193 lines
7.5 KiB
C++
193 lines
7.5 KiB
C++
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* This program verifies the integrity of the partitions after an A/B OTA
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* update. It gets invoked by init, and will only perform the verification if
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* it's the first boot post an A/B OTA update.
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*
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* It relies on dm-verity to capture any corruption on the partitions being
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* verified. dm-verity must be in enforcing mode, so that it will reboot the
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* device on dm-verity failures. When that happens, the bootloader should
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* mark the slot as unbootable and stops trying. Other dm-verity modes (
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* for example, veritymode=EIO) are not accepted and simply lead to a
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* verification failure.
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*
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* The current slot will be marked as having booted successfully if the
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* verifier reaches the end after the verification.
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*
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*/
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <string.h>
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#include <string>
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#include <vector>
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#include <android-base/file.h>
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#include <android-base/parseint.h>
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#include <android-base/strings.h>
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#include <android-base/unique_fd.h>
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#include <cutils/properties.h>
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#include <hardware/boot_control.h>
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#define LOG_TAG "update_verifier"
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#include <log/log.h>
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constexpr auto CARE_MAP_FILE = "/data/ota_package/care_map.txt";
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constexpr int BLOCKSIZE = 4096;
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static bool read_blocks(const std::string& blk_device_prefix, const std::string& range_str) {
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char slot_suffix[PROPERTY_VALUE_MAX];
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property_get("ro.boot.slot_suffix", slot_suffix, "");
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std::string blk_device = blk_device_prefix + std::string(slot_suffix);
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android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(blk_device.c_str(), O_RDONLY)));
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if (fd.get() == -1) {
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SLOGE("Error reading partition %s: %s\n", blk_device.c_str(), strerror(errno));
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return false;
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}
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// For block range string, first integer 'count' equals 2 * total number of valid ranges,
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// followed by 'count' number comma separated integers. Every two integers reprensent a
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// block range with the first number included in range but second number not included.
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// For example '4,64536,65343,74149,74150' represents: [64536,65343) and [74149,74150).
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std::vector<std::string> ranges = android::base::Split(range_str, ",");
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size_t range_count;
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bool status = android::base::ParseUint(ranges[0].c_str(), &range_count);
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if (!status || (range_count == 0) || (range_count % 2 != 0) ||
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(range_count != ranges.size()-1)) {
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SLOGE("Error in parsing range string.\n");
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return false;
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}
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size_t blk_count = 0;
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for (size_t i = 1; i < ranges.size(); i += 2) {
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unsigned int range_start, range_end;
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bool parse_status = android::base::ParseUint(ranges[i].c_str(), &range_start);
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parse_status = parse_status && android::base::ParseUint(ranges[i+1].c_str(), &range_end);
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if (!parse_status || range_start >= range_end) {
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SLOGE("Invalid range pair %s, %s.\n", ranges[i].c_str(), ranges[i+1].c_str());
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return false;
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}
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if (lseek64(fd.get(), static_cast<off64_t>(range_start) * BLOCKSIZE, SEEK_SET) == -1) {
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SLOGE("lseek to %u failed: %s.\n", range_start, strerror(errno));
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return false;
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}
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size_t size = (range_end - range_start) * BLOCKSIZE;
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std::vector<uint8_t> buf(size);
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if (!android::base::ReadFully(fd.get(), buf.data(), size)) {
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SLOGE("Failed to read blocks %u to %u: %s.\n", range_start, range_end,
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strerror(errno));
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return false;
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}
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blk_count += (range_end - range_start);
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}
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SLOGI("Finished reading %zu blocks on %s.\n", blk_count, blk_device.c_str());
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return true;
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}
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static bool verify_image(const std::string& care_map_name) {
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android::base::unique_fd care_map_fd(TEMP_FAILURE_RETRY(open(care_map_name.c_str(), O_RDONLY)));
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// If the device is flashed before the current boot, it may not have care_map.txt
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// in /data/ota_package. To allow the device to continue booting in this situation,
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// we should print a warning and skip the block verification.
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if (care_map_fd.get() == -1) {
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SLOGI("Warning: care map %s not found.\n", care_map_name.c_str());
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return true;
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}
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// Care map file has four lines (two lines if vendor partition is not present):
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// First line has the block device name, e.g./dev/block/.../by-name/system.
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// Second line holds all ranges of blocks to verify.
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// The next two lines have the same format but for vendor partition.
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std::string file_content;
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if (!android::base::ReadFdToString(care_map_fd.get(), &file_content)) {
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SLOGE("Error reading care map contents to string.\n");
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return false;
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}
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std::vector<std::string> lines;
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lines = android::base::Split(android::base::Trim(file_content), "\n");
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if (lines.size() != 2 && lines.size() != 4) {
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SLOGE("Invalid lines in care_map: found %zu lines, expecting 2 or 4 lines.\n",
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lines.size());
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return false;
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}
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for (size_t i = 0; i < lines.size(); i += 2) {
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if (!read_blocks(lines[i], lines[i+1])) {
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return false;
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}
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}
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return true;
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}
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int main(int argc, char** argv) {
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for (int i = 1; i < argc; i++) {
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SLOGI("Started with arg %d: %s\n", i, argv[i]);
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}
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const hw_module_t* hw_module;
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if (hw_get_module("bootctrl", &hw_module) != 0) {
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SLOGE("Error getting bootctrl module.\n");
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return -1;
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}
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boot_control_module_t* module = reinterpret_cast<boot_control_module_t*>(
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const_cast<hw_module_t*>(hw_module));
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module->init(module);
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unsigned current_slot = module->getCurrentSlot(module);
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int is_successful= module->isSlotMarkedSuccessful(module, current_slot);
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SLOGI("Booting slot %u: isSlotMarkedSuccessful=%d\n", current_slot, is_successful);
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if (is_successful == 0) {
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// The current slot has not booted successfully.
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#ifdef PRODUCT_SUPPORTS_VERITY
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char verity_mode[PROPERTY_VALUE_MAX];
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if (property_get("ro.boot.veritymode", verity_mode, "") == -1) {
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SLOGE("Failed to get dm-verity mode");
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return -1;
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} else if (strcasecmp(verity_mode, "eio") == 0) {
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// We shouldn't see verity in EIO mode if the current slot hasn't booted
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// successfully before. Therefore, fail the verification when veritymode=eio.
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SLOGE("Found dm-verity in EIO mode, skip verification.");
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return -1;
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} else if (strcmp(verity_mode, "enforcing") != 0) {
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SLOGE("Unexpected dm-verity mode : %s, expecting enforcing.", verity_mode);
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return -1;
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} else if (!verify_image(CARE_MAP_FILE)) {
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SLOGE("Failed to verify all blocks in care map file.\n");
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return -1;
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}
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#else
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SLOGI("dm-verity not enabled; marking without verification.\n");
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#endif
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int ret = module->markBootSuccessful(module);
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if (ret != 0) {
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SLOGE("Error marking booted successfully: %s\n", strerror(-ret));
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return -1;
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}
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SLOGI("Marked slot %u as booted successfully.\n", current_slot);
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}
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SLOGI("Leaving update_verifier.\n");
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return 0;
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}
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