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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) {
Tianjie Xu8dcbd1b2017-04-02 03:12:15 +000077 if (partition != "system" && partition != "vendor") {
78 LOG(ERROR) << "partition name must be system or vendor: " << partition;
79 return false;
80 }
Tianjie Xub0ac8722017-01-18 18:41:53 -080081 // Iterate the content of "/sys/block/dm-X/dm/name". If it matches "system"
82 // (or "vendor"), then dm-X is a dm-wrapped system/vendor partition.
83 // Afterwards, update_verifier will read every block on the care_map_file of
84 // "/dev/block/dm-X" to ensure the partition's integrity.
85 dirent** namelist;
86 int n = scandir(DM_PATH_PREFIX, &namelist, dm_name_filter, alphasort);
87 if (n == -1) {
88 PLOG(ERROR) << "Failed to scan dir " << DM_PATH_PREFIX;
89 return false;
90 }
91 if (n == 0) {
92 LOG(ERROR) << "dm block device not found for " << partition;
93 return false;
94 }
95
96 std::string dm_block_device;
97 while (n--) {
98 std::string path = DM_PATH_PREFIX + std::string(namelist[n]->d_name) + DM_PATH_SUFFIX;
99 std::string content;
100 if (!android::base::ReadFileToString(path, &content)) {
101 PLOG(WARNING) << "Failed to read " << path;
102 } else if (android::base::Trim(content) == partition) {
103 dm_block_device = DEV_PATH + std::string(namelist[n]->d_name);
104 while (n--) {
105 free(namelist[n]);
106 }
107 break;
108 }
109 free(namelist[n]);
110 }
111 free(namelist);
112
113 if (dm_block_device.empty()) {
114 LOG(ERROR) << "Failed to find dm block device for " << partition;
115 return false;
116 }
117 android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(dm_block_device.c_str(), O_RDONLY)));
Tao Bao4f8d2172017-01-13 15:36:32 -0800118 if (fd.get() == -1) {
Tianjie Xub0ac8722017-01-18 18:41:53 -0800119 PLOG(ERROR) << "Error reading " << dm_block_device << " for partition " << partition;
Tao Bao4f8d2172017-01-13 15:36:32 -0800120 return false;
121 }
122
123 // For block range string, first integer 'count' equals 2 * total number of valid ranges,
124 // followed by 'count' number comma separated integers. Every two integers reprensent a
125 // block range with the first number included in range but second number not included.
126 // For example '4,64536,65343,74149,74150' represents: [64536,65343) and [74149,74150).
127 std::vector<std::string> ranges = android::base::Split(range_str, ",");
128 size_t range_count;
129 bool status = android::base::ParseUint(ranges[0], &range_count);
130 if (!status || (range_count == 0) || (range_count % 2 != 0) ||
131 (range_count != ranges.size() - 1)) {
132 LOG(ERROR) << "Error in parsing range string.";
133 return false;
134 }
135
136 size_t blk_count = 0;
137 for (size_t i = 1; i < ranges.size(); i += 2) {
138 unsigned int range_start, range_end;
139 bool parse_status = android::base::ParseUint(ranges[i], &range_start);
140 parse_status = parse_status && android::base::ParseUint(ranges[i + 1], &range_end);
141 if (!parse_status || range_start >= range_end) {
142 LOG(ERROR) << "Invalid range pair " << ranges[i] << ", " << ranges[i + 1];
143 return false;
Tianjie Xud007cf22016-02-29 16:08:06 -0800144 }
145
Tao Bao4f8d2172017-01-13 15:36:32 -0800146 if (lseek64(fd.get(), static_cast<off64_t>(range_start) * BLOCKSIZE, SEEK_SET) == -1) {
147 PLOG(ERROR) << "lseek to " << range_start << " failed";
148 return false;
Tianjie Xud007cf22016-02-29 16:08:06 -0800149 }
150
Tao Bao4f8d2172017-01-13 15:36:32 -0800151 size_t size = (range_end - range_start) * BLOCKSIZE;
152 std::vector<uint8_t> buf(size);
153 if (!android::base::ReadFully(fd.get(), buf.data(), size)) {
154 PLOG(ERROR) << "Failed to read blocks " << range_start << " to " << range_end;
155 return false;
Tianjie Xud007cf22016-02-29 16:08:06 -0800156 }
Tao Bao4f8d2172017-01-13 15:36:32 -0800157 blk_count += (range_end - range_start);
158 }
Tianjie Xud007cf22016-02-29 16:08:06 -0800159
Tianjie Xub0ac8722017-01-18 18:41:53 -0800160 LOG(INFO) << "Finished reading " << blk_count << " blocks on " << dm_block_device;
Tao Bao4f8d2172017-01-13 15:36:32 -0800161 return true;
Tianjie Xud007cf22016-02-29 16:08:06 -0800162}
163
164static bool verify_image(const std::string& care_map_name) {
165 android::base::unique_fd care_map_fd(TEMP_FAILURE_RETRY(open(care_map_name.c_str(), O_RDONLY)));
166 // If the device is flashed before the current boot, it may not have care_map.txt
167 // in /data/ota_package. To allow the device to continue booting in this situation,
168 // we should print a warning and skip the block verification.
169 if (care_map_fd.get() == -1) {
Tom Cherry031f4072017-03-31 17:17:34 -0700170 PLOG(WARNING) << "Failed to open " << care_map_name;
Tianjie Xud007cf22016-02-29 16:08:06 -0800171 return true;
172 }
173 // Care map file has four lines (two lines if vendor partition is not present):
Tianjie Xu253e2232017-03-31 22:27:37 +0000174 // First line has the block partition name (system/vendor).
Tianjie Xud007cf22016-02-29 16:08:06 -0800175 // Second line holds all ranges of blocks to verify.
176 // The next two lines have the same format but for vendor partition.
177 std::string file_content;
178 if (!android::base::ReadFdToString(care_map_fd.get(), &file_content)) {
179 LOG(ERROR) << "Error reading care map contents to string.";
180 return false;
181 }
182
183 std::vector<std::string> lines;
184 lines = android::base::Split(android::base::Trim(file_content), "\n");
185 if (lines.size() != 2 && lines.size() != 4) {
186 LOG(ERROR) << "Invalid lines in care_map: found " << lines.size()
187 << " lines, expecting 2 or 4 lines.";
188 return false;
189 }
190
191 for (size_t i = 0; i < lines.size(); i += 2) {
192 if (!read_blocks(lines[i], lines[i+1])) {
193 return false;
194 }
195 }
196
197 return true;
198}
199
Tianjie Xu253e2232017-03-31 22:27:37 +0000200static int reboot_device() {
201 if (android_reboot(ANDROID_RB_RESTART2, 0, nullptr) == -1) {
202 LOG(ERROR) << "Failed to reboot.";
203 return -1;
204 }
205 while (true) pause();
206}
207
Tao Bao7197ee02015-12-05 21:21:27 -0800208int main(int argc, char** argv) {
Tao Bao7197ee02015-12-05 21:21:27 -0800209 for (int i = 1; i < argc; i++) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700210 LOG(INFO) << "Started with arg " << i << ": " << argv[i];
Tao Bao7197ee02015-12-05 21:21:27 -0800211 }
212
Chris Phoenix0157c782017-01-20 11:34:00 -0800213 sp<IBootControl> module = IBootControl::getService();
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800214 if (module == nullptr) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700215 LOG(ERROR) << "Error getting bootctrl module.";
Tianjie Xu253e2232017-03-31 22:27:37 +0000216 return reboot_device();
Tao Bao7197ee02015-12-05 21:21:27 -0800217 }
218
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800219 uint32_t current_slot = module->getCurrentSlot();
220 BoolResult is_successful = module->isSlotMarkedSuccessful(current_slot);
221 LOG(INFO) << "Booting slot " << current_slot << ": isSlotMarkedSuccessful="
222 << static_cast<int32_t>(is_successful);
Tao Bao7197ee02015-12-05 21:21:27 -0800223
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800224 if (is_successful == BoolResult::FALSE) {
Tao Bao7197ee02015-12-05 21:21:27 -0800225 // The current slot has not booted successfully.
Tao Baodb57f0d2017-03-10 14:21:25 -0800226
227#ifdef PRODUCT_SUPPORTS_VERITY
Tao Bao4f8d2172017-01-13 15:36:32 -0800228 std::string verity_mode = android::base::GetProperty("ro.boot.veritymode", "");
229 if (verity_mode.empty()) {
Tianjie Xud007cf22016-02-29 16:08:06 -0800230 LOG(ERROR) << "Failed to get dm-verity mode.";
Tianjie Xu253e2232017-03-31 22:27:37 +0000231 return reboot_device();
Tao Bao4f8d2172017-01-13 15:36:32 -0800232 } else if (android::base::EqualsIgnoreCase(verity_mode, "eio")) {
Tianjie Xu253e2232017-03-31 22:27:37 +0000233 // We shouldn't see verity in EIO mode if the current slot hasn't booted successfully before.
234 // Continue the verification until we fail to read some blocks.
235 LOG(WARNING) << "Found dm-verity in EIO mode.";
Tao Bao4f8d2172017-01-13 15:36:32 -0800236 } else if (verity_mode != "enforcing") {
Tianjie Xud007cf22016-02-29 16:08:06 -0800237 LOG(ERROR) << "Unexpected dm-verity mode : " << verity_mode << ", expecting enforcing.";
Tianjie Xu253e2232017-03-31 22:27:37 +0000238 return reboot_device();
239 }
240
241 if (!verify_image(CARE_MAP_FILE)) {
Tianjie Xud007cf22016-02-29 16:08:06 -0800242 LOG(ERROR) << "Failed to verify all blocks in care map file.";
Tianjie Xu253e2232017-03-31 22:27:37 +0000243 return reboot_device();
Tianjie Xud007cf22016-02-29 16:08:06 -0800244 }
Tao Baodb57f0d2017-03-10 14:21:25 -0800245#else
246 LOG(WARNING) << "dm-verity not enabled; marking without verification.";
247#endif
Tao Bao7197ee02015-12-05 21:21:27 -0800248
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800249 CommandResult cr;
250 module->markBootSuccessful([&cr](CommandResult result) { cr = result; });
251 if (!cr.success) {
252 LOG(ERROR) << "Error marking booted successfully: " << cr.errMsg;
Tianjie Xu253e2232017-03-31 22:27:37 +0000253 return reboot_device();
Tao Bao7197ee02015-12-05 21:21:27 -0800254 }
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700255 LOG(INFO) << "Marked slot " << current_slot << " as booted successfully.";
Tao Bao7197ee02015-12-05 21:21:27 -0800256 }
257
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700258 LOG(INFO) << "Leaving update_verifier.";
Tao Bao7197ee02015-12-05 21:21:27 -0800259 return 0;
260}