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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 Xu253e2232017-03-31 22:27:37 +000022 * 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
Tianjie Xub0ac8722017-01-18 18:41:53 -080038#include <dirent.h>
Tianjie Xud007cf22016-02-29 16:08:06 -080039#include <errno.h>
40#include <fcntl.h>
41#include <stdio.h>
Tao Bao7197ee02015-12-05 21:21:27 -080042#include <string.h>
Tianjie Xu253e2232017-03-31 22:27:37 +000043#include <unistd.h>
Tao Bao7197ee02015-12-05 21:21:27 -080044
Tianjie Xud007cf22016-02-29 16:08:06 -080045#include <string>
46#include <vector>
47
48#include <android-base/file.h>
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -070049#include <android-base/logging.h>
Tianjie Xud007cf22016-02-29 16:08:06 -080050#include <android-base/parseint.h>
Tao Bao4f8d2172017-01-13 15:36:32 -080051#include <android-base/properties.h>
Tianjie Xud007cf22016-02-29 16:08:06 -080052#include <android-base/strings.h>
53#include <android-base/unique_fd.h>
Connor O'Brienad43d2d2016-11-21 12:47:33 -080054#include <android/hardware/boot/1.0/IBootControl.h>
Tianjie Xu253e2232017-03-31 22:27:37 +000055#include <cutils/android_reboot.h>
Connor O'Brienad43d2d2016-11-21 12:47:33 -080056
57using android::sp;
58using android::hardware::boot::V1_0::IBootControl;
59using android::hardware::boot::V1_0::BoolResult;
60using android::hardware::boot::V1_0::CommandResult;
Tao Bao7197ee02015-12-05 21:21:27 -080061
Tianjie Xud007cf22016-02-29 16:08:06 -080062constexpr auto CARE_MAP_FILE = "/data/ota_package/care_map.txt";
Tianjie Xub0ac8722017-01-18 18:41:53 -080063constexpr auto DM_PATH_PREFIX = "/sys/block/";
64constexpr auto DM_PATH_SUFFIX = "/dm/name";
65constexpr auto DEV_PATH = "/dev/block/";
Tianjie Xud007cf22016-02-29 16:08:06 -080066constexpr int BLOCKSIZE = 4096;
67
Tianjie Xub0ac8722017-01-18 18:41:53 -080068// Find directories in format of "/sys/block/dm-X".
69static int dm_name_filter(const dirent* de) {
70 if (android::base::StartsWith(de->d_name, "dm-")) {
71 return 1;
72 }
73 return 0;
74}
75
Tianjie Xu253e2232017-03-31 22:27:37 +000076static bool read_blocks(const std::string& partition, const std::string& range_str) {
77 CHECK(partition == "system" || partition == "vendor")
78 << "partition name should be system or vendor" << partition;
Tianjie Xub0ac8722017-01-18 18:41:53 -080079
80 // Iterate the content of "/sys/block/dm-X/dm/name". If it matches "system"
81 // (or "vendor"), then dm-X is a dm-wrapped system/vendor partition.
82 // Afterwards, update_verifier will read every block on the care_map_file of
83 // "/dev/block/dm-X" to ensure the partition's integrity.
84 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
95 std::string dm_block_device;
96 while (n--) {
97 std::string path = DM_PATH_PREFIX + std::string(namelist[n]->d_name) + DM_PATH_SUFFIX;
98 std::string content;
99 if (!android::base::ReadFileToString(path, &content)) {
100 PLOG(WARNING) << "Failed to read " << path;
101 } else if (android::base::Trim(content) == partition) {
102 dm_block_device = DEV_PATH + std::string(namelist[n]->d_name);
103 while (n--) {
104 free(namelist[n]);
105 }
106 break;
107 }
108 free(namelist[n]);
109 }
110 free(namelist);
111
112 if (dm_block_device.empty()) {
113 LOG(ERROR) << "Failed to find dm block device for " << partition;
114 return false;
115 }
116 android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(dm_block_device.c_str(), O_RDONLY)));
Tao Bao4f8d2172017-01-13 15:36:32 -0800117 if (fd.get() == -1) {
Tianjie Xub0ac8722017-01-18 18:41:53 -0800118 PLOG(ERROR) << "Error reading " << dm_block_device << " for partition " << partition;
Tao Bao4f8d2172017-01-13 15:36:32 -0800119 return false;
120 }
121
122 // For block range string, first integer 'count' equals 2 * total number of valid ranges,
123 // followed by 'count' number comma separated integers. Every two integers reprensent a
124 // block range with the first number included in range but second number not included.
125 // For example '4,64536,65343,74149,74150' represents: [64536,65343) and [74149,74150).
126 std::vector<std::string> ranges = android::base::Split(range_str, ",");
127 size_t range_count;
128 bool status = android::base::ParseUint(ranges[0], &range_count);
129 if (!status || (range_count == 0) || (range_count % 2 != 0) ||
130 (range_count != ranges.size() - 1)) {
131 LOG(ERROR) << "Error in parsing range string.";
132 return false;
133 }
134
135 size_t blk_count = 0;
136 for (size_t i = 1; i < ranges.size(); i += 2) {
137 unsigned int range_start, range_end;
138 bool parse_status = android::base::ParseUint(ranges[i], &range_start);
139 parse_status = parse_status && android::base::ParseUint(ranges[i + 1], &range_end);
140 if (!parse_status || range_start >= range_end) {
141 LOG(ERROR) << "Invalid range pair " << ranges[i] << ", " << ranges[i + 1];
142 return false;
Tianjie Xud007cf22016-02-29 16:08:06 -0800143 }
144
Tao Bao4f8d2172017-01-13 15:36:32 -0800145 if (lseek64(fd.get(), static_cast<off64_t>(range_start) * BLOCKSIZE, SEEK_SET) == -1) {
146 PLOG(ERROR) << "lseek to " << range_start << " failed";
147 return false;
Tianjie Xud007cf22016-02-29 16:08:06 -0800148 }
149
Tao Bao4f8d2172017-01-13 15:36:32 -0800150 size_t size = (range_end - range_start) * BLOCKSIZE;
151 std::vector<uint8_t> buf(size);
152 if (!android::base::ReadFully(fd.get(), buf.data(), size)) {
153 PLOG(ERROR) << "Failed to read blocks " << range_start << " to " << range_end;
154 return false;
Tianjie Xud007cf22016-02-29 16:08:06 -0800155 }
Tao Bao4f8d2172017-01-13 15:36:32 -0800156 blk_count += (range_end - range_start);
157 }
Tianjie Xud007cf22016-02-29 16:08:06 -0800158
Tianjie Xub0ac8722017-01-18 18:41:53 -0800159 LOG(INFO) << "Finished reading " << blk_count << " blocks on " << dm_block_device;
Tao Bao4f8d2172017-01-13 15:36:32 -0800160 return true;
Tianjie Xud007cf22016-02-29 16:08:06 -0800161}
162
163static bool verify_image(const std::string& care_map_name) {
164 android::base::unique_fd care_map_fd(TEMP_FAILURE_RETRY(open(care_map_name.c_str(), O_RDONLY)));
165 // If the device is flashed before the current boot, it may not have care_map.txt
166 // in /data/ota_package. To allow the device to continue booting in this situation,
167 // we should print a warning and skip the block verification.
168 if (care_map_fd.get() == -1) {
169 LOG(WARNING) << "Warning: care map " << care_map_name << " not found.";
170 return true;
171 }
172 // Care map file has four lines (two lines if vendor partition is not present):
Tianjie Xu253e2232017-03-31 22:27:37 +0000173 // First line has the block partition name (system/vendor).
Tianjie Xud007cf22016-02-29 16:08:06 -0800174 // Second line holds all ranges of blocks to verify.
175 // The next two lines have the same format but for vendor partition.
176 std::string file_content;
177 if (!android::base::ReadFdToString(care_map_fd.get(), &file_content)) {
178 LOG(ERROR) << "Error reading care map contents to string.";
179 return false;
180 }
181
182 std::vector<std::string> lines;
183 lines = android::base::Split(android::base::Trim(file_content), "\n");
184 if (lines.size() != 2 && lines.size() != 4) {
185 LOG(ERROR) << "Invalid lines in care_map: found " << lines.size()
186 << " lines, expecting 2 or 4 lines.";
187 return false;
188 }
189
190 for (size_t i = 0; i < lines.size(); i += 2) {
191 if (!read_blocks(lines[i], lines[i+1])) {
192 return false;
193 }
194 }
195
196 return true;
197}
198
Tianjie Xu253e2232017-03-31 22:27:37 +0000199static int reboot_device() {
200 if (android_reboot(ANDROID_RB_RESTART2, 0, nullptr) == -1) {
201 LOG(ERROR) << "Failed to reboot.";
202 return -1;
203 }
204 while (true) pause();
205}
206
Tao Bao7197ee02015-12-05 21:21:27 -0800207int main(int argc, char** argv) {
Tao Bao7197ee02015-12-05 21:21:27 -0800208 for (int i = 1; i < argc; i++) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700209 LOG(INFO) << "Started with arg " << i << ": " << argv[i];
Tao Bao7197ee02015-12-05 21:21:27 -0800210 }
211
Chris Phoenix0157c782017-01-20 11:34:00 -0800212 sp<IBootControl> module = IBootControl::getService();
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800213 if (module == nullptr) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700214 LOG(ERROR) << "Error getting bootctrl module.";
Tianjie Xu253e2232017-03-31 22:27:37 +0000215 return reboot_device();
Tao Bao7197ee02015-12-05 21:21:27 -0800216 }
217
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800218 uint32_t current_slot = module->getCurrentSlot();
219 BoolResult is_successful = module->isSlotMarkedSuccessful(current_slot);
220 LOG(INFO) << "Booting slot " << current_slot << ": isSlotMarkedSuccessful="
221 << static_cast<int32_t>(is_successful);
Tao Bao7197ee02015-12-05 21:21:27 -0800222
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800223 if (is_successful == BoolResult::FALSE) {
Tao Bao7197ee02015-12-05 21:21:27 -0800224 // The current slot has not booted successfully.
Tao Baodb57f0d2017-03-10 14:21:25 -0800225
226#ifdef PRODUCT_SUPPORTS_VERITY
Tao Bao4f8d2172017-01-13 15:36:32 -0800227 std::string verity_mode = android::base::GetProperty("ro.boot.veritymode", "");
228 if (verity_mode.empty()) {
Tianjie Xud007cf22016-02-29 16:08:06 -0800229 LOG(ERROR) << "Failed to get dm-verity mode.";
Tianjie Xu253e2232017-03-31 22:27:37 +0000230 return reboot_device();
Tao Bao4f8d2172017-01-13 15:36:32 -0800231 } else if (android::base::EqualsIgnoreCase(verity_mode, "eio")) {
Tianjie Xu253e2232017-03-31 22:27:37 +0000232 // We shouldn't see verity in EIO mode if the current slot hasn't booted successfully before.
233 // Continue the verification until we fail to read some blocks.
234 LOG(WARNING) << "Found dm-verity in EIO mode.";
Tao Bao4f8d2172017-01-13 15:36:32 -0800235 } else if (verity_mode != "enforcing") {
Tianjie Xud007cf22016-02-29 16:08:06 -0800236 LOG(ERROR) << "Unexpected dm-verity mode : " << verity_mode << ", expecting enforcing.";
Tianjie Xu253e2232017-03-31 22:27:37 +0000237 return reboot_device();
238 }
239
240 if (!verify_image(CARE_MAP_FILE)) {
Tianjie Xud007cf22016-02-29 16:08:06 -0800241 LOG(ERROR) << "Failed to verify all blocks in care map file.";
Tianjie Xu253e2232017-03-31 22:27:37 +0000242 return reboot_device();
Tianjie Xud007cf22016-02-29 16:08:06 -0800243 }
Tao Baodb57f0d2017-03-10 14:21:25 -0800244#else
245 LOG(WARNING) << "dm-verity not enabled; marking without verification.";
246#endif
Tao Bao7197ee02015-12-05 21:21:27 -0800247
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800248 CommandResult cr;
249 module->markBootSuccessful([&cr](CommandResult result) { cr = result; });
250 if (!cr.success) {
251 LOG(ERROR) << "Error marking booted successfully: " << cr.errMsg;
Tianjie Xu253e2232017-03-31 22:27:37 +0000252 return reboot_device();
Tao Bao7197ee02015-12-05 21:21:27 -0800253 }
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700254 LOG(INFO) << "Marked slot " << current_slot << " as booted successfully.";
Tao Bao7197ee02015-12-05 21:21:27 -0800255 }
256
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700257 LOG(INFO) << "Leaving update_verifier.";
Tao Bao7197ee02015-12-05 21:21:27 -0800258 return 0;
259}