summaryrefslogtreecommitdiffstats
path: root/uncrypt/uncrypt.cpp
blob: 2a32108a3888c3d9fde1963abfd8ef61074e5462 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
/*
 * 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 <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/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/stringprintf.h>
#include <android-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 "bootloader.h"
#include "unique_fd.h"

#define WINDOW_SIZE 5

static const std::string CACHE_BLOCK_MAP = "/cache/recovery/block.map";
static const std::string COMMAND_FILE = "/cache/recovery/command";
static const std::string STATUS_FILE = "/cache/recovery/uncrypt_status";
static const std::string UNCRYPT_PATH_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 %" PRId64 ": %s", offset, strerror(errno));
        return -1;
    }
    if (!android::base::WriteFully(wfd, buffer, size)) {
        ALOGE("error writing offset %" PRId64 ": %s", offset, strerror(errno));
        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 = 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");
        return NULL;
    }

    fstab = fs_mgr_read_fstab(fstab_path);
    if (!fstab) {
        ALOGE("failed to read %s", 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(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)) {
        ALOGE("failed to open \"%s\": %s", uncrypt_path_file.c_str(), strerror(errno));
        return false;
    }

    // Remove the trailing '\n' if present.
    *package_name = android::base::Trim(uncrypt_path);
    return true;
}

static int produce_block_map(const char* path, const char* map_file, const char* blk_dev,
                             bool encrypted, int status_fd) {
    std::string err;
    if (!android::base::RemoveFileIfExists(map_file, &err)) {
        ALOGE("failed to remove the existing map file %s: %s", 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;
    }

    // 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", path);
        return -1;
    }

    ALOGI(" block size: %ld bytes", static_cast<long>(sb.st_blksize));

    int blocks = ((sb.st_size-1) / sb.st_blksize) + 1;
    ALOGI("  file size: %" PRId64 " bytes, %d blocks", sb.st_size, blocks);

    std::vector<int> ranges;

    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", tmp_map_file.c_str(), strerror(errno));
        return -1;
    }

    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;

    unique_fd fd(open(path, O_RDONLY));
    if (!fd) {
        ALOGE("failed to open %s for reading: %s", path, strerror(errno));
        return -1;
    }

    unique_fd wfd(-1);
    if (encrypted) {
        wfd = open(blk_dev, O_WRONLY);
        if (!wfd) {
            ALOGE("failed to open fd for writing: %s", strerror(errno));
            return -1;
        }
    }

    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;
          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.get(), FIBMAP, &block) != 0) {
                ALOGE("failed to find block %d", head_block);
                return -1;
            }
            add_block_to_ranges(ranges, block);
            if (encrypted) {
                if (write_at_offset(buffers[head].data(), sb.st_blksize, wfd.get(),
                        static_cast<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 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", strerror(errno));
                return -1;
            }
            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.get(), FIBMAP, &block) != 0) {
            ALOGE("failed to find block %d", head_block);
            return -1;
        }
        add_block_to_ranges(ranges, block);
        if (encrypted) {
            if (write_at_offset(buffers[head].data(), sb.st_blksize, wfd.get(),
                    static_cast<off64_t>(sb.st_blksize) * block) != 0) {
                return -1;
            }
        }
        head = (head + 1) % WINDOW_SIZE;
        ++head_block;
    }

    if (!android::base::WriteStringToFd(
            android::base::StringPrintf("%zu\n", ranges.size() / 2), mapfd.get())) {
        ALOGE("failed to write %s: %s", 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", tmp_map_file.c_str(), strerror(errno));
            return -1;
        }
    }

    if (fsync(mapfd.get()) == -1) {
        ALOGE("failed to fsync \"%s\": %s", tmp_map_file.c_str(), strerror(errno));
        return -1;
    }
    if (close(mapfd.get() == -1)) {
        ALOGE("failed to close %s: %s", tmp_map_file.c_str(), strerror(errno));
        return -1;
    }
    mapfd = -1;

    if (encrypted) {
        if (fsync(wfd.get()) == -1) {
            ALOGE("failed to fsync \"%s\": %s", blk_dev, strerror(errno));
            return -1;
        }
        if (close(wfd.get()) == -1) {
            ALOGE("failed to close %s: %s", 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", 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", dir_name.c_str(), strerror(errno));
        return -1;
    }
    if (fsync(dfd.get()) == -1) {
        ALOGE("failed to fsync %s: %s", dir_name.c_str(), strerror(errno));
        return -1;
    }
    if (close(dfd.get() == -1)) {
        ALOGE("failed to close %s: %s", dir_name.c_str(), strerror(errno));
        return -1;
    }
    dfd = -1;
    return 0;
}

static std::string get_misc_blk_device() {
    struct fstab* fstab = read_fstab();
    if (fstab == nullptr) {
        return "";
    }
    for (int i = 0; i < fstab->num_entries; ++i) {
        fstab_rec* v = &fstab->recs[i];
        if (v->mount_point != nullptr && strcmp(v->mount_point, "/misc") == 0) {
            return v->blk_device;
        }
    }
    return "";
}

static int read_bootloader_message(bootloader_message* out) {
    std::string misc_blk_device = get_misc_blk_device();
    if (misc_blk_device.empty()) {
        ALOGE("failed to find /misc partition.");
        return -1;
    }
    unique_fd fd(open(misc_blk_device.c_str(), O_RDONLY));
    if (!fd) {
        ALOGE("failed to open %s: %s", misc_blk_device.c_str(), strerror(errno));
        return -1;
    }
    if (!android::base::ReadFully(fd.get(), out, sizeof(*out))) {
        ALOGE("failed to read %s: %s", misc_blk_device.c_str(), strerror(errno));
        return -1;
    }
    return 0;
}

static int write_bootloader_message(const bootloader_message* in) {
    std::string misc_blk_device = get_misc_blk_device();
    if (misc_blk_device.empty()) {
        ALOGE("failed to find /misc partition.");
        return -1;
    }
    unique_fd fd(open(misc_blk_device.c_str(), O_WRONLY | O_SYNC));
    if (!fd) {
        ALOGE("failed to open %s: %s", misc_blk_device.c_str(), strerror(errno));
        return -1;
    }
    if (!android::base::WriteFully(fd.get(), in, sizeof(*in))) {
        ALOGE("failed to write %s: %s", misc_blk_device.c_str(), strerror(errno));
        return -1;
    }
    // TODO: O_SYNC and fsync() duplicates each other?
    if (fsync(fd.get()) == -1) {
        ALOGE("failed to fsync %s: %s", misc_blk_device.c_str(), strerror(errno));
        return -1;
    }
    return 0;
}

static 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", encryptable ? "yes" : "no");
    ALOGI("  encrypted: %s", 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;
}

static int uncrypt_wrapper(const char* input_path, const char* map_file,
                           const std::string& status_file) {
    // The pipe has been created by the system server.
    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 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 --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], "--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;
}