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Tao Bao7197ee02015-12-05 21:21:27 -08001/*
2 * Copyright (C) 2015 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/*
18 * This program verifies the integrity of the partitions after an A/B OTA
19 * update. It gets invoked by init, and will only perform the verification if
20 * it's the first boot post an A/B OTA update.
21 *
Tianjie Xu3958a952017-03-01 15:31:25 -080022 * Update_verifier relies on dm-verity to capture any corruption on the partitions
23 * being verified. And its behavior varies depending on the dm-verity mode.
24 * Upon detection of failures:
25 * enforcing mode: dm-verity reboots the device
26 * eio mode: dm-verity fails the read and update_verifier reboots the device
27 * other mode: not supported and update_verifier reboots the device
28 *
29 * After a predefined number of failing boot attempts, the bootloader should
Tianjie Xud007cf22016-02-29 16:08:06 -080030 * mark the slot as unbootable and stops trying. Other dm-verity modes (
31 * for example, veritymode=EIO) are not accepted and simply lead to a
32 * verification failure.
Tao Bao7197ee02015-12-05 21:21:27 -080033 *
34 * The current slot will be marked as having booted successfully if the
35 * verifier reaches the end after the verification.
Tao Bao7197ee02015-12-05 21:21:27 -080036 */
37
Tao Bao83b07802017-04-26 14:30:56 -070038#include "update_verifier/update_verifier.h"
39
Tianjie Xub0ac8722017-01-18 18:41:53 -080040#include <dirent.h>
Tianjie Xud007cf22016-02-29 16:08:06 -080041#include <errno.h>
42#include <fcntl.h>
43#include <stdio.h>
Tao Bao7197ee02015-12-05 21:21:27 -080044#include <string.h>
Tianjie Xu3958a952017-03-01 15:31:25 -080045#include <unistd.h>
Tao Bao7197ee02015-12-05 21:21:27 -080046
Tianjie Xu8fa8f0b2017-04-27 11:47:35 -070047#include <algorithm>
Wei Wang5226f472017-08-02 10:27:31 -070048#include <future>
Tianjie Xud007cf22016-02-29 16:08:06 -080049#include <string>
50#include <vector>
51
52#include <android-base/file.h>
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -070053#include <android-base/logging.h>
Tianjie Xud007cf22016-02-29 16:08:06 -080054#include <android-base/parseint.h>
Tao Bao4f8d2172017-01-13 15:36:32 -080055#include <android-base/properties.h>
Tianjie Xud007cf22016-02-29 16:08:06 -080056#include <android-base/strings.h>
57#include <android-base/unique_fd.h>
Connor O'Brienad43d2d2016-11-21 12:47:33 -080058#include <android/hardware/boot/1.0/IBootControl.h>
Tianjie Xu3958a952017-03-01 15:31:25 -080059#include <cutils/android_reboot.h>
Connor O'Brienad43d2d2016-11-21 12:47:33 -080060
61using android::sp;
62using android::hardware::boot::V1_0::IBootControl;
63using android::hardware::boot::V1_0::BoolResult;
64using android::hardware::boot::V1_0::CommandResult;
Tao Bao7197ee02015-12-05 21:21:27 -080065
Tianjie Xub0ac8722017-01-18 18:41:53 -080066// Find directories in format of "/sys/block/dm-X".
67static int dm_name_filter(const dirent* de) {
68 if (android::base::StartsWith(de->d_name, "dm-")) {
69 return 1;
70 }
71 return 0;
72}
73
Tianjie Xu3958a952017-03-01 15:31:25 -080074static bool read_blocks(const std::string& partition, const std::string& range_str) {
Tianjie Xu5a176c02017-03-31 16:36:12 -070075 if (partition != "system" && partition != "vendor") {
76 LOG(ERROR) << "partition name must be system or vendor: " << partition;
77 return false;
78 }
Tianjie Xub0ac8722017-01-18 18:41:53 -080079 // Iterate the content of "/sys/block/dm-X/dm/name". If it matches "system"
80 // (or "vendor"), then dm-X is a dm-wrapped system/vendor partition.
81 // Afterwards, update_verifier will read every block on the care_map_file of
82 // "/dev/block/dm-X" to ensure the partition's integrity.
Tao Bao83b07802017-04-26 14:30:56 -070083 static constexpr auto DM_PATH_PREFIX = "/sys/block/";
Tianjie Xub0ac8722017-01-18 18:41:53 -080084 dirent** namelist;
85 int n = scandir(DM_PATH_PREFIX, &namelist, dm_name_filter, alphasort);
86 if (n == -1) {
87 PLOG(ERROR) << "Failed to scan dir " << DM_PATH_PREFIX;
88 return false;
89 }
90 if (n == 0) {
91 LOG(ERROR) << "dm block device not found for " << partition;
92 return false;
93 }
94
Tao Bao83b07802017-04-26 14:30:56 -070095 static constexpr auto DM_PATH_SUFFIX = "/dm/name";
96 static constexpr auto DEV_PATH = "/dev/block/";
Tianjie Xub0ac8722017-01-18 18:41:53 -080097 std::string dm_block_device;
98 while (n--) {
99 std::string path = DM_PATH_PREFIX + std::string(namelist[n]->d_name) + DM_PATH_SUFFIX;
100 std::string content;
101 if (!android::base::ReadFileToString(path, &content)) {
102 PLOG(WARNING) << "Failed to read " << path;
David Zeuthen8ed97382017-05-08 13:41:28 -0400103 } else {
104 std::string dm_block_name = android::base::Trim(content);
105#ifdef BOARD_AVB_ENABLE
106 // AVB is using 'vroot' for the root block device but we're expecting 'system'.
107 if (dm_block_name == "vroot") {
108 dm_block_name = "system";
Tianjie Xub0ac8722017-01-18 18:41:53 -0800109 }
David Zeuthen8ed97382017-05-08 13:41:28 -0400110#endif
111 if (dm_block_name == partition) {
112 dm_block_device = DEV_PATH + std::string(namelist[n]->d_name);
113 while (n--) {
114 free(namelist[n]);
115 }
116 break;
117 }
Tianjie Xub0ac8722017-01-18 18:41:53 -0800118 }
119 free(namelist[n]);
120 }
121 free(namelist);
122
123 if (dm_block_device.empty()) {
124 LOG(ERROR) << "Failed to find dm block device for " << partition;
125 return false;
126 }
Tao Bao4f8d2172017-01-13 15:36:32 -0800127
128 // For block range string, first integer 'count' equals 2 * total number of valid ranges,
129 // followed by 'count' number comma separated integers. Every two integers reprensent a
130 // block range with the first number included in range but second number not included.
131 // For example '4,64536,65343,74149,74150' represents: [64536,65343) and [74149,74150).
132 std::vector<std::string> ranges = android::base::Split(range_str, ",");
133 size_t range_count;
134 bool status = android::base::ParseUint(ranges[0], &range_count);
135 if (!status || (range_count == 0) || (range_count % 2 != 0) ||
136 (range_count != ranges.size() - 1)) {
137 LOG(ERROR) << "Error in parsing range string.";
138 return false;
139 }
140
Wei Wang5226f472017-08-02 10:27:31 -0700141 std::vector<std::future<bool>> threads;
142 size_t thread_num = std::thread::hardware_concurrency() ?: 4;
143 thread_num = std::min(thread_num, range_count / 2);
144 size_t group_range_count = range_count / thread_num;
Tianjie Xud007cf22016-02-29 16:08:06 -0800145
Wei Wang5226f472017-08-02 10:27:31 -0700146 for (size_t t = 0; t < thread_num; t++) {
147 auto thread_func = [t, group_range_count, &dm_block_device, &ranges, &partition]() {
148 size_t blk_count = 0;
149 static constexpr size_t kBlockSize = 4096;
150 std::vector<uint8_t> buf(1024 * kBlockSize);
151 android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(dm_block_device.c_str(), O_RDONLY)));
152 if (fd.get() == -1) {
153 PLOG(ERROR) << "Error reading " << dm_block_device << " for partition " << partition;
Tianjie Xu8fa8f0b2017-04-27 11:47:35 -0700154 return false;
155 }
Wei Wang5226f472017-08-02 10:27:31 -0700156
157 for (size_t i = 1 + group_range_count * t; i < group_range_count * (t + 1) + 1; i += 2) {
158 unsigned int range_start, range_end;
159 bool parse_status = android::base::ParseUint(ranges[i], &range_start);
160 parse_status = parse_status && android::base::ParseUint(ranges[i + 1], &range_end);
161 if (!parse_status || range_start >= range_end) {
162 LOG(ERROR) << "Invalid range pair " << ranges[i] << ", " << ranges[i + 1];
163 return false;
164 }
165
166 if (lseek64(fd.get(), static_cast<off64_t>(range_start) * kBlockSize, SEEK_SET) == -1) {
167 PLOG(ERROR) << "lseek to " << range_start << " failed";
168 return false;
169 }
170
171 size_t remain = (range_end - range_start) * kBlockSize;
172 while (remain > 0) {
173 size_t to_read = std::min(remain, 1024 * kBlockSize);
174 if (!android::base::ReadFully(fd.get(), buf.data(), to_read)) {
175 PLOG(ERROR) << "Failed to read blocks " << range_start << " to " << range_end;
176 return false;
177 }
178 remain -= to_read;
179 }
180 blk_count += (range_end - range_start);
181 }
182 LOG(INFO) << "Finished reading " << blk_count << " blocks on " << dm_block_device;
183 return true;
184 };
185
186 threads.emplace_back(std::async(std::launch::async, thread_func));
Tao Bao4f8d2172017-01-13 15:36:32 -0800187 }
Tianjie Xud007cf22016-02-29 16:08:06 -0800188
Wei Wang5226f472017-08-02 10:27:31 -0700189 bool ret = true;
190 for (auto& t : threads) {
191 ret = t.get() && ret;
192 }
193 LOG(INFO) << "Finished reading blocks on " << dm_block_device << " with " << thread_num
194 << " threads.";
195 return ret;
Tianjie Xud007cf22016-02-29 16:08:06 -0800196}
197
Tao Bao5a1dee02017-07-21 15:15:31 -0700198// Returns true to indicate a passing verification (or the error should be ignored); Otherwise
199// returns false on fatal errors, where we should reject the current boot and trigger a fallback.
200// Note that update_verifier should be backward compatible to not reject care_map.txt from old
201// releases, which could otherwise fail to boot into the new release. For example, we've changed
202// the care_map format between N and O. An O update_verifier would fail to work with N
203// care_map.txt. This could be a result of sideloading an O OTA while the device having a pending N
204// update.
Tao Bao83b07802017-04-26 14:30:56 -0700205bool verify_image(const std::string& care_map_name) {
Tao Bao5a1dee02017-07-21 15:15:31 -0700206 android::base::unique_fd care_map_fd(TEMP_FAILURE_RETRY(open(care_map_name.c_str(), O_RDONLY)));
207 // If the device is flashed before the current boot, it may not have care_map.txt
208 // in /data/ota_package. To allow the device to continue booting in this situation,
209 // we should print a warning and skip the block verification.
210 if (care_map_fd.get() == -1) {
211 PLOG(WARNING) << "Failed to open " << care_map_name;
Tianjie Xud007cf22016-02-29 16:08:06 -0800212 return true;
Tao Bao5a1dee02017-07-21 15:15:31 -0700213 }
214 // Care map file has four lines (two lines if vendor partition is not present):
215 // First line has the block partition name (system/vendor).
216 // Second line holds all ranges of blocks to verify.
217 // The next two lines have the same format but for vendor partition.
218 std::string file_content;
219 if (!android::base::ReadFdToString(care_map_fd.get(), &file_content)) {
220 LOG(ERROR) << "Error reading care map contents to string.";
221 return false;
222 }
223
224 std::vector<std::string> lines;
225 lines = android::base::Split(android::base::Trim(file_content), "\n");
226 if (lines.size() != 2 && lines.size() != 4) {
227 LOG(ERROR) << "Invalid lines in care_map: found " << lines.size()
228 << " lines, expecting 2 or 4 lines.";
229 return false;
230 }
231
232 for (size_t i = 0; i < lines.size(); i += 2) {
233 // We're seeing an N care_map.txt. Skip the verification since it's not compatible with O
234 // update_verifier (the last few metadata blocks can't be read via device mapper).
235 if (android::base::StartsWith(lines[i], "/dev/block/")) {
236 LOG(WARNING) << "Found legacy care_map.txt; skipped.";
237 return true;
238 }
239 if (!read_blocks(lines[i], lines[i+1])) {
240 return false;
241 }
242 }
243
244 return true;
Tianjie Xud007cf22016-02-29 16:08:06 -0800245}
246
Tianjie Xu3958a952017-03-01 15:31:25 -0800247static int reboot_device() {
248 if (android_reboot(ANDROID_RB_RESTART2, 0, nullptr) == -1) {
249 LOG(ERROR) << "Failed to reboot.";
250 return -1;
251 }
252 while (true) pause();
253}
254
Tao Bao83b07802017-04-26 14:30:56 -0700255int update_verifier(int argc, char** argv) {
Tao Bao7197ee02015-12-05 21:21:27 -0800256 for (int i = 1; i < argc; i++) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700257 LOG(INFO) << "Started with arg " << i << ": " << argv[i];
Tao Bao7197ee02015-12-05 21:21:27 -0800258 }
259
Chris Phoenix0157c782017-01-20 11:34:00 -0800260 sp<IBootControl> module = IBootControl::getService();
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800261 if (module == nullptr) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700262 LOG(ERROR) << "Error getting bootctrl module.";
Tianjie Xu3958a952017-03-01 15:31:25 -0800263 return reboot_device();
Tao Bao7197ee02015-12-05 21:21:27 -0800264 }
265
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800266 uint32_t current_slot = module->getCurrentSlot();
267 BoolResult is_successful = module->isSlotMarkedSuccessful(current_slot);
268 LOG(INFO) << "Booting slot " << current_slot << ": isSlotMarkedSuccessful="
269 << static_cast<int32_t>(is_successful);
Tao Bao7197ee02015-12-05 21:21:27 -0800270
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800271 if (is_successful == BoolResult::FALSE) {
Tao Bao7197ee02015-12-05 21:21:27 -0800272 // The current slot has not booted successfully.
Tao Baodb57f0d2017-03-10 14:21:25 -0800273
David Zeuthen8ed97382017-05-08 13:41:28 -0400274#if defined(PRODUCT_SUPPORTS_VERITY) || defined(BOARD_AVB_ENABLE)
David Zeuthen1a0929c2017-08-07 18:47:27 -0400275 bool skip_verification = false;
Tao Bao4f8d2172017-01-13 15:36:32 -0800276 std::string verity_mode = android::base::GetProperty("ro.boot.veritymode", "");
277 if (verity_mode.empty()) {
David Zeuthen1a0929c2017-08-07 18:47:27 -0400278 // With AVB it's possible to disable verification entirely and
279 // in this case ro.boot.veritymode is empty.
280#if defined(BOARD_AVB_ENABLE)
281 LOG(WARNING) << "verification has been disabled; marking without verification.";
282 skip_verification = true;
283#else
Tianjie Xud007cf22016-02-29 16:08:06 -0800284 LOG(ERROR) << "Failed to get dm-verity mode.";
Tianjie Xu3958a952017-03-01 15:31:25 -0800285 return reboot_device();
David Zeuthen1a0929c2017-08-07 18:47:27 -0400286#endif
Tao Bao4f8d2172017-01-13 15:36:32 -0800287 } else if (android::base::EqualsIgnoreCase(verity_mode, "eio")) {
Tianjie Xu3958a952017-03-01 15:31:25 -0800288 // We shouldn't see verity in EIO mode if the current slot hasn't booted successfully before.
289 // Continue the verification until we fail to read some blocks.
290 LOG(WARNING) << "Found dm-verity in EIO mode.";
David Zeuthen1a0929c2017-08-07 18:47:27 -0400291 } else if (android::base::EqualsIgnoreCase(verity_mode, "disabled")) {
292 LOG(WARNING) << "dm-verity in disabled mode; marking without verification.";
293 skip_verification = true;
Tao Bao4f8d2172017-01-13 15:36:32 -0800294 } else if (verity_mode != "enforcing") {
Tianjie Xud007cf22016-02-29 16:08:06 -0800295 LOG(ERROR) << "Unexpected dm-verity mode : " << verity_mode << ", expecting enforcing.";
Tianjie Xu3958a952017-03-01 15:31:25 -0800296 return reboot_device();
297 }
298
David Zeuthen1a0929c2017-08-07 18:47:27 -0400299 if (!skip_verification) {
300 static constexpr auto CARE_MAP_FILE = "/data/ota_package/care_map.txt";
301 if (!verify_image(CARE_MAP_FILE)) {
302 LOG(ERROR) << "Failed to verify all blocks in care map file.";
303 return reboot_device();
304 }
Tianjie Xud007cf22016-02-29 16:08:06 -0800305 }
Tao Baodb57f0d2017-03-10 14:21:25 -0800306#else
307 LOG(WARNING) << "dm-verity not enabled; marking without verification.";
308#endif
Tao Bao7197ee02015-12-05 21:21:27 -0800309
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800310 CommandResult cr;
311 module->markBootSuccessful([&cr](CommandResult result) { cr = result; });
312 if (!cr.success) {
313 LOG(ERROR) << "Error marking booted successfully: " << cr.errMsg;
Tianjie Xu3958a952017-03-01 15:31:25 -0800314 return reboot_device();
Tao Bao7197ee02015-12-05 21:21:27 -0800315 }
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700316 LOG(INFO) << "Marked slot " << current_slot << " as booted successfully.";
Tao Bao7197ee02015-12-05 21:21:27 -0800317 }
318
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700319 LOG(INFO) << "Leaving update_verifier.";
Tao Bao7197ee02015-12-05 21:21:27 -0800320 return 0;
321}