fs_mgr_avb.cpp revision 6879cc1e2ee91f47fa05a01dfbce9dfef7504501 
1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "fs_mgr_avb.h"
18
19#include <fcntl.h>
20#include <libgen.h>
21#include <string.h>
22#include <sys/ioctl.h>
23#include <sys/types.h>
24
25#include <sstream>
26#include <string>
27#include <vector>
28
29#include <android-base/file.h>
30#include <android-base/parseint.h>
31#include <android-base/properties.h>
32#include <android-base/stringprintf.h>
33#include <android-base/strings.h>
34#include <android-base/unique_fd.h>
35#include <libavb/libavb.h>
36
37#include "fs_mgr.h"
38#include "fs_mgr_priv.h"
39#include "fs_mgr_priv_avb_ops.h"
40#include "fs_mgr_priv_dm_ioctl.h"
41#include "fs_mgr_priv_sha.h"
42
43static inline bool nibble_value(const char& c, uint8_t* value) {
44    FS_MGR_CHECK(value != nullptr);
45
46    switch (c) {
47        case '0' ... '9':
48            *value = c - '0';
49            break;
50        case 'a' ... 'f':
51            *value = c - 'a' + 10;
52            break;
53        case 'A' ... 'F':
54            *value = c - 'A' + 10;
55            break;
56        default:
57            return false;
58    }
59
60    return true;
61}
62
63static bool hex_to_bytes(uint8_t* bytes, size_t bytes_len, const std::string& hex) {
64    FS_MGR_CHECK(bytes != nullptr);
65
66    if (hex.size() % 2 != 0) {
67        return false;
68    }
69    if (hex.size() / 2 > bytes_len) {
70        return false;
71    }
72    for (size_t i = 0, j = 0, n = hex.size(); i < n; i += 2, ++j) {
73        uint8_t high;
74        if (!nibble_value(hex[i], &high)) {
75            return false;
76        }
77        uint8_t low;
78        if (!nibble_value(hex[i + 1], &low)) {
79            return false;
80        }
81        bytes[j] = (high << 4) | low;
82    }
83    return true;
84}
85
86static std::string bytes_to_hex(const uint8_t* bytes, size_t bytes_len) {
87    FS_MGR_CHECK(bytes != nullptr);
88
89    static const char* hex_digits = "0123456789abcdef";
90    std::string hex;
91
92    for (size_t i = 0; i < bytes_len; i++) {
93        hex.push_back(hex_digits[(bytes[i] & 0xF0) >> 4]);
94        hex.push_back(hex_digits[bytes[i] & 0x0F]);
95    }
96    return hex;
97}
98
99template <typename Hasher>
100static std::pair<size_t, bool> verify_vbmeta_digest(const AvbSlotVerifyData& verify_data,
101                                                    const uint8_t* expected_digest) {
102    size_t total_size = 0;
103    Hasher hasher;
104    for (size_t n = 0; n < verify_data.num_vbmeta_images; n++) {
105        hasher.update(verify_data.vbmeta_images[n].vbmeta_data,
106                      verify_data.vbmeta_images[n].vbmeta_size);
107        total_size += verify_data.vbmeta_images[n].vbmeta_size;
108    }
109
110    bool matched = (memcmp(hasher.finalize(), expected_digest, Hasher::DIGEST_SIZE) == 0);
111
112    return std::make_pair(total_size, matched);
113}
114
115// Reads the following values from kernel cmdline and provides the
116// VerifyVbmetaImages() to verify AvbSlotVerifyData.
117//   - androidboot.vbmeta.device_state
118//   - androidboot.vbmeta.hash_alg
119//   - androidboot.vbmeta.size
120//   - androidboot.vbmeta.digest
121class FsManagerAvbVerifier {
122  public:
123    // The factory method to return a unique_ptr<FsManagerAvbVerifier>
124    static std::unique_ptr<FsManagerAvbVerifier> Create();
125    bool VerifyVbmetaImages(const AvbSlotVerifyData& verify_data);
126    bool IsDeviceUnlocked() { return is_device_unlocked_; }
127
128  protected:
129    FsManagerAvbVerifier() = default;
130
131  private:
132    enum HashAlgorithm {
133        kInvalid = 0,
134        kSHA256 = 1,
135        kSHA512 = 2,
136    };
137
138    HashAlgorithm hash_alg_;
139    uint8_t digest_[SHA512_DIGEST_LENGTH];
140    size_t vbmeta_size_;
141    bool is_device_unlocked_;
142};
143
144std::unique_ptr<FsManagerAvbVerifier> FsManagerAvbVerifier::Create() {
145    std::string cmdline;
146    if (!android::base::ReadFileToString("/proc/cmdline", &cmdline)) {
147        PERROR << "Failed to read /proc/cmdline";
148        return nullptr;
149    }
150
151    std::unique_ptr<FsManagerAvbVerifier> avb_verifier(new FsManagerAvbVerifier());
152    if (!avb_verifier) {
153        LERROR << "Failed to create unique_ptr<FsManagerAvbVerifier>";
154        return nullptr;
155    }
156
157    std::string digest;
158    std::string hash_alg;
159    for (const auto& entry : android::base::Split(android::base::Trim(cmdline), " ")) {
160        std::vector<std::string> pieces = android::base::Split(entry, "=");
161        const std::string& key = pieces[0];
162        const std::string& value = pieces[1];
163
164        if (key == "androidboot.vbmeta.device_state") {
165            avb_verifier->is_device_unlocked_ = (value == "unlocked");
166        } else if (key == "androidboot.vbmeta.hash_alg") {
167            hash_alg = value;
168        } else if (key == "androidboot.vbmeta.size") {
169            if (!android::base::ParseUint(value.c_str(), &avb_verifier->vbmeta_size_)) {
170                return nullptr;
171            }
172        } else if (key == "androidboot.vbmeta.digest") {
173            digest = value;
174        }
175    }
176
177    // Reads hash algorithm.
178    size_t expected_digest_size = 0;
179    if (hash_alg == "sha256") {
180        expected_digest_size = SHA256_DIGEST_LENGTH * 2;
181        avb_verifier->hash_alg_ = kSHA256;
182    } else if (hash_alg == "sha512") {
183        expected_digest_size = SHA512_DIGEST_LENGTH * 2;
184        avb_verifier->hash_alg_ = kSHA512;
185    } else {
186        LERROR << "Unknown hash algorithm: " << hash_alg.c_str();
187        return nullptr;
188    }
189
190    // Reads digest.
191    if (digest.size() != expected_digest_size) {
192        LERROR << "Unexpected digest size: " << digest.size()
193               << " (expected: " << expected_digest_size << ")";
194        return nullptr;
195    }
196
197    if (!hex_to_bytes(avb_verifier->digest_, sizeof(avb_verifier->digest_), digest)) {
198        LERROR << "Hash digest contains non-hexidecimal character: " << digest.c_str();
199        return nullptr;
200    }
201
202    return avb_verifier;
203}
204
205bool FsManagerAvbVerifier::VerifyVbmetaImages(const AvbSlotVerifyData& verify_data) {
206    if (verify_data.num_vbmeta_images == 0) {
207        LERROR << "No vbmeta images";
208        return false;
209    }
210
211    size_t total_size = 0;
212    bool digest_matched = false;
213
214    if (hash_alg_ == kSHA256) {
215        std::tie(total_size, digest_matched) =
216            verify_vbmeta_digest<SHA256Hasher>(verify_data, digest_);
217    } else if (hash_alg_ == kSHA512) {
218        std::tie(total_size, digest_matched) =
219            verify_vbmeta_digest<SHA512Hasher>(verify_data, digest_);
220    }
221
222    if (total_size != vbmeta_size_) {
223        LERROR << "total vbmeta size mismatch: " << total_size << " (expected: " << vbmeta_size_
224               << ")";
225        return false;
226    }
227
228    if (!digest_matched) {
229        LERROR << "vbmeta digest mismatch";
230        return false;
231    }
232
233    return true;
234}
235
236// Constructs dm-verity arguments for sending DM_TABLE_LOAD ioctl to kernel.
237// See the following link for more details:
238// https://gitlab.com/cryptsetup/cryptsetup/wikis/DMVerity
239static std::string construct_verity_table(const AvbHashtreeDescriptor& hashtree_desc,
240                                          const std::string& salt, const std::string& root_digest,
241                                          const std::string& blk_device) {
242    // Loads androidboot.veritymode from kernel cmdline.
243    std::string verity_mode;
244    if (!fs_mgr_get_boot_config("veritymode", &verity_mode)) {
245        verity_mode = "enforcing";  // Defaults to enforcing when it's absent.
246    }
247
248    // Converts veritymode to the format used in kernel.
249    std::string dm_verity_mode;
250    if (verity_mode == "enforcing") {
251        dm_verity_mode = "restart_on_corruption";
252    } else if (verity_mode == "logging") {
253        dm_verity_mode = "ignore_corruption";
254    } else if (verity_mode != "eio") {  // Default dm_verity_mode is eio.
255        LERROR << "Unknown androidboot.veritymode: " << verity_mode;
256        return "";
257    }
258
259    // dm-verity construction parameters:
260    //   <version> <dev> <hash_dev>
261    //   <data_block_size> <hash_block_size>
262    //   <num_data_blocks> <hash_start_block>
263    //   <algorithm> <digest> <salt>
264    //   [<#opt_params> <opt_params>]
265    std::ostringstream verity_table;
266    verity_table << hashtree_desc.dm_verity_version << " " << blk_device << " " << blk_device << " "
267                 << hashtree_desc.data_block_size << " " << hashtree_desc.hash_block_size << " "
268                 << hashtree_desc.image_size / hashtree_desc.data_block_size << " "
269                 << hashtree_desc.tree_offset / hashtree_desc.hash_block_size << " "
270                 << hashtree_desc.hash_algorithm << " " << root_digest << " " << salt;
271
272    // Continued from the above optional parameters:
273    //   [<#opt_params> <opt_params>]
274    int optional_argc = 0;
275    std::ostringstream optional_args;
276
277    // dm-verity optional parameters for FEC (forward error correction):
278    //   use_fec_from_device <fec_dev>
279    //   fec_roots <num>
280    //   fec_blocks <num>
281    //   fec_start <offset>
282    if (hashtree_desc.fec_size > 0) {
283        // Note that fec_blocks is the size that FEC covers, *NOT* the
284        // size of the FEC data. Since we use FEC for everything up until
285        // the FEC data, it's the same as the offset (fec_start).
286        optional_argc += 8;
287        // clang-format off
288        optional_args << "use_fec_from_device " << blk_device
289                      << " fec_roots " << hashtree_desc.fec_num_roots
290                      << " fec_blocks " << hashtree_desc.fec_offset / hashtree_desc.data_block_size
291                      << " fec_start " << hashtree_desc.fec_offset / hashtree_desc.data_block_size
292                      << " ";
293        // clang-format on
294    }
295
296    if (!dm_verity_mode.empty()) {
297        optional_argc += 1;
298        optional_args << dm_verity_mode << " ";
299    }
300
301    // Always use ignore_zero_blocks.
302    optional_argc += 1;
303    optional_args << "ignore_zero_blocks";
304
305    verity_table << " " << optional_argc << " " << optional_args.str();
306    return verity_table.str();
307}
308
309static bool load_verity_table(struct dm_ioctl* io, const std::string& dm_device_name, int fd,
310                              uint64_t image_size, const std::string& verity_table) {
311    fs_mgr_verity_ioctl_init(io, dm_device_name, DM_STATUS_TABLE_FLAG);
312
313    // The buffer consists of [dm_ioctl][dm_target_spec][verity_params].
314    char* buffer = (char*)io;
315
316    // Builds the dm_target_spec arguments.
317    struct dm_target_spec* dm_target = (struct dm_target_spec*)&buffer[sizeof(struct dm_ioctl)];
318    io->target_count = 1;
319    dm_target->status = 0;
320    dm_target->sector_start = 0;
321    dm_target->length = image_size / 512;
322    strcpy(dm_target->target_type, "verity");
323
324    // Builds the verity params.
325    char* verity_params = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec);
326    size_t bufsize = DM_BUF_SIZE - (verity_params - buffer);
327
328    LINFO << "Loading verity table: '" << verity_table << "'";
329
330    // Copies verity_table to verity_params (including the terminating null byte).
331    if (verity_table.size() > bufsize - 1) {
332        LERROR << "Verity table size too large: " << verity_table.size()
333               << " (max allowable size: " << bufsize - 1 << ")";
334        return false;
335    }
336    memcpy(verity_params, verity_table.c_str(), verity_table.size() + 1);
337
338    // Sets ext target boundary.
339    verity_params += verity_table.size() + 1;
340    verity_params = (char*)(((unsigned long)verity_params + 7) & ~7);
341    dm_target->next = verity_params - buffer;
342
343    // Sends the ioctl to load the verity table.
344    if (ioctl(fd, DM_TABLE_LOAD, io)) {
345        PERROR << "Error loading verity table";
346        return false;
347    }
348
349    return true;
350}
351
352static bool hashtree_dm_verity_setup(struct fstab_rec* fstab_entry,
353                                     const AvbHashtreeDescriptor& hashtree_desc,
354                                     const std::string& salt, const std::string& root_digest,
355                                     bool wait_for_verity_dev) {
356    // Gets the device mapper fd.
357    android::base::unique_fd fd(open("/dev/device-mapper", O_RDWR));
358    if (fd < 0) {
359        PERROR << "Error opening device mapper";
360        return false;
361    }
362
363    // Creates the device.
364    alignas(dm_ioctl) char buffer[DM_BUF_SIZE];
365    struct dm_ioctl* io = (struct dm_ioctl*)buffer;
366    const std::string mount_point(basename(fstab_entry->mount_point));
367    if (!fs_mgr_create_verity_device(io, mount_point, fd)) {
368        LERROR << "Couldn't create verity device!";
369        return false;
370    }
371
372    // Gets the name of the device file.
373    std::string verity_blk_name;
374    if (!fs_mgr_get_verity_device_name(io, mount_point, fd, &verity_blk_name)) {
375        LERROR << "Couldn't get verity device number!";
376        return false;
377    }
378
379    std::string verity_table =
380        construct_verity_table(hashtree_desc, salt, root_digest, fstab_entry->blk_device);
381    if (verity_table.empty()) {
382        LERROR << "Failed to construct verity table.";
383        return false;
384    }
385
386    // Loads the verity mapping table.
387    if (!load_verity_table(io, mount_point, fd, hashtree_desc.image_size, verity_table)) {
388        LERROR << "Couldn't load verity table!";
389        return false;
390    }
391
392    // Activates the device.
393    if (!fs_mgr_resume_verity_table(io, mount_point, fd)) {
394        return false;
395    }
396
397    // Marks the underlying block device as read-only.
398    fs_mgr_set_blk_ro(fstab_entry->blk_device);
399
400    // Updates fstab_rec->blk_device to verity device name.
401    free(fstab_entry->blk_device);
402    fstab_entry->blk_device = strdup(verity_blk_name.c_str());
403
404    // Makes sure we've set everything up properly.
405    if (wait_for_verity_dev && fs_mgr_test_access(verity_blk_name.c_str()) < 0) {
406        return false;
407    }
408
409    return true;
410}
411
412static bool get_hashtree_descriptor(const std::string& partition_name,
413                                    const AvbSlotVerifyData& verify_data,
414                                    AvbHashtreeDescriptor* out_hashtree_desc, std::string* out_salt,
415                                    std::string* out_digest) {
416    bool found = false;
417    const uint8_t* desc_partition_name;
418
419    for (size_t i = 0; i < verify_data.num_vbmeta_images && !found; i++) {
420        // Get descriptors from vbmeta_images[i].
421        size_t num_descriptors;
422        std::unique_ptr<const AvbDescriptor* [], decltype(&avb_free)> descriptors(
423            avb_descriptor_get_all(verify_data.vbmeta_images[i].vbmeta_data,
424                                   verify_data.vbmeta_images[i].vbmeta_size, &num_descriptors),
425            avb_free);
426
427        if (!descriptors || num_descriptors < 1) {
428            continue;
429        }
430
431        // Ensures that hashtree descriptor is in /vbmeta or /boot or in
432        // the same partition for verity setup.
433        std::string vbmeta_partition_name(verify_data.vbmeta_images[i].partition_name);
434        if (vbmeta_partition_name != "vbmeta" &&
435            vbmeta_partition_name != "boot" &&  // for legacy device to append top-level vbmeta
436            vbmeta_partition_name != partition_name) {
437            LWARNING << "Skip vbmeta image at " << verify_data.vbmeta_images[i].partition_name
438                     << " for partition: " << partition_name.c_str();
439            continue;
440        }
441
442        for (size_t j = 0; j < num_descriptors && !found; j++) {
443            AvbDescriptor desc;
444            if (!avb_descriptor_validate_and_byteswap(descriptors[j], &desc)) {
445                LWARNING << "Descriptor[" << j << "] is invalid";
446                continue;
447            }
448            if (desc.tag == AVB_DESCRIPTOR_TAG_HASHTREE) {
449                desc_partition_name = (const uint8_t*)descriptors[j] + sizeof(AvbHashtreeDescriptor);
450                if (!avb_hashtree_descriptor_validate_and_byteswap(
451                        (AvbHashtreeDescriptor*)descriptors[j], out_hashtree_desc)) {
452                    continue;
453                }
454                if (out_hashtree_desc->partition_name_len != partition_name.length()) {
455                    continue;
456                }
457                // Notes that desc_partition_name is not NUL-terminated.
458                std::string hashtree_partition_name((const char*)desc_partition_name,
459                                                    out_hashtree_desc->partition_name_len);
460                if (hashtree_partition_name == partition_name) {
461                    found = true;
462                }
463            }
464        }
465    }
466
467    if (!found) {
468        LERROR << "Partition descriptor not found: " << partition_name.c_str();
469        return false;
470    }
471
472    const uint8_t* desc_salt = desc_partition_name + out_hashtree_desc->partition_name_len;
473    *out_salt = bytes_to_hex(desc_salt, out_hashtree_desc->salt_len);
474
475    const uint8_t* desc_digest = desc_salt + out_hashtree_desc->salt_len;
476    *out_digest = bytes_to_hex(desc_digest, out_hashtree_desc->root_digest_len);
477
478    return true;
479}
480
481FsManagerAvbUniquePtr FsManagerAvbHandle::Open(const fstab& fstab) {
482    FsManagerAvbOps avb_ops(fstab);
483    return DoOpen(&avb_ops);
484}
485
486FsManagerAvbUniquePtr FsManagerAvbHandle::Open(ByNameSymlinkMap&& by_name_symlink_map) {
487    if (by_name_symlink_map.empty()) {
488        LERROR << "Empty by_name_symlink_map when opening FsManagerAvbHandle";
489        return nullptr;
490    }
491    FsManagerAvbOps avb_ops(std::move(by_name_symlink_map));
492    return DoOpen(&avb_ops);
493}
494
495FsManagerAvbUniquePtr FsManagerAvbHandle::DoOpen(FsManagerAvbOps* avb_ops) {
496    // Gets the expected hash value of vbmeta images from kernel cmdline.
497    std::unique_ptr<FsManagerAvbVerifier> avb_verifier = FsManagerAvbVerifier::Create();
498    if (!avb_verifier) {
499        LERROR << "Failed to create FsManagerAvbVerifier";
500        return nullptr;
501    }
502
503    FsManagerAvbUniquePtr avb_handle(new FsManagerAvbHandle());
504    if (!avb_handle) {
505        LERROR << "Failed to allocate FsManagerAvbHandle";
506        return nullptr;
507    }
508
509    AvbSlotVerifyFlags flags = avb_verifier->IsDeviceUnlocked()
510                                   ? AVB_SLOT_VERIFY_FLAGS_ALLOW_VERIFICATION_ERROR
511                                   : AVB_SLOT_VERIFY_FLAGS_NONE;
512    AvbSlotVerifyResult verify_result =
513        avb_ops->AvbSlotVerify(fs_mgr_get_slot_suffix(), flags, &avb_handle->avb_slot_data_);
514
515    // Only allow two verify results:
516    //   - AVB_SLOT_VERIFY_RESULT_OK.
517    //   - AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION (for UNLOCKED state).
518    //     If the device is UNLOCKED, i.e., |allow_verification_error| is true for
519    //     AvbSlotVerify(), then the following return values are all non-fatal:
520    //       * AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION
521    //       * AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED
522    //       * AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX
523    //     The latter two results were checked by bootloader prior to start fs_mgr so
524    //     we just need to handle the first result here. See *dummy* operations in
525    //     FsManagerAvbOps and the comments in external/avb/libavb/avb_slot_verify.h
526    //     for more details.
527    switch (verify_result) {
528        case AVB_SLOT_VERIFY_RESULT_OK:
529            avb_handle->status_ = kFsManagerAvbHandleSuccess;
530            break;
531        case AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION:
532            if (!avb_verifier->IsDeviceUnlocked()) {
533                LERROR << "ERROR_VERIFICATION isn't allowed when the device is LOCKED";
534                return nullptr;
535            }
536            avb_handle->status_ = kFsManagerAvbHandleErrorVerification;
537            break;
538        default:
539            LERROR << "avb_slot_verify failed, result: " << verify_result;
540            return nullptr;
541    }
542
543    // Verifies vbmeta images against the digest passed from bootloader.
544    if (!avb_verifier->VerifyVbmetaImages(*avb_handle->avb_slot_data_)) {
545        LERROR << "VerifyVbmetaImages failed";
546        return nullptr;
547    }
548
549    // Sets the MAJOR.MINOR for init to set it into "ro.boot.avb_version".
550    avb_handle->avb_version_ =
551        android::base::StringPrintf("%d.%d", AVB_VERSION_MAJOR, AVB_VERSION_MINOR);
552
553    // Checks whether FLAGS_HASHTREE_DISABLED is set.
554    AvbVBMetaImageHeader vbmeta_header;
555    avb_vbmeta_image_header_to_host_byte_order(
556        (AvbVBMetaImageHeader*)avb_handle->avb_slot_data_->vbmeta_images[0].vbmeta_data,
557        &vbmeta_header);
558
559    bool hashtree_disabled =
560        ((AvbVBMetaImageFlags)vbmeta_header.flags & AVB_VBMETA_IMAGE_FLAGS_HASHTREE_DISABLED);
561    if (hashtree_disabled) {
562        avb_handle->status_ = kFsManagerAvbHandleHashtreeDisabled;
563    }
564
565    LINFO << "Returning avb_handle with status: " << avb_handle->status_;
566    return avb_handle;
567}
568
569bool FsManagerAvbHandle::SetUpAvb(struct fstab_rec* fstab_entry, bool wait_for_verity_dev) {
570    if (!fstab_entry) return false;
571    if (!avb_slot_data_ || avb_slot_data_->num_vbmeta_images < 1) {
572        return false;
573    }
574
575    if (status_ == kFsManagerAvbHandleUninitialized) return false;
576    if (status_ == kFsManagerAvbHandleHashtreeDisabled) {
577        LINFO << "AVB HASHTREE disabled on:" << fstab_entry->mount_point;
578        return true;
579    }
580
581    std::string partition_name(basename(fstab_entry->mount_point));
582    if (!avb_validate_utf8((const uint8_t*)partition_name.c_str(), partition_name.length())) {
583        LERROR << "Partition name: " << partition_name.c_str() << " is not valid UTF-8.";
584        return false;
585    }
586
587    AvbHashtreeDescriptor hashtree_descriptor;
588    std::string salt;
589    std::string root_digest;
590    if (!get_hashtree_descriptor(partition_name, *avb_slot_data_, &hashtree_descriptor, &salt,
591                                 &root_digest)) {
592        return false;
593    }
594
595    // Converts HASHTREE descriptor to verity_table_params.
596    if (!hashtree_dm_verity_setup(fstab_entry, hashtree_descriptor, salt, root_digest,
597                                  wait_for_verity_dev)) {
598        return false;
599    }
600    return true;
601}
602