Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 25dd0386 authored by Yabin Cui's avatar Yabin Cui
Browse files

uncrypt: generate map file by renaming tmp file. 

Writing map file directly can break consistency in map file if
it fails in the middle. Instead, we write a temporary file and
rename the temporary file to map file.

Bug: 26883096
Change-Id: I5e99e942e1b75e758af5f7a48f8a08a0b0041d6a
parent 9d72d417

uncrypt/uncrypt.cpp

+93 −75
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ 
#include <errno.h>

#include <fcntl.h>

#include <inttypes.h>

#include <libgen.h>

#include <linux/fs.h>

#include <stdarg.h>

#include <stdio.h>
@@ -52,9 +53,12 @@ 
#include <sys/types.h>

#include <unistd.h>



#include <algorithm>

#include <memory>

#include <vector>



#include <android-base/file.h>

#include <android-base/stringprintf.h>

#include <android-base/strings.h>

#include <cutils/android_reboot.h>

#include <cutils/properties.h>
@@ -78,44 +82,22 @@ static int write_at_offset(unsigned char* buffer, size_t size, int wfd, off64_t 
        ALOGE("error seeking to offset %" PRId64 ": %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 %" PRId64 ": %s\n",

                  offset + static_cast<off64_t>(written), strerror(errno));

    if (!android::base::WriteFully(wfd, buffer, size)) {

        ALOGE("error writing offset %" PRId64 ": %s\n", offset, 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]) {

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)[*range_used*2-1];

        ++ranges.back();

    } 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;

        ranges.push_back(new_block);

        ranges.push_back(new_block + 1);

    }

}
@@ -183,12 +165,17 @@ static bool find_uncrypt_package(std::string& package_name) 


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);

    std::string err;

    if (!android::base::RemoveFileIfExists(map_file, &err)) {

        ALOGE("failed to remove the existing map file %s: %s\n", map_file, err.c_str());

        return -1;

    }

    std::string tmp_map_file = std::string(map_file) + ".tmp";

    unique_fd mapfd(open(tmp_map_file.c_str(), O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR));

    if (!mapfd) {

        ALOGE("failed to open %s: %s\n", tmp_map_file.c_str(), strerror(errno));

        return -1;

    }

    std::unique_ptr<FILE, int(*)(FILE*)> mapf(fdopen(mapfd, "w"), fclose);



    // Make sure we can write to the status_file.

    if (!android::base::WriteStringToFd("0\n", status_fd)) {
@@ -207,37 +194,32 @@ static int produce_block_map(const char* path, const char* map_file, const char* 
    int blocks = ((sb.st_size-1) / sb.st_blksize) + 1;

    ALOGI("  file size: %" PRId64 " bytes, %d blocks\n", 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;

    std::vector<int> ranges;



    fprintf(mapf.get(), "%s\n%" PRId64 " %ld\n",

    std::string s = android::base::StringPrintf("%s\n%" PRId64 " %ld\n",

                       blk_dev, sb.st_size, static_cast<long>(sb.st_blksize));

    if (!android::base::WriteStringToFd(s, mapfd.get())) {

        ALOGE("failed to write %s: %s\n", tmp_map_file.c_str(), strerror(errno));

        return -1;

    }



    unsigned char* buffers[WINDOW_SIZE];

    std::vector<std::vector<unsigned char>> buffers;

    if (encrypted) {

        for (size_t i = 0; i < WINDOW_SIZE; ++i) {

            buffers[i] = reinterpret_cast<unsigned char*>(malloc(sb.st_blksize));

        }

        buffers.resize(WINDOW_SIZE, std::vector<unsigned char>(sb.st_blksize));

    }

    int head_block = 0;

    int head = 0, tail = 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));

    unique_fd fd(open(path, O_RDONLY));

    if (!fd) {

        ALOGE("failed to open %s for reading: %s\n", path, strerror(errno));

        return -1;

    }



    int wfd = -1;

    unique_fd wfd_holder(wfd);

    unique_fd wfd(-1);

    if (encrypted) {

        wfd = open(blk_dev, O_WRONLY);

        wfd_holder = unique_fd(wfd);

        if (wfd == -1) {

        if (!wfd) {

            ALOGE("failed to open fd for writing: %s\n", strerror(errno));

            return -1;

        }
@@ -256,13 +238,13 @@ static int produce_block_map(const char* path, const char* map_file, const char* 
        if ((tail+1) % WINDOW_SIZE == head) {

            // write out head buffer

            int block = head_block;

            if (ioctl(fd, FIBMAP, &block) != 0) {

            if (ioctl(fd.get(), FIBMAP, &block) != 0) {

                ALOGE("failed to find block %d\n", head_block);

                return -1;

            }

            add_block_to_ranges(&ranges, &range_alloc, &range_used, block);

            add_block_to_ranges(ranges, block);

            if (encrypted) {

                if (write_at_offset(buffers[head], sb.st_blksize, wfd,

                if (write_at_offset(buffers[head].data(), sb.st_blksize, wfd.get(),

                        static_cast<off64_t>(sb.st_blksize) * block) != 0) {

                    return -1;

                }
@@ -273,17 +255,13 @@ static int produce_block_map(const char* path, const char* map_file, const char* 


        // read next block to tail

        if (encrypted) {

            size_t so_far = 0;

            while (so_far < static_cast<size_t>(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) {

            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.get(), buffers[tail].data(), to_read)) {

                ALOGE("failed to read: %s\n", strerror(errno));

                return -1;

            }

                so_far += this_read;

                pos += this_read;

            }

            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
@@ -296,13 +274,13 @@ static int produce_block_map(const char* path, const char* map_file, const char* 
    while (head != tail) {

        // write out head buffer

        int block = head_block;

        if (ioctl(fd, FIBMAP, &block) != 0) {

        if (ioctl(fd.get(), FIBMAP, &block) != 0) {

            ALOGE("failed to find block %d\n", head_block);

            return -1;

        }

        add_block_to_ranges(&ranges, &range_alloc, &range_used, block);

        add_block_to_ranges(ranges, block);

        if (encrypted) {

            if (write_at_offset(buffers[head], sb.st_blksize, wfd,

            if (write_at_offset(buffers[head].data(), sb.st_blksize, wfd.get(),

                    static_cast<off64_t>(sb.st_blksize) * block) != 0) {

                return -1;

            }
@@ -311,22 +289,62 @@ static int produce_block_map(const char* path, const char* map_file, const char* 
        ++head_block;

    }



    fprintf(mapf.get(), "%d\n", range_used);

    for (int i = 0; i < range_used; ++i) {

        fprintf(mapf.get(), "%d %d\n", ranges[i*2], ranges[i*2+1]);

    if (!android::base::WriteStringToFd(

            android::base::StringPrintf("%zu\n", ranges.size() / 2), mapfd.get())) {

        ALOGE("failed to write %s: %s\n", tmp_map_file.c_str(), strerror(errno));

        return -1;

    }

    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.get())) {

            ALOGE("failed to write %s: %s\n", tmp_map_file.c_str(), strerror(errno));

            return -1;

        }

    }



    if (fsync(mapfd) == -1) {

        ALOGE("failed to fsync \"%s\": %s\n", map_file, strerror(errno));

    if (fsync(mapfd.get()) == -1) {

        ALOGE("failed to fsync \"%s\": %s\n", tmp_map_file.c_str(), strerror(errno));

        return -1;

    }

    if (close(mapfd.get() == -1)) {

        ALOGE("failed to close %s: %s\n", tmp_map_file.c_str(), strerror(errno));

        return -1;

    }

    mapfd = -1;



    if (encrypted) {

        if (fsync(wfd) == -1) {

        if (fsync(wfd.get()) == -1) {

            ALOGE("failed to fsync \"%s\": %s\n", blk_dev, strerror(errno));

            return -1;

        }

        if (close(wfd.get()) == -1) {

            ALOGE("failed to close %s: %s\n", blk_dev, strerror(errno));

            return -1;

        }

        wfd = -1;

    }



    if (rename(tmp_map_file.c_str(), map_file) == -1) {

        ALOGE("failed to rename %s to %s: %s\n", tmp_map_file.c_str(), map_file, strerror(errno));

        return -1;

    }

    // Sync dir to make rename() result written to disk.

    std::string file_name = map_file;

    std::string dir_name = dirname(&file_name[0]);

    unique_fd dfd(open(dir_name.c_str(), O_RDONLY | O_DIRECTORY));

    if (!dfd) {

        ALOGE("failed to open dir %s: %s\n", dir_name.c_str(), strerror(errno));

        return -1;

    }

    if (fsync(dfd.get()) == -1) {

        ALOGE("failed to fsync %s: %s\n", dir_name.c_str(), strerror(errno));

        return -1;

    }

    if (close(dfd.get() == -1)) {

        ALOGE("failed to close %s: %s\n", dir_name.c_str(), strerror(errno));

        return -1;

    }

    dfd = -1;

    return 0;

}