1 /*
2 * Copyright (C) 2007 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 #define TRACE_TAG SYNC
18
19 #include "daemon/file_sync_service.h"
20
21 #include "sysdeps.h"
22
23 #include <dirent.h>
24 #include <errno.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <sys/stat.h>
29 #include <sys/time.h>
30 #include <sys/types.h>
31 #include <unistd.h>
32 #include <utime.h>
33
34 #include <memory>
35 #include <string>
36 #include <vector>
37
38 #include <android-base/file.h>
39 #include <android-base/macros.h>
40 #include <android-base/stringprintf.h>
41 #include <android-base/strings.h>
42
43 #include <private/android_filesystem_config.h>
44 #include <private/android_logger.h>
45
46 #if defined(__ANDROID__)
47 #include <selinux/android.h>
48 #include <sys/xattr.h>
49 #endif
50
51 #include "adb.h"
52 #include "adb_io.h"
53 #include "adb_trace.h"
54 #include "adb_utils.h"
55 #include "file_sync_protocol.h"
56 #include "security_log_tags.h"
57 #include "sysdeps/errno.h"
58
59 using android::base::Dirname;
60 using android::base::StringPrintf;
61
should_use_fs_config(const std::string & path)62 static bool should_use_fs_config(const std::string& path) {
63 #if defined(__ANDROID__)
64 // TODO: use fs_config to configure permissions on /data too.
65 return !android::base::StartsWith(path, "/data/");
66 #else
67 UNUSED(path);
68 return false;
69 #endif
70 }
71
update_capabilities(const char * path,uint64_t capabilities)72 static bool update_capabilities(const char* path, uint64_t capabilities) {
73 #if defined(__ANDROID__)
74 if (capabilities == 0) {
75 // Ensure we clean up in case the capabilities weren't 0 in the past.
76 removexattr(path, XATTR_NAME_CAPS);
77 return true;
78 }
79
80 vfs_cap_data cap_data = {};
81 cap_data.magic_etc = VFS_CAP_REVISION_2 | VFS_CAP_FLAGS_EFFECTIVE;
82 cap_data.data[0].permitted = (capabilities & 0xffffffff);
83 cap_data.data[0].inheritable = 0;
84 cap_data.data[1].permitted = (capabilities >> 32);
85 cap_data.data[1].inheritable = 0;
86 return setxattr(path, XATTR_NAME_CAPS, &cap_data, sizeof(cap_data), 0) != -1;
87 #else
88 UNUSED(path, capabilities);
89 return true;
90 #endif
91 }
92
secure_mkdirs(const std::string & path)93 static bool secure_mkdirs(const std::string& path) {
94 if (path[0] != '/') return false;
95
96 std::vector<std::string> path_components = android::base::Split(path, "/");
97 std::string partial_path;
98 for (const auto& path_component : path_components) {
99 uid_t uid = -1;
100 gid_t gid = -1;
101 unsigned int mode = 0775;
102 uint64_t capabilities = 0;
103
104 if (path_component.empty()) {
105 continue;
106 }
107
108 if (partial_path.empty() || partial_path.back() != OS_PATH_SEPARATOR) {
109 partial_path += OS_PATH_SEPARATOR;
110 }
111 partial_path += path_component;
112
113 if (should_use_fs_config(partial_path)) {
114 fs_config(partial_path.c_str(), 1, nullptr, &uid, &gid, &mode, &capabilities);
115 }
116 if (adb_mkdir(partial_path.c_str(), mode) == -1) {
117 if (errno != EEXIST) {
118 return false;
119 }
120 } else {
121 if (chown(partial_path.c_str(), uid, gid) == -1) return false;
122
123 #if defined(__ANDROID__)
124 // Not all filesystems support setting SELinux labels. http://b/23530370.
125 selinux_android_restorecon(partial_path.c_str(), 0);
126 #endif
127
128 if (!update_capabilities(partial_path.c_str(), capabilities)) return false;
129 }
130 }
131 return true;
132 }
133
do_lstat_v1(int s,const char * path)134 static bool do_lstat_v1(int s, const char* path) {
135 syncmsg msg = {};
136 msg.stat_v1.id = ID_LSTAT_V1;
137
138 struct stat st = {};
139 lstat(path, &st);
140 msg.stat_v1.mode = st.st_mode;
141 msg.stat_v1.size = st.st_size;
142 msg.stat_v1.time = st.st_mtime;
143 return WriteFdExactly(s, &msg.stat_v1, sizeof(msg.stat_v1));
144 }
145
do_stat_v2(int s,uint32_t id,const char * path)146 static bool do_stat_v2(int s, uint32_t id, const char* path) {
147 syncmsg msg = {};
148 msg.stat_v2.id = id;
149
150 decltype(&stat) stat_fn;
151 if (id == ID_STAT_V2) {
152 stat_fn = stat;
153 } else {
154 stat_fn = lstat;
155 }
156
157 struct stat st = {};
158 int rc = stat_fn(path, &st);
159 if (rc == -1) {
160 msg.stat_v2.error = errno_to_wire(errno);
161 } else {
162 msg.stat_v2.dev = st.st_dev;
163 msg.stat_v2.ino = st.st_ino;
164 msg.stat_v2.mode = st.st_mode;
165 msg.stat_v2.nlink = st.st_nlink;
166 msg.stat_v2.uid = st.st_uid;
167 msg.stat_v2.gid = st.st_gid;
168 msg.stat_v2.size = st.st_size;
169 msg.stat_v2.atime = st.st_atime;
170 msg.stat_v2.mtime = st.st_mtime;
171 msg.stat_v2.ctime = st.st_ctime;
172 }
173
174 return WriteFdExactly(s, &msg.stat_v2, sizeof(msg.stat_v2));
175 }
176
do_list(int s,const char * path)177 static bool do_list(int s, const char* path) {
178 dirent* de;
179
180 syncmsg msg;
181 msg.dent.id = ID_DENT;
182
183 std::unique_ptr<DIR, int(*)(DIR*)> d(opendir(path), closedir);
184 if (!d) goto done;
185
186 while ((de = readdir(d.get()))) {
187 std::string filename(StringPrintf("%s/%s", path, de->d_name));
188
189 struct stat st;
190 if (lstat(filename.c_str(), &st) == 0) {
191 size_t d_name_length = strlen(de->d_name);
192 msg.dent.mode = st.st_mode;
193 msg.dent.size = st.st_size;
194 msg.dent.time = st.st_mtime;
195 msg.dent.namelen = d_name_length;
196
197 if (!WriteFdExactly(s, &msg.dent, sizeof(msg.dent)) ||
198 !WriteFdExactly(s, de->d_name, d_name_length)) {
199 return false;
200 }
201 }
202 }
203
204 done:
205 msg.dent.id = ID_DONE;
206 msg.dent.mode = 0;
207 msg.dent.size = 0;
208 msg.dent.time = 0;
209 msg.dent.namelen = 0;
210 return WriteFdExactly(s, &msg.dent, sizeof(msg.dent));
211 }
212
213 // Make sure that SendFail from adb_io.cpp isn't accidentally used in this file.
214 #pragma GCC poison SendFail
215
SendSyncFail(int fd,const std::string & reason)216 static bool SendSyncFail(int fd, const std::string& reason) {
217 D("sync: failure: %s", reason.c_str());
218
219 syncmsg msg;
220 msg.data.id = ID_FAIL;
221 msg.data.size = reason.size();
222 return WriteFdExactly(fd, &msg.data, sizeof(msg.data)) && WriteFdExactly(fd, reason);
223 }
224
SendSyncFailErrno(int fd,const std::string & reason)225 static bool SendSyncFailErrno(int fd, const std::string& reason) {
226 return SendSyncFail(fd, StringPrintf("%s: %s", reason.c_str(), strerror(errno)));
227 }
228
handle_send_file(int s,const char * path,uint32_t * timestamp,uid_t uid,gid_t gid,uint64_t capabilities,mode_t mode,std::vector<char> & buffer,bool do_unlink)229 static bool handle_send_file(int s, const char* path, uint32_t* timestamp, uid_t uid, gid_t gid,
230 uint64_t capabilities, mode_t mode, std::vector<char>& buffer,
231 bool do_unlink) {
232 int rc;
233 syncmsg msg;
234
235 __android_log_security_bswrite(SEC_TAG_ADB_SEND_FILE, path);
236
237 unique_fd fd(adb_open_mode(path, O_WRONLY | O_CREAT | O_EXCL | O_CLOEXEC, mode));
238
239 if (fd < 0 && errno == ENOENT) {
240 if (!secure_mkdirs(Dirname(path))) {
241 SendSyncFailErrno(s, "secure_mkdirs failed");
242 goto fail;
243 }
244 fd.reset(adb_open_mode(path, O_WRONLY | O_CREAT | O_EXCL | O_CLOEXEC, mode));
245 }
246 if (fd < 0 && errno == EEXIST) {
247 fd.reset(adb_open_mode(path, O_WRONLY | O_CLOEXEC, mode));
248 }
249 if (fd < 0) {
250 SendSyncFailErrno(s, "couldn't create file");
251 goto fail;
252 } else {
253 if (fchown(fd.get(), uid, gid) == -1) {
254 SendSyncFailErrno(s, "fchown failed");
255 goto fail;
256 }
257
258 #if defined(__ANDROID__)
259 // Not all filesystems support setting SELinux labels. http://b/23530370.
260 selinux_android_restorecon(path, 0);
261 #endif
262
263 // fchown clears the setuid bit - restore it if present.
264 // Ignore the result of calling fchmod. It's not supported
265 // by all filesystems, so we don't check for success. b/12441485
266 fchmod(fd.get(), mode);
267 }
268
269 rc = posix_fadvise(fd.get(), 0, 0,
270 POSIX_FADV_SEQUENTIAL | POSIX_FADV_NOREUSE | POSIX_FADV_WILLNEED);
271 if (rc != 0) {
272 D("[ Failed to fadvise: %s ]", strerror(rc));
273 }
274
275 while (true) {
276 if (!ReadFdExactly(s, &msg.data, sizeof(msg.data))) goto fail;
277
278 if (msg.data.id != ID_DATA) {
279 if (msg.data.id == ID_DONE) {
280 *timestamp = msg.data.size;
281 break;
282 }
283 SendSyncFail(s, "invalid data message");
284 goto abort;
285 }
286
287 if (msg.data.size > buffer.size()) { // TODO: resize buffer?
288 SendSyncFail(s, "oversize data message");
289 goto abort;
290 }
291
292 if (!ReadFdExactly(s, &buffer[0], msg.data.size)) goto abort;
293
294 if (!WriteFdExactly(fd.get(), &buffer[0], msg.data.size)) {
295 SendSyncFailErrno(s, "write failed");
296 goto fail;
297 }
298 }
299
300 if (!update_capabilities(path, capabilities)) {
301 SendSyncFailErrno(s, "update_capabilities failed");
302 goto fail;
303 }
304
305 msg.status.id = ID_OKAY;
306 msg.status.msglen = 0;
307 return WriteFdExactly(s, &msg.status, sizeof(msg.status));
308
309 fail:
310 // If there's a problem on the device, we'll send an ID_FAIL message and
311 // close the socket. Unfortunately the kernel will sometimes throw that
312 // data away if the other end keeps writing without reading (which is
313 // the case with old versions of adb). To maintain compatibility, keep
314 // reading and throwing away ID_DATA packets until the other side notices
315 // that we've reported an error.
316 while (true) {
317 if (!ReadFdExactly(s, &msg.data, sizeof(msg.data))) break;
318
319 if (msg.data.id == ID_DONE) {
320 break;
321 } else if (msg.data.id != ID_DATA) {
322 char id[5];
323 memcpy(id, &msg.data.id, sizeof(msg.data.id));
324 id[4] = '\0';
325 D("handle_send_fail received unexpected id '%s' during failure", id);
326 break;
327 }
328
329 if (msg.data.size > buffer.size()) {
330 D("handle_send_fail received oversized packet of length '%u' during failure",
331 msg.data.size);
332 break;
333 }
334
335 if (!ReadFdExactly(s, &buffer[0], msg.data.size)) break;
336 }
337
338 abort:
339 if (do_unlink) adb_unlink(path);
340 return false;
341 }
342
343 #if defined(_WIN32)
344 extern bool handle_send_link(int s, const std::string& path,
345 uint32_t* timestamp, std::vector<char>& buffer)
346 __attribute__((error("no symlinks on Windows")));
347 #else
handle_send_link(int s,const std::string & path,uint32_t * timestamp,std::vector<char> & buffer)348 static bool handle_send_link(int s, const std::string& path, uint32_t* timestamp,
349 std::vector<char>& buffer) {
350 syncmsg msg;
351
352 if (!ReadFdExactly(s, &msg.data, sizeof(msg.data))) return false;
353
354 if (msg.data.id != ID_DATA) {
355 SendSyncFail(s, "invalid data message: expected ID_DATA");
356 return false;
357 }
358
359 unsigned int len = msg.data.size;
360 if (len > buffer.size()) { // TODO: resize buffer?
361 SendSyncFail(s, "oversize data message");
362 return false;
363 }
364 if (!ReadFdExactly(s, &buffer[0], len)) return false;
365
366 std::string buf_link;
367 if (!android::base::Readlink(path, &buf_link) || (buf_link != &buffer[0])) {
368 adb_unlink(path.c_str());
369 auto ret = symlink(&buffer[0], path.c_str());
370 if (ret && errno == ENOENT) {
371 if (!secure_mkdirs(Dirname(path))) {
372 SendSyncFailErrno(s, "secure_mkdirs failed");
373 return false;
374 }
375 ret = symlink(&buffer[0], path.c_str());
376 }
377 if (ret) {
378 SendSyncFailErrno(s, "symlink failed");
379 return false;
380 }
381 }
382
383 if (!ReadFdExactly(s, &msg.data, sizeof(msg.data))) return false;
384
385 if (msg.data.id == ID_DONE) {
386 *timestamp = msg.data.size;
387 msg.status.id = ID_OKAY;
388 msg.status.msglen = 0;
389 if (!WriteFdExactly(s, &msg.status, sizeof(msg.status))) return false;
390 } else {
391 SendSyncFail(s, "invalid data message: expected ID_DONE");
392 return false;
393 }
394
395 return true;
396 }
397 #endif
398
do_send(int s,const std::string & spec,std::vector<char> & buffer)399 static bool do_send(int s, const std::string& spec, std::vector<char>& buffer) {
400 // 'spec' is of the form "/some/path,0755". Break it up.
401 size_t comma = spec.find_last_of(',');
402 if (comma == std::string::npos) {
403 SendSyncFail(s, "missing , in ID_SEND");
404 return false;
405 }
406
407 std::string path = spec.substr(0, comma);
408
409 errno = 0;
410 mode_t mode = strtoul(spec.substr(comma + 1).c_str(), nullptr, 0);
411 if (errno != 0) {
412 SendSyncFail(s, "bad mode");
413 return false;
414 }
415
416 // Don't delete files before copying if they are not "regular" or symlinks.
417 struct stat st;
418 bool do_unlink = (lstat(path.c_str(), &st) == -1) || S_ISREG(st.st_mode) ||
419 (S_ISLNK(st.st_mode) && !S_ISLNK(mode));
420 if (do_unlink) {
421 adb_unlink(path.c_str());
422 }
423
424 bool result;
425 uint32_t timestamp;
426 if (S_ISLNK(mode)) {
427 result = handle_send_link(s, path, ×tamp, buffer);
428 } else {
429 // Copy user permission bits to "group" and "other" permissions.
430 mode &= 0777;
431 mode |= ((mode >> 3) & 0070);
432 mode |= ((mode >> 3) & 0007);
433
434 uid_t uid = -1;
435 gid_t gid = -1;
436 uint64_t capabilities = 0;
437 if (should_use_fs_config(path)) {
438 unsigned int broken_api_hack = mode;
439 fs_config(path.c_str(), 0, nullptr, &uid, &gid, &broken_api_hack, &capabilities);
440 mode = broken_api_hack;
441 }
442
443 result = handle_send_file(s, path.c_str(), ×tamp, uid, gid, capabilities, mode, buffer,
444 do_unlink);
445 }
446
447 if (!result) {
448 return false;
449 }
450
451 struct timeval tv[2];
452 tv[0].tv_sec = timestamp;
453 tv[0].tv_usec = 0;
454 tv[1].tv_sec = timestamp;
455 tv[1].tv_usec = 0;
456 lutimes(path.c_str(), tv);
457 return true;
458 }
459
do_recv(int s,const char * path,std::vector<char> & buffer)460 static bool do_recv(int s, const char* path, std::vector<char>& buffer) {
461 __android_log_security_bswrite(SEC_TAG_ADB_RECV_FILE, path);
462
463 unique_fd fd(adb_open(path, O_RDONLY | O_CLOEXEC));
464 if (fd < 0) {
465 SendSyncFailErrno(s, "open failed");
466 return false;
467 }
468
469 int rc = posix_fadvise(fd.get(), 0, 0, POSIX_FADV_SEQUENTIAL | POSIX_FADV_NOREUSE);
470 if (rc != 0) {
471 D("[ Failed to fadvise: %s ]", strerror(rc));
472 }
473
474 syncmsg msg;
475 msg.data.id = ID_DATA;
476 while (true) {
477 int r = adb_read(fd.get(), &buffer[0], buffer.size() - sizeof(msg.data));
478 if (r <= 0) {
479 if (r == 0) break;
480 SendSyncFailErrno(s, "read failed");
481 return false;
482 }
483 msg.data.size = r;
484 if (!WriteFdExactly(s, &msg.data, sizeof(msg.data)) || !WriteFdExactly(s, &buffer[0], r)) {
485 return false;
486 }
487 }
488
489 msg.data.id = ID_DONE;
490 msg.data.size = 0;
491 return WriteFdExactly(s, &msg.data, sizeof(msg.data));
492 }
493
sync_id_to_name(uint32_t id)494 static const char* sync_id_to_name(uint32_t id) {
495 switch (id) {
496 case ID_LSTAT_V1:
497 return "lstat_v1";
498 case ID_LSTAT_V2:
499 return "lstat_v2";
500 case ID_STAT_V2:
501 return "stat_v2";
502 case ID_LIST:
503 return "list";
504 case ID_SEND:
505 return "send";
506 case ID_RECV:
507 return "recv";
508 case ID_QUIT:
509 return "quit";
510 default:
511 return "???";
512 }
513 }
514
handle_sync_command(int fd,std::vector<char> & buffer)515 static bool handle_sync_command(int fd, std::vector<char>& buffer) {
516 D("sync: waiting for request");
517
518 ATRACE_CALL();
519 SyncRequest request;
520 if (!ReadFdExactly(fd, &request, sizeof(request))) {
521 SendSyncFail(fd, "command read failure");
522 return false;
523 }
524 size_t path_length = request.path_length;
525 if (path_length > 1024) {
526 SendSyncFail(fd, "path too long");
527 return false;
528 }
529 char name[1025];
530 if (!ReadFdExactly(fd, name, path_length)) {
531 SendSyncFail(fd, "filename read failure");
532 return false;
533 }
534 name[path_length] = 0;
535
536 std::string id_name = sync_id_to_name(request.id);
537 std::string trace_name = StringPrintf("%s(%s)", id_name.c_str(), name);
538 ATRACE_NAME(trace_name.c_str());
539
540 D("sync: %s('%s')", id_name.c_str(), name);
541 switch (request.id) {
542 case ID_LSTAT_V1:
543 if (!do_lstat_v1(fd, name)) return false;
544 break;
545 case ID_LSTAT_V2:
546 case ID_STAT_V2:
547 if (!do_stat_v2(fd, request.id, name)) return false;
548 break;
549 case ID_LIST:
550 if (!do_list(fd, name)) return false;
551 break;
552 case ID_SEND:
553 if (!do_send(fd, name, buffer)) return false;
554 break;
555 case ID_RECV:
556 if (!do_recv(fd, name, buffer)) return false;
557 break;
558 case ID_QUIT:
559 return false;
560 default:
561 SendSyncFail(fd, StringPrintf("unknown command %08x", request.id));
562 return false;
563 }
564
565 return true;
566 }
567
file_sync_service(unique_fd fd)568 void file_sync_service(unique_fd fd) {
569 std::vector<char> buffer(SYNC_DATA_MAX);
570
571 while (handle_sync_command(fd.get(), buffer)) {
572 }
573
574 D("sync: done");
575 }
576