/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// This program takes a file on an ext4 filesystem and produces a list
// of the blocks that file occupies, which enables the file contents
// to be read directly from the block device without mounting the
// filesystem.
//
// If the filesystem is using an encrypted block device, it will also
// read the file and rewrite it to the same blocks of the underlying
// (unencrypted) block device, so the file contents can be read
// without the need for the decryption key.
//
// The output of this program is a "block map" which looks like this:
//
// /dev/block/platform/msm_sdcc.1/by-name/userdata # block device
// 49652 4096 # file size in bytes, block size
// 3 # count of block ranges
// 1000 1008 # block range 0
// 2100 2102 # ... block range 1
// 30 33 # ... block range 2
//
// Each block range represents a half-open interval; the line "30 33"
// reprents the blocks [30, 31, 32].
//
// Recovery can take this block map file and retrieve the underlying
// file data to use as an update package.
/**
* In addition to the uncrypt work, uncrypt also takes care of setting and
* clearing the bootloader control block (BCB) at /misc partition.
*
* uncrypt is triggered as init services on demand. It uses socket to
* communicate with its caller (i.e. system_server). The socket is managed by
* init (i.e. created prior to the service starts, and destroyed when uncrypt
* exits).
*
* Below is the uncrypt protocol.
*
* a. caller b. init c. uncrypt
* --------------- ------------ --------------
* a1. ctl.start:
* setup-bcb /
* clear-bcb /
* uncrypt
*
* b2. create socket at
* /dev/socket/uncrypt
*
* c3. listen and accept
*
* a4. send a 4-byte int
* (message length)
* c5. receive message length
* a6. send message
* c7. receive message
* c8. <do the work; may send
* the progress>
* a9. <may handle progress>
* c10. <upon finishing>
* send "100" or "-1"
*
* a11. receive status code
* a12. send a 4-byte int to
* ack the receive of the
* final status code
* c13. receive and exit
*
* b14. destroy the socket
*
* Note that a12 and c13 are necessary to ensure a11 happens before the socket
* gets destroyed in b14.
*/
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <libgen.h>
#include <linux/fs.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <algorithm>
#include <memory>
#include <vector>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <bootloader_message/bootloader_message.h>
#include <cutils/android_reboot.h>
#include <cutils/sockets.h>
#include <fs_mgr.h>
#include "error_code.h"
static constexpr int WINDOW_SIZE = 5;
static constexpr int FIBMAP_RETRY_LIMIT = 3;
// uncrypt provides three services: SETUP_BCB, CLEAR_BCB and UNCRYPT.
//
// SETUP_BCB and CLEAR_BCB services use socket communication and do not rely
// on /cache partitions. They will handle requests to reboot into recovery
// (for applying updates for non-A/B devices, or factory resets for all
// devices).
//
// UNCRYPT service still needs files on /cache partition (UNCRYPT_PATH_FILE
// and CACHE_BLOCK_MAP). It will be working (and needed) only for non-A/B
// devices, on which /cache partitions always exist.
static const std::string CACHE_BLOCK_MAP = "/cache/recovery/block.map";
static const std::string UNCRYPT_PATH_FILE = "/cache/recovery/uncrypt_file";
static const std::string UNCRYPT_STATUS = "/cache/recovery/uncrypt_status";
static const std::string UNCRYPT_SOCKET = "uncrypt";
static struct fstab* fstab = nullptr;
static int write_at_offset(unsigned char* buffer, size_t size, int wfd, off64_t offset) {
if (TEMP_FAILURE_RETRY(lseek64(wfd, offset, SEEK_SET)) == -1) {
PLOG(ERROR) << "error seeking to offset " << offset;
return -1;
}
if (!android::base::WriteFully(wfd, buffer, size)) {
PLOG(ERROR) << "error writing offset " << offset;
return -1;
}
return 0;
}
static void add_block_to_ranges(std::vector<int>& ranges, int new_block) {
if (!ranges.empty() && new_block == ranges.back()) {
// If the new block comes immediately after the current range,
// all we have to do is extend the current range.
++ranges.back();
} else {
// We need to start a new range.
ranges.push_back(new_block);
ranges.push_back(new_block + 1);
}
}
static struct fstab* read_fstab() {
fstab = fs_mgr_read_fstab_default();
if (!fstab) {
LOG(ERROR) << "failed to read default fstab";
return NULL;
}
return fstab;
}
static const char* find_block_device(const char* path, bool* encryptable, bool* encrypted) {
// Look for a volume whose mount point is the prefix of path and
// return its block device. Set encrypted if it's currently
// encrypted.
for (int i = 0; i < fstab->num_entries; ++i) {
struct fstab_rec* v = &fstab->recs[i];
if (!v->mount_point) {
continue;
}
int len = strlen(v->mount_point);
if (strncmp(path, v->mount_point, len) == 0 &&
(path[len] == '/' || path[len] == 0)) {
*encrypted = false;
*encryptable = false;
if (fs_mgr_is_encryptable(v) || fs_mgr_is_file_encrypted(v)) {
*encryptable = true;
if (android::base::GetProperty("ro.crypto.state", "") == "encrypted") {
*encrypted = true;
}
}
return v->blk_device;
}
}
return NULL;
}
static bool write_status_to_socket(int status, int socket) {
// If socket equals -1, uncrypt is in debug mode without socket communication.
// Skip writing and return success.
if (socket == -1) {
return true;
}
int status_out = htonl(status);
return android::base::WriteFully(socket, &status_out, sizeof(int));
}
// Parse uncrypt_file to find the update package name.
static bool find_uncrypt_package(const std::string& uncrypt_path_file, std::string* package_name) {
CHECK(package_name != nullptr);
std::string uncrypt_path;
if (!android::base::ReadFileToString(uncrypt_path_file, &uncrypt_path)) {
PLOG(ERROR) << "failed to open \"" << uncrypt_path_file << "\"";
return false;
}
// Remove the trailing '\n' if present.
*package_name = android::base::Trim(uncrypt_path);
return true;
}
static int retry_fibmap(const int fd, const char* name, int* block, const int head_block) {
CHECK(block != nullptr);
for (size_t i = 0; i < FIBMAP_RETRY_LIMIT; i++) {
if (fsync(fd) == -1) {
PLOG(ERROR) << "failed to fsync \"" << name << "\"";
return kUncryptFileSyncError;
}
if (ioctl(fd, FIBMAP, block) != 0) {
PLOG(ERROR) << "failed to find block " << head_block;
return kUncryptIoctlError;
}
if (*block != 0) {
return kUncryptNoError;
}
sleep(1);
}
LOG(ERROR) << "fibmap of " << head_block << "always returns 0";
return kUncryptIoctlError;
}
static int produce_block_map(const char* path, const char* map_file, const char* blk_dev,
bool encrypted, int socket) {
std::string err;
if (!android::base::RemoveFileIfExists(map_file, &err)) {
LOG(ERROR) << "failed to remove the existing map file " << map_file << ": " << err;
return kUncryptFileRemoveError;
}
std::string tmp_map_file = std::string(map_file) + ".tmp";
android::base::unique_fd mapfd(open(tmp_map_file.c_str(),
O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR));
if (mapfd == -1) {
PLOG(ERROR) << "failed to open " << tmp_map_file;
return kUncryptFileOpenError;
}
// Make sure we can write to the socket.
if (!write_status_to_socket(0, socket)) {
LOG(ERROR) << "failed to write to socket " << socket;
return kUncryptSocketWriteError;
}
struct stat sb;
if (stat(path, &sb) != 0) {
LOG(ERROR) << "failed to stat " << path;
return kUncryptFileStatError;
}
LOG(INFO) << " block size: " << sb.st_blksize << " bytes";
int blocks = ((sb.st_size-1) / sb.st_blksize) + 1;
LOG(INFO) << " file size: " << sb.st_size << " bytes, " << blocks << " blocks";
std::vector<int> ranges;
std::string s = android::base::StringPrintf("%s\n%" PRId64 " %" PRId64 "\n",
blk_dev, static_cast<int64_t>(sb.st_size),
static_cast<int64_t>(sb.st_blksize));
if (!android::base::WriteStringToFd(s, mapfd)) {
PLOG(ERROR) << "failed to write " << tmp_map_file;
return kUncryptWriteError;
}
std::vector<std::vector<unsigned char>> buffers;
if (encrypted) {
buffers.resize(WINDOW_SIZE, std::vector<unsigned char>(sb.st_blksize));
}
int head_block = 0;
int head = 0, tail = 0;
android::base::unique_fd fd(open(path, O_RDONLY));
if (fd == -1) {
PLOG(ERROR) << "failed to open " << path << " for reading";
return kUncryptFileOpenError;
}
android::base::unique_fd wfd;
if (encrypted) {
wfd.reset(open(blk_dev, O_WRONLY));
if (wfd == -1) {
PLOG(ERROR) << "failed to open " << blk_dev << " for writing";
return kUncryptBlockOpenError;
}
}
off64_t pos = 0;
int last_progress = 0;
while (pos < sb.st_size) {
// Update the status file, progress must be between [0, 99].
int progress = static_cast<int>(100 * (double(pos) / double(sb.st_size)));
if (progress > last_progress) {
last_progress = progress;
write_status_to_socket(progress, socket);
}
if ((tail+1) % WINDOW_SIZE == head) {
// write out head buffer
int block = head_block;
if (ioctl(fd, FIBMAP, &block) != 0) {
PLOG(ERROR) << "failed to find block " << head_block;
return kUncryptIoctlError;
}
if (block == 0) {
LOG(ERROR) << "failed to find block " << head_block << ", retrying";
int error = retry_fibmap(fd, path, &block, head_block);
if (error != kUncryptNoError) {
return error;
}
}
add_block_to_ranges(ranges, block);
if (encrypted) {
if (write_at_offset(buffers[head].data(), sb.st_blksize, wfd,
static_cast<off64_t>(sb.st_blksize) * block) != 0) {
return kUncryptWriteError;
}
}
head = (head + 1) % WINDOW_SIZE;
++head_block;
}
// read next block to tail
if (encrypted) {
size_t to_read = static_cast<size_t>(
std::min(static_cast<off64_t>(sb.st_blksize), sb.st_size - pos));
if (!android::base::ReadFully(fd, buffers[tail].data(), to_read)) {
PLOG(ERROR) << "failed to read " << path;
return kUncryptReadError;
}
pos += to_read;
} else {
// If we're not encrypting; we don't need to actually read
// anything, just skip pos forward as if we'd read a
// block.
pos += sb.st_blksize;
}
tail = (tail+1) % WINDOW_SIZE;
}
while (head != tail) {
// write out head buffer
int block = head_block;
if (ioctl(fd, FIBMAP, &block) != 0) {
PLOG(ERROR) << "failed to find block " << head_block;
return kUncryptIoctlError;
}
if (block == 0) {
LOG(ERROR) << "failed to find block " << head_block << ", retrying";
int error = retry_fibmap(fd, path, &block, head_block);
if (error != kUncryptNoError) {
return error;
}
}
add_block_to_ranges(ranges, block);
if (encrypted) {
if (write_at_offset(buffers[head].data(), sb.st_blksize, wfd,
static_cast<off64_t>(sb.st_blksize) * block) != 0) {
return kUncryptWriteError;
}
}
head = (head + 1) % WINDOW_SIZE;
++head_block;
}
if (!android::base::WriteStringToFd(
android::base::StringPrintf("%zu\n", ranges.size() / 2), mapfd)) {
PLOG(ERROR) << "failed to write " << tmp_map_file;
return kUncryptWriteError;
}
for (size_t i = 0; i < ranges.size(); i += 2) {
if (!android::base::WriteStringToFd(
android::base::StringPrintf("%d %d\n", ranges[i], ranges[i+1]), mapfd)) {
PLOG(ERROR) << "failed to write " << tmp_map_file;
return kUncryptWriteError;
}
}
if (fsync(mapfd) == -1) {
PLOG(ERROR) << "failed to fsync \"" << tmp_map_file << "\"";
return kUncryptFileSyncError;
}
if (close(mapfd.release()) == -1) {
PLOG(ERROR) << "failed to close " << tmp_map_file;
return kUncryptFileCloseError;
}
if (encrypted) {
if (fsync(wfd) == -1) {
PLOG(ERROR) << "failed to fsync \"" << blk_dev << "\"";
return kUncryptFileSyncError;
}
if (close(wfd.release()) == -1) {
PLOG(ERROR) << "failed to close " << blk_dev;
return kUncryptFileCloseError;
}
}
if (rename(tmp_map_file.c_str(), map_file) == -1) {
PLOG(ERROR) << "failed to rename " << tmp_map_file << " to " << map_file;
return kUncryptFileRenameError;
}
// Sync dir to make rename() result written to disk.
std::string file_name = map_file;
std::string dir_name = dirname(&file_name[0]);
android::base::unique_fd dfd(open(dir_name.c_str(), O_RDONLY | O_DIRECTORY));
if (dfd == -1) {
PLOG(ERROR) << "failed to open dir " << dir_name;
return kUncryptFileOpenError;
}
if (fsync(dfd) == -1) {
PLOG(ERROR) << "failed to fsync " << dir_name;
return kUncryptFileSyncError;
}
if (close(dfd.release()) == -1) {
PLOG(ERROR) << "failed to close " << dir_name;
return kUncryptFileCloseError;
}
return 0;
}
static int uncrypt(const char* input_path, const char* map_file, const int socket) {
LOG(INFO) << "update package is \"" << input_path << "\"";
// Turn the name of the file we're supposed to convert into an
// absolute path, so we can find what filesystem it's on.
char path[PATH_MAX+1];
if (realpath(input_path, path) == NULL) {
PLOG(ERROR) << "failed to convert \"" << input_path << "\" to absolute path";
return 1;
}
bool encryptable;
bool encrypted;
const char* blk_dev = find_block_device(path, &encryptable, &encrypted);
if (blk_dev == NULL) {
LOG(ERROR) << "failed to find block device for " << path;
return 1;
}
// If the filesystem it's on isn't encrypted, we only produce the
// block map, we don't rewrite the file contents (it would be
// pointless to do so).
LOG(INFO) << "encryptable: " << (encryptable ? "yes" : "no");
LOG(INFO) << " encrypted: " << (encrypted ? "yes" : "no");
// Recovery supports installing packages from 3 paths: /cache,
// /data, and /sdcard. (On a particular device, other locations
// may work, but those are three we actually expect.)
//
// On /data we want to convert the file to a block map so that we
// can read the package without mounting the partition. On /cache
// and /sdcard we leave the file alone.
if (strncmp(path, "/data/", 6) == 0) {
LOG(INFO) << "writing block map " << map_file;
return produce_block_map(path, map_file, blk_dev, encrypted, socket);
}
return 0;
}
static void log_uncrypt_error_code(UncryptErrorCode error_code) {
if (!android::base::WriteStringToFile(android::base::StringPrintf(
"uncrypt_error: %d\n", error_code), UNCRYPT_STATUS)) {
PLOG(WARNING) << "failed to write to " << UNCRYPT_STATUS;
}
}
static bool uncrypt_wrapper(const char* input_path, const char* map_file, const int socket) {
// Initialize the uncrypt error to kUncryptErrorPlaceholder.
log_uncrypt_error_code(kUncryptErrorPlaceholder);
std::string package;
if (input_path == nullptr) {
if (!find_uncrypt_package(UNCRYPT_PATH_FILE, &package)) {
write_status_to_socket(-1, socket);
// Overwrite the error message.
log_uncrypt_error_code(kUncryptPackageMissingError);
return false;
}
input_path = package.c_str();
}
CHECK(map_file != nullptr);
auto start = std::chrono::system_clock::now();
int status = uncrypt(input_path, map_file, socket);
std::chrono::duration<double> duration = std::chrono::system_clock::now() - start;
int count = static_cast<int>(duration.count());
std::string uncrypt_message = android::base::StringPrintf("uncrypt_time: %d\n", count);
if (status != 0) {
// Log the time cost and error code if uncrypt fails.
uncrypt_message += android::base::StringPrintf("uncrypt_error: %d\n", status);
if (!android::base::WriteStringToFile(uncrypt_message, UNCRYPT_STATUS)) {
PLOG(WARNING) << "failed to write to " << UNCRYPT_STATUS;
}
write_status_to_socket(-1, socket);
return false;
}
if (!android::base::WriteStringToFile(uncrypt_message, UNCRYPT_STATUS)) {
PLOG(WARNING) << "failed to write to " << UNCRYPT_STATUS;
}
write_status_to_socket(100, socket);
return true;
}
static bool clear_bcb(const int socket) {
std::string err;
if (!clear_bootloader_message(&err)) {
LOG(ERROR) << "failed to clear bootloader message: " << err;
write_status_to_socket(-1, socket);
return false;
}
write_status_to_socket(100, socket);
return true;
}
static bool setup_bcb(const int socket) {
// c5. receive message length
int length;
if (!android::base::ReadFully(socket, &length, 4)) {
PLOG(ERROR) << "failed to read the length";
return false;
}
length = ntohl(length);
// c7. receive message
std::string content;
content.resize(length);
if (!android::base::ReadFully(socket, &content[0], length)) {
PLOG(ERROR) << "failed to read the message";
return false;
}
LOG(INFO) << " received command: [" << content << "] (" << content.size() << ")";
std::vector<std::string> options = android::base::Split(content, "\n");
std::string wipe_package;
for (auto& option : options) {
if (android::base::StartsWith(option, "--wipe_package=")) {
std::string path = option.substr(strlen("--wipe_package="));
if (!android::base::ReadFileToString(path, &wipe_package)) {
PLOG(ERROR) << "failed to read " << path;
return false;
}
option = android::base::StringPrintf("--wipe_package_size=%zu", wipe_package.size());
}
}
// c8. setup the bcb command
std::string err;
if (!write_bootloader_message(options, &err)) {
LOG(ERROR) << "failed to set bootloader message: " << err;
write_status_to_socket(-1, socket);
return false;
}
if (!wipe_package.empty() && !write_wipe_package(wipe_package, &err)) {
PLOG(ERROR) << "failed to set wipe package: " << err;
write_status_to_socket(-1, socket);
return false;
}
// c10. send "100" status
write_status_to_socket(100, socket);
return true;
}
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 --clear-bcb Clear BCB data in misc partition.\n", exename);
fprintf(stderr, "%s --setup-bcb Setup BCB data by command file.\n", exename);
}
int main(int argc, char** argv) {
enum { UNCRYPT, SETUP_BCB, CLEAR_BCB, UNCRYPT_DEBUG } action;
const char* input_path = nullptr;
const char* map_file = CACHE_BLOCK_MAP.c_str();
if (argc == 2 && strcmp(argv[1], "--clear-bcb") == 0) {
action = CLEAR_BCB;
} else if (argc == 2 && strcmp(argv[1], "--setup-bcb") == 0) {
action = SETUP_BCB;
} else if (argc == 1) {
action = UNCRYPT;
} else if (argc == 3) {
input_path = argv[1];
map_file = argv[2];
action = UNCRYPT_DEBUG;
} else {
usage(argv[0]);
return 2;
}
if ((fstab = read_fstab()) == nullptr) {
log_uncrypt_error_code(kUncryptFstabReadError);
return 1;
}
if (action == UNCRYPT_DEBUG) {
LOG(INFO) << "uncrypt called in debug mode, skip socket communication";
bool success = uncrypt_wrapper(input_path, map_file, -1);
if (success) {
LOG(INFO) << "uncrypt succeeded";
} else{
LOG(INFO) << "uncrypt failed";
}
return success ? 0 : 1;
}
// c3. The socket is created by init when starting the service. uncrypt
// will use the socket to communicate with its caller.
android::base::unique_fd service_socket(android_get_control_socket(UNCRYPT_SOCKET.c_str()));
if (service_socket == -1) {
PLOG(ERROR) << "failed to open socket \"" << UNCRYPT_SOCKET << "\"";
log_uncrypt_error_code(kUncryptSocketOpenError);
return 1;
}
fcntl(service_socket, F_SETFD, FD_CLOEXEC);
if (listen(service_socket, 1) == -1) {
PLOG(ERROR) << "failed to listen on socket " << service_socket.get();
log_uncrypt_error_code(kUncryptSocketListenError);
return 1;
}
android::base::unique_fd socket_fd(accept4(service_socket, nullptr, nullptr, SOCK_CLOEXEC));
if (socket_fd == -1) {
PLOG(ERROR) << "failed to accept on socket " << service_socket.get();
log_uncrypt_error_code(kUncryptSocketAcceptError);
return 1;
}
bool success = false;
switch (action) {
case UNCRYPT:
success = uncrypt_wrapper(input_path, map_file, socket_fd);
break;
case SETUP_BCB:
success = setup_bcb(socket_fd);
break;
case CLEAR_BCB:
success = clear_bcb(socket_fd);
break;
default: // Should never happen.
LOG(ERROR) << "Invalid uncrypt action code: " << action;
return 1;
}
// c13. Read a 4-byte code from the client before uncrypt exits. This is to
// ensure the client to receive the last status code before the socket gets
// destroyed.
int code;
if (android::base::ReadFully(socket_fd, &code, 4)) {
LOG(INFO) << " received " << code << ", exiting now";
} else {
PLOG(ERROR) << "failed to read the code";
}
return success ? 0 : 1;
}