aboutsummaryrefslogtreecommitdiff
path: root/lib/libavb/avb_cmdline.c
blob: cb54e658c4878101075f334372672fdddab14c55 (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
// SPDX-License-Identifier: MIT
/*
 * Copyright (C) 2016 The Android Open Source Project
 */

#include "avb_cmdline.h"
#include "avb_sha.h"
#include "avb_util.h"
#include "avb_version.h"
#include <log.h>
#include <malloc.h>

#define NUM_GUIDS 3

/* Substitutes all variables (e.g. $(ANDROID_SYSTEM_PARTUUID)) with
 * values. Returns NULL on OOM, otherwise the cmdline with values
 * replaced.
 */
char* avb_sub_cmdline(AvbOps* ops,
                      const char* cmdline,
                      const char* ab_suffix,
                      bool using_boot_for_vbmeta,
                      const AvbCmdlineSubstList* additional_substitutions) {
  const char* part_name_str[NUM_GUIDS] = {"system", "boot", "vbmeta"};
  const char* replace_str[NUM_GUIDS] = {"$(ANDROID_SYSTEM_PARTUUID)",
                                        "$(ANDROID_BOOT_PARTUUID)",
                                        "$(ANDROID_VBMETA_PARTUUID)"};
  char* ret = NULL;
  AvbIOResult io_ret;
  size_t n;

  /* Special-case for when the top-level vbmeta struct is in the boot
   * partition.
   */
  if (using_boot_for_vbmeta) {
    part_name_str[2] = "boot";
  }

  /* Replace unique partition GUIDs */
  for (n = 0; n < NUM_GUIDS; n++) {
    char part_name[AVB_PART_NAME_MAX_SIZE];
    char guid_buf[37];

    /* Don't attempt to query the partition guid unless its search string is
     * present in the command line. Note: the original cmdline is used here,
     * not the replaced one. See b/116010959.
     */
    if (avb_strstr(cmdline, replace_str[n]) == NULL) {
      continue;
    }

    if (!avb_str_concat(part_name,
                        sizeof part_name,
                        part_name_str[n],
                        avb_strlen(part_name_str[n]),
                        ab_suffix,
                        avb_strlen(ab_suffix))) {
      avb_error("Partition name and suffix does not fit.\n");
      goto fail;
    }

    io_ret = ops->get_unique_guid_for_partition(
        ops, part_name, guid_buf, sizeof guid_buf);
    if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
      goto fail;
    } else if (io_ret != AVB_IO_RESULT_OK) {
      avb_error("Error getting unique GUID for partition.\n");
      goto fail;
    }

    if (ret == NULL) {
      ret = avb_replace(cmdline, replace_str[n], guid_buf);
    } else {
      char* new_ret = avb_replace(ret, replace_str[n], guid_buf);
      avb_free(ret);
      ret = new_ret;
    }
    if (ret == NULL) {
      goto fail;
    }
  }

  /* It's possible there is no _PARTUUID for replacement above.
   * Duplicate cmdline to ret for additional substitutions below.
   */
  if (ret == NULL) {
    ret = avb_strdup(cmdline);
    if (ret == NULL) {
      goto fail;
    }
  }

  /* Replace any additional substitutions. */
  if (additional_substitutions != NULL) {
    for (n = 0; n < additional_substitutions->size; ++n) {
      char* new_ret = avb_replace(ret,
                                  additional_substitutions->tokens[n],
                                  additional_substitutions->values[n]);
      avb_free(ret);
      ret = new_ret;
      if (ret == NULL) {
        goto fail;
      }
    }
  }

  return ret;

fail:
  if (ret != NULL) {
    avb_free(ret);
  }
  return NULL;
}

static int cmdline_append_option(AvbSlotVerifyData* slot_data,
                                 const char* key,
                                 const char* value) {
  size_t offset, key_len, value_len;
  char* new_cmdline;

  key_len = avb_strlen(key);
  value_len = avb_strlen(value);

  offset = 0;
  if (slot_data->cmdline != NULL) {
    offset = avb_strlen(slot_data->cmdline);
    if (offset > 0) {
      offset += 1;
    }
  }

  new_cmdline = avb_calloc(offset + key_len + value_len + 2);
  if (new_cmdline == NULL) {
    return 0;
  }
  if (offset > 0) {
    avb_memcpy(new_cmdline, slot_data->cmdline, offset - 1);
    new_cmdline[offset - 1] = ' ';
  }
  avb_memcpy(new_cmdline + offset, key, key_len);
  new_cmdline[offset + key_len] = '=';
  avb_memcpy(new_cmdline + offset + key_len + 1, value, value_len);
  if (slot_data->cmdline != NULL) {
    avb_free(slot_data->cmdline);
  }
  slot_data->cmdline = new_cmdline;

  return 1;
}

#define AVB_MAX_DIGITS_UINT64 32

/* Writes |value| to |digits| in base 10 followed by a NUL byte.
 * Returns number of characters written excluding the NUL byte.
 */
static size_t uint64_to_base10(uint64_t value,
                               char digits[AVB_MAX_DIGITS_UINT64]) {
  char rev_digits[AVB_MAX_DIGITS_UINT64];
  size_t n, num_digits;

  for (num_digits = 0; num_digits < AVB_MAX_DIGITS_UINT64 - 1;) {
    rev_digits[num_digits++] = avb_div_by_10(&value) + '0';
    if (value == 0) {
      break;
    }
  }

  for (n = 0; n < num_digits; n++) {
    digits[n] = rev_digits[num_digits - 1 - n];
  }
  digits[n] = '\0';
  return n;
}

static int cmdline_append_version(AvbSlotVerifyData* slot_data,
                                  const char* key,
                                  uint64_t major_version,
                                  uint64_t minor_version) {
  char major_digits[AVB_MAX_DIGITS_UINT64];
  char minor_digits[AVB_MAX_DIGITS_UINT64];
  char combined[AVB_MAX_DIGITS_UINT64 * 2 + 1];
  size_t num_major_digits, num_minor_digits;

  num_major_digits = uint64_to_base10(major_version, major_digits);
  num_minor_digits = uint64_to_base10(minor_version, minor_digits);
  avb_memcpy(combined, major_digits, num_major_digits);
  combined[num_major_digits] = '.';
  avb_memcpy(combined + num_major_digits + 1, minor_digits, num_minor_digits);
  combined[num_major_digits + 1 + num_minor_digits] = '\0';

  return cmdline_append_option(slot_data, key, combined);
}

static int cmdline_append_uint64_base10(AvbSlotVerifyData* slot_data,
                                        const char* key,
                                        uint64_t value) {
  char digits[AVB_MAX_DIGITS_UINT64];
  uint64_to_base10(value, digits);
  return cmdline_append_option(slot_data, key, digits);
}

static int cmdline_append_hex(AvbSlotVerifyData* slot_data,
                              const char* key,
                              const uint8_t* data,
                              size_t data_len) {
  int ret;
  char* hex_data = avb_bin2hex(data, data_len);
  if (hex_data == NULL) {
    return 0;
  }
  ret = cmdline_append_option(slot_data, key, hex_data);
  avb_free(hex_data);
  return ret;
}

AvbSlotVerifyResult avb_append_options(
    AvbOps* ops,
    AvbSlotVerifyFlags flags,
    AvbSlotVerifyData* slot_data,
    AvbVBMetaImageHeader* toplevel_vbmeta,
    AvbAlgorithmType algorithm_type,
    AvbHashtreeErrorMode hashtree_error_mode,
    AvbHashtreeErrorMode resolved_hashtree_error_mode) {
  AvbSlotVerifyResult ret;
  const char* verity_mode;
  bool is_device_unlocked;
  AvbIOResult io_ret;

  /* Add androidboot.vbmeta.device option... except if not using a vbmeta
   * partition since it doesn't make sense in that case.
   */
  if (!(flags & AVB_SLOT_VERIFY_FLAGS_NO_VBMETA_PARTITION)) {
    if (!cmdline_append_option(slot_data,
                               "androidboot.vbmeta.device",
                               "PARTUUID=$(ANDROID_VBMETA_PARTUUID)")) {
      ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
      goto out;
    }
  }

  /* Add androidboot.vbmeta.avb_version option. */
  if (!cmdline_append_version(slot_data,
                              "androidboot.vbmeta.avb_version",
                              AVB_VERSION_MAJOR,
                              AVB_VERSION_MINOR)) {
    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
    goto out;
  }

  /* Set androidboot.avb.device_state to "locked" or "unlocked". */
  io_ret = ops->read_is_device_unlocked(ops, &is_device_unlocked);
  if (io_ret == AVB_IO_RESULT_ERROR_OOM) {
    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
    goto out;
  } else if (io_ret != AVB_IO_RESULT_OK) {
    avb_error("Error getting device state.\n");
    ret = AVB_SLOT_VERIFY_RESULT_ERROR_IO;
    goto out;
  }
  if (!cmdline_append_option(slot_data,
                             "androidboot.vbmeta.device_state",
                             is_device_unlocked ? "unlocked" : "locked")) {
    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
    goto out;
  }

  /* Set androidboot.vbmeta.{hash_alg, size, digest} - use same hash
   * function as is used to sign vbmeta.
   */
  switch (algorithm_type) {
    /* Explicit fallthrough. */
    case AVB_ALGORITHM_TYPE_NONE:
    case AVB_ALGORITHM_TYPE_SHA256_RSA2048:
    case AVB_ALGORITHM_TYPE_SHA256_RSA4096:
    case AVB_ALGORITHM_TYPE_SHA256_RSA8192: {
      size_t n, total_size = 0;
      uint8_t vbmeta_digest[AVB_SHA256_DIGEST_SIZE];
      avb_slot_verify_data_calculate_vbmeta_digest(
          slot_data, AVB_DIGEST_TYPE_SHA256, vbmeta_digest);
      for (n = 0; n < slot_data->num_vbmeta_images; n++) {
        total_size += slot_data->vbmeta_images[n].vbmeta_size;
      }
      if (!cmdline_append_option(
              slot_data, "androidboot.vbmeta.hash_alg", "sha256") ||
          !cmdline_append_uint64_base10(
              slot_data, "androidboot.vbmeta.size", total_size) ||
          !cmdline_append_hex(slot_data,
                              "androidboot.vbmeta.digest",
                              vbmeta_digest,
                              AVB_SHA256_DIGEST_SIZE)) {
        ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
        goto out;
      }
    } break;
    /* Explicit fallthrough. */
    case AVB_ALGORITHM_TYPE_SHA512_RSA2048:
    case AVB_ALGORITHM_TYPE_SHA512_RSA4096:
    case AVB_ALGORITHM_TYPE_SHA512_RSA8192: {
      size_t n, total_size = 0;
      uint8_t vbmeta_digest[AVB_SHA512_DIGEST_SIZE];
      avb_slot_verify_data_calculate_vbmeta_digest(
          slot_data, AVB_DIGEST_TYPE_SHA512, vbmeta_digest);
      for (n = 0; n < slot_data->num_vbmeta_images; n++) {
        total_size += slot_data->vbmeta_images[n].vbmeta_size;
      }
      if (!cmdline_append_option(
              slot_data, "androidboot.vbmeta.hash_alg", "sha512") ||
          !cmdline_append_uint64_base10(
              slot_data, "androidboot.vbmeta.size", total_size) ||
          !cmdline_append_hex(slot_data,
                              "androidboot.vbmeta.digest",
                              vbmeta_digest,
                              AVB_SHA512_DIGEST_SIZE)) {
        ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
        goto out;
      }
    } break;
    case _AVB_ALGORITHM_NUM_TYPES:
      avb_assert_not_reached();
      break;
  }

  /* Set androidboot.veritymode and androidboot.vbmeta.invalidate_on_error */
  if (toplevel_vbmeta->flags & AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED) {
    verity_mode = "disabled";
  } else {
    const char* dm_verity_mode;
    char* new_ret;

    switch (resolved_hashtree_error_mode) {
      case AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE:
        if (!cmdline_append_option(
                slot_data, "androidboot.vbmeta.invalidate_on_error", "yes")) {
          ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
          goto out;
        }
        verity_mode = "enforcing";
        dm_verity_mode = "restart_on_corruption";
        break;
      case AVB_HASHTREE_ERROR_MODE_RESTART:
        verity_mode = "enforcing";
        dm_verity_mode = "restart_on_corruption";
        break;
      case AVB_HASHTREE_ERROR_MODE_EIO:
        verity_mode = "eio";
        /* For now there's no option to specify the EIO mode. So
         * just use 'ignore_zero_blocks' since that's already set
         * and dm-verity-target.c supports specifying this multiple
         * times.
         */
        dm_verity_mode = "ignore_zero_blocks";
        break;
      case AVB_HASHTREE_ERROR_MODE_LOGGING:
        verity_mode = "logging";
        dm_verity_mode = "ignore_corruption";
        break;
      case AVB_HASHTREE_ERROR_MODE_MANAGED_RESTART_AND_EIO:
        // Should never get here because MANAGED_RESTART_AND_EIO is
        // remapped by avb_manage_hashtree_error_mode().
        avb_assert_not_reached();
        ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT;
        goto out;
      default:
        ret = AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_ARGUMENT;
        goto out;
    }
    new_ret = avb_replace(
        slot_data->cmdline, "$(ANDROID_VERITY_MODE)", dm_verity_mode);
    avb_free(slot_data->cmdline);
    slot_data->cmdline = new_ret;
    if (slot_data->cmdline == NULL) {
      ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
      goto out;
    }
  }
  if (!cmdline_append_option(
          slot_data, "androidboot.veritymode", verity_mode)) {
    ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
    goto out;
  }
  if (hashtree_error_mode == AVB_HASHTREE_ERROR_MODE_MANAGED_RESTART_AND_EIO) {
    if (!cmdline_append_option(
            slot_data, "androidboot.veritymode.managed", "yes")) {
      ret = AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
      goto out;
    }
  }

  ret = AVB_SLOT_VERIFY_RESULT_OK;

out:

  return ret;
}

AvbCmdlineSubstList* avb_new_cmdline_subst_list() {
  return (AvbCmdlineSubstList*)avb_calloc(sizeof(AvbCmdlineSubstList));
}

void avb_free_cmdline_subst_list(AvbCmdlineSubstList* cmdline_subst) {
  size_t i;
  for (i = 0; i < cmdline_subst->size; ++i) {
    avb_free(cmdline_subst->tokens[i]);
    avb_free(cmdline_subst->values[i]);
  }
  cmdline_subst->size = 0;
  avb_free(cmdline_subst);
}

AvbSlotVerifyResult avb_add_root_digest_substitution(
    const char* part_name,
    const uint8_t* digest,
    size_t digest_size,
    AvbCmdlineSubstList* out_cmdline_subst) {
  const char* kDigestSubPrefix = "$(AVB_";
  const char* kDigestSubSuffix = "_ROOT_DIGEST)";
  size_t part_name_len = avb_strlen(part_name);
  size_t list_index = out_cmdline_subst->size;

  avb_assert(part_name_len < AVB_PART_NAME_MAX_SIZE);
  avb_assert(digest_size <= AVB_SHA512_DIGEST_SIZE);
  if (part_name_len >= AVB_PART_NAME_MAX_SIZE ||
      digest_size > AVB_SHA512_DIGEST_SIZE) {
    return AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
  }

  if (out_cmdline_subst->size >= AVB_MAX_NUM_CMDLINE_SUBST) {
    /* The list is full. Currently dynamic growth of this list is not supported.
     */
    return AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA;
  }

  /* Construct the token to replace in the command line based on the partition
   * name. For partition 'foo', this will be '$(AVB_FOO_ROOT_DIGEST)'.
   */
  out_cmdline_subst->tokens[list_index] =
      avb_strdupv(kDigestSubPrefix, part_name, kDigestSubSuffix, NULL);
  if (out_cmdline_subst->tokens[list_index] == NULL) {
    goto fail;
  }
  avb_uppercase(out_cmdline_subst->tokens[list_index]);

  /* The digest value is hex encoded when inserted in the command line. */
  out_cmdline_subst->values[list_index] = avb_bin2hex(digest, digest_size);
  if (out_cmdline_subst->values[list_index] == NULL) {
    goto fail;
  }

  out_cmdline_subst->size++;
  return AVB_SLOT_VERIFY_RESULT_OK;

fail:
  if (out_cmdline_subst->tokens[list_index]) {
    avb_free(out_cmdline_subst->tokens[list_index]);
  }
  if (out_cmdline_subst->values[list_index]) {
    avb_free(out_cmdline_subst->values[list_index]);
  }
  return AVB_SLOT_VERIFY_RESULT_ERROR_OOM;
}