| /* |
| * 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. |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <linux/fs.h> |
| #include <stdarg.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/mman.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| |
| #include <memory> |
| |
| #include <base/file.h> |
| #include <base/strings.h> |
| #include <cutils/android_reboot.h> |
| #include <cutils/properties.h> |
| #include <fs_mgr.h> |
| |
| #define LOG_TAG "uncrypt" |
| #include <log/log.h> |
| |
| #include "unique_fd.h" |
| |
| #define WINDOW_SIZE 5 |
| |
| static const std::string cache_block_map = "/cache/recovery/block.map"; |
| static const std::string status_file = "/cache/recovery/uncrypt_status"; |
| static const std::string uncrypt_file = "/cache/recovery/uncrypt_file"; |
| |
| static struct fstab* fstab = NULL; |
| |
| 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) { |
| ALOGE("error seeking to offset %lld: %s\n", offset, strerror(errno)); |
| return -1; |
| } |
| size_t written = 0; |
| while (written < size) { |
| ssize_t wrote = TEMP_FAILURE_RETRY(write(wfd, buffer + written, size - written)); |
| if (wrote == -1) { |
| ALOGE("error writing offset %lld: %s\n", (offset + written), strerror(errno)); |
| return -1; |
| } |
| written += wrote; |
| } |
| return 0; |
| } |
| |
| static void add_block_to_ranges(int** ranges, int* range_alloc, int* range_used, int new_block) { |
| // If the current block start is < 0, set the start to the new |
| // block. (This only happens for the very first block of the very |
| // first range.) |
| if ((*ranges)[*range_used*2-2] < 0) { |
| (*ranges)[*range_used*2-2] = new_block; |
| (*ranges)[*range_used*2-1] = new_block; |
| } |
| |
| if (new_block == (*ranges)[*range_used*2-1]) { |
| // If the new block comes immediately after the current range, |
| // all we have to do is extend the current range. |
| ++(*ranges)[*range_used*2-1]; |
| } else { |
| // We need to start a new range. |
| |
| // If there isn't enough room in the array, we need to expand it. |
| if (*range_used >= *range_alloc) { |
| *range_alloc *= 2; |
| *ranges = reinterpret_cast<int*>(realloc(*ranges, *range_alloc * 2 * sizeof(int))); |
| } |
| |
| ++*range_used; |
| (*ranges)[*range_used*2-2] = new_block; |
| (*ranges)[*range_used*2-1] = new_block+1; |
| } |
| } |
| |
| static struct fstab* read_fstab() { |
| fstab = NULL; |
| |
| // The fstab path is always "/fstab.${ro.hardware}". |
| char fstab_path[PATH_MAX+1] = "/fstab."; |
| if (!property_get("ro.hardware", fstab_path+strlen(fstab_path), "")) { |
| ALOGE("failed to get ro.hardware\n"); |
| return NULL; |
| } |
| |
| fstab = fs_mgr_read_fstab(fstab_path); |
| if (!fstab) { |
| ALOGE("failed to read %s\n", fstab_path); |
| 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; |
| char buffer[PROPERTY_VALUE_MAX+1]; |
| if (property_get("ro.crypto.state", buffer, "") && |
| strcmp(buffer, "encrypted") == 0) { |
| *encrypted = true; |
| } |
| } |
| return v->blk_device; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| // Parse uncrypt_file to find the update package name. |
| static bool find_uncrypt_package(std::string& package_name) |
| { |
| if (!android::base::ReadFileToString(uncrypt_file, &package_name)) { |
| ALOGE("failed to open \"%s\": %s\n", uncrypt_file.c_str(), strerror(errno)); |
| return false; |
| } |
| |
| // Remove the trailing '\n' if present. |
| package_name = android::base::Trim(package_name); |
| |
| return true; |
| } |
| |
| static int produce_block_map(const char* path, const char* map_file, const char* blk_dev, |
| bool encrypted, int status_fd) { |
| int mapfd = open(map_file, O_WRONLY | O_CREAT | O_SYNC, S_IRUSR | S_IWUSR); |
| if (mapfd == -1) { |
| ALOGE("failed to open %s\n", map_file); |
| return -1; |
| } |
| FILE* mapf = fdopen(mapfd, "w"); |
| unique_file mapf_holder(mapf); |
| |
| // Make sure we can write to the status_file. |
| if (!android::base::WriteStringToFd("0\n", status_fd)) { |
| ALOGE("failed to update \"%s\"\n", status_file.c_str()); |
| return -1; |
| } |
| |
| struct stat sb; |
| if (stat(path, &sb) != 0) { |
| ALOGE("failed to stat %s\n", path); |
| return -1; |
| } |
| |
| ALOGI(" block size: %ld bytes\n", (long)sb.st_blksize); |
| |
| int blocks = ((sb.st_size-1) / sb.st_blksize) + 1; |
| ALOGI(" file size: %lld bytes, %d blocks\n", (long long)sb.st_size, blocks); |
| |
| int range_alloc = 1; |
| int range_used = 1; |
| int* ranges = reinterpret_cast<int*>(malloc(range_alloc * 2 * sizeof(int))); |
| ranges[0] = -1; |
| ranges[1] = -1; |
| |
| fprintf(mapf, "%s\n%lld %lu\n", blk_dev, (long long)sb.st_size, (unsigned long)sb.st_blksize); |
| |
| unsigned char* buffers[WINDOW_SIZE]; |
| if (encrypted) { |
| for (size_t i = 0; i < WINDOW_SIZE; ++i) { |
| buffers[i] = reinterpret_cast<unsigned char*>(malloc(sb.st_blksize)); |
| } |
| } |
| int head_block = 0; |
| int head = 0, tail = 0; |
| size_t pos = 0; |
| |
| int fd = open(path, O_RDONLY); |
| unique_fd fd_holder(fd); |
| if (fd == -1) { |
| ALOGE("failed to open fd for reading: %s\n", strerror(errno)); |
| return -1; |
| } |
| |
| int wfd = -1; |
| unique_fd wfd_holder(wfd); |
| if (encrypted) { |
| wfd = open(blk_dev, O_WRONLY); |
| wfd_holder = unique_fd(wfd); |
| if (wfd == -1) { |
| ALOGE("failed to open fd for writing: %s\n", strerror(errno)); |
| return -1; |
| } |
| } |
| |
| 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; |
| android::base::WriteStringToFd(std::to_string(progress) + "\n", status_fd); |
| } |
| |
| if ((tail+1) % WINDOW_SIZE == head) { |
| // write out head buffer |
| int block = head_block; |
| if (ioctl(fd, FIBMAP, &block) != 0) { |
| ALOGE("failed to find block %d\n", head_block); |
| return -1; |
| } |
| add_block_to_ranges(&ranges, &range_alloc, &range_used, block); |
| if (encrypted) { |
| if (write_at_offset(buffers[head], sb.st_blksize, wfd, |
| (off64_t)sb.st_blksize * block) != 0) { |
| return -1; |
| } |
| } |
| head = (head + 1) % WINDOW_SIZE; |
| ++head_block; |
| } |
| |
| // read next block to tail |
| if (encrypted) { |
| size_t so_far = 0; |
| while (so_far < sb.st_blksize && pos < sb.st_size) { |
| ssize_t this_read = |
| TEMP_FAILURE_RETRY(read(fd, buffers[tail] + so_far, sb.st_blksize - so_far)); |
| if (this_read == -1) { |
| ALOGE("failed to read: %s\n", strerror(errno)); |
| return -1; |
| } |
| so_far += this_read; |
| pos += this_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) { |
| ALOGE("failed to find block %d\n", head_block); |
| return -1; |
| } |
| add_block_to_ranges(&ranges, &range_alloc, &range_used, block); |
| if (encrypted) { |
| if (write_at_offset(buffers[head], sb.st_blksize, wfd, |
| (off64_t)sb.st_blksize * block) != 0) { |
| return -1; |
| } |
| } |
| head = (head + 1) % WINDOW_SIZE; |
| ++head_block; |
| } |
| |
| fprintf(mapf, "%d\n", range_used); |
| for (int i = 0; i < range_used; ++i) { |
| fprintf(mapf, "%d %d\n", ranges[i*2], ranges[i*2+1]); |
| } |
| |
| if (fsync(mapfd) == -1) { |
| ALOGE("failed to fsync \"%s\": %s\n", map_file, strerror(errno)); |
| return -1; |
| } |
| if (encrypted) { |
| if (fsync(wfd) == -1) { |
| ALOGE("failed to fsync \"%s\": %s\n", blk_dev, strerror(errno)); |
| return -1; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static void wipe_misc() { |
| ALOGI("removing old commands from misc"); |
| for (int i = 0; i < fstab->num_entries; ++i) { |
| struct fstab_rec* v = &fstab->recs[i]; |
| if (!v->mount_point) continue; |
| if (strcmp(v->mount_point, "/misc") == 0) { |
| int fd = open(v->blk_device, O_WRONLY | O_SYNC); |
| unique_fd fd_holder(fd); |
| |
| uint8_t zeroes[1088]; // sizeof(bootloader_message) from recovery |
| memset(zeroes, 0, sizeof(zeroes)); |
| |
| size_t written = 0; |
| size_t size = sizeof(zeroes); |
| while (written < size) { |
| ssize_t w = TEMP_FAILURE_RETRY(write(fd, zeroes, size-written)); |
| if (w == -1) { |
| ALOGE("zero write failed: %s\n", strerror(errno)); |
| return; |
| } else { |
| written += w; |
| } |
| } |
| if (fsync(fd) == -1) { |
| ALOGE("failed to fsync \"%s\": %s\n", v->blk_device, strerror(errno)); |
| return; |
| } |
| } |
| } |
| } |
| |
| static void reboot_to_recovery() { |
| ALOGI("rebooting to recovery"); |
| property_set("sys.powerctl", "reboot,recovery"); |
| while (true) { |
| pause(); |
| } |
| ALOGE("reboot didn't succeed?"); |
| } |
| |
| int uncrypt(const char* input_path, const char* map_file, int status_fd) { |
| |
| ALOGI("update package is \"%s\"", 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) { |
| ALOGE("failed to convert \"%s\" to absolute path: %s", input_path, strerror(errno)); |
| return 1; |
| } |
| |
| if (read_fstab() == NULL) { |
| return 1; |
| } |
| |
| bool encryptable; |
| bool encrypted; |
| const char* blk_dev = find_block_device(path, &encryptable, &encrypted); |
| if (blk_dev == NULL) { |
| ALOGE("failed to find block device for %s", 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). |
| ALOGI("encryptable: %s\n", encryptable ? "yes" : "no"); |
| ALOGI(" encrypted: %s\n", 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) { |
| ALOGI("writing block map %s", map_file); |
| if (produce_block_map(path, map_file, blk_dev, encrypted, status_fd) != 0) { |
| return 1; |
| } |
| } |
| |
| return 0; |
| } |
| |
| int main(int argc, char** argv) { |
| const char* input_path; |
| const char* map_file; |
| |
| if (argc != 3 && argc != 1 && (argc == 2 && strcmp(argv[1], "--reboot") != 0)) { |
| fprintf(stderr, "usage: %s [--reboot] [<transform_path> <map_file>]\n", argv[0]); |
| return 2; |
| } |
| |
| // When uncrypt is started with "--reboot", it wipes misc and reboots. |
| // Otherwise it uncrypts the package and writes the block map. |
| if (argc == 2) { |
| if (read_fstab() == NULL) { |
| return 1; |
| } |
| wipe_misc(); |
| reboot_to_recovery(); |
| } else { |
| // The pipe has been created by the system server. |
| int status_fd = open(status_file.c_str(), O_WRONLY | O_CREAT | O_SYNC, S_IRUSR | S_IWUSR); |
| if (status_fd == -1) { |
| ALOGE("failed to open pipe \"%s\": %s\n", status_file.c_str(), strerror(errno)); |
| return 1; |
| } |
| unique_fd status_fd_holder(status_fd); |
| |
| if (argc == 3) { |
| // when command-line args are given this binary is being used |
| // for debugging. |
| input_path = argv[1]; |
| map_file = argv[2]; |
| } else { |
| std::string package; |
| if (!find_uncrypt_package(package)) { |
| android::base::WriteStringToFd("-1\n", status_fd); |
| return 1; |
| } |
| input_path = package.c_str(); |
| map_file = cache_block_map.c_str(); |
| } |
| |
| int status = uncrypt(input_path, map_file, status_fd); |
| if (status != 0) { |
| android::base::WriteStringToFd("-1\n", status_fd); |
| return 1; |
| } |
| |
| android::base::WriteStringToFd("100\n", status_fd); |
| } |
| |
| return 0; |
| } |