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