summaryrefslogtreecommitdiffstats
path: root/adb/adb_auth_host.c
blob: 1d486676ee6e6b417c7be40c07139dd3afb43683 (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) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stdio.h>
#include <stdlib.h>

#ifdef _WIN32
#  ifndef WIN32_LEAN_AND_MEAN
#    define WIN32_LEAN_AND_MEAN
#  endif
#  include "windows.h"
#  include "shlobj.h"
#else
#  include <sys/types.h>
#  include <sys/stat.h>
#  include <unistd.h>
#endif
#include <string.h>

#include "sysdeps.h"
#include "adb.h"
#include "adb_auth.h"

/* HACK: we need the RSAPublicKey struct
 * but RSA_verify conflits with openssl */
#define RSA_verify RSA_verify_mincrypt
#include "mincrypt/rsa.h"
#undef RSA_verify

#include <cutils/list.h>

#include <openssl/evp.h>
#include <openssl/objects.h>
#include <openssl/pem.h>
#include <openssl/rsa.h>
#include <openssl/sha.h>

#if defined(OPENSSL_IS_BORINGSSL)
#include <openssl/base64.h>
#endif

#define TRACE_TAG TRACE_AUTH

#define ANDROID_PATH   ".android"
#define ADB_KEY_FILE   "adbkey"


struct adb_private_key {
    struct listnode node;
    RSA *rsa;
};

static struct listnode key_list;


/* Convert OpenSSL RSA private key to android pre-computed RSAPublicKey format */
static int RSA_to_RSAPublicKey(RSA *rsa, RSAPublicKey *pkey)
{
    int ret = 1;
    unsigned int i;

    BN_CTX* ctx = BN_CTX_new();
    BIGNUM* r32 = BN_new();
    BIGNUM* rr = BN_new();
    BIGNUM* r = BN_new();
    BIGNUM* rem = BN_new();
    BIGNUM* n = BN_new();
    BIGNUM* n0inv = BN_new();

    if (RSA_size(rsa) != RSANUMBYTES) {
        ret = 0;
        goto out;
    }

    BN_set_bit(r32, 32);
    BN_copy(n, rsa->n);
    BN_set_bit(r, RSANUMWORDS * 32);
    BN_mod_sqr(rr, r, n, ctx);
    BN_div(NULL, rem, n, r32, ctx);
    BN_mod_inverse(n0inv, rem, r32, ctx);

    pkey->len = RSANUMWORDS;
    pkey->n0inv = 0 - BN_get_word(n0inv);
    for (i = 0; i < RSANUMWORDS; i++) {
        BN_div(rr, rem, rr, r32, ctx);
        pkey->rr[i] = BN_get_word(rem);
        BN_div(n, rem, n, r32, ctx);
        pkey->n[i] = BN_get_word(rem);
    }
    pkey->exponent = BN_get_word(rsa->e);

out:
    BN_free(n0inv);
    BN_free(n);
    BN_free(rem);
    BN_free(r);
    BN_free(rr);
    BN_free(r32);
    BN_CTX_free(ctx);

    return ret;
}

static void get_user_info(char *buf, size_t len)
{
    char hostname[1024], username[1024];
    int ret = -1;

    if (getenv("HOSTNAME") != NULL) {
        strncpy(hostname, getenv("HOSTNAME"), sizeof(hostname));
        hostname[sizeof(hostname)-1] = '\0';
        ret = 0;
    }

#ifndef _WIN32
    if (ret < 0)
        ret = gethostname(hostname, sizeof(hostname));
#endif
    if (ret < 0)
        strcpy(hostname, "unknown");

    ret = -1;

    if (getenv("LOGNAME") != NULL) {
        strncpy(username, getenv("LOGNAME"), sizeof(username));
        username[sizeof(username)-1] = '\0';
        ret = 0;
    }

#if !defined _WIN32 && !defined ADB_HOST_ON_TARGET
    if (ret < 0)
        ret = getlogin_r(username, sizeof(username));
#endif
    if (ret < 0)
        strcpy(username, "unknown");

    ret = snprintf(buf, len, " %s@%s", username, hostname);
    if (ret >= (signed)len)
        buf[len - 1] = '\0';
}

static int write_public_keyfile(RSA *private_key, const char *private_key_path)
{
    RSAPublicKey pkey;
    FILE *outfile = NULL;
    char path[PATH_MAX], info[MAX_PAYLOAD];
    uint8_t *encoded = NULL;
    size_t encoded_length;
    int ret = 0;

    if (snprintf(path, sizeof(path), "%s.pub", private_key_path) >=
        (int)sizeof(path)) {
        D("Path too long while writing public key\n");
        return 0;
    }

    if (!RSA_to_RSAPublicKey(private_key, &pkey)) {
        D("Failed to convert to publickey\n");
        return 0;
    }

    outfile = fopen(path, "w");
    if (!outfile) {
        D("Failed to open '%s'\n", path);
        return 0;
    }

    D("Writing public key to '%s'\n", path);

#if defined(OPENSSL_IS_BORINGSSL)
    if (!EVP_EncodedLength(&encoded_length, sizeof(pkey))) {
        D("Public key too large to base64 encode");
        goto out;
    }
#else
    /* While we switch from OpenSSL to BoringSSL we have to implement
     * |EVP_EncodedLength| here. */
    encoded_length = 1 + ((sizeof(pkey) + 2) / 3 * 4);
#endif

    encoded = malloc(encoded_length);
    if (encoded == NULL) {
        D("Allocation failure");
        goto out;
    }

    encoded_length = EVP_EncodeBlock(encoded, (uint8_t*) &pkey, sizeof(pkey));
    get_user_info(info, sizeof(info));

    if (fwrite(encoded, encoded_length, 1, outfile) != 1 ||
        fwrite(info, strlen(info), 1, outfile) != 1) {
        D("Write error while writing public key");
        goto out;
    }

    ret = 1;

 out:
    if (outfile != NULL) {
        fclose(outfile);
    }
    if (encoded != NULL) {
        free(encoded);
    }
    return ret;
}

static int generate_key(const char *file)
{
    EVP_PKEY* pkey = EVP_PKEY_new();
    BIGNUM* exponent = BN_new();
    RSA* rsa = RSA_new();
    mode_t old_mask;
    FILE *f = NULL;
    int ret = 0;

    D("generate_key '%s'\n", file);

    if (!pkey || !exponent || !rsa) {
        D("Failed to allocate key\n");
        goto out;
    }

    BN_set_word(exponent, RSA_F4);
    RSA_generate_key_ex(rsa, 2048, exponent, NULL);
    EVP_PKEY_set1_RSA(pkey, rsa);

    old_mask = umask(077);

    f = fopen(file, "w");
    if (!f) {
        D("Failed to open '%s'\n", file);
        umask(old_mask);
        goto out;
    }

    umask(old_mask);

    if (!PEM_write_PrivateKey(f, pkey, NULL, NULL, 0, NULL, NULL)) {
        D("Failed to write key\n");
        goto out;
    }

    if (!write_public_keyfile(rsa, file)) {
        D("Failed to write public key\n");
        goto out;
    }

    ret = 1;

out:
    if (f)
        fclose(f);
    EVP_PKEY_free(pkey);
    RSA_free(rsa);
    BN_free(exponent);
    return ret;
}

static int read_key(const char *file, struct listnode *list)
{
    struct adb_private_key *key;
    FILE *f;

    D("read_key '%s'\n", file);

    f = fopen(file, "r");
    if (!f) {
        D("Failed to open '%s'\n", file);
        return 0;
    }

    key = malloc(sizeof(*key));
    if (!key) {
        D("Failed to alloc key\n");
        fclose(f);
        return 0;
    }
    key->rsa = RSA_new();

    if (!PEM_read_RSAPrivateKey(f, &key->rsa, NULL, NULL)) {
        D("Failed to read key\n");
        fclose(f);
        RSA_free(key->rsa);
        free(key);
        return 0;
    }

    fclose(f);
    list_add_tail(list, &key->node);
    return 1;
}

static int get_user_keyfilepath(char *filename, size_t len)
{
    const char *format, *home;
    char android_dir[PATH_MAX];
    struct stat buf;
#ifdef _WIN32
    char path[PATH_MAX];
    home = getenv("ANDROID_SDK_HOME");
    if (!home) {
        SHGetFolderPath(NULL, CSIDL_PROFILE, NULL, 0, path);
        home = path;
    }
    format = "%s\\%s";
#else
    home = getenv("HOME");
    if (!home)
        return -1;
    format = "%s/%s";
#endif

    D("home '%s'\n", home);

    if (snprintf(android_dir, sizeof(android_dir), format, home,
                        ANDROID_PATH) >= (int)sizeof(android_dir))
        return -1;

    if (stat(android_dir, &buf)) {
        if (adb_mkdir(android_dir, 0750) < 0) {
            D("Cannot mkdir '%s'", android_dir);
            return -1;
        }
    }

    return snprintf(filename, len, format, android_dir, ADB_KEY_FILE);
}

static int get_user_key(struct listnode *list)
{
    struct stat buf;
    char path[PATH_MAX];
    int ret;

    ret = get_user_keyfilepath(path, sizeof(path));
    if (ret < 0 || ret >= (signed)sizeof(path)) {
        D("Error getting user key filename");
        return 0;
    }

    D("user key '%s'\n", path);

    if (stat(path, &buf) == -1) {
        if (!generate_key(path)) {
            D("Failed to generate new key\n");
            return 0;
        }
    }

    return read_key(path, list);
}

static void get_vendor_keys(struct listnode *list)
{
    const char *adb_keys_path;
    char keys_path[MAX_PAYLOAD];
    char *path;
    char *save;
    struct stat buf;

    adb_keys_path = getenv("ADB_VENDOR_KEYS");
    if (!adb_keys_path)
        return;
    strncpy(keys_path, adb_keys_path, sizeof(keys_path));

    path = adb_strtok_r(keys_path, ENV_PATH_SEPARATOR_STR, &save);
    while (path) {
        D("Reading: '%s'\n", path);

        if (stat(path, &buf))
            D("Can't read '%s'\n", path);
        else if (!read_key(path, list))
            D("Failed to read '%s'\n", path);

        path = adb_strtok_r(NULL, ENV_PATH_SEPARATOR_STR, &save);
    }
}

int adb_auth_sign(void *node, void *token, size_t token_size, void *sig)
{
    unsigned int len;
    struct adb_private_key *key = node_to_item(node, struct adb_private_key, node);

    if (token_size != TOKEN_SIZE) {
        D("Unexpected token size %zd\n", token_size);
        return 0;
    }

    if (!RSA_sign(NID_sha1, token, token_size, sig, &len, key->rsa)) {
        return 0;
    }

    D("adb_auth_sign len=%d\n", len);
    return (int)len;
}

void *adb_auth_nextkey(void *current)
{
    struct listnode *item;

    if (list_empty(&key_list))
        return NULL;

    if (!current)
        return list_head(&key_list);

    list_for_each(item, &key_list) {
        if (item == current) {
            /* current is the last item, we tried all the keys */
            if (item->next == &key_list)
                return NULL;
            return item->next;
        }
    }

    return NULL;
}

int adb_auth_get_userkey(unsigned char *data, size_t len)
{
    char path[PATH_MAX];
    char *file;
    int ret;

    ret = get_user_keyfilepath(path, sizeof(path) - 4);
    if (ret < 0 || ret >= (signed)(sizeof(path) - 4)) {
        D("Error getting user key filename");
        return 0;
    }
    strcat(path, ".pub");

    file = load_file(path, (unsigned*)&ret);
    if (!file) {
        D("Can't load '%s'\n", path);
        return 0;
    }

    if (len < (size_t)(ret + 1)) {
        D("%s: Content too large ret=%d\n", path, ret);
        return 0;
    }

    memcpy(data, file, ret);
    data[ret] = '\0';

    return ret + 1;
}

int adb_auth_keygen(const char* filename) {
    adb_trace_mask |= (1 << TRACE_AUTH);
    return (generate_key(filename) == 0);
}

void adb_auth_init(void)
{
    int ret;

    D("adb_auth_init\n");

    list_init(&key_list);

    ret = get_user_key(&key_list);
    if (!ret) {
        D("Failed to get user key\n");
        return;
    }

    get_vendor_keys(&key_list);
}