summaryrefslogtreecommitdiffstats
blob: 64f6b4037cc436a9ce4c87460f570fbf091d95fb (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <stdarg.h>
#include <dirent.h>
#include <limits.h>
#include <errno.h>

#include <cutils/misc.h>
#include <cutils/sockets.h>
#include <cutils/multiuser.h>

#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#include <sys/_system_properties.h>

#include <sys/socket.h>
#include <sys/un.h>
#include <sys/select.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/mman.h>
#include <sys/atomics.h>
#include <private/android_filesystem_config.h>

#include <selinux/selinux.h>
#include <selinux/label.h>

#include "property_service.h"
#include "init.h"
#include "util.h"
#include "log.h"

#define PERSISTENT_PROPERTY_DIR  "/data/property"

static int persistent_properties_loaded = 0;
static int property_area_inited = 0;

static int property_set_fd = -1;

/* White list of permissions for setting property services. */
struct {
    const char *prefix;
    unsigned int uid;
    unsigned int gid;
} property_perms[] = {
    { "net.rmnet0.",      AID_RADIO,    0 },
    { "net.gprs.",        AID_RADIO,    0 },
    { "net.ppp",          AID_RADIO,    0 },
    { "net.qmi",          AID_RADIO,    0 },
    { "net.lte",          AID_RADIO,    0 },
    { "net.cdma",         AID_RADIO,    0 },
    { "ril.",             AID_RADIO,    0 },
    { "gsm.",             AID_RADIO,    0 },
    { "persist.radio",    AID_RADIO,    0 },
    { "net.dns",          AID_RADIO,    0 },
    { "sys.usb.config",   AID_RADIO,    0 },
    { "net.",             AID_SYSTEM,   0 },
    { "dev.",             AID_SYSTEM,   0 },
    { "runtime.",         AID_SYSTEM,   0 },
    { "hw.",              AID_SYSTEM,   0 },
    { "sys.",             AID_SYSTEM,   0 },
    { "service.",         AID_SYSTEM,   0 },
    { "wlan.",            AID_SYSTEM,   0 },
    { "bluetooth.",       AID_BLUETOOTH,   0 },
    { "dhcp.",            AID_SYSTEM,   0 },
    { "dhcp.",            AID_DHCP,     0 },
    { "debug.",           AID_SYSTEM,   0 },
    { "debug.",           AID_SHELL,    0 },
    { "log.",             AID_SHELL,    0 },
    { "service.adb.root", AID_SHELL,    0 },
    { "service.adb.tcp.port", AID_SHELL,    0 },
    { "persist.sys.",     AID_SYSTEM,   0 },
    { "persist.service.", AID_SYSTEM,   0 },
    { "persist.security.", AID_SYSTEM,   0 },
    { "persist.service.bdroid.", AID_BLUETOOTH,   0 },
    { "selinux."         , AID_SYSTEM,   0 },
    { NULL, 0, 0 }
};

/*
 * White list of UID that are allowed to start/stop services.
 * Currently there are no user apps that require.
 */
struct {
    const char *service;
    unsigned int uid;
    unsigned int gid;
} control_perms[] = {
    { "dumpstate",AID_SHELL, AID_LOG },
    { "ril-daemon",AID_RADIO, AID_RADIO },
     {NULL, 0, 0 }
};

typedef struct {
    void *data;
    size_t size;
    int fd;
} workspace;

static int init_workspace(workspace *w, size_t size)
{
    void *data;
    int fd;

        /* dev is a tmpfs that we can use to carve a shared workspace
         * out of, so let's do that...
         */
    fd = open(PROP_FILENAME, O_RDWR | O_CREAT | O_NOFOLLOW, 0644);
    if (fd < 0)
        return -1;

    if (ftruncate(fd, size) < 0)
        goto out;

    data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if(data == MAP_FAILED)
        goto out;

    close(fd);

    fd = open(PROP_FILENAME, O_RDONLY | O_NOFOLLOW);
    if (fd < 0)
        return -1;

    w->data = data;
    w->size = size;
    w->fd = fd;
    return 0;

out:
    close(fd);
    return -1;
}

/* (8 header words + 372 toc words) = 1520 bytes */
/* 1536 bytes header and toc + 372 prop_infos @ 128 bytes = 49152 bytes */

#define PA_COUNT_MAX  372
#define PA_INFO_START 1536
#define PA_SIZE       49152

static workspace pa_workspace;
static prop_info *pa_info_array;

extern prop_area *__system_property_area__;

static int init_property_area(void)
{
    prop_area *pa;

    if(pa_info_array)
        return -1;

    if(init_workspace(&pa_workspace, PA_SIZE))
        return -1;

    fcntl(pa_workspace.fd, F_SETFD, FD_CLOEXEC);

    pa_info_array = (void*) (((char*) pa_workspace.data) + PA_INFO_START);

    pa = pa_workspace.data;
    memset(pa, 0, PA_SIZE);
    pa->magic = PROP_AREA_MAGIC;
    pa->version = PROP_AREA_VERSION;

        /* plug into the lib property services */
    __system_property_area__ = pa;
    property_area_inited = 1;
    return 0;
}

static void update_prop_info(prop_info *pi, const char *value, unsigned len)
{
    pi->serial = pi->serial | 1;
    memcpy(pi->value, value, len + 1);
    pi->serial = (len << 24) | ((pi->serial + 1) & 0xffffff);
    __futex_wake(&pi->serial, INT32_MAX);
}

static int check_mac_perms(const char *name, char *sctx)
{
    if (is_selinux_enabled() <= 0)
        return 1;

    char *tctx = NULL;
    const char *class = "property_service";
    const char *perm = "set";
    int result = 0;

    if (!sctx)
        goto err;

    if (!sehandle_prop)
        goto err;

    if (selabel_lookup(sehandle_prop, &tctx, name, 1) != 0)
        goto err;

    if (selinux_check_access(sctx, tctx, class, perm, name) == 0)
        result = 1;

    freecon(tctx);
 err:
    return result;
}

static int check_control_mac_perms(const char *name, char *sctx)
{
    /*
     *  Create a name prefix out of ctl.<service name>
     *  The new prefix allows the use of the existing
     *  property service backend labeling while avoiding
     *  mislabels based on true property prefixes.
     */
    char ctl_name[PROP_VALUE_MAX+4];
    int ret = snprintf(ctl_name, sizeof(ctl_name), "ctl.%s", name);

    if (ret < 0 || (size_t) ret >= sizeof(ctl_name))
        return 0;

    return check_mac_perms(ctl_name, sctx);
}

/*
 * Checks permissions for starting/stoping system services.
 * AID_SYSTEM and AID_ROOT are always allowed.
 *
 * Returns 1 if uid allowed, 0 otherwise.
 */
static int check_control_perms(const char *name, unsigned int uid, unsigned int gid, char *sctx) {

    int i;
    if (uid == AID_SYSTEM || uid == AID_ROOT)
      return check_control_mac_perms(name, sctx);

    /* Search the ACL */
    for (i = 0; control_perms[i].service; i++) {
        if (strcmp(control_perms[i].service, name) == 0) {
            if ((uid && control_perms[i].uid == uid) ||
                (gid && control_perms[i].gid == gid)) {
                return check_control_mac_perms(name, sctx);
            }
        }
    }
    return 0;
}

/*
 * Checks permissions for setting system properties.
 * Returns 1 if uid allowed, 0 otherwise.
 */
static int check_perms(const char *name, unsigned int uid, unsigned int gid, char *sctx)
{
    int i;
    unsigned int app_id;

    if(!strncmp(name, "ro.", 3))
        name +=3;

    if (uid == 0)
        return check_mac_perms(name, sctx);

    app_id = multiuser_get_app_id(uid);
    if (app_id == AID_BLUETOOTH) {
        uid = app_id;
    }

    for (i = 0; property_perms[i].prefix; i++) {
        if (strncmp(property_perms[i].prefix, name,
                    strlen(property_perms[i].prefix)) == 0) {
            if ((uid && property_perms[i].uid == uid) ||
                (gid && property_perms[i].gid == gid)) {

                return check_mac_perms(name, sctx);
            }
        }
    }

    return 0;
}

const char* property_get(const char *name)
{
    prop_info *pi;

    if(strlen(name) >= PROP_NAME_MAX) return 0;

    pi = (prop_info*) __system_property_find(name);

    if(pi != 0) {
        return pi->value;
    } else {
        return 0;
    }
}

static void write_persistent_property(const char *name, const char *value)
{
    char tempPath[PATH_MAX];
    char path[PATH_MAX];
    int fd;

    snprintf(tempPath, sizeof(tempPath), "%s/.temp.XXXXXX", PERSISTENT_PROPERTY_DIR);
    fd = mkstemp(tempPath);
    if (fd < 0) {
        ERROR("Unable to write persistent property to temp file %s errno: %d\n", tempPath, errno);
        return;
    }
    write(fd, value, strlen(value));
    close(fd);

    snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, name);
    if (rename(tempPath, path)) {
        unlink(tempPath);
        ERROR("Unable to rename persistent property file %s to %s\n", tempPath, path);
    }
}

int property_set(const char *name, const char *value)
{
    prop_area *pa;
    prop_info *pi;

    size_t namelen = strlen(name);
    size_t valuelen = strlen(value);

    if(namelen >= PROP_NAME_MAX) return -1;
    if(valuelen >= PROP_VALUE_MAX) return -1;
    if(namelen < 1) return -1;

    pi = (prop_info*) __system_property_find(name);

    if(pi != 0) {
        /* ro.* properties may NEVER be modified once set */
        if(!strncmp(name, "ro.", 3)) return -1;

        pa = __system_property_area__;
        update_prop_info(pi, value, valuelen);
        pa->serial++;
        __futex_wake(&pa->serial, INT32_MAX);
    } else {
        pa = __system_property_area__;
        if(pa->count == PA_COUNT_MAX) return -1;

        pi = pa_info_array + pa->count;
        pi->serial = (valuelen << 24);
        memcpy(pi->name, name, namelen + 1);
        memcpy(pi->value, value, valuelen + 1);

        pa->toc[pa->count] =
            (namelen << 24) | (((unsigned) pi) - ((unsigned) pa));

        pa->count++;
        pa->serial++;
        __futex_wake(&pa->serial, INT32_MAX);
    }
    /* If name starts with "net." treat as a DNS property. */
    if (strncmp("net.", name, strlen("net.")) == 0)  {
        if (strcmp("net.change", name) == 0) {
            return 0;
        }
       /*
        * The 'net.change' property is a special property used track when any
        * 'net.*' property name is updated. It is _ONLY_ updated here. Its value
        * contains the last updated 'net.*' property.
        */
        property_set("net.change", name);
    } else if (persistent_properties_loaded &&
            strncmp("persist.", name, strlen("persist.")) == 0) {
        /*
         * Don't write properties to disk until after we have read all default properties
         * to prevent them from being overwritten by default values.
         */
        write_persistent_property(name, value);
    } else if (strcmp("selinux.reload_policy", name) == 0 &&
               strcmp("1", value) == 0) {
        selinux_reload_policy();
    }
    property_changed(name, value);
    return 0;
}

void handle_property_set_fd()
{
    prop_msg msg;
    int s;
    int r;
    int res;
    struct ucred cr;
    struct sockaddr_un addr;
    socklen_t addr_size = sizeof(addr);
    socklen_t cr_size = sizeof(cr);
    char * source_ctx = NULL;

    if ((s = accept(property_set_fd, (struct sockaddr *) &addr, &addr_size)) < 0) {
        return;
    }

    /* Check socket options here */
    if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, &cr, &cr_size) < 0) {
        close(s);
        ERROR("Unable to receive socket options\n");
        return;
    }

    r = TEMP_FAILURE_RETRY(recv(s, &msg, sizeof(msg), 0));
    if(r != sizeof(prop_msg)) {
        ERROR("sys_prop: mis-match msg size received: %d expected: %d errno: %d\n",
              r, sizeof(prop_msg), errno);
        close(s);
        return;
    }

    switch(msg.cmd) {
    case PROP_MSG_SETPROP:
        msg.name[PROP_NAME_MAX-1] = 0;
        msg.value[PROP_VALUE_MAX-1] = 0;

        getpeercon(s, &source_ctx);

        if(memcmp(msg.name,"ctl.",4) == 0) {
            // Keep the old close-socket-early behavior when handling
            // ctl.* properties.
            close(s);
            if (check_control_perms(msg.value, cr.uid, cr.gid, source_ctx)) {
                handle_control_message((char*) msg.name + 4, (char*) msg.value);
            } else {
                ERROR("sys_prop: Unable to %s service ctl [%s] uid:%d gid:%d pid:%d\n",
                        msg.name + 4, msg.value, cr.uid, cr.gid, cr.pid);
            }
        } else {
            if (check_perms(msg.name, cr.uid, cr.gid, source_ctx)) {
                property_set((char*) msg.name, (char*) msg.value);
            } else {
                ERROR("sys_prop: permission denied uid:%d  name:%s\n",
                      cr.uid, msg.name);
            }

            // Note: bionic's property client code assumes that the
            // property server will not close the socket until *AFTER*
            // the property is written to memory.
            close(s);
        }
        freecon(source_ctx);
        break;

    default:
        close(s);
        break;
    }
}

void get_property_workspace(int *fd, int *sz)
{
    *fd = pa_workspace.fd;
    *sz = pa_workspace.size;
}

static void load_properties(char *data)
{
    char *key, *value, *eol, *sol, *tmp;

    sol = data;
    while((eol = strchr(sol, '\n'))) {
        key = sol;
        *eol++ = 0;
        sol = eol;

        value = strchr(key, '=');
        if(value == 0) continue;
        *value++ = 0;

        while(isspace(*key)) key++;
        if(*key == '#') continue;
        tmp = value - 2;
        while((tmp > key) && isspace(*tmp)) *tmp-- = 0;

        while(isspace(*value)) value++;
        tmp = eol - 2;
        while((tmp > value) && isspace(*tmp)) *tmp-- = 0;

        property_set(key, value);
    }
}

static void load_properties_from_file(const char *fn)
{
    char *data;
    unsigned sz;

    data = read_file(fn, &sz);

    if(data != 0) {
        load_properties(data);
        free(data);
    }
}

static void load_persistent_properties()
{
    DIR* dir = opendir(PERSISTENT_PROPERTY_DIR);
    int dir_fd;
    struct dirent*  entry;
    char value[PROP_VALUE_MAX];
    int fd, length;
    struct stat sb;

    if (dir) {
        dir_fd = dirfd(dir);
        while ((entry = readdir(dir)) != NULL) {
            if (strncmp("persist.", entry->d_name, strlen("persist.")))
                continue;
#if HAVE_DIRENT_D_TYPE
            if (entry->d_type != DT_REG)
                continue;
#endif
            /* open the file and read the property value */
            fd = openat(dir_fd, entry->d_name, O_RDONLY | O_NOFOLLOW);
            if (fd < 0) {
                ERROR("Unable to open persistent property file \"%s\" errno: %d\n",
                      entry->d_name, errno);
                continue;
            }
            if (fstat(fd, &sb) < 0) {
                ERROR("fstat on property file \"%s\" failed errno: %d\n", entry->d_name, errno);
                close(fd);
                continue;
            }

            // File must not be accessible to others, be owned by root/root, and
            // not be a hard link to any other file.
            if (((sb.st_mode & (S_IRWXG | S_IRWXO)) != 0)
                    || (sb.st_uid != 0)
                    || (sb.st_gid != 0)
                    || (sb.st_nlink != 1)) {
                ERROR("skipping insecure property file %s (uid=%lu gid=%lu nlink=%d mode=%o)\n",
                      entry->d_name, sb.st_uid, sb.st_gid, sb.st_nlink, sb.st_mode);
                close(fd);
                continue;
            }

            length = read(fd, value, sizeof(value) - 1);
            if (length >= 0) {
                value[length] = 0;
                property_set(entry->d_name, value);
            } else {
                ERROR("Unable to read persistent property file %s errno: %d\n",
                      entry->d_name, errno);
            }
            close(fd);
        }
        closedir(dir);
    } else {
        ERROR("Unable to open persistent property directory %s errno: %d\n", PERSISTENT_PROPERTY_DIR, errno);
    }

    persistent_properties_loaded = 1;
}

void property_init(void)
{
    init_property_area();
}

void property_load_boot_defaults(void)
{
    load_properties_from_file(PROP_PATH_RAMDISK_DEFAULT);
}

int properties_inited(void)
{
    return property_area_inited;
}

static void load_override_properties() {
#ifdef ALLOW_LOCAL_PROP_OVERRIDE
    const char *debuggable = property_get("ro.debuggable");
    if (debuggable && (strcmp(debuggable, "1") == 0)) {
        load_properties_from_file(PROP_PATH_LOCAL_OVERRIDE);
    }
#endif /* ALLOW_LOCAL_PROP_OVERRIDE */
}


/* When booting an encrypted system, /data is not mounted when the
 * property service is started, so any properties stored there are
 * not loaded.  Vold triggers init to load these properties once it
 * has mounted /data.
 */
void load_persist_props(void)
{
    load_override_properties();
    /* Read persistent properties after all default values have been loaded. */
    load_persistent_properties();
}

void start_property_service(void)
{
    int fd;

    load_properties_from_file(PROP_PATH_SYSTEM_BUILD);
    load_properties_from_file(PROP_PATH_SYSTEM_DEFAULT);
    load_override_properties();
    /* Read persistent properties after all default values have been loaded. */
    load_persistent_properties();

    fd = create_socket(PROP_SERVICE_NAME, SOCK_STREAM, 0666, 0, 0);
    if(fd < 0) return;
    fcntl(fd, F_SETFD, FD_CLOEXEC);
    fcntl(fd, F_SETFL, O_NONBLOCK);

    listen(fd, 8);
    property_set_fd = fd;
}

int get_property_set_fd()
{
    return property_set_fd;
}