installd.c revision 47a351834f202386b01a27d42ec41ceb1f17b754 
1/*
2** Copyright 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 <sys/capability.h>
18#include <linux/prctl.h>
19#include <selinux/android.h>
20#include <selinux/avc.h>
21
22#include "installd.h"
23
24
25#define BUFFER_MAX    1024  /* input buffer for commands */
26#define TOKEN_MAX     8     /* max number of arguments in buffer */
27#define REPLY_MAX     256   /* largest reply allowed */
28
29static int do_ping(char **arg, char reply[REPLY_MAX])
30{
31    return 0;
32}
33
34static int do_install(char **arg, char reply[REPLY_MAX])
35{
36    return install(arg[0], atoi(arg[1]), atoi(arg[2]), arg[3]); /* pkgname, uid, gid, seinfo */
37}
38
39static int do_dexopt(char **arg, char reply[REPLY_MAX])
40{
41        /* apk_path, uid, is_public */
42    return dexopt(arg[0], atoi(arg[1]), atoi(arg[2]));
43}
44
45static int do_move_dex(char **arg, char reply[REPLY_MAX])
46{
47    return move_dex(arg[0], arg[1]); /* src, dst */
48}
49
50static int do_rm_dex(char **arg, char reply[REPLY_MAX])
51{
52    return rm_dex(arg[0]); /* pkgname */
53}
54
55static int do_remove(char **arg, char reply[REPLY_MAX])
56{
57    return uninstall(arg[0], atoi(arg[1])); /* pkgname, userid */
58}
59
60static int do_rename(char **arg, char reply[REPLY_MAX])
61{
62    return renamepkg(arg[0], arg[1]); /* oldpkgname, newpkgname */
63}
64
65static int do_fixuid(char **arg, char reply[REPLY_MAX])
66{
67    return fix_uid(arg[0], atoi(arg[1]), atoi(arg[2])); /* pkgname, uid, gid */
68}
69
70static int do_free_cache(char **arg, char reply[REPLY_MAX]) /* TODO int:free_size */
71{
72    return free_cache((int64_t)atoll(arg[0])); /* free_size */
73}
74
75static int do_rm_cache(char **arg, char reply[REPLY_MAX])
76{
77    return delete_cache(arg[0], atoi(arg[1])); /* pkgname, userid */
78}
79
80static int do_get_size(char **arg, char reply[REPLY_MAX])
81{
82    int64_t codesize = 0;
83    int64_t datasize = 0;
84    int64_t cachesize = 0;
85    int64_t asecsize = 0;
86    int res = 0;
87
88        /* pkgdir, userid, apkpath */
89    res = get_size(arg[0], atoi(arg[1]), arg[2], arg[3], arg[4], arg[5],
90            &codesize, &datasize, &cachesize, &asecsize);
91
92    /*
93     * Each int64_t can take up 22 characters printed out. Make sure it
94     * doesn't go over REPLY_MAX in the future.
95     */
96    snprintf(reply, REPLY_MAX, "%" PRId64 " %" PRId64 " %" PRId64 " %" PRId64,
97            codesize, datasize, cachesize, asecsize);
98    return res;
99}
100
101static int do_rm_user_data(char **arg, char reply[REPLY_MAX])
102{
103    return delete_user_data(arg[0], atoi(arg[1])); /* pkgname, userid */
104}
105
106static int do_mk_user_data(char **arg, char reply[REPLY_MAX])
107{
108    return make_user_data(arg[0], atoi(arg[1]), atoi(arg[2]), arg[3]);
109                             /* pkgname, uid, userid, seinfo */
110}
111
112static int do_rm_user(char **arg, char reply[REPLY_MAX])
113{
114    return delete_user(atoi(arg[0])); /* userid */
115}
116
117static int do_movefiles(char **arg, char reply[REPLY_MAX])
118{
119    return movefiles();
120}
121
122static int do_linklib(char **arg, char reply[REPLY_MAX])
123{
124    return linklib(arg[0], arg[1], atoi(arg[2]));
125}
126
127struct cmdinfo {
128    const char *name;
129    unsigned numargs;
130    int (*func)(char **arg, char reply[REPLY_MAX]);
131};
132
133struct cmdinfo cmds[] = {
134    { "ping",                 0, do_ping },
135    { "install",              4, do_install },
136    { "dexopt",               3, do_dexopt },
137    { "movedex",              2, do_move_dex },
138    { "rmdex",                1, do_rm_dex },
139    { "remove",               2, do_remove },
140    { "rename",               2, do_rename },
141    { "fixuid",               3, do_fixuid },
142    { "freecache",            1, do_free_cache },
143    { "rmcache",              2, do_rm_cache },
144    { "getsize",              6, do_get_size },
145    { "rmuserdata",           2, do_rm_user_data },
146    { "movefiles",            0, do_movefiles },
147    { "linklib",              3, do_linklib },
148    { "mkuserdata",           4, do_mk_user_data },
149    { "rmuser",               1, do_rm_user },
150};
151
152static int readx(int s, void *_buf, int count)
153{
154    char *buf = _buf;
155    int n = 0, r;
156    if (count < 0) return -1;
157    while (n < count) {
158        r = read(s, buf + n, count - n);
159        if (r < 0) {
160            if (errno == EINTR) continue;
161            ALOGE("read error: %s\n", strerror(errno));
162            return -1;
163        }
164        if (r == 0) {
165            ALOGE("eof\n");
166            return -1; /* EOF */
167        }
168        n += r;
169    }
170    return 0;
171}
172
173static int writex(int s, const void *_buf, int count)
174{
175    const char *buf = _buf;
176    int n = 0, r;
177    if (count < 0) return -1;
178    while (n < count) {
179        r = write(s, buf + n, count - n);
180        if (r < 0) {
181            if (errno == EINTR) continue;
182            ALOGE("write error: %s\n", strerror(errno));
183            return -1;
184        }
185        n += r;
186    }
187    return 0;
188}
189
190
191/* Tokenize the command buffer, locate a matching command,
192 * ensure that the required number of arguments are provided,
193 * call the function(), return the result.
194 */
195static int execute(int s, char cmd[BUFFER_MAX])
196{
197    char reply[REPLY_MAX];
198    char *arg[TOKEN_MAX+1];
199    unsigned i;
200    unsigned n = 0;
201    unsigned short count;
202    int ret = -1;
203
204    // ALOGI("execute('%s')\n", cmd);
205
206        /* default reply is "" */
207    reply[0] = 0;
208
209        /* n is number of args (not counting arg[0]) */
210    arg[0] = cmd;
211    while (*cmd) {
212        if (isspace(*cmd)) {
213            *cmd++ = 0;
214            n++;
215            arg[n] = cmd;
216            if (n == TOKEN_MAX) {
217                ALOGE("too many arguments\n");
218                goto done;
219            }
220        }
221        cmd++;
222    }
223
224    for (i = 0; i < sizeof(cmds) / sizeof(cmds[0]); i++) {
225        if (!strcmp(cmds[i].name,arg[0])) {
226            if (n != cmds[i].numargs) {
227                ALOGE("%s requires %d arguments (%d given)\n",
228                     cmds[i].name, cmds[i].numargs, n);
229            } else {
230                ret = cmds[i].func(arg + 1, reply);
231            }
232            goto done;
233        }
234    }
235    ALOGE("unsupported command '%s'\n", arg[0]);
236
237done:
238    if (reply[0]) {
239        n = snprintf(cmd, BUFFER_MAX, "%d %s", ret, reply);
240    } else {
241        n = snprintf(cmd, BUFFER_MAX, "%d", ret);
242    }
243    if (n > BUFFER_MAX) n = BUFFER_MAX;
244    count = n;
245
246    // ALOGI("reply: '%s'\n", cmd);
247    if (writex(s, &count, sizeof(count))) return -1;
248    if (writex(s, cmd, count)) return -1;
249    return 0;
250}
251
252/**
253 * Initialize all the global variables that are used elsewhere. Returns 0 upon
254 * success and -1 on error.
255 */
256void free_globals() {
257    size_t i;
258
259    for (i = 0; i < android_system_dirs.count; i++) {
260        if (android_system_dirs.dirs[i].path != NULL) {
261            free(android_system_dirs.dirs[i].path);
262        }
263    }
264
265    free(android_system_dirs.dirs);
266}
267
268int initialize_globals() {
269    // Get the android data directory.
270    if (get_path_from_env(&android_data_dir, "ANDROID_DATA") < 0) {
271        return -1;
272    }
273
274    // Get the android app directory.
275    if (copy_and_append(&android_app_dir, &android_data_dir, APP_SUBDIR) < 0) {
276        return -1;
277    }
278
279    // Get the android protected app directory.
280    if (copy_and_append(&android_app_private_dir, &android_data_dir, PRIVATE_APP_SUBDIR) < 0) {
281        return -1;
282    }
283
284    // Get the android app native library directory.
285    if (copy_and_append(&android_app_lib_dir, &android_data_dir, APP_LIB_SUBDIR) < 0) {
286        return -1;
287    }
288
289    // Get the sd-card ASEC mount point.
290    if (get_path_from_env(&android_asec_dir, "ASEC_MOUNTPOINT") < 0) {
291        return -1;
292    }
293
294    // Get the android media directory.
295    if (copy_and_append(&android_media_dir, &android_data_dir, MEDIA_SUBDIR) < 0) {
296        return -1;
297    }
298
299    // Take note of the system and vendor directories.
300    android_system_dirs.count = 2;
301
302    android_system_dirs.dirs = calloc(android_system_dirs.count, sizeof(dir_rec_t));
303    if (android_system_dirs.dirs == NULL) {
304        ALOGE("Couldn't allocate array for dirs; aborting\n");
305        return -1;
306    }
307
308    // system
309    if (get_path_from_env(&android_system_dirs.dirs[0], "ANDROID_ROOT") < 0) {
310        free_globals();
311        return -1;
312    }
313
314    // append "app/" to dirs[0]
315    char *system_app_path = build_string2(android_system_dirs.dirs[0].path, APP_SUBDIR);
316    android_system_dirs.dirs[0].path = system_app_path;
317    android_system_dirs.dirs[0].len = strlen(system_app_path);
318
319    // vendor
320    // TODO replace this with an environment variable (doesn't exist yet)
321    android_system_dirs.dirs[1].path = "/vendor/app/";
322    android_system_dirs.dirs[1].len = strlen(android_system_dirs.dirs[1].path);
323
324    return 0;
325}
326
327int initialize_directories() {
328    int res = -1;
329
330    // Read current filesystem layout version to handle upgrade paths
331    char version_path[PATH_MAX];
332    snprintf(version_path, PATH_MAX, "%s.layout_version", android_data_dir.path);
333
334    int oldVersion;
335    if (fs_read_atomic_int(version_path, &oldVersion) == -1) {
336        oldVersion = 0;
337    }
338    int version = oldVersion;
339
340    // /data/user
341    char *user_data_dir = build_string2(android_data_dir.path, SECONDARY_USER_PREFIX);
342    // /data/data
343    char *legacy_data_dir = build_string2(android_data_dir.path, PRIMARY_USER_PREFIX);
344    // /data/user/0
345    char *primary_data_dir = build_string3(android_data_dir.path, SECONDARY_USER_PREFIX, "0");
346    if (!user_data_dir || !legacy_data_dir || !primary_data_dir) {
347        goto fail;
348    }
349
350    // Make the /data/user directory if necessary
351    if (access(user_data_dir, R_OK) < 0) {
352        if (mkdir(user_data_dir, 0711) < 0) {
353            goto fail;
354        }
355        if (chown(user_data_dir, AID_SYSTEM, AID_SYSTEM) < 0) {
356            goto fail;
357        }
358        if (chmod(user_data_dir, 0711) < 0) {
359            goto fail;
360        }
361    }
362    // Make the /data/user/0 symlink to /data/data if necessary
363    if (access(primary_data_dir, R_OK) < 0) {
364        if (symlink(legacy_data_dir, primary_data_dir)) {
365            goto fail;
366        }
367    }
368
369    if (version == 0) {
370        // Introducing multi-user, so migrate /data/media contents into /data/media/0
371        ALOGD("Upgrading /data/media for multi-user");
372
373        // Ensure /data/media
374        if (fs_prepare_dir(android_media_dir.path, 0770, AID_MEDIA_RW, AID_MEDIA_RW) == -1) {
375            goto fail;
376        }
377
378        // /data/media.tmp
379        char media_tmp_dir[PATH_MAX];
380        snprintf(media_tmp_dir, PATH_MAX, "%smedia.tmp", android_data_dir.path);
381
382        // Only copy when upgrade not already in progress
383        if (access(media_tmp_dir, F_OK) == -1) {
384            if (rename(android_media_dir.path, media_tmp_dir) == -1) {
385                ALOGE("Failed to move legacy media path: %s", strerror(errno));
386                goto fail;
387            }
388        }
389
390        // Create /data/media again
391        if (fs_prepare_dir(android_media_dir.path, 0770, AID_MEDIA_RW, AID_MEDIA_RW) == -1) {
392            goto fail;
393        }
394
395        if (selinux_android_restorecon(android_media_dir.path)) {
396            goto fail;
397        }
398
399        // /data/media/0
400        char owner_media_dir[PATH_MAX];
401        snprintf(owner_media_dir, PATH_MAX, "%s0", android_media_dir.path);
402
403        // Move any owner data into place
404        if (access(media_tmp_dir, F_OK) == 0) {
405            if (rename(media_tmp_dir, owner_media_dir) == -1) {
406                ALOGE("Failed to move owner media path: %s", strerror(errno));
407                goto fail;
408            }
409        }
410
411        // Ensure media directories for any existing users
412        DIR *dir;
413        struct dirent *dirent;
414        char user_media_dir[PATH_MAX];
415
416        dir = opendir(user_data_dir);
417        if (dir != NULL) {
418            while ((dirent = readdir(dir))) {
419                if (dirent->d_type == DT_DIR) {
420                    const char *name = dirent->d_name;
421
422                    // skip "." and ".."
423                    if (name[0] == '.') {
424                        if (name[1] == 0) continue;
425                        if ((name[1] == '.') && (name[2] == 0)) continue;
426                    }
427
428                    // /data/media/<user_id>
429                    snprintf(user_media_dir, PATH_MAX, "%s%s", android_media_dir.path, name);
430                    if (fs_prepare_dir(user_media_dir, 0770, AID_MEDIA_RW, AID_MEDIA_RW) == -1) {
431                        goto fail;
432                    }
433                }
434            }
435            closedir(dir);
436        }
437
438        version = 1;
439    }
440
441    // /data/media/obb
442    char media_obb_dir[PATH_MAX];
443    snprintf(media_obb_dir, PATH_MAX, "%sobb", android_media_dir.path);
444
445    if (version == 1) {
446        // Introducing /data/media/obb for sharing OBB across users; migrate
447        // any existing OBB files from owner.
448        ALOGD("Upgrading to shared /data/media/obb");
449
450        // /data/media/0/Android/obb
451        char owner_obb_path[PATH_MAX];
452        snprintf(owner_obb_path, PATH_MAX, "%s0/Android/obb", android_media_dir.path);
453
454        // Only move if target doesn't already exist
455        if (access(media_obb_dir, F_OK) != 0 && access(owner_obb_path, F_OK) == 0) {
456            if (rename(owner_obb_path, media_obb_dir) == -1) {
457                ALOGE("Failed to move OBB from owner: %s", strerror(errno));
458                goto fail;
459            }
460        }
461
462        version = 2;
463    }
464
465    if (ensure_media_user_dirs(0) == -1) {
466        ALOGE("Failed to setup media for user 0");
467        goto fail;
468    }
469    if (fs_prepare_dir(media_obb_dir, 0770, AID_MEDIA_RW, AID_MEDIA_RW) == -1) {
470        goto fail;
471    }
472
473    // Persist layout version if changed
474    if (version != oldVersion) {
475        if (fs_write_atomic_int(version_path, version) == -1) {
476            ALOGE("Failed to save version to %s: %s", version_path, strerror(errno));
477            goto fail;
478        }
479    }
480
481    // Success!
482    res = 0;
483
484fail:
485    free(user_data_dir);
486    free(legacy_data_dir);
487    free(primary_data_dir);
488    return res;
489}
490
491static void drop_privileges() {
492    if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
493        ALOGE("prctl(PR_SET_KEEPCAPS) failed: %s\n", strerror(errno));
494        exit(1);
495    }
496
497    if (setgid(AID_INSTALL) < 0) {
498        ALOGE("setgid() can't drop privileges; exiting.\n");
499        exit(1);
500    }
501
502    if (setuid(AID_INSTALL) < 0) {
503        ALOGE("setuid() can't drop privileges; exiting.\n");
504        exit(1);
505    }
506
507    struct __user_cap_header_struct capheader;
508    struct __user_cap_data_struct capdata[2];
509    memset(&capheader, 0, sizeof(capheader));
510    memset(&capdata, 0, sizeof(capdata));
511    capheader.version = _LINUX_CAPABILITY_VERSION_3;
512    capheader.pid = 0;
513
514    capdata[CAP_TO_INDEX(CAP_DAC_OVERRIDE)].permitted |= CAP_TO_MASK(CAP_DAC_OVERRIDE);
515    capdata[CAP_TO_INDEX(CAP_CHOWN)].permitted        |= CAP_TO_MASK(CAP_CHOWN);
516    capdata[CAP_TO_INDEX(CAP_SETUID)].permitted       |= CAP_TO_MASK(CAP_SETUID);
517    capdata[CAP_TO_INDEX(CAP_SETGID)].permitted       |= CAP_TO_MASK(CAP_SETGID);
518
519    capdata[0].effective = capdata[0].permitted;
520    capdata[1].effective = capdata[1].permitted;
521    capdata[0].inheritable = 0;
522    capdata[1].inheritable = 0;
523
524    if (capset(&capheader, &capdata[0]) < 0) {
525        ALOGE("capset failed: %s\n", strerror(errno));
526        exit(1);
527    }
528}
529
530int main(const int argc, const char *argv[]) {
531    char buf[BUFFER_MAX];
532    struct sockaddr addr;
533    socklen_t alen;
534    int lsocket, s, count;
535    int selinux_enabled = (is_selinux_enabled() > 0);
536
537    ALOGI("installd firing up\n");
538
539    if (initialize_globals() < 0) {
540        ALOGE("Could not initialize globals; exiting.\n");
541        exit(1);
542    }
543
544    if (initialize_directories() < 0) {
545        ALOGE("Could not create directories; exiting.\n");
546        exit(1);
547    }
548
549    if (selinux_enabled && selinux_status_open(true) < 0) {
550        ALOGE("Could not open selinux status; exiting.\n");
551        exit(1);
552    }
553
554    drop_privileges();
555
556    lsocket = android_get_control_socket(SOCKET_PATH);
557    if (lsocket < 0) {
558        ALOGE("Failed to get socket from environment: %s\n", strerror(errno));
559        exit(1);
560    }
561    if (listen(lsocket, 5)) {
562        ALOGE("Listen on socket failed: %s\n", strerror(errno));
563        exit(1);
564    }
565    fcntl(lsocket, F_SETFD, FD_CLOEXEC);
566
567    for (;;) {
568        alen = sizeof(addr);
569        s = accept(lsocket, &addr, &alen);
570        if (s < 0) {
571            ALOGE("Accept failed: %s\n", strerror(errno));
572            continue;
573        }
574        fcntl(s, F_SETFD, FD_CLOEXEC);
575
576        ALOGI("new connection\n");
577        for (;;) {
578            unsigned short count;
579            if (readx(s, &count, sizeof(count))) {
580                ALOGE("failed to read size\n");
581                break;
582            }
583            if ((count < 1) || (count >= BUFFER_MAX)) {
584                ALOGE("invalid size %d\n", count);
585                break;
586            }
587            if (readx(s, buf, count)) {
588                ALOGE("failed to read command\n");
589                break;
590            }
591            buf[count] = 0;
592            if (selinux_enabled && selinux_status_updated() > 0) {
593                selinux_android_seapp_context_reload();
594            }
595            if (execute(s, buf)) break;
596        }
597        ALOGI("closing connection\n");
598        close(s);
599    }
600
601    return 0;
602}
603