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 <stdlib.h>
18 #include <sys/mount.h>
19 #include <sys/socket.h>
20 #include <sys/stat.h>
21 #include <sys/types.h>
22 #include <sys/wait.h>
23 #include <netinet/in.h>
24 #include <arpa/inet.h>
25 #include <dirent.h>
26 #include <errno.h>
27 #include <fcntl.h>
28 #include <fs_mgr.h>
29 #include <stdio.h>
30 #include <string.h>
31 #include <stdint.h>
32 #include <inttypes.h>
33 #include <ctype.h>
34 
35 #define LOG_TAG "VoldCmdListener"
36 
37 #include <android-base/logging.h>
38 #include <android-base/stringprintf.h>
39 #include <cutils/fs.h>
40 
41 #include <sysutils/SocketClient.h>
42 #include <private/android_filesystem_config.h>
43 
44 #include "CommandListener.h"
45 #include "VolumeManager.h"
46 #include "VolumeBase.h"
47 #include "ResponseCode.h"
48 #include "Process.h"
49 #include "Loop.h"
50 #include "Devmapper.h"
51 #include "MoveTask.h"
52 #include "TrimTask.h"
53 
54 #define DUMP_ARGS 0
55 #define DEBUG_APPFUSE 0
56 
CommandListener()57 CommandListener::CommandListener() :
58                  FrameworkListener("vold", true) {
59     registerCmd(new DumpCmd());
60     registerCmd(new VolumeCmd());
61     registerCmd(new AsecCmd());
62     registerCmd(new ObbCmd());
63     registerCmd(new StorageCmd());
64     registerCmd(new FstrimCmd());
65     registerCmd(new AppFuseCmd());
66 }
67 
68 #if DUMP_ARGS
dumpArgs(int argc,char ** argv,int argObscure)69 void CommandListener::dumpArgs(int argc, char **argv, int argObscure) {
70     char buffer[4096];
71     char *p = buffer;
72 
73     memset(buffer, 0, sizeof(buffer));
74     int i;
75     for (i = 0; i < argc; i++) {
76         unsigned int len = strlen(argv[i]) + 1; // Account for space
77         if (i == argObscure) {
78             len += 2; // Account for {}
79         }
80         if (((p - buffer) + len) < (sizeof(buffer)-1)) {
81             if (i == argObscure) {
82                 *p++ = '{';
83                 *p++ = '}';
84                 *p++ = ' ';
85                 continue;
86             }
87             strcpy(p, argv[i]);
88             p+= strlen(argv[i]);
89             if (i != (argc -1)) {
90                 *p++ = ' ';
91             }
92         }
93     }
94     SLOGD("%s", buffer);
95 }
96 #else
dumpArgs(int,char **,int)97 void CommandListener::dumpArgs(int /*argc*/, char ** /*argv*/, int /*argObscure*/) { }
98 #endif
99 
sendGenericOkFail(SocketClient * cli,int cond)100 int CommandListener::sendGenericOkFail(SocketClient *cli, int cond) {
101     if (!cond) {
102         return cli->sendMsg(ResponseCode::CommandOkay, "Command succeeded", false);
103     } else {
104         return cli->sendMsg(ResponseCode::OperationFailed, "Command failed", false);
105     }
106 }
107 
DumpCmd()108 CommandListener::DumpCmd::DumpCmd() :
109                  VoldCommand("dump") {
110 }
111 
runCommand(SocketClient * cli,int,char **)112 int CommandListener::DumpCmd::runCommand(SocketClient *cli,
113                                          int /*argc*/, char ** /*argv*/) {
114     cli->sendMsg(0, "Dumping loop status", false);
115     if (Loop::dumpState(cli)) {
116         cli->sendMsg(ResponseCode::CommandOkay, "Loop dump failed", true);
117     }
118     cli->sendMsg(0, "Dumping DM status", false);
119     if (Devmapper::dumpState(cli)) {
120         cli->sendMsg(ResponseCode::CommandOkay, "Devmapper dump failed", true);
121     }
122     cli->sendMsg(0, "Dumping mounted filesystems", false);
123     FILE *fp = fopen("/proc/mounts", "r");
124     if (fp) {
125         char line[1024];
126         while (fgets(line, sizeof(line), fp)) {
127             line[strlen(line)-1] = '\0';
128             cli->sendMsg(0, line, false);;
129         }
130         fclose(fp);
131     }
132 
133     cli->sendMsg(ResponseCode::CommandOkay, "dump complete", false);
134     return 0;
135 }
136 
VolumeCmd()137 CommandListener::VolumeCmd::VolumeCmd() :
138                  VoldCommand("volume") {
139 }
140 
runCommand(SocketClient * cli,int argc,char ** argv)141 int CommandListener::VolumeCmd::runCommand(SocketClient *cli,
142                                            int argc, char **argv) {
143     dumpArgs(argc, argv, -1);
144 
145     if (argc < 2) {
146         cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing Argument", false);
147         return 0;
148     }
149 
150     VolumeManager *vm = VolumeManager::Instance();
151     std::lock_guard<std::mutex> lock(vm->getLock());
152 
153     // TODO: tease out methods not directly related to volumes
154 
155     std::string cmd(argv[1]);
156     if (cmd == "reset") {
157         return sendGenericOkFail(cli, vm->reset());
158 
159     } else if (cmd == "shutdown") {
160         return sendGenericOkFail(cli, vm->shutdown());
161 
162     } else if (cmd == "debug") {
163         return sendGenericOkFail(cli, vm->setDebug(true));
164 
165     } else if (cmd == "partition" && argc > 3) {
166         // partition [diskId] [public|private|mixed] [ratio]
167         std::string id(argv[2]);
168         auto disk = vm->findDisk(id);
169         if (disk == nullptr) {
170             return cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown disk", false);
171         }
172 
173         std::string type(argv[3]);
174         if (type == "public") {
175             return sendGenericOkFail(cli, disk->partitionPublic());
176         } else if (type == "private") {
177             return sendGenericOkFail(cli, disk->partitionPrivate());
178         } else if (type == "mixed") {
179             if (argc < 4) {
180                 return cli->sendMsg(ResponseCode::CommandSyntaxError, nullptr, false);
181             }
182             int frac = atoi(argv[4]);
183             return sendGenericOkFail(cli, disk->partitionMixed(frac));
184         } else {
185             return cli->sendMsg(ResponseCode::CommandSyntaxError, nullptr, false);
186         }
187 
188     } else if (cmd == "mkdirs" && argc > 2) {
189         // mkdirs [path]
190         return sendGenericOkFail(cli, vm->mkdirs(argv[2]));
191 
192     } else if (cmd == "user_added" && argc > 3) {
193         // user_added [user] [serial]
194         return sendGenericOkFail(cli, vm->onUserAdded(atoi(argv[2]), atoi(argv[3])));
195 
196     } else if (cmd == "user_removed" && argc > 2) {
197         // user_removed [user]
198         return sendGenericOkFail(cli, vm->onUserRemoved(atoi(argv[2])));
199 
200     } else if (cmd == "user_started" && argc > 2) {
201         // user_started [user]
202         return sendGenericOkFail(cli, vm->onUserStarted(atoi(argv[2])));
203 
204     } else if (cmd == "user_stopped" && argc > 2) {
205         // user_stopped [user]
206         return sendGenericOkFail(cli, vm->onUserStopped(atoi(argv[2])));
207 
208     } else if (cmd == "mount" && argc > 2) {
209         // mount [volId] [flags] [user]
210         std::string id(argv[2]);
211         auto vol = vm->findVolume(id);
212         if (vol == nullptr) {
213             return cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown volume", false);
214         }
215 
216         int mountFlags = (argc > 3) ? atoi(argv[3]) : 0;
217         userid_t mountUserId = (argc > 4) ? atoi(argv[4]) : -1;
218 
219         vol->setMountFlags(mountFlags);
220         vol->setMountUserId(mountUserId);
221 
222         int res = vol->mount();
223         if (mountFlags & android::vold::VolumeBase::MountFlags::kPrimary) {
224             vm->setPrimary(vol);
225         }
226         return sendGenericOkFail(cli, res);
227 
228     } else if (cmd == "unmount" && argc > 2) {
229         // unmount [volId]
230         std::string id(argv[2]);
231         auto vol = vm->findVolume(id);
232         if (vol == nullptr) {
233             return cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown volume", false);
234         }
235 
236         return sendGenericOkFail(cli, vol->unmount());
237 
238     } else if (cmd == "format" && argc > 3) {
239         // format [volId] [fsType|auto]
240         std::string id(argv[2]);
241         std::string fsType(argv[3]);
242         auto vol = vm->findVolume(id);
243         if (vol == nullptr) {
244             return cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown volume", false);
245         }
246 
247         return sendGenericOkFail(cli, vol->format(fsType));
248 
249     } else if (cmd == "move_storage" && argc > 3) {
250         // move_storage [fromVolId] [toVolId]
251         auto fromVol = vm->findVolume(std::string(argv[2]));
252         auto toVol = vm->findVolume(std::string(argv[3]));
253         if (fromVol == nullptr || toVol == nullptr) {
254             return cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown volume", false);
255         }
256 
257         (new android::vold::MoveTask(fromVol, toVol))->start();
258         return sendGenericOkFail(cli, 0);
259 
260     } else if (cmd == "benchmark" && argc > 2) {
261         // benchmark [volId]
262         std::string id(argv[2]);
263         nsecs_t res = vm->benchmarkPrivate(id);
264         return cli->sendMsg(ResponseCode::CommandOkay,
265                 android::base::StringPrintf("%" PRId64, res).c_str(), false);
266 
267     } else if (cmd == "forget_partition" && argc > 2) {
268         // forget_partition [partGuid]
269         std::string partGuid(argv[2]);
270         return sendGenericOkFail(cli, vm->forgetPartition(partGuid));
271 
272     } else if (cmd == "remount_uid" && argc > 3) {
273         // remount_uid [uid] [none|default|read|write]
274         uid_t uid = atoi(argv[2]);
275         std::string mode(argv[3]);
276         return sendGenericOkFail(cli, vm->remountUid(uid, mode));
277     }
278 
279     return cli->sendMsg(ResponseCode::CommandSyntaxError, nullptr, false);
280 }
281 
StorageCmd()282 CommandListener::StorageCmd::StorageCmd() :
283                  VoldCommand("storage") {
284 }
285 
runCommand(SocketClient * cli,int argc,char ** argv)286 int CommandListener::StorageCmd::runCommand(SocketClient *cli,
287                                                       int argc, char **argv) {
288     /* Guarantied to be initialized by vold's main() before the CommandListener is active */
289     extern struct fstab *fstab;
290 
291     dumpArgs(argc, argv, -1);
292 
293     if (argc < 2) {
294         cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing Argument", false);
295         return 0;
296     }
297 
298     if (!strcmp(argv[1], "mountall")) {
299         if (argc != 2) {
300             cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: mountall", false);
301             return 0;
302         }
303         fs_mgr_mount_all(fstab);
304         cli->sendMsg(ResponseCode::CommandOkay, "Mountall ran successfully", false);
305         return 0;
306     }
307     if (!strcmp(argv[1], "users")) {
308         DIR *dir;
309         struct dirent *de;
310 
311         if (argc < 3) {
312             cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing Argument: user <mountpoint>", false);
313             return 0;
314         }
315         if (!(dir = opendir("/proc"))) {
316             cli->sendMsg(ResponseCode::OperationFailed, "Failed to open /proc", true);
317             return 0;
318         }
319 
320         while ((de = readdir(dir))) {
321             int pid = Process::getPid(de->d_name);
322 
323             if (pid < 0) {
324                 continue;
325             }
326 
327             char processName[255];
328             Process::getProcessName(pid, processName, sizeof(processName));
329 
330             if (Process::checkFileDescriptorSymLinks(pid, argv[2]) ||
331                 Process::checkFileMaps(pid, argv[2]) ||
332                 Process::checkSymLink(pid, argv[2], "cwd") ||
333                 Process::checkSymLink(pid, argv[2], "root") ||
334                 Process::checkSymLink(pid, argv[2], "exe")) {
335 
336                 char msg[1024];
337                 snprintf(msg, sizeof(msg), "%d %s", pid, processName);
338                 cli->sendMsg(ResponseCode::StorageUsersListResult, msg, false);
339             }
340         }
341         closedir(dir);
342         cli->sendMsg(ResponseCode::CommandOkay, "Storage user list complete", false);
343     } else {
344         cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown storage cmd", false);
345     }
346     return 0;
347 }
348 
AsecCmd()349 CommandListener::AsecCmd::AsecCmd() :
350                  VoldCommand("asec") {
351 }
352 
listAsecsInDirectory(SocketClient * cli,const char * directory)353 void CommandListener::AsecCmd::listAsecsInDirectory(SocketClient *cli, const char *directory) {
354     DIR *d = opendir(directory);
355 
356     if (!d) {
357         cli->sendMsg(ResponseCode::OperationFailed, "Failed to open asec dir", true);
358         return;
359     }
360 
361     size_t dirent_len = offsetof(struct dirent, d_name) +
362             fpathconf(dirfd(d), _PC_NAME_MAX) + 1;
363 
364     struct dirent *dent = (struct dirent *) malloc(dirent_len);
365     if (dent == NULL) {
366         cli->sendMsg(ResponseCode::OperationFailed, "Failed to allocate memory", true);
367         return;
368     }
369 
370     struct dirent *result;
371 
372     while (!readdir_r(d, dent, &result) && result != NULL) {
373         if (dent->d_name[0] == '.')
374             continue;
375         if (dent->d_type != DT_REG)
376             continue;
377         size_t name_len = strlen(dent->d_name);
378         if (name_len > 5 && name_len < 260 &&
379                 !strcmp(&dent->d_name[name_len - 5], ".asec")) {
380             char id[255];
381             memset(id, 0, sizeof(id));
382             strlcpy(id, dent->d_name, name_len - 4);
383             cli->sendMsg(ResponseCode::AsecListResult, id, false);
384         }
385     }
386     closedir(d);
387 
388     free(dent);
389 }
390 
runCommand(SocketClient * cli,int argc,char ** argv)391 int CommandListener::AsecCmd::runCommand(SocketClient *cli,
392                                                       int argc, char **argv) {
393     if (argc < 2) {
394         cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing Argument", false);
395         return 0;
396     }
397 
398     VolumeManager *vm = VolumeManager::Instance();
399     int rc = 0;
400 
401     if (!strcmp(argv[1], "list")) {
402         dumpArgs(argc, argv, -1);
403 
404         listAsecsInDirectory(cli, VolumeManager::SEC_ASECDIR_EXT);
405         listAsecsInDirectory(cli, VolumeManager::SEC_ASECDIR_INT);
406     } else if (!strcmp(argv[1], "create")) {
407         dumpArgs(argc, argv, 5);
408         if (argc != 8) {
409             cli->sendMsg(ResponseCode::CommandSyntaxError,
410                     "Usage: asec create <container-id> <size_mb> <fstype> <key> <ownerUid> "
411                     "<isExternal>", false);
412             return 0;
413         }
414 
415         unsigned long numSectors = (atoi(argv[3]) * (1024 * 1024)) / 512;
416         const bool isExternal = (atoi(argv[7]) == 1);
417         rc = vm->createAsec(argv[2], numSectors, argv[4], argv[5], atoi(argv[6]), isExternal);
418     } else if (!strcmp(argv[1], "resize")) {
419         dumpArgs(argc, argv, -1);
420         if (argc != 5) {
421             cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec resize <container-id> <size_mb> <key>", false);
422             return 0;
423         }
424         unsigned long numSectors = (atoi(argv[3]) * (1024 * 1024)) / 512;
425         rc = vm->resizeAsec(argv[2], numSectors, argv[4]);
426     } else if (!strcmp(argv[1], "finalize")) {
427         dumpArgs(argc, argv, -1);
428         if (argc != 3) {
429             cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec finalize <container-id>", false);
430             return 0;
431         }
432         rc = vm->finalizeAsec(argv[2]);
433     } else if (!strcmp(argv[1], "fixperms")) {
434         dumpArgs(argc, argv, -1);
435         if  (argc != 5) {
436             cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec fixperms <container-id> <gid> <filename>", false);
437             return 0;
438         }
439 
440         char *endptr;
441         gid_t gid = (gid_t) strtoul(argv[3], &endptr, 10);
442         if (*endptr != '\0') {
443             cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec fixperms <container-id> <gid> <filename>", false);
444             return 0;
445         }
446 
447         rc = vm->fixupAsecPermissions(argv[2], gid, argv[4]);
448     } else if (!strcmp(argv[1], "destroy")) {
449         dumpArgs(argc, argv, -1);
450         if (argc < 3) {
451             cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec destroy <container-id> [force]", false);
452             return 0;
453         }
454         bool force = false;
455         if (argc > 3 && !strcmp(argv[3], "force")) {
456             force = true;
457         }
458         rc = vm->destroyAsec(argv[2], force);
459     } else if (!strcmp(argv[1], "mount")) {
460         dumpArgs(argc, argv, 3);
461         if (argc != 6) {
462             cli->sendMsg(ResponseCode::CommandSyntaxError,
463                     "Usage: asec mount <namespace-id> <key> <ownerUid> <ro|rw>", false);
464             return 0;
465         }
466         bool readOnly = true;
467         if (!strcmp(argv[5], "rw")) {
468             readOnly = false;
469         }
470         rc = vm->mountAsec(argv[2], argv[3], atoi(argv[4]), readOnly);
471     } else if (!strcmp(argv[1], "unmount")) {
472         dumpArgs(argc, argv, -1);
473         if (argc < 3) {
474             cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec unmount <container-id> [force]", false);
475             return 0;
476         }
477         bool force = false;
478         if (argc > 3 && !strcmp(argv[3], "force")) {
479             force = true;
480         }
481         rc = vm->unmountAsec(argv[2], force);
482     } else if (!strcmp(argv[1], "rename")) {
483         dumpArgs(argc, argv, -1);
484         if (argc != 4) {
485             cli->sendMsg(ResponseCode::CommandSyntaxError,
486                     "Usage: asec rename <old_id> <new_id>", false);
487             return 0;
488         }
489         rc = vm->renameAsec(argv[2], argv[3]);
490     } else if (!strcmp(argv[1], "path")) {
491         dumpArgs(argc, argv, -1);
492         if (argc != 3) {
493             cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec path <container-id>", false);
494             return 0;
495         }
496         char path[255];
497 
498         if (!(rc = vm->getAsecMountPath(argv[2], path, sizeof(path)))) {
499             cli->sendMsg(ResponseCode::AsecPathResult, path, false);
500             return 0;
501         }
502     } else if (!strcmp(argv[1], "fspath")) {
503         dumpArgs(argc, argv, -1);
504         if (argc != 3) {
505             cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: asec fspath <container-id>", false);
506             return 0;
507         }
508         char path[255];
509 
510         if (!(rc = vm->getAsecFilesystemPath(argv[2], path, sizeof(path)))) {
511             cli->sendMsg(ResponseCode::AsecPathResult, path, false);
512             return 0;
513         }
514     } else {
515         dumpArgs(argc, argv, -1);
516         cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown asec cmd", false);
517     }
518 
519     if (!rc) {
520         cli->sendMsg(ResponseCode::CommandOkay, "asec operation succeeded", false);
521     } else {
522         rc = ResponseCode::convertFromErrno();
523         cli->sendMsg(rc, "asec operation failed", true);
524     }
525 
526     return 0;
527 }
528 
ObbCmd()529 CommandListener::ObbCmd::ObbCmd() :
530                  VoldCommand("obb") {
531 }
532 
runCommand(SocketClient * cli,int argc,char ** argv)533 int CommandListener::ObbCmd::runCommand(SocketClient *cli,
534                                                       int argc, char **argv) {
535     if (argc < 2) {
536         cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing Argument", false);
537         return 0;
538     }
539 
540     VolumeManager *vm = VolumeManager::Instance();
541     int rc = 0;
542 
543     if (!strcmp(argv[1], "list")) {
544         dumpArgs(argc, argv, -1);
545 
546         rc = vm->listMountedObbs(cli);
547     } else if (!strcmp(argv[1], "mount")) {
548             dumpArgs(argc, argv, 3);
549             if (argc != 5) {
550                 cli->sendMsg(ResponseCode::CommandSyntaxError,
551                         "Usage: obb mount <filename> <key> <ownerGid>", false);
552                 return 0;
553             }
554             rc = vm->mountObb(argv[2], argv[3], atoi(argv[4]));
555     } else if (!strcmp(argv[1], "unmount")) {
556         dumpArgs(argc, argv, -1);
557         if (argc < 3) {
558             cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: obb unmount <source file> [force]", false);
559             return 0;
560         }
561         bool force = false;
562         if (argc > 3 && !strcmp(argv[3], "force")) {
563             force = true;
564         }
565         rc = vm->unmountObb(argv[2], force);
566     } else if (!strcmp(argv[1], "path")) {
567         dumpArgs(argc, argv, -1);
568         if (argc != 3) {
569             cli->sendMsg(ResponseCode::CommandSyntaxError, "Usage: obb path <source file>", false);
570             return 0;
571         }
572         char path[255];
573 
574         if (!(rc = vm->getObbMountPath(argv[2], path, sizeof(path)))) {
575             cli->sendMsg(ResponseCode::AsecPathResult, path, false);
576             return 0;
577         }
578     } else {
579         dumpArgs(argc, argv, -1);
580         cli->sendMsg(ResponseCode::CommandSyntaxError, "Unknown obb cmd", false);
581     }
582 
583     if (!rc) {
584         cli->sendMsg(ResponseCode::CommandOkay, "obb operation succeeded", false);
585     } else {
586         rc = ResponseCode::convertFromErrno();
587         cli->sendMsg(rc, "obb operation failed", true);
588     }
589 
590     return 0;
591 }
592 
FstrimCmd()593 CommandListener::FstrimCmd::FstrimCmd() :
594                  VoldCommand("fstrim") {
595 }
runCommand(SocketClient * cli,int argc,char ** argv)596 int CommandListener::FstrimCmd::runCommand(SocketClient *cli,
597                                                       int argc, char **argv) {
598     if ((cli->getUid() != 0) && (cli->getUid() != AID_SYSTEM)) {
599         cli->sendMsg(ResponseCode::CommandNoPermission, "No permission to run fstrim commands", false);
600         return 0;
601     }
602 
603     if (argc < 2) {
604         cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing Argument", false);
605         return 0;
606     }
607 
608     VolumeManager *vm = VolumeManager::Instance();
609     std::lock_guard<std::mutex> lock(vm->getLock());
610 
611     int flags = 0;
612 
613     std::string cmd(argv[1]);
614     if (cmd == "dotrim") {
615         flags = 0;
616     } else if (cmd == "dotrimbench") {
617         flags = android::vold::TrimTask::Flags::kBenchmarkAfter;
618     } else if (cmd == "dodtrim") {
619         flags = android::vold::TrimTask::Flags::kDeepTrim;
620     } else if (cmd == "dodtrimbench") {
621         flags = android::vold::TrimTask::Flags::kDeepTrim
622                 | android::vold::TrimTask::Flags::kBenchmarkAfter;
623     }
624 
625     (new android::vold::TrimTask(flags))->start();
626     return sendGenericOkFail(cli, 0);
627 }
628 
629 static size_t kAppFuseMaxMountPointName = 32;
630 
getMountPath(uid_t uid,const std::string & name,std::string * path)631 static android::status_t getMountPath(uid_t uid, const std::string& name, std::string* path) {
632     if (name.size() > kAppFuseMaxMountPointName) {
633         LOG(ERROR) << "AppFuse mount name is too long.";
634         return -EINVAL;
635     }
636     for (size_t i = 0; i < name.size(); i++) {
637         if (!isalnum(name[i])) {
638             LOG(ERROR) << "AppFuse mount name contains invalid character.";
639             return -EINVAL;
640         }
641     }
642     *path = android::base::StringPrintf("/mnt/appfuse/%d_%s", uid, name.c_str());
643     return android::OK;
644 }
645 
mountInNamespace(uid_t uid,int device_fd,const std::string & path)646 static android::status_t mountInNamespace(uid_t uid, int device_fd, const std::string& path) {
647     // Remove existing mount.
648     android::vold::ForceUnmount(path);
649 
650     const auto opts = android::base::StringPrintf(
651             "fd=%i,"
652             "rootmode=40000,"
653             "default_permissions,"
654             "allow_other,"
655             "user_id=%d,group_id=%d,"
656             "context=\"u:object_r:app_fuse_file:s0\","
657             "fscontext=u:object_r:app_fusefs:s0",
658             device_fd,
659             uid,
660             uid);
661 
662     const int result = TEMP_FAILURE_RETRY(mount(
663             "/dev/fuse", path.c_str(), "fuse",
664             MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_NOATIME, opts.c_str()));
665     if (result != 0) {
666         PLOG(ERROR) << "Failed to mount " << path;
667         return -errno;
668     }
669 
670     return android::OK;
671 }
672 
runCommandInNamespace(const std::string & command,uid_t uid,pid_t pid,const std::string & path,int device_fd)673 static android::status_t runCommandInNamespace(const std::string& command,
674                                                uid_t uid,
675                                                pid_t pid,
676                                                const std::string& path,
677                                                int device_fd) {
678     if (DEBUG_APPFUSE) {
679         LOG(DEBUG) << "Run app fuse command " << command << " for the path " << path
680                    << " in namespace " << uid;
681     }
682 
683     const android::vold::ScopedDir dir(opendir("/proc"));
684     if (dir.get() == nullptr) {
685         PLOG(ERROR) << "Failed to open /proc";
686         return -errno;
687     }
688 
689     // Obtains process file descriptor.
690     const std::string pid_str = android::base::StringPrintf("%d", pid);
691     const android::vold::ScopedFd pid_fd(
692             openat(dirfd(dir.get()), pid_str.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC));
693     if (pid_fd.get() == -1) {
694         PLOG(ERROR) << "Failed to open /proc/" << pid;
695         return -errno;
696     }
697 
698     // Check UID of process.
699     {
700         struct stat sb;
701         const int result = fstat(pid_fd.get(), &sb);
702         if (result == -1) {
703             PLOG(ERROR) << "Failed to stat /proc/" << pid;
704             return -errno;
705         }
706         if (sb.st_uid != uid) {
707             LOG(ERROR) << "Mismatch UID expected=" << uid << ", actual=" << sb.st_uid;
708             return -EPERM;
709         }
710     }
711 
712     // Matches so far, but refuse to touch if in root namespace
713     {
714         char rootName[PATH_MAX];
715         char pidName[PATH_MAX];
716         const int root_result =
717                 android::vold::SaneReadLinkAt(dirfd(dir.get()), "1/ns/mnt", rootName, PATH_MAX);
718         const int pid_result =
719                 android::vold::SaneReadLinkAt(pid_fd.get(), "ns/mnt", pidName, PATH_MAX);
720         if (root_result == -1) {
721             LOG(ERROR) << "Failed to readlink for /proc/1/ns/mnt";
722             return -EPERM;
723         }
724         if (pid_result == -1) {
725             LOG(ERROR) << "Failed to readlink for /proc/" << pid << "/ns/mnt";
726             return -EPERM;
727         }
728         if (!strcmp(rootName, pidName)) {
729             LOG(ERROR) << "Don't mount appfuse in root namespace";
730             return -EPERM;
731         }
732     }
733 
734     // We purposefully leave the namespace open across the fork
735     android::vold::ScopedFd ns_fd(openat(pid_fd.get(), "ns/mnt", O_RDONLY));
736     if (ns_fd.get() < 0) {
737         PLOG(ERROR) << "Failed to open namespace for /proc/" << pid << "/ns/mnt";
738         return -errno;
739     }
740 
741     int child = fork();
742     if (child == 0) {
743         if (setns(ns_fd.get(), CLONE_NEWNS) != 0) {
744             PLOG(ERROR) << "Failed to setns";
745             _exit(-errno);
746         }
747 
748         if (command == "mount") {
749             _exit(mountInNamespace(uid, device_fd, path));
750         } else if (command == "unmount") {
751             android::vold::ForceUnmount(path);
752             _exit(android::OK);
753         } else {
754             LOG(ERROR) << "Unknown appfuse command " << command;
755             _exit(-EPERM);
756         }
757     }
758 
759     if (child == -1) {
760         PLOG(ERROR) << "Failed to folk child process";
761         return -errno;
762     }
763 
764     android::status_t status;
765     TEMP_FAILURE_RETRY(waitpid(child, &status, 0));
766 
767     return status;
768 }
769 
AppFuseCmd()770 CommandListener::AppFuseCmd::AppFuseCmd() : VoldCommand("appfuse") {}
771 
runCommand(SocketClient * cli,int argc,char ** argv)772 int CommandListener::AppFuseCmd::runCommand(SocketClient *cli, int argc, char **argv) {
773     if (argc < 2) {
774         cli->sendMsg(ResponseCode::CommandSyntaxError, "Missing argument", false);
775         return 0;
776     }
777 
778     const std::string command(argv[1]);
779 
780     if (command == "mount" && argc == 5) {
781         const uid_t uid = atoi(argv[2]);
782         const pid_t pid = atoi(argv[3]);
783         const std::string name(argv[4]);
784 
785         // Check mount point name.
786         std::string path;
787         if (getMountPath(uid, name, &path) != android::OK) {
788             return cli->sendMsg(ResponseCode::CommandParameterError,
789                                 "Invalid mount point name.",
790                                 false);
791         }
792 
793         // Create directories.
794         {
795             const android::status_t result = android::vold::PrepareDir(path, 0700, 0, 0);
796             if (result != android::OK) {
797                 PLOG(ERROR) << "Failed to prepare directory " << path;
798                 return sendGenericOkFail(cli, result);
799             }
800         }
801 
802         // Open device FD.
803         android::vold::ScopedFd device_fd(open("/dev/fuse", O_RDWR));
804         if (device_fd.get() == -1) {
805             PLOG(ERROR) << "Failed to open /dev/fuse";
806             return sendGenericOkFail(cli, -errno);
807         }
808 
809         // Mount.
810         {
811             const android::status_t result =
812                     runCommandInNamespace(command, uid, pid, path, device_fd.get());
813             if (result != android::OK) {
814                 return sendGenericOkFail(cli, result);
815             }
816         }
817 
818         return sendFd(cli, device_fd.get());
819     } else if (command == "unmount" && argc == 5) {
820         const uid_t uid = atoi(argv[2]);
821         const uid_t pid = atoi(argv[3]);
822         const std::string name(argv[4]);
823 
824         // Check mount point name.
825         std::string path;
826         if (getMountPath(uid, name, &path) != android::OK) {
827             return cli->sendMsg(ResponseCode::CommandParameterError,
828                                 "Invalid mount point name.",
829                                 false);
830         }
831 
832         const android::status_t result =
833                 runCommandInNamespace(command, uid, pid, path, -1 /* device_fd */);
834         return sendGenericOkFail(cli, result);
835     }
836 
837     return cli->sendMsg(ResponseCode::CommandSyntaxError,  "Unknown appfuse cmd", false);
838 }
839 
sendFd(SocketClient * cli,int fd)840 android::status_t CommandListener::AppFuseCmd::sendFd(SocketClient *cli, int fd) {
841     struct iovec data;
842     char dataBuffer[128];
843     char controlBuffer[CMSG_SPACE(sizeof(int))];
844     struct msghdr message;
845 
846     // Message.
847     memset(&message, 0, sizeof(struct msghdr));
848     message.msg_iov = &data;
849     message.msg_iovlen = 1;
850     message.msg_control = controlBuffer;
851     message.msg_controllen = CMSG_SPACE(sizeof(int));
852 
853     // Data.
854     data.iov_base = dataBuffer;
855     data.iov_len = snprintf(dataBuffer,
856                             sizeof(dataBuffer),
857                             "200 %d AppFuse command succeeded",
858                             cli->getCmdNum()) + 1;
859 
860     // Control.
861     struct cmsghdr* const controlMessage = CMSG_FIRSTHDR(&message);
862     memset(controlBuffer, 0, CMSG_SPACE(sizeof(int)));
863     controlMessage->cmsg_level = SOL_SOCKET;
864     controlMessage->cmsg_type = SCM_RIGHTS;
865     controlMessage->cmsg_len = CMSG_LEN(sizeof(int));
866     *((int *) CMSG_DATA(controlMessage)) = fd;
867 
868     const int result = TEMP_FAILURE_RETRY(sendmsg(cli->getSocket(), &message, 0));
869     if (result == -1) {
870         PLOG(ERROR) << "Failed to send FD from vold";
871         return -errno;
872     }
873 
874     return android::OK;
875 }
876