1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <errno.h>
18 #include <libgen.h>
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <sys/stat.h>
23 #include <sys/statfs.h>
24 #include <sys/types.h>
25 #include <fcntl.h>
26 #include <unistd.h>
27
28 #include "mincrypt/sha.h"
29 #include "applypatch.h"
30 #include "mtdutils/mtdutils.h"
31 #include "edify/expr.h"
32
33 static int LoadPartitionContents(const char* filename, FileContents* file);
34 static ssize_t FileSink(unsigned char* data, ssize_t len, void* token);
35 static int GenerateTarget(FileContents* source_file,
36 const Value* source_patch_value,
37 FileContents* copy_file,
38 const Value* copy_patch_value,
39 const char* source_filename,
40 const char* target_filename,
41 const uint8_t target_sha1[SHA_DIGEST_SIZE],
42 size_t target_size,
43 const Value* bonus_data);
44
45 static int mtd_partitions_scanned = 0;
46
47 // Read a file into memory; optionally (retouch_flag == RETOUCH_DO_MASK) mask
48 // the retouched entries back to their original value (such that SHA-1 checks
49 // don't fail due to randomization); store the file contents and associated
50 // metadata in *file.
51 //
52 // Return 0 on success.
LoadFileContents(const char * filename,FileContents * file,int retouch_flag)53 int LoadFileContents(const char* filename, FileContents* file,
54 int retouch_flag) {
55 file->data = NULL;
56
57 // A special 'filename' beginning with "MTD:" or "EMMC:" means to
58 // load the contents of a partition.
59 if (strncmp(filename, "MTD:", 4) == 0 ||
60 strncmp(filename, "EMMC:", 5) == 0) {
61 return LoadPartitionContents(filename, file);
62 }
63
64 if (stat(filename, &file->st) != 0) {
65 printf("failed to stat \"%s\": %s\n", filename, strerror(errno));
66 return -1;
67 }
68
69 file->size = file->st.st_size;
70 file->data = malloc(file->size);
71
72 FILE* f = fopen(filename, "rb");
73 if (f == NULL) {
74 printf("failed to open \"%s\": %s\n", filename, strerror(errno));
75 free(file->data);
76 file->data = NULL;
77 return -1;
78 }
79
80 ssize_t bytes_read = fread(file->data, 1, file->size, f);
81 if (bytes_read != file->size) {
82 printf("short read of \"%s\" (%ld bytes of %ld)\n",
83 filename, (long)bytes_read, (long)file->size);
84 free(file->data);
85 file->data = NULL;
86 return -1;
87 }
88 fclose(f);
89
90 // apply_patch[_check] functions are blind to randomization. Randomization
91 // is taken care of in [Undo]RetouchBinariesFn. If there is a mismatch
92 // within a file, this means the file is assumed "corrupt" for simplicity.
93 if (retouch_flag) {
94 int32_t desired_offset = 0;
95 if (retouch_mask_data(file->data, file->size,
96 &desired_offset, NULL) != RETOUCH_DATA_MATCHED) {
97 printf("error trying to mask retouch entries\n");
98 free(file->data);
99 file->data = NULL;
100 return -1;
101 }
102 }
103
104 SHA(file->data, file->size, file->sha1);
105 return 0;
106 }
107
108 static size_t* size_array;
109 // comparison function for qsort()ing an int array of indexes into
110 // size_array[].
compare_size_indices(const void * a,const void * b)111 static int compare_size_indices(const void* a, const void* b) {
112 int aa = *(int*)a;
113 int bb = *(int*)b;
114 if (size_array[aa] < size_array[bb]) {
115 return -1;
116 } else if (size_array[aa] > size_array[bb]) {
117 return 1;
118 } else {
119 return 0;
120 }
121 }
122
123 // Load the contents of an MTD or EMMC partition into the provided
124 // FileContents. filename should be a string of the form
125 // "MTD:<partition_name>:<size_1>:<sha1_1>:<size_2>:<sha1_2>:..." (or
126 // "EMMC:<partition_device>:..."). The smallest size_n bytes for
127 // which that prefix of the partition contents has the corresponding
128 // sha1 hash will be loaded. It is acceptable for a size value to be
129 // repeated with different sha1s. Will return 0 on success.
130 //
131 // This complexity is needed because if an OTA installation is
132 // interrupted, the partition might contain either the source or the
133 // target data, which might be of different lengths. We need to know
134 // the length in order to read from a partition (there is no
135 // "end-of-file" marker), so the caller must specify the possible
136 // lengths and the hash of the data, and we'll do the load expecting
137 // to find one of those hashes.
138 enum PartitionType { MTD, EMMC };
139
LoadPartitionContents(const char * filename,FileContents * file)140 static int LoadPartitionContents(const char* filename, FileContents* file) {
141 char* copy = strdup(filename);
142 const char* magic = strtok(copy, ":");
143
144 enum PartitionType type;
145
146 if (strcmp(magic, "MTD") == 0) {
147 type = MTD;
148 } else if (strcmp(magic, "EMMC") == 0) {
149 type = EMMC;
150 } else {
151 printf("LoadPartitionContents called with bad filename (%s)\n",
152 filename);
153 return -1;
154 }
155 const char* partition = strtok(NULL, ":");
156
157 int i;
158 int colons = 0;
159 for (i = 0; filename[i] != '\0'; ++i) {
160 if (filename[i] == ':') {
161 ++colons;
162 }
163 }
164 if (colons < 3 || colons%2 == 0) {
165 printf("LoadPartitionContents called with bad filename (%s)\n",
166 filename);
167 }
168
169 int pairs = (colons-1)/2; // # of (size,sha1) pairs in filename
170 int* index = malloc(pairs * sizeof(int));
171 size_t* size = malloc(pairs * sizeof(size_t));
172 char** sha1sum = malloc(pairs * sizeof(char*));
173
174 for (i = 0; i < pairs; ++i) {
175 const char* size_str = strtok(NULL, ":");
176 size[i] = strtol(size_str, NULL, 10);
177 if (size[i] == 0) {
178 printf("LoadPartitionContents called with bad size (%s)\n", filename);
179 return -1;
180 }
181 sha1sum[i] = strtok(NULL, ":");
182 index[i] = i;
183 }
184
185 // sort the index[] array so it indexes the pairs in order of
186 // increasing size.
187 size_array = size;
188 qsort(index, pairs, sizeof(int), compare_size_indices);
189
190 MtdReadContext* ctx = NULL;
191 FILE* dev = NULL;
192
193 switch (type) {
194 case MTD:
195 if (!mtd_partitions_scanned) {
196 mtd_scan_partitions();
197 mtd_partitions_scanned = 1;
198 }
199
200 const MtdPartition* mtd = mtd_find_partition_by_name(partition);
201 if (mtd == NULL) {
202 printf("mtd partition \"%s\" not found (loading %s)\n",
203 partition, filename);
204 return -1;
205 }
206
207 ctx = mtd_read_partition(mtd);
208 if (ctx == NULL) {
209 printf("failed to initialize read of mtd partition \"%s\"\n",
210 partition);
211 return -1;
212 }
213 break;
214
215 case EMMC:
216 dev = fopen(partition, "rb");
217 if (dev == NULL) {
218 printf("failed to open emmc partition \"%s\": %s\n",
219 partition, strerror(errno));
220 return -1;
221 }
222 }
223
224 SHA_CTX sha_ctx;
225 SHA_init(&sha_ctx);
226 uint8_t parsed_sha[SHA_DIGEST_SIZE];
227
228 // allocate enough memory to hold the largest size.
229 file->data = malloc(size[index[pairs-1]]);
230 char* p = (char*)file->data;
231 file->size = 0; // # bytes read so far
232
233 for (i = 0; i < pairs; ++i) {
234 // Read enough additional bytes to get us up to the next size
235 // (again, we're trying the possibilities in order of increasing
236 // size).
237 size_t next = size[index[i]] - file->size;
238 size_t read = 0;
239 if (next > 0) {
240 switch (type) {
241 case MTD:
242 read = mtd_read_data(ctx, p, next);
243 break;
244
245 case EMMC:
246 read = fread(p, 1, next, dev);
247 break;
248 }
249 if (next != read) {
250 printf("short read (%d bytes of %d) for partition \"%s\"\n",
251 read, next, partition);
252 free(file->data);
253 file->data = NULL;
254 return -1;
255 }
256 SHA_update(&sha_ctx, p, read);
257 file->size += read;
258 }
259
260 // Duplicate the SHA context and finalize the duplicate so we can
261 // check it against this pair's expected hash.
262 SHA_CTX temp_ctx;
263 memcpy(&temp_ctx, &sha_ctx, sizeof(SHA_CTX));
264 const uint8_t* sha_so_far = SHA_final(&temp_ctx);
265
266 if (ParseSha1(sha1sum[index[i]], parsed_sha) != 0) {
267 printf("failed to parse sha1 %s in %s\n",
268 sha1sum[index[i]], filename);
269 free(file->data);
270 file->data = NULL;
271 return -1;
272 }
273
274 if (memcmp(sha_so_far, parsed_sha, SHA_DIGEST_SIZE) == 0) {
275 // we have a match. stop reading the partition; we'll return
276 // the data we've read so far.
277 printf("partition read matched size %d sha %s\n",
278 size[index[i]], sha1sum[index[i]]);
279 break;
280 }
281
282 p += read;
283 }
284
285 switch (type) {
286 case MTD:
287 mtd_read_close(ctx);
288 break;
289
290 case EMMC:
291 fclose(dev);
292 break;
293 }
294
295
296 if (i == pairs) {
297 // Ran off the end of the list of (size,sha1) pairs without
298 // finding a match.
299 printf("contents of partition \"%s\" didn't match %s\n",
300 partition, filename);
301 free(file->data);
302 file->data = NULL;
303 return -1;
304 }
305
306 const uint8_t* sha_final = SHA_final(&sha_ctx);
307 for (i = 0; i < SHA_DIGEST_SIZE; ++i) {
308 file->sha1[i] = sha_final[i];
309 }
310
311 // Fake some stat() info.
312 file->st.st_mode = 0644;
313 file->st.st_uid = 0;
314 file->st.st_gid = 0;
315
316 free(copy);
317 free(index);
318 free(size);
319 free(sha1sum);
320
321 return 0;
322 }
323
324
325 // Save the contents of the given FileContents object under the given
326 // filename. Return 0 on success.
SaveFileContents(const char * filename,const FileContents * file)327 int SaveFileContents(const char* filename, const FileContents* file) {
328 int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
329 if (fd < 0) {
330 printf("failed to open \"%s\" for write: %s\n",
331 filename, strerror(errno));
332 return -1;
333 }
334
335 ssize_t bytes_written = FileSink(file->data, file->size, &fd);
336 if (bytes_written != file->size) {
337 printf("short write of \"%s\" (%ld bytes of %ld) (%s)\n",
338 filename, (long)bytes_written, (long)file->size,
339 strerror(errno));
340 close(fd);
341 return -1;
342 }
343 fsync(fd);
344 close(fd);
345
346 if (chmod(filename, file->st.st_mode) != 0) {
347 printf("chmod of \"%s\" failed: %s\n", filename, strerror(errno));
348 return -1;
349 }
350 if (chown(filename, file->st.st_uid, file->st.st_gid) != 0) {
351 printf("chown of \"%s\" failed: %s\n", filename, strerror(errno));
352 return -1;
353 }
354
355 return 0;
356 }
357
358 // Write a memory buffer to 'target' partition, a string of the form
359 // "MTD:<partition>[:...]" or "EMMC:<partition_device>:". Return 0 on
360 // success.
WriteToPartition(unsigned char * data,size_t len,const char * target)361 int WriteToPartition(unsigned char* data, size_t len,
362 const char* target) {
363 char* copy = strdup(target);
364 const char* magic = strtok(copy, ":");
365
366 enum PartitionType type;
367 if (strcmp(magic, "MTD") == 0) {
368 type = MTD;
369 } else if (strcmp(magic, "EMMC") == 0) {
370 type = EMMC;
371 } else {
372 printf("WriteToPartition called with bad target (%s)\n", target);
373 return -1;
374 }
375 const char* partition = strtok(NULL, ":");
376
377 if (partition == NULL) {
378 printf("bad partition target name \"%s\"\n", target);
379 return -1;
380 }
381
382 switch (type) {
383 case MTD:
384 if (!mtd_partitions_scanned) {
385 mtd_scan_partitions();
386 mtd_partitions_scanned = 1;
387 }
388
389 const MtdPartition* mtd = mtd_find_partition_by_name(partition);
390 if (mtd == NULL) {
391 printf("mtd partition \"%s\" not found for writing\n",
392 partition);
393 return -1;
394 }
395
396 MtdWriteContext* ctx = mtd_write_partition(mtd);
397 if (ctx == NULL) {
398 printf("failed to init mtd partition \"%s\" for writing\n",
399 partition);
400 return -1;
401 }
402
403 size_t written = mtd_write_data(ctx, (char*)data, len);
404 if (written != len) {
405 printf("only wrote %d of %d bytes to MTD %s\n",
406 written, len, partition);
407 mtd_write_close(ctx);
408 return -1;
409 }
410
411 if (mtd_erase_blocks(ctx, -1) < 0) {
412 printf("error finishing mtd write of %s\n", partition);
413 mtd_write_close(ctx);
414 return -1;
415 }
416
417 if (mtd_write_close(ctx)) {
418 printf("error closing mtd write of %s\n", partition);
419 return -1;
420 }
421 break;
422
423 case EMMC:
424 {
425 size_t start = 0;
426 int success = 0;
427 int fd = open(partition, O_RDWR);
428 if (fd < 0) {
429 printf("failed to open %s: %s\n", partition, strerror(errno));
430 return -1;
431 }
432 int attempt;
433
434 for (attempt = 0; attempt < 10; ++attempt) {
435 size_t next_sync = start + (1<<20);
436 printf("raw write %s attempt %d start at %d\n", partition, attempt+1, start);
437 lseek(fd, start, SEEK_SET);
438 while (start < len) {
439 size_t to_write = len - start;
440 if (to_write > 4096) to_write = 4096;
441
442 ssize_t written = write(fd, data+start, to_write);
443 if (written < 0) {
444 if (errno == EINTR) {
445 written = 0;
446 } else {
447 printf("failed write writing to %s (%s)\n",
448 partition, strerror(errno));
449 return -1;
450 }
451 }
452 start += written;
453 if (start >= next_sync) {
454 fsync(fd);
455 next_sync = start + (1<<20);
456 }
457 }
458 fsync(fd);
459
460 // drop caches so our subsequent verification read
461 // won't just be reading the cache.
462 sync();
463 int dc = open("/proc/sys/vm/drop_caches", O_WRONLY);
464 write(dc, "3\n", 2);
465 close(dc);
466 sleep(1);
467 printf(" caches dropped\n");
468
469 // verify
470 lseek(fd, 0, SEEK_SET);
471 unsigned char buffer[4096];
472 start = len;
473 size_t p;
474 for (p = 0; p < len; p += sizeof(buffer)) {
475 size_t to_read = len - p;
476 if (to_read > sizeof(buffer)) to_read = sizeof(buffer);
477
478 size_t so_far = 0;
479 while (so_far < to_read) {
480 ssize_t read_count = read(fd, buffer+so_far, to_read-so_far);
481 if (read_count < 0) {
482 if (errno == EINTR) {
483 read_count = 0;
484 } else {
485 printf("verify read error %s at %d: %s\n",
486 partition, p, strerror(errno));
487 return -1;
488 }
489 }
490 if ((size_t)read_count < to_read) {
491 printf("short verify read %s at %d: %d %d %s\n",
492 partition, p, read_count, to_read, strerror(errno));
493 }
494 so_far += read_count;
495 }
496
497 if (memcmp(buffer, data+p, to_read)) {
498 printf("verification failed starting at %d\n", p);
499 start = p;
500 break;
501 }
502 }
503
504 if (start == len) {
505 printf("verification read succeeded (attempt %d)\n", attempt+1);
506 success = true;
507 break;
508 }
509
510 sleep(2);
511 }
512
513 if (!success) {
514 printf("failed to verify after all attempts\n");
515 return -1;
516 }
517
518 if (close(fd) != 0) {
519 printf("error closing %s (%s)\n", partition, strerror(errno));
520 return -1;
521 }
522 // hack: sync and sleep after closing in hopes of getting
523 // the data actually onto flash.
524 printf("sleeping after close\n");
525 sync();
526 sleep(5);
527 break;
528 }
529 }
530
531 free(copy);
532 return 0;
533 }
534
535
536 // Take a string 'str' of 40 hex digits and parse it into the 20
537 // byte array 'digest'. 'str' may contain only the digest or be of
538 // the form "<digest>:<anything>". Return 0 on success, -1 on any
539 // error.
ParseSha1(const char * str,uint8_t * digest)540 int ParseSha1(const char* str, uint8_t* digest) {
541 int i;
542 const char* ps = str;
543 uint8_t* pd = digest;
544 for (i = 0; i < SHA_DIGEST_SIZE * 2; ++i, ++ps) {
545 int digit;
546 if (*ps >= '0' && *ps <= '9') {
547 digit = *ps - '0';
548 } else if (*ps >= 'a' && *ps <= 'f') {
549 digit = *ps - 'a' + 10;
550 } else if (*ps >= 'A' && *ps <= 'F') {
551 digit = *ps - 'A' + 10;
552 } else {
553 return -1;
554 }
555 if (i % 2 == 0) {
556 *pd = digit << 4;
557 } else {
558 *pd |= digit;
559 ++pd;
560 }
561 }
562 if (*ps != '\0') return -1;
563 return 0;
564 }
565
566 // Search an array of sha1 strings for one matching the given sha1.
567 // Return the index of the match on success, or -1 if no match is
568 // found.
FindMatchingPatch(uint8_t * sha1,char * const * const patch_sha1_str,int num_patches)569 int FindMatchingPatch(uint8_t* sha1, char* const * const patch_sha1_str,
570 int num_patches) {
571 int i;
572 uint8_t patch_sha1[SHA_DIGEST_SIZE];
573 for (i = 0; i < num_patches; ++i) {
574 if (ParseSha1(patch_sha1_str[i], patch_sha1) == 0 &&
575 memcmp(patch_sha1, sha1, SHA_DIGEST_SIZE) == 0) {
576 return i;
577 }
578 }
579 return -1;
580 }
581
582 // Returns 0 if the contents of the file (argv[2]) or the cached file
583 // match any of the sha1's on the command line (argv[3:]). Returns
584 // nonzero otherwise.
applypatch_check(const char * filename,int num_patches,char ** const patch_sha1_str)585 int applypatch_check(const char* filename,
586 int num_patches, char** const patch_sha1_str) {
587 FileContents file;
588 file.data = NULL;
589
590 // It's okay to specify no sha1s; the check will pass if the
591 // LoadFileContents is successful. (Useful for reading
592 // partitions, where the filename encodes the sha1s; no need to
593 // check them twice.)
594 if (LoadFileContents(filename, &file, RETOUCH_DO_MASK) != 0 ||
595 (num_patches > 0 &&
596 FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0)) {
597 printf("file \"%s\" doesn't have any of expected "
598 "sha1 sums; checking cache\n", filename);
599
600 free(file.data);
601 file.data = NULL;
602
603 // If the source file is missing or corrupted, it might be because
604 // we were killed in the middle of patching it. A copy of it
605 // should have been made in CACHE_TEMP_SOURCE. If that file
606 // exists and matches the sha1 we're looking for, the check still
607 // passes.
608
609 if (LoadFileContents(CACHE_TEMP_SOURCE, &file, RETOUCH_DO_MASK) != 0) {
610 printf("failed to load cache file\n");
611 return 1;
612 }
613
614 if (FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0) {
615 printf("cache bits don't match any sha1 for \"%s\"\n", filename);
616 free(file.data);
617 return 1;
618 }
619 }
620
621 free(file.data);
622 return 0;
623 }
624
ShowLicenses()625 int ShowLicenses() {
626 ShowBSDiffLicense();
627 return 0;
628 }
629
FileSink(unsigned char * data,ssize_t len,void * token)630 ssize_t FileSink(unsigned char* data, ssize_t len, void* token) {
631 int fd = *(int *)token;
632 ssize_t done = 0;
633 ssize_t wrote;
634 while (done < (ssize_t) len) {
635 wrote = write(fd, data+done, len-done);
636 if (wrote <= 0) {
637 printf("error writing %d bytes: %s\n", (int)(len-done), strerror(errno));
638 return done;
639 }
640 done += wrote;
641 }
642 return done;
643 }
644
645 typedef struct {
646 unsigned char* buffer;
647 ssize_t size;
648 ssize_t pos;
649 } MemorySinkInfo;
650
MemorySink(unsigned char * data,ssize_t len,void * token)651 ssize_t MemorySink(unsigned char* data, ssize_t len, void* token) {
652 MemorySinkInfo* msi = (MemorySinkInfo*)token;
653 if (msi->size - msi->pos < len) {
654 return -1;
655 }
656 memcpy(msi->buffer + msi->pos, data, len);
657 msi->pos += len;
658 return len;
659 }
660
661 // Return the amount of free space (in bytes) on the filesystem
662 // containing filename. filename must exist. Return -1 on error.
FreeSpaceForFile(const char * filename)663 size_t FreeSpaceForFile(const char* filename) {
664 struct statfs sf;
665 if (statfs(filename, &sf) != 0) {
666 printf("failed to statfs %s: %s\n", filename, strerror(errno));
667 return -1;
668 }
669 return sf.f_bsize * sf.f_bfree;
670 }
671
CacheSizeCheck(size_t bytes)672 int CacheSizeCheck(size_t bytes) {
673 if (MakeFreeSpaceOnCache(bytes) < 0) {
674 printf("unable to make %ld bytes available on /cache\n", (long)bytes);
675 return 1;
676 } else {
677 return 0;
678 }
679 }
680
print_short_sha1(const uint8_t sha1[SHA_DIGEST_SIZE])681 static void print_short_sha1(const uint8_t sha1[SHA_DIGEST_SIZE]) {
682 int i;
683 const char* hex = "0123456789abcdef";
684 for (i = 0; i < 4; ++i) {
685 putchar(hex[(sha1[i]>>4) & 0xf]);
686 putchar(hex[sha1[i] & 0xf]);
687 }
688 }
689
690 // This function applies binary patches to files in a way that is safe
691 // (the original file is not touched until we have the desired
692 // replacement for it) and idempotent (it's okay to run this program
693 // multiple times).
694 //
695 // - if the sha1 hash of <target_filename> is <target_sha1_string>,
696 // does nothing and exits successfully.
697 //
698 // - otherwise, if the sha1 hash of <source_filename> is one of the
699 // entries in <patch_sha1_str>, the corresponding patch from
700 // <patch_data> (which must be a VAL_BLOB) is applied to produce a
701 // new file (the type of patch is automatically detected from the
702 // blob daat). If that new file has sha1 hash <target_sha1_str>,
703 // moves it to replace <target_filename>, and exits successfully.
704 // Note that if <source_filename> and <target_filename> are not the
705 // same, <source_filename> is NOT deleted on success.
706 // <target_filename> may be the string "-" to mean "the same as
707 // source_filename".
708 //
709 // - otherwise, or if any error is encountered, exits with non-zero
710 // status.
711 //
712 // <source_filename> may refer to a partition to read the source data.
713 // See the comments for the LoadPartition Contents() function above
714 // for the format of such a filename.
715
applypatch(const char * source_filename,const char * target_filename,const char * target_sha1_str,size_t target_size,int num_patches,char ** const patch_sha1_str,Value ** patch_data,Value * bonus_data)716 int applypatch(const char* source_filename,
717 const char* target_filename,
718 const char* target_sha1_str,
719 size_t target_size,
720 int num_patches,
721 char** const patch_sha1_str,
722 Value** patch_data,
723 Value* bonus_data) {
724 printf("patch %s: ", source_filename);
725
726 if (target_filename[0] == '-' &&
727 target_filename[1] == '\0') {
728 target_filename = source_filename;
729 }
730
731 uint8_t target_sha1[SHA_DIGEST_SIZE];
732 if (ParseSha1(target_sha1_str, target_sha1) != 0) {
733 printf("failed to parse tgt-sha1 \"%s\"\n", target_sha1_str);
734 return 1;
735 }
736
737 FileContents copy_file;
738 FileContents source_file;
739 copy_file.data = NULL;
740 source_file.data = NULL;
741 const Value* source_patch_value = NULL;
742 const Value* copy_patch_value = NULL;
743
744 // We try to load the target file into the source_file object.
745 if (LoadFileContents(target_filename, &source_file,
746 RETOUCH_DO_MASK) == 0) {
747 if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_SIZE) == 0) {
748 // The early-exit case: the patch was already applied, this file
749 // has the desired hash, nothing for us to do.
750 printf("already ");
751 print_short_sha1(target_sha1);
752 putchar('\n');
753 free(source_file.data);
754 return 0;
755 }
756 }
757
758 if (source_file.data == NULL ||
759 (target_filename != source_filename &&
760 strcmp(target_filename, source_filename) != 0)) {
761 // Need to load the source file: either we failed to load the
762 // target file, or we did but it's different from the source file.
763 free(source_file.data);
764 source_file.data = NULL;
765 LoadFileContents(source_filename, &source_file,
766 RETOUCH_DO_MASK);
767 }
768
769 if (source_file.data != NULL) {
770 int to_use = FindMatchingPatch(source_file.sha1,
771 patch_sha1_str, num_patches);
772 if (to_use >= 0) {
773 source_patch_value = patch_data[to_use];
774 }
775 }
776
777 if (source_patch_value == NULL) {
778 free(source_file.data);
779 source_file.data = NULL;
780 printf("source file is bad; trying copy\n");
781
782 if (LoadFileContents(CACHE_TEMP_SOURCE, ©_file,
783 RETOUCH_DO_MASK) < 0) {
784 // fail.
785 printf("failed to read copy file\n");
786 return 1;
787 }
788
789 int to_use = FindMatchingPatch(copy_file.sha1,
790 patch_sha1_str, num_patches);
791 if (to_use >= 0) {
792 copy_patch_value = patch_data[to_use];
793 }
794
795 if (copy_patch_value == NULL) {
796 // fail.
797 printf("copy file doesn't match source SHA-1s either\n");
798 free(copy_file.data);
799 return 1;
800 }
801 }
802
803 int result = GenerateTarget(&source_file, source_patch_value,
804 ©_file, copy_patch_value,
805 source_filename, target_filename,
806 target_sha1, target_size, bonus_data);
807 free(source_file.data);
808 free(copy_file.data);
809
810 return result;
811 }
812
GenerateTarget(FileContents * source_file,const Value * source_patch_value,FileContents * copy_file,const Value * copy_patch_value,const char * source_filename,const char * target_filename,const uint8_t target_sha1[SHA_DIGEST_SIZE],size_t target_size,const Value * bonus_data)813 static int GenerateTarget(FileContents* source_file,
814 const Value* source_patch_value,
815 FileContents* copy_file,
816 const Value* copy_patch_value,
817 const char* source_filename,
818 const char* target_filename,
819 const uint8_t target_sha1[SHA_DIGEST_SIZE],
820 size_t target_size,
821 const Value* bonus_data) {
822 int retry = 1;
823 SHA_CTX ctx;
824 int output;
825 MemorySinkInfo msi;
826 FileContents* source_to_use;
827 char* outname;
828 int made_copy = 0;
829
830 // assume that target_filename (eg "/system/app/Foo.apk") is located
831 // on the same filesystem as its top-level directory ("/system").
832 // We need something that exists for calling statfs().
833 char target_fs[strlen(target_filename)+1];
834 char* slash = strchr(target_filename+1, '/');
835 if (slash != NULL) {
836 int count = slash - target_filename;
837 strncpy(target_fs, target_filename, count);
838 target_fs[count] = '\0';
839 } else {
840 strcpy(target_fs, target_filename);
841 }
842
843 do {
844 // Is there enough room in the target filesystem to hold the patched
845 // file?
846
847 if (strncmp(target_filename, "MTD:", 4) == 0 ||
848 strncmp(target_filename, "EMMC:", 5) == 0) {
849 // If the target is a partition, we're actually going to
850 // write the output to /tmp and then copy it to the
851 // partition. statfs() always returns 0 blocks free for
852 // /tmp, so instead we'll just assume that /tmp has enough
853 // space to hold the file.
854
855 // We still write the original source to cache, in case
856 // the partition write is interrupted.
857 if (MakeFreeSpaceOnCache(source_file->size) < 0) {
858 printf("not enough free space on /cache\n");
859 return 1;
860 }
861 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) {
862 printf("failed to back up source file\n");
863 return 1;
864 }
865 made_copy = 1;
866 retry = 0;
867 } else {
868 int enough_space = 0;
869 if (retry > 0) {
870 size_t free_space = FreeSpaceForFile(target_fs);
871 enough_space =
872 (free_space > (256 << 10)) && // 256k (two-block) minimum
873 (free_space > (target_size * 3 / 2)); // 50% margin of error
874 if (!enough_space) {
875 printf("target %ld bytes; free space %ld bytes; retry %d; enough %d\n",
876 (long)target_size, (long)free_space, retry, enough_space);
877 }
878 }
879
880 if (!enough_space) {
881 retry = 0;
882 }
883
884 if (!enough_space && source_patch_value != NULL) {
885 // Using the original source, but not enough free space. First
886 // copy the source file to cache, then delete it from the original
887 // location.
888
889 if (strncmp(source_filename, "MTD:", 4) == 0 ||
890 strncmp(source_filename, "EMMC:", 5) == 0) {
891 // It's impossible to free space on the target filesystem by
892 // deleting the source if the source is a partition. If
893 // we're ever in a state where we need to do this, fail.
894 printf("not enough free space for target but source "
895 "is partition\n");
896 return 1;
897 }
898
899 if (MakeFreeSpaceOnCache(source_file->size) < 0) {
900 printf("not enough free space on /cache\n");
901 return 1;
902 }
903
904 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) {
905 printf("failed to back up source file\n");
906 return 1;
907 }
908 made_copy = 1;
909 unlink(source_filename);
910
911 size_t free_space = FreeSpaceForFile(target_fs);
912 printf("(now %ld bytes free for target) ", (long)free_space);
913 }
914 }
915
916 const Value* patch;
917 if (source_patch_value != NULL) {
918 source_to_use = source_file;
919 patch = source_patch_value;
920 } else {
921 source_to_use = copy_file;
922 patch = copy_patch_value;
923 }
924
925 if (patch->type != VAL_BLOB) {
926 printf("patch is not a blob\n");
927 return 1;
928 }
929
930 SinkFn sink = NULL;
931 void* token = NULL;
932 output = -1;
933 outname = NULL;
934 if (strncmp(target_filename, "MTD:", 4) == 0 ||
935 strncmp(target_filename, "EMMC:", 5) == 0) {
936 // We store the decoded output in memory.
937 msi.buffer = malloc(target_size);
938 if (msi.buffer == NULL) {
939 printf("failed to alloc %ld bytes for output\n",
940 (long)target_size);
941 return 1;
942 }
943 msi.pos = 0;
944 msi.size = target_size;
945 sink = MemorySink;
946 token = &msi;
947 } else {
948 // We write the decoded output to "<tgt-file>.patch".
949 outname = (char*)malloc(strlen(target_filename) + 10);
950 strcpy(outname, target_filename);
951 strcat(outname, ".patch");
952
953 output = open(outname, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
954 if (output < 0) {
955 printf("failed to open output file %s: %s\n",
956 outname, strerror(errno));
957 return 1;
958 }
959 sink = FileSink;
960 token = &output;
961 }
962
963 char* header = patch->data;
964 ssize_t header_bytes_read = patch->size;
965
966 SHA_init(&ctx);
967
968 int result;
969
970 if (header_bytes_read >= 8 &&
971 memcmp(header, "BSDIFF40", 8) == 0) {
972 result = ApplyBSDiffPatch(source_to_use->data, source_to_use->size,
973 patch, 0, sink, token, &ctx);
974 } else if (header_bytes_read >= 8 &&
975 memcmp(header, "IMGDIFF2", 8) == 0) {
976 result = ApplyImagePatch(source_to_use->data, source_to_use->size,
977 patch, sink, token, &ctx, bonus_data);
978 } else {
979 printf("Unknown patch file format\n");
980 return 1;
981 }
982
983 if (output >= 0) {
984 fsync(output);
985 close(output);
986 }
987
988 if (result != 0) {
989 if (retry == 0) {
990 printf("applying patch failed\n");
991 return result != 0;
992 } else {
993 printf("applying patch failed; retrying\n");
994 }
995 if (outname != NULL) {
996 unlink(outname);
997 }
998 } else {
999 // succeeded; no need to retry
1000 break;
1001 }
1002 } while (retry-- > 0);
1003
1004 const uint8_t* current_target_sha1 = SHA_final(&ctx);
1005 if (memcmp(current_target_sha1, target_sha1, SHA_DIGEST_SIZE) != 0) {
1006 printf("patch did not produce expected sha1\n");
1007 return 1;
1008 } else {
1009 printf("now ");
1010 print_short_sha1(target_sha1);
1011 putchar('\n');
1012 }
1013
1014 if (output < 0) {
1015 // Copy the temp file to the partition.
1016 if (WriteToPartition(msi.buffer, msi.pos, target_filename) != 0) {
1017 printf("write of patched data to %s failed\n", target_filename);
1018 return 1;
1019 }
1020 free(msi.buffer);
1021 } else {
1022 // Give the .patch file the same owner, group, and mode of the
1023 // original source file.
1024 if (chmod(outname, source_to_use->st.st_mode) != 0) {
1025 printf("chmod of \"%s\" failed: %s\n", outname, strerror(errno));
1026 return 1;
1027 }
1028 if (chown(outname, source_to_use->st.st_uid,
1029 source_to_use->st.st_gid) != 0) {
1030 printf("chown of \"%s\" failed: %s\n", outname, strerror(errno));
1031 return 1;
1032 }
1033
1034 // Finally, rename the .patch file to replace the target file.
1035 if (rename(outname, target_filename) != 0) {
1036 printf("rename of .patch to \"%s\" failed: %s\n",
1037 target_filename, strerror(errno));
1038 return 1;
1039 }
1040 }
1041
1042 // If this run of applypatch created the copy, and we're here, we
1043 // can delete it.
1044 if (made_copy) unlink(CACHE_TEMP_SOURCE);
1045
1046 // Success!
1047 return 0;
1048 }
1049