p12 -password pass:abcd
 *
 * or with a certificate chain:
 *
 * openssl pkcs12 -export -in axTLS.x509_1024.pem -inkey axTLS.key_1024.pem
 * -certfile axTLS.ca_x509.pem -keypbe PBE-SHA1-RC4-128 -certpbe
 * PBE-SHA1-RC4-128 -name "p12_withCA" -out axTLS.withCA.p12 -password pass:abcd
 *
 * Note that the PBE has to be specified with PBE-SHA1-RC4-128. The
 * private/public keys/certs have to use RSA encryption. Both the integrity
 * and privacy passwords are the same.
 *
 * The PKCS#8 files were generated with something like:
 *
 * PEM format:
 * openssl pkcs8 -in axTLS.key_512.pem -passout pass:abcd -topk8 -v1
 * PBE-SHA1-RC4-128 -out axTLS.encrypted_pem.p8
 *
 * DER format:
 * openssl pkcs8 -in axTLS.key_512.pem -passout pass:abcd -topk8 -outform DER
 * -v1 PBE-SHA1-RC4-128 -out axTLS.encrypted.p8
 */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "os_port.h"
#include "ssl.h"

/* all commented out if not used */
#ifdef CONFIG_SSL_USE_PKCS12

#define BLOCK_SIZE          64
#define PKCS12_KEY_ID       1
#define PKCS12_IV_ID        2
#define PKCS12_MAC_ID       3

static char *make_uni_pass(const char *password, int *uni_pass_len);
static int p8_decrypt(const char *uni_pass, int uni_pass_len, 
                        const uint8_t *salt, int iter, 
                        uint8_t *priv_key, int priv_key_len, int id);
static int p8_add_key(SSL_CTX *ssl_ctx, uint8_t *priv_key);
static int get_pbe_params(uint8_t *buf, int *offset, 
        const uint8_t **salt, int *iterations);

/*
 * Take a raw pkcs8 block and then decrypt it and turn it into a normal key.
 */
int pkcs8_decode(SSL_CTX *ssl_ctx, SSLObjLoader *ssl_obj, const char *password)
{
    uint8_t *buf = ssl_obj->buf;
    int len, offset = 0;
    int iterations;
    int ret = SSL_NOT_OK;
    uint8_t *version = NULL;
    const uint8_t *salt;
    uint8_t *priv_key;
    int uni_pass_len;
    char *uni_pass = make_uni_pass(password, &uni_pass_len);

    if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0)
    {
#ifdef CONFIG_SSL_FULL_MODE
        printf("Error: Invalid p8 ASN.1 file\n");
#endif
        goto error;
    }

    /* unencrypted key? */
    if (asn1_get_int(buf, &offset, &version) > 0 && *version == 0)
    {
        ret = p8_add_key(ssl_ctx, buf);
        goto error;
    }

    if (get_pbe_params(buf, &offset, &salt, &iterations) < 0)
        goto error;

    if ((len = asn1_next_obj(buf, &offset, ASN1_OCTET_STRING)) < 0)
        goto error;

    priv_key = &buf[offset];

    p8_decrypt(uni_pass, uni_pass_len, salt, 
                        iterations, priv_key, len, PKCS12_KEY_ID);
    ret = p8_add_key(ssl_ctx, priv_key);

error:
    free(version);
    free(uni_pass);
    return ret;
}

/*
 * Take the unencrypted pkcs8 and turn it into a private key 
 */
static int p8_add_key(SSL_CTX *ssl_ctx, uint8_t *priv_key)
{
    uint8_t *buf = priv_key;
    int len, offset = 0;
    int ret = SSL_NOT_OK;

    /* Skip the preamble and go straight to the private key.
       We only support rsaEncryption (1.2.840.113549.1.1.1)  */
    if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            asn1_skip_obj(buf, &offset, ASN1_INTEGER) < 0 ||
            asn1_skip_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            (len = asn1_next_obj(buf, &offset, ASN1_OCTET_STRING)) < 0)
        goto error;

    ret = asn1_get_private_key(&buf[offset], len, &ssl_ctx->rsa_ctx);

error:
    return ret;
}

/*
 * Create the unicode password 
 */
static char *make_uni_pass(const char *password, int *uni_pass_len)
{
    int pass_len = 0, i;
    char *uni_pass;

    if (password == NULL)
    {
        password = "";
    }

    uni_pass = (char *)malloc((strlen(password)+1)*2);

    /* modify the password into a unicode version */
    for (i = 0; i < (int)strlen(password); i++)
    {
        uni_pass[pass_len++] = 0;
        uni_pass[pass_len++] = password[i];
    }

    uni_pass[pass_len++] = 0;       /* null terminate */
    uni_pass[pass_len++] = 0;
    *uni_pass_len = pass_len;
    return uni_pass;
}

/*
 * Decrypt a pkcs8 block.
 */
static int p8_decrypt(const char *uni_pass, int uni_pass_len,
                        const uint8_t *salt, int iter, 
                        uint8_t *priv_key, int priv_key_len, int id)
{
    uint8_t p[BLOCK_SIZE*2];
    uint8_t d[BLOCK_SIZE];
    uint8_t Ai[SHA1_SIZE];
    SHA1_CTX sha_ctx;
    RC4_CTX rc4_ctx;
    int i;

    for (i = 0; i < BLOCK_SIZE; i++)
    {
        p[i] = salt[i % SALT_SIZE];
        p[BLOCK_SIZE+i] = uni_pass[i % uni_pass_len];
        d[i] = id;
    }

    /* get the key - no IV since we are using RC4 */
    SHA1_Init(&sha_ctx);
    SHA1_Update(&sha_ctx, d, sizeof(d));
    SHA1_Update(&sha_ctx, p, sizeof(p));
    SHA1_Final(Ai, &sha_ctx);

    for (i = 1; i < iter; i++)
    {
        SHA1_Init(&sha_ctx);
        SHA1_Update(&sha_ctx, Ai, SHA1_SIZE);
        SHA1_Final(Ai, &sha_ctx);
    }

    /* do the decryption */
    if (id == PKCS12_KEY_ID)
    {
        RC4_setup(&rc4_ctx, Ai, 16);
        RC4_crypt(&rc4_ctx, priv_key, priv_key, priv_key_len);
    }
    else  /* MAC */
        memcpy(priv_key, Ai, SHA1_SIZE);

    return 0;
}

/*
 * Take a raw pkcs12 block and the decrypt it and turn it into a certificate(s)
 * and keys.
 */
int pkcs12_decode(SSL_CTX *ssl_ctx, SSLObjLoader *ssl_obj, const char *password)
{
    uint8_t *buf = ssl_obj->buf;
    int len, iterations, auth_safes_start, 
              auth_safes_end, auth_safes_len, key_offset, offset = 0;
    int all_certs = 0;
    uint8_t *version = NULL, *auth_safes = NULL, *cert, *orig_mac;
    uint8_t key[SHA1_SIZE];
    uint8_t mac[SHA1_SIZE];
    const uint8_t *salt;
    int uni_pass_len, ret = SSL_OK;
    char *uni_pass = make_uni_pass(password, &uni_pass_len);
    static const uint8_t pkcs_data[] = /* pkc7 data */
        { 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x07, 0x01 };
    static const uint8_t pkcs_encrypted[] = /* pkc7 encrypted */
        { 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x07, 0x06 };
    static const uint8_t pkcs8_key_bag[] = /* 1.2.840.113549.1.12.10.1.2 */
        { 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x0c, 0x0a, 0x01, 0x02 };

    if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0)
    {
#ifdef CONFIG_SSL_FULL_MODE
        printf("Error: Invalid p12 ASN.1 file\n");
#endif
        goto error;
    }

    if (asn1_get_int(buf, &offset, &version) < 0 || *version != 3)
    {
        ret = SSL_ERROR_INVALID_VERSION;
        goto error;
    }

    /* remove all the boring pcks7 bits */
    if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 || 
                (len = asn1_next_obj(buf, &offset, ASN1_OID)) < 0 ||
                len != sizeof(pkcs_data) || 
                memcmp(&buf[offset], pkcs_data, sizeof(pkcs_data)))
        goto error;

    offset += len;

    if (asn1_next_obj(buf, &offset, ASN1_EXPLICIT_TAG) < 0 ||
            asn1_next_obj(buf, &offset, ASN1_OCTET_STRING) < 0)
        goto error;

    /* work out the MAC start/end points (done on AuthSafes) */
    auth_safes_start = offset;
    auth_safes_end = offset;
    if (asn1_skip_obj(buf, &auth_safes_end, ASN1_SEQUENCE) < 0)
        goto error;

    auth_safes_len = auth_safes_end - auth_safes_start;
    auth_safes = malloc(auth_safes_len);

    memcpy(auth_safes, &buf[auth_safes_start], auth_safes_len);

    if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            (len = asn1_next_obj(buf, &offset, ASN1_OID)) < 0 ||
            (len != sizeof(pkcs_encrypted) || 
            memcmp(&buf[offset], pkcs_encrypted, sizeof(pkcs_encrypted))))
        goto error;

    offset += len;

    if (asn1_next_obj(buf, &offset, ASN1_EXPLICIT_TAG) < 0 ||
            asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            asn1_skip_obj(buf, &offset, ASN1_INTEGER) < 0 ||
            asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            (len = asn1_next_obj(buf, &offset, ASN1_OID)) < 0 ||
            len != sizeof(pkcs_data) || 
            memcmp(&buf[offset], pkcs_data, sizeof(pkcs_data)))
        goto error;

    offset += len;

    /* work out the salt for the certificate */
    if (get_pbe_params(buf, &offset, &salt, &iterations) < 0 ||
            (len = asn1_next_obj(buf, &offset, ASN1_IMPLICIT_TAG)) < 0)
        goto error;

    /* decrypt the certificate */
    cert = &buf[offset];
    if ((ret = p8_decrypt(uni_pass, uni_pass_len, salt, iterations, cert, 
                            len, PKCS12_KEY_ID)) < 0)
        goto error;

    offset += len;

    /* load the certificate */
    key_offset = 0;
    all_certs = asn1_next_obj(cert, &key_offset, ASN1_SEQUENCE);

    /* keep going until all certs are loaded */
    while (key_offset < all_certs)
    {
        int cert_offset = key_offset;

        if (asn1_skip_obj(cert, &cert_offset, ASN1_SEQUENCE) < 0 ||
                asn1_next_obj(cert, &key_offset, ASN1_SEQUENCE) < 0 ||
                asn1_skip_obj(cert, &key_offset, ASN1_OID) < 0 ||
                asn1_next_obj(cert, &key_offset, ASN1_EXPLICIT_TAG) < 0 ||
                asn1_next_obj(cert, &key_offset, ASN1_SEQUENCE) < 0 ||
                asn1_skip_obj(cert, &key_offset, ASN1_OID) < 0 ||
                asn1_next_obj(cert, &key_offset, ASN1_EXPLICIT_TAG) < 0 ||
                (len = asn1_next_obj(cert, &key_offset, ASN1_OCTET_STRING)) < 0)
            goto error;

        if ((ret = add_cert(ssl_ctx, &cert[key_offset], len)) < 0)
            goto error;

        key_offset = cert_offset;
    }

    if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            (len = asn1_next_obj(buf, &offset, ASN1_OID)) < 0 ||
            len != sizeof(pkcs_data) || 
            memcmp(&buf[offset], pkcs_data, sizeof(pkcs_data)))
        goto error;

    offset += len;

    if (asn1_next_obj(buf, &offset, ASN1_EXPLICIT_TAG) < 0 ||
            asn1_next_obj(buf, &offset, ASN1_OCTET_STRING) < 0 ||
            asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            (len = asn1_next_obj(buf, &offset, ASN1_OID)) < 0 ||
            (len != sizeof(pkcs8_key_bag)) || 
            memcmp(&buf[offset], pkcs8_key_bag, sizeof(pkcs8_key_bag)))
        goto error;

    offset += len;

    /* work out the salt for the private key */
    if (asn1_next_obj(buf, &offset, ASN1_EXPLICIT_TAG) < 0 ||
            asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            get_pbe_params(buf, &offset, &salt, &iterations) < 0 ||
            (len = asn1_next_obj(buf, &offset, ASN1_OCTET_STRING)) < 0)
        goto error;

    /* decrypt the private key */
    cert = &buf[offset];
    if ((ret = p8_decrypt(uni_pass, uni_pass_len, salt, iterations, cert, 
                            len, PKCS12_KEY_ID)) < 0)
        goto error;

    offset += len;

    /* load the private key */
    if ((ret = p8_add_key(ssl_ctx, cert)) < 0)
        goto error;

    /* miss out on friendly name, local key id etc */
    if (asn1_skip_obj(buf, &offset, ASN1_SET) < 0)
        goto error;

    /* work out the MAC */
    if (asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            asn1_next_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            asn1_skip_obj(buf, &offset, ASN1_SEQUENCE) < 0 ||
            (len = asn1_next_obj(buf, &offset, ASN1_OCTET_STRING)) < 0 ||
            len != SHA1_SIZE)
        goto error;

    orig_mac = &buf[offset];
    offset += len;

    /* get the salt */
    if ((len = asn1_next_obj(buf, &offset, ASN1_OCTET_STRING)) < 0 || len != 8)
        goto error;

    salt = &buf[offset];

    /* work out what the mac should be */
    if ((ret = p8_decrypt(uni_pass, uni_pass_len, salt, iterations, 
                            key, SHA1_SIZE, PKCS12_MAC_ID)) < 0)
        goto error;

    hmac_sha1(auth_safes, auth_safes_len, key, SHA1_SIZE, mac);

    if (memcmp(mac, orig_mac, SHA1_SIZE))
    {
        ret = SSL_ERROR_INVALID_HMAC;                  
        goto error;
    }

error:
    free(version);
    free(uni_pass);
    free(auth_safes);
    return ret;
}

/*
 * Retrieve the salt/iteration details from a PBE block.
 */
static int get_pbe_params(uint8_t *buf, int *offset, 
        const uint8_t **salt, int *iterations)
{
    static const uint8_t pbeSH1RC4[] = /* pbeWithSHAAnd128BitRC4  */
            { 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x0c, 0x01, 0x01 };

    int i, len;
    uint8_t *iter = NULL;
    int error_code = SSL_ERROR_NOT_SUPPORTED;

    /* Get the PBE type */
    if (asn1_next_obj(buf, offset, ASN1_SEQUENCE) < 0 ||
            (len = asn1_next_obj(buf, offset, ASN1_OID)) < 0)
        goto error;

    /* we expect pbeWithSHAAnd128BitRC4 (1.2.840.113549.1.12.1.1) 
       which is the only algorithm we support */
    if (len != sizeof(pbeSH1RC4) || 
                    memcmp(&buf[*offset], pbeSH1RC4, sizeof(pbeSH1RC4)))
    {
#ifdef CONFIG_SSL_FULL_MODE
        printf("Error: pkcs8/pkcs12 must use \"PBE-SHA1-RC4-128\"\n");
#endif
        goto error;
    }

    *offset += len;

    if (asn1_next_obj(buf, offset, ASN1_SEQUENCE) < 0 ||
            (len = asn1_next_obj(buf, offset, ASN1_OCTET_STRING)) < 0 || 
            len != 8)
        goto error;

    *salt = &buf[*offset];
    *offset += len;

    if ((len = asn1_get_int(buf, offset, &iter)) < 0)
        goto error;

    *iterations = 0;
    for (i = 0; i < len; i++)
    {
        (*iterations) <<= 8;
        (*iterations) += iter[i];
    }

    free(iter);
    error_code = SSL_OK;       /* got here - we are ok */

error:
    return error_code;
}

#endif