Touch blocks in care_map in update_verifier

LOCAL_CLANG := true

LOCAL_SRC_FILES := update_verifier.cpp

LOCAL_MODULE := update_verifier

LOCAL_SHARED_LIBRARIES := libhardware libbase

LOCAL_SHARED_LIBRARIES := \

    libbase \

    libcutils \

    libhardware \

    liblog

LOCAL_CFLAGS := -Werror

LOCAL_C_INCLUDES += $(LOCAL_PATH)/..

include $(BUILD_EXECUTABLE)

 * It relies on dm-verity to capture any corruption on the partitions being

 * verified. dm-verity must be in enforcing mode, so that it will reboot the

 * device on dm-verity failures. When that happens, the bootloader should

 * mark the slot as unbootable and stops trying. We should never see a device

 * started in dm-verity logging mode but with isSlotMarkedSuccessful equals to

 * 0.

 * mark the slot as unbootable and stops trying. Other dm-verity modes (

 * for example, veritymode=EIO) are not accepted and simply lead to a

 * verification failure.

 *

 * The current slot will be marked as having booted successfully if the

 * verifier reaches the end after the verification.

 *

 * TODO: The actual verification part will be added later after we have the

 * A/B OTA package format in place.

 */

#include <errno.h>

#include <fcntl.h>

#include <stdio.h>

#include <string.h>

#include <string>

#include <vector>

#include <android-base/file.h>

#include <android-base/logging.h>

#include <android-base/parseint.h>

#include <android-base/strings.h>

#include <android-base/unique_fd.h>

#include <cutils/properties.h>

#include <hardware/boot_control.h>

constexpr auto CARE_MAP_FILE = "/data/ota_package/care_map.txt";

constexpr int BLOCKSIZE = 4096;

static bool read_blocks(const std::string& blk_device_prefix, const std::string& range_str) {

    char slot_suffix[PROPERTY_VALUE_MAX];

    property_get("ro.boot.slot_suffix", slot_suffix, "");

    std::string blk_device = blk_device_prefix + std::string(slot_suffix);

    android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(blk_device.c_str(), O_RDONLY)));

    if (fd.get() == -1) {

        PLOG(ERROR) << "Error reading partition " << blk_device;

        return false;

    }

    // For block range string, first integer 'count' equals 2 * total number of valid ranges,

    // followed by 'count' number comma separated integers. Every two integers reprensent a

    // block range with the first number included in range but second number not included.

    // For example '4,64536,65343,74149,74150' represents: [64536,65343) and [74149,74150).

    std::vector<std::string> ranges = android::base::Split(range_str, ",");

    size_t range_count;

    bool status = android::base::ParseUint(ranges[0].c_str(), &range_count);

    if (!status || (range_count == 0) || (range_count % 2 != 0) ||

            (range_count != ranges.size()-1)) {

        LOG(ERROR) << "Error in parsing range string.";

        return false;

    }

    size_t blk_count = 0;

    for (size_t i = 1; i < ranges.size(); i += 2) {

        unsigned int range_start, range_end;

        bool parse_status = android::base::ParseUint(ranges[i].c_str(), &range_start);

        parse_status = parse_status && android::base::ParseUint(ranges[i+1].c_str(), &range_end);

        if (!parse_status || range_start >= range_end) {

            LOG(ERROR) << "Invalid range pair " << ranges[i] << ", " << ranges[i+1];

            return false;

        }

        if (lseek64(fd.get(), static_cast<off64_t>(range_start) * BLOCKSIZE, SEEK_SET) == -1) {

            PLOG(ERROR) << "lseek to " << range_start << " failed";

            return false;

        }

        size_t size = (range_end - range_start) * BLOCKSIZE;

        std::vector<uint8_t> buf(size);

        if (!android::base::ReadFully(fd.get(), buf.data(), size)) {

            PLOG(ERROR) << "Failed to read blocks " << range_start << " to " << range_end;

            return false;

        }

        blk_count += (range_end - range_start);

    }

    LOG(INFO) << "Finished reading " << blk_count << " blocks on " << blk_device;

    return true;

}

static bool verify_image(const std::string& care_map_name) {

    android::base::unique_fd care_map_fd(TEMP_FAILURE_RETRY(open(care_map_name.c_str(), O_RDONLY)));

    // If the device is flashed before the current boot, it may not have care_map.txt

    // in /data/ota_package. To allow the device to continue booting in this situation,

    // we should print a warning and skip the block verification.

    if (care_map_fd.get() == -1) {

        LOG(WARNING) << "Warning: care map " << care_map_name << " not found.";

        return true;

    }

    // Care map file has four lines (two lines if vendor partition is not present):

    // First line has the block device name, e.g./dev/block/.../by-name/system.

    // Second line holds all ranges of blocks to verify.

    // The next two lines have the same format but for vendor partition.

    std::string file_content;

    if (!android::base::ReadFdToString(care_map_fd.get(), &file_content)) {

        LOG(ERROR) << "Error reading care map contents to string.";

        return false;

    }

    std::vector<std::string> lines;

    lines = android::base::Split(android::base::Trim(file_content), "\n");

    if (lines.size() != 2 && lines.size() != 4) {

        LOG(ERROR) << "Invalid lines in care_map: found " << lines.size()

                   << " lines, expecting 2 or 4 lines.";

        return false;

    }

    for (size_t i = 0; i < lines.size(); i += 2) {

        if (!read_blocks(lines[i], lines[i+1])) {

            return false;

        }

    }

    return true;

}

int main(int argc, char** argv) {

  for (int i = 1; i < argc; i++) {

    LOG(INFO) << "Started with arg " << i << ": " << argv[i];

  if (is_successful == 0) {

    // The current slot has not booted successfully.

    // TODO: Add the actual verification after we have the A/B OTA package

    // format in place.

    // TODO: Assert the dm-verity mode. Bootloader should never boot a newly

    // flashed slot (isSlotMarkedSuccessful == 0) with dm-verity logging mode.

    char verity_mode[PROPERTY_VALUE_MAX];

    if (property_get("ro.boot.veritymode", verity_mode, "") == -1) {

      LOG(ERROR) << "Failed to get dm-verity mode.";

      return -1;

    } else if (strcasecmp(verity_mode, "eio") == 0) {

      // We shouldn't see verity in EIO mode if the current slot hasn't booted

      // successfully before. Therefore, fail the verification when veritymode=eio.

      LOG(ERROR) << "Found dm-verity in EIO mode, skip verification.";

      return -1;

    } else if (strcmp(verity_mode, "enforcing") != 0) {

      LOG(ERROR) << "Unexpected dm-verity mode : " << verity_mode << ", expecting enforcing.";

      return -1;

    } else if (!verify_image(CARE_MAP_FILE)) {

      LOG(ERROR) << "Failed to verify all blocks in care map file.";

      return -1;

    }

    int ret = module->markBootSuccessful(module);

    if (ret != 0) {