574 lines
20 KiB
C++
574 lines
20 KiB
C++
/*
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* Copyright (C) 2014 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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// This program takes a file on an ext4 filesystem and produces a list
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// of the blocks that file occupies, which enables the file contents
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// to be read directly from the block device without mounting the
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// filesystem.
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//
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// If the filesystem is using an encrypted block device, it will also
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// read the file and rewrite it to the same blocks of the underlying
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// (unencrypted) block device, so the file contents can be read
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// without the need for the decryption key.
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//
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// The output of this program is a "block map" which looks like this:
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//
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// /dev/block/platform/msm_sdcc.1/by-name/userdata # block device
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// 49652 4096 # file size in bytes, block size
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// 3 # count of block ranges
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// 1000 1008 # block range 0
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// 2100 2102 # ... block range 1
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// 30 33 # ... block range 2
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//
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// Each block range represents a half-open interval; the line "30 33"
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// reprents the blocks [30, 31, 32].
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//
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// Recovery can take this block map file and retrieve the underlying
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// file data to use as an update package.
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#include <errno.h>
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#include <fcntl.h>
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#include <inttypes.h>
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#include <libgen.h>
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#include <linux/fs.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <algorithm>
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#include <memory>
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#include <vector>
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#include <android-base/file.h>
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#include <android-base/logging.h>
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#include <android-base/stringprintf.h>
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#include <android-base/strings.h>
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#include <cutils/android_reboot.h>
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#include <cutils/properties.h>
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#include <fs_mgr.h>
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#define LOG_TAG "uncrypt"
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#include <log/log.h>
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#include "bootloader.h"
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#include "unique_fd.h"
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#define WINDOW_SIZE 5
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static const std::string CACHE_BLOCK_MAP = "/cache/recovery/block.map";
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static const std::string COMMAND_FILE = "/cache/recovery/command";
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static const std::string STATUS_FILE = "/cache/recovery/uncrypt_status";
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static const std::string UNCRYPT_PATH_FILE = "/cache/recovery/uncrypt_file";
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static struct fstab* fstab = NULL;
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static int write_at_offset(unsigned char* buffer, size_t size, int wfd, off64_t offset) {
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if (TEMP_FAILURE_RETRY(lseek64(wfd, offset, SEEK_SET)) == -1) {
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ALOGE("error seeking to offset %" PRId64 ": %s", offset, strerror(errno));
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return -1;
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}
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if (!android::base::WriteFully(wfd, buffer, size)) {
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ALOGE("error writing offset %" PRId64 ": %s", offset, strerror(errno));
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return -1;
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}
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return 0;
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}
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static void add_block_to_ranges(std::vector<int>& ranges, int new_block) {
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if (!ranges.empty() && new_block == ranges.back()) {
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// If the new block comes immediately after the current range,
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// all we have to do is extend the current range.
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++ranges.back();
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} else {
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// We need to start a new range.
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ranges.push_back(new_block);
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ranges.push_back(new_block + 1);
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}
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}
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static struct fstab* read_fstab() {
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fstab = NULL;
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// The fstab path is always "/fstab.${ro.hardware}".
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char fstab_path[PATH_MAX+1] = "/fstab.";
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if (!property_get("ro.hardware", fstab_path+strlen(fstab_path), "")) {
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ALOGE("failed to get ro.hardware");
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return NULL;
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}
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fstab = fs_mgr_read_fstab(fstab_path);
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if (!fstab) {
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ALOGE("failed to read %s", fstab_path);
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return NULL;
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}
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return fstab;
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}
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static const char* find_block_device(const char* path, bool* encryptable, bool* encrypted) {
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// Look for a volume whose mount point is the prefix of path and
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// return its block device. Set encrypted if it's currently
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// encrypted.
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for (int i = 0; i < fstab->num_entries; ++i) {
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struct fstab_rec* v = &fstab->recs[i];
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if (!v->mount_point) {
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continue;
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}
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int len = strlen(v->mount_point);
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if (strncmp(path, v->mount_point, len) == 0 &&
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(path[len] == '/' || path[len] == 0)) {
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*encrypted = false;
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*encryptable = false;
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if (fs_mgr_is_encryptable(v) || fs_mgr_is_file_encrypted(v)) {
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*encryptable = true;
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char buffer[PROPERTY_VALUE_MAX+1];
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if (property_get("ro.crypto.state", buffer, "") &&
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strcmp(buffer, "encrypted") == 0) {
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*encrypted = true;
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}
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}
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return v->blk_device;
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}
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}
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return NULL;
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}
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// Parse uncrypt_file to find the update package name.
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static bool find_uncrypt_package(const std::string& uncrypt_path_file, std::string* package_name) {
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CHECK(package_name != nullptr);
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std::string uncrypt_path;
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if (!android::base::ReadFileToString(uncrypt_path_file, &uncrypt_path)) {
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ALOGE("failed to open \"%s\": %s", uncrypt_path_file.c_str(), strerror(errno));
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return false;
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}
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// Remove the trailing '\n' if present.
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*package_name = android::base::Trim(uncrypt_path);
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return true;
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}
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static int produce_block_map(const char* path, const char* map_file, const char* blk_dev,
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bool encrypted, int status_fd) {
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std::string err;
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if (!android::base::RemoveFileIfExists(map_file, &err)) {
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ALOGE("failed to remove the existing map file %s: %s", map_file, err.c_str());
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return -1;
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}
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std::string tmp_map_file = std::string(map_file) + ".tmp";
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unique_fd mapfd(open(tmp_map_file.c_str(), O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR));
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if (!mapfd) {
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ALOGE("failed to open %s: %s\n", tmp_map_file.c_str(), strerror(errno));
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return -1;
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}
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// Make sure we can write to the status_file.
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if (!android::base::WriteStringToFd("0\n", status_fd)) {
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ALOGE("failed to update \"%s\"\n", STATUS_FILE.c_str());
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return -1;
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}
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struct stat sb;
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if (stat(path, &sb) != 0) {
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ALOGE("failed to stat %s", path);
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return -1;
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}
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ALOGI(" block size: %ld bytes", static_cast<long>(sb.st_blksize));
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int blocks = ((sb.st_size-1) / sb.st_blksize) + 1;
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ALOGI(" file size: %" PRId64 " bytes, %d blocks", sb.st_size, blocks);
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std::vector<int> ranges;
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std::string s = android::base::StringPrintf("%s\n%" PRId64 " %ld\n",
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blk_dev, sb.st_size, static_cast<long>(sb.st_blksize));
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if (!android::base::WriteStringToFd(s, mapfd.get())) {
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ALOGE("failed to write %s: %s", tmp_map_file.c_str(), strerror(errno));
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return -1;
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}
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std::vector<std::vector<unsigned char>> buffers;
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if (encrypted) {
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buffers.resize(WINDOW_SIZE, std::vector<unsigned char>(sb.st_blksize));
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}
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int head_block = 0;
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int head = 0, tail = 0;
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unique_fd fd(open(path, O_RDONLY));
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if (!fd) {
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ALOGE("failed to open %s for reading: %s", path, strerror(errno));
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return -1;
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}
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unique_fd wfd(-1);
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if (encrypted) {
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wfd = open(blk_dev, O_WRONLY);
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if (!wfd) {
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ALOGE("failed to open fd for writing: %s", strerror(errno));
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return -1;
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}
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}
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off64_t pos = 0;
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int last_progress = 0;
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while (pos < sb.st_size) {
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// Update the status file, progress must be between [0, 99].
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int progress = static_cast<int>(100 * (double(pos) / double(sb.st_size)));
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if (progress > last_progress) {
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last_progress = progress;
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android::base::WriteStringToFd(std::to_string(progress) + "\n", status_fd);
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}
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if ((tail+1) % WINDOW_SIZE == head) {
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// write out head buffer
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int block = head_block;
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if (ioctl(fd.get(), FIBMAP, &block) != 0) {
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ALOGE("failed to find block %d", head_block);
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return -1;
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}
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add_block_to_ranges(ranges, block);
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if (encrypted) {
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if (write_at_offset(buffers[head].data(), sb.st_blksize, wfd.get(),
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static_cast<off64_t>(sb.st_blksize) * block) != 0) {
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return -1;
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}
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}
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head = (head + 1) % WINDOW_SIZE;
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++head_block;
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}
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// read next block to tail
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if (encrypted) {
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size_t to_read = static_cast<size_t>(
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std::min(static_cast<off64_t>(sb.st_blksize), sb.st_size - pos));
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if (!android::base::ReadFully(fd.get(), buffers[tail].data(), to_read)) {
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ALOGE("failed to read: %s", strerror(errno));
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return -1;
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}
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pos += to_read;
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} else {
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// If we're not encrypting; we don't need to actually read
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// anything, just skip pos forward as if we'd read a
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// block.
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pos += sb.st_blksize;
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}
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tail = (tail+1) % WINDOW_SIZE;
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}
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while (head != tail) {
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// write out head buffer
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int block = head_block;
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if (ioctl(fd.get(), FIBMAP, &block) != 0) {
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ALOGE("failed to find block %d", head_block);
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return -1;
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}
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add_block_to_ranges(ranges, block);
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if (encrypted) {
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if (write_at_offset(buffers[head].data(), sb.st_blksize, wfd.get(),
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static_cast<off64_t>(sb.st_blksize) * block) != 0) {
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return -1;
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}
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}
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head = (head + 1) % WINDOW_SIZE;
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++head_block;
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}
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if (!android::base::WriteStringToFd(
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android::base::StringPrintf("%zu\n", ranges.size() / 2), mapfd.get())) {
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ALOGE("failed to write %s: %s", tmp_map_file.c_str(), strerror(errno));
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return -1;
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}
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for (size_t i = 0; i < ranges.size(); i += 2) {
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if (!android::base::WriteStringToFd(
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android::base::StringPrintf("%d %d\n", ranges[i], ranges[i+1]), mapfd.get())) {
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ALOGE("failed to write %s: %s", tmp_map_file.c_str(), strerror(errno));
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return -1;
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}
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}
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if (fsync(mapfd.get()) == -1) {
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ALOGE("failed to fsync \"%s\": %s", tmp_map_file.c_str(), strerror(errno));
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return -1;
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}
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if (close(mapfd.get() == -1)) {
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ALOGE("failed to close %s: %s", tmp_map_file.c_str(), strerror(errno));
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return -1;
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}
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mapfd = -1;
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if (encrypted) {
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if (fsync(wfd.get()) == -1) {
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ALOGE("failed to fsync \"%s\": %s", blk_dev, strerror(errno));
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return -1;
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}
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if (close(wfd.get()) == -1) {
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ALOGE("failed to close %s: %s", blk_dev, strerror(errno));
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return -1;
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}
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wfd = -1;
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}
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if (rename(tmp_map_file.c_str(), map_file) == -1) {
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ALOGE("failed to rename %s to %s: %s", tmp_map_file.c_str(), map_file, strerror(errno));
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return -1;
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}
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// Sync dir to make rename() result written to disk.
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std::string file_name = map_file;
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std::string dir_name = dirname(&file_name[0]);
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unique_fd dfd(open(dir_name.c_str(), O_RDONLY | O_DIRECTORY));
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if (!dfd) {
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ALOGE("failed to open dir %s: %s", dir_name.c_str(), strerror(errno));
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return -1;
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}
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if (fsync(dfd.get()) == -1) {
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ALOGE("failed to fsync %s: %s", dir_name.c_str(), strerror(errno));
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return -1;
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}
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if (close(dfd.get() == -1)) {
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ALOGE("failed to close %s: %s", dir_name.c_str(), strerror(errno));
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return -1;
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}
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dfd = -1;
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return 0;
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}
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static std::string get_misc_blk_device() {
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struct fstab* fstab = read_fstab();
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if (fstab == nullptr) {
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return "";
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}
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for (int i = 0; i < fstab->num_entries; ++i) {
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fstab_rec* v = &fstab->recs[i];
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if (v->mount_point != nullptr && strcmp(v->mount_point, "/misc") == 0) {
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return v->blk_device;
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}
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}
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return "";
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}
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static int read_bootloader_message(bootloader_message* out) {
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std::string misc_blk_device = get_misc_blk_device();
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if (misc_blk_device.empty()) {
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ALOGE("failed to find /misc partition.");
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return -1;
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}
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unique_fd fd(open(misc_blk_device.c_str(), O_RDONLY));
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if (!fd) {
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ALOGE("failed to open %s: %s", misc_blk_device.c_str(), strerror(errno));
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return -1;
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}
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if (!android::base::ReadFully(fd.get(), out, sizeof(*out))) {
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ALOGE("failed to read %s: %s", misc_blk_device.c_str(), strerror(errno));
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return -1;
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}
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return 0;
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}
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static int write_bootloader_message(const bootloader_message* in) {
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std::string misc_blk_device = get_misc_blk_device();
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if (misc_blk_device.empty()) {
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ALOGE("failed to find /misc partition.");
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return -1;
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}
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unique_fd fd(open(misc_blk_device.c_str(), O_WRONLY | O_SYNC));
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if (!fd) {
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ALOGE("failed to open %s: %s", misc_blk_device.c_str(), strerror(errno));
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return -1;
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}
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if (!android::base::WriteFully(fd.get(), in, sizeof(*in))) {
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ALOGE("failed to write %s: %s", misc_blk_device.c_str(), strerror(errno));
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return -1;
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}
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// TODO: O_SYNC and fsync() duplicates each other?
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if (fsync(fd.get()) == -1) {
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ALOGE("failed to fsync %s: %s", misc_blk_device.c_str(), strerror(errno));
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return -1;
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}
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return 0;
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}
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static void reboot_to_recovery() {
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ALOGI("rebooting to recovery");
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property_set("sys.powerctl", "reboot,recovery");
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while (true) {
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pause();
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}
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ALOGE("reboot didn't succeed?");
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}
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static int uncrypt(const char* input_path, const char* map_file, int status_fd) {
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ALOGI("update package is \"%s\"", input_path);
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// Turn the name of the file we're supposed to convert into an
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// absolute path, so we can find what filesystem it's on.
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char path[PATH_MAX+1];
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if (realpath(input_path, path) == NULL) {
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ALOGE("failed to convert \"%s\" to absolute path: %s", input_path, strerror(errno));
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return 1;
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}
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if (read_fstab() == NULL) {
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return 1;
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}
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bool encryptable;
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bool encrypted;
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const char* blk_dev = find_block_device(path, &encryptable, &encrypted);
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if (blk_dev == NULL) {
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ALOGE("failed to find block device for %s", path);
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return 1;
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}
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// If the filesystem it's on isn't encrypted, we only produce the
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// block map, we don't rewrite the file contents (it would be
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// pointless to do so).
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ALOGI("encryptable: %s", encryptable ? "yes" : "no");
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ALOGI(" encrypted: %s", encrypted ? "yes" : "no");
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// Recovery supports installing packages from 3 paths: /cache,
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// /data, and /sdcard. (On a particular device, other locations
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// may work, but those are three we actually expect.)
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//
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// On /data we want to convert the file to a block map so that we
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// can read the package without mounting the partition. On /cache
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// and /sdcard we leave the file alone.
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if (strncmp(path, "/data/", 6) == 0) {
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ALOGI("writing block map %s", map_file);
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if (produce_block_map(path, map_file, blk_dev, encrypted, status_fd) != 0) {
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return 1;
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}
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}
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return 0;
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}
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static int uncrypt_wrapper(const char* input_path, const char* map_file,
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const std::string& status_file) {
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// The pipe has been created by the system server.
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unique_fd status_fd(open(status_file.c_str(), O_WRONLY | O_CREAT | O_SYNC, S_IRUSR | S_IWUSR));
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if (!status_fd) {
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ALOGE("failed to open pipe \"%s\": %s", status_file.c_str(), strerror(errno));
|
|
return 1;
|
|
}
|
|
|
|
std::string package;
|
|
if (input_path == nullptr) {
|
|
if (!find_uncrypt_package(UNCRYPT_PATH_FILE, &package)) {
|
|
android::base::WriteStringToFd("-1\n", status_fd.get());
|
|
return 1;
|
|
}
|
|
input_path = package.c_str();
|
|
}
|
|
CHECK(map_file != nullptr);
|
|
int status = uncrypt(input_path, map_file, status_fd.get());
|
|
if (status != 0) {
|
|
android::base::WriteStringToFd("-1\n", status_fd.get());
|
|
return 1;
|
|
}
|
|
android::base::WriteStringToFd("100\n", status_fd.get());
|
|
return 0;
|
|
}
|
|
|
|
static int clear_bcb(const std::string& status_file) {
|
|
unique_fd status_fd(open(status_file.c_str(), O_WRONLY | O_CREAT | O_SYNC, S_IRUSR | S_IWUSR));
|
|
if (!status_fd) {
|
|
ALOGE("failed to open pipe \"%s\": %s", status_file.c_str(), strerror(errno));
|
|
return 1;
|
|
}
|
|
bootloader_message boot = {};
|
|
if (write_bootloader_message(&boot) != 0) {
|
|
android::base::WriteStringToFd("-1\n", status_fd.get());
|
|
return 1;
|
|
}
|
|
android::base::WriteStringToFd("100\n", status_fd.get());
|
|
return 0;
|
|
}
|
|
|
|
static int setup_bcb(const std::string& command_file, const std::string& status_file) {
|
|
unique_fd status_fd(open(status_file.c_str(), O_WRONLY | O_CREAT | O_SYNC, S_IRUSR | S_IWUSR));
|
|
if (!status_fd) {
|
|
ALOGE("failed to open pipe \"%s\": %s", status_file.c_str(), strerror(errno));
|
|
return 1;
|
|
}
|
|
std::string content;
|
|
if (!android::base::ReadFileToString(command_file, &content)) {
|
|
ALOGE("failed to read \"%s\": %s", command_file.c_str(), strerror(errno));
|
|
android::base::WriteStringToFd("-1\n", status_fd.get());
|
|
return 1;
|
|
}
|
|
bootloader_message boot = {};
|
|
strlcpy(boot.command, "boot-recovery", sizeof(boot.command));
|
|
strlcpy(boot.recovery, "recovery\n", sizeof(boot.recovery));
|
|
strlcat(boot.recovery, content.c_str(), sizeof(boot.recovery));
|
|
if (write_bootloader_message(&boot) != 0) {
|
|
ALOGE("failed to set bootloader message");
|
|
android::base::WriteStringToFd("-1\n", status_fd.get());
|
|
return 1;
|
|
}
|
|
android::base::WriteStringToFd("100\n", status_fd.get());
|
|
return 0;
|
|
}
|
|
|
|
static int read_bcb() {
|
|
bootloader_message boot;
|
|
if (read_bootloader_message(&boot) != 0) {
|
|
ALOGE("failed to get bootloader message");
|
|
return 1;
|
|
}
|
|
printf("bcb command: %s\n", boot.command);
|
|
printf("bcb recovery:\n%s\n", boot.recovery);
|
|
return 0;
|
|
}
|
|
|
|
static void usage(const char* exename) {
|
|
fprintf(stderr, "Usage of %s:\n", exename);
|
|
fprintf(stderr, "%s [<package_path> <map_file>] Uncrypt ota package.\n", exename);
|
|
fprintf(stderr, "%s --reboot Clear BCB data and reboot to recovery.\n", exename);
|
|
fprintf(stderr, "%s --clear-bcb Clear BCB data in misc partition.\n", exename);
|
|
fprintf(stderr, "%s --setup-bcb Setup BCB data by command file.\n", exename);
|
|
fprintf(stderr, "%s --read-bcb Read BCB data from misc partition.\n", exename);
|
|
}
|
|
|
|
int main(int argc, char** argv) {
|
|
if (argc == 2) {
|
|
if (strcmp(argv[1], "--reboot") == 0) {
|
|
reboot_to_recovery();
|
|
} else if (strcmp(argv[1], "--clear-bcb") == 0) {
|
|
return clear_bcb(STATUS_FILE);
|
|
} else if (strcmp(argv[1], "--setup-bcb") == 0) {
|
|
return setup_bcb(COMMAND_FILE, STATUS_FILE);
|
|
} else if (strcmp(argv[1], "--read-bcb") == 0) {
|
|
return read_bcb();
|
|
}
|
|
} else if (argc == 1 || argc == 3) {
|
|
const char* input_path = nullptr;
|
|
const char* map_file = CACHE_BLOCK_MAP.c_str();
|
|
if (argc == 3) {
|
|
input_path = argv[1];
|
|
map_file = argv[2];
|
|
}
|
|
return uncrypt_wrapper(input_path, map_file, STATUS_FILE);
|
|
}
|
|
usage(argv[0]);
|
|
return 2;
|
|
}
|