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 #include "property_service.h"
18
19 #include <android/api-level.h>
20 #include <ctype.h>
21 #include <errno.h>
22 #include <fcntl.h>
23 #include <inttypes.h>
24 #include <limits.h>
25 #include <netinet/in.h>
26 #include <stdarg.h>
27 #include <stddef.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <sys/mman.h>
32 #include <sys/poll.h>
33 #include <sys/select.h>
34 #include <sys/types.h>
35 #include <sys/un.h>
36 #include <unistd.h>
37 #include <wchar.h>
38
39 #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
40 #include <sys/_system_properties.h>
41
42 #include <map>
43 #include <memory>
44 #include <mutex>
45 #include <optional>
46 #include <queue>
47 #include <string_view>
48 #include <thread>
49 #include <vector>
50
51 #include <InitProperties.sysprop.h>
52 #include <android-base/chrono_utils.h>
53 #include <android-base/file.h>
54 #include <android-base/logging.h>
55 #include <android-base/parseint.h>
56 #include <android-base/properties.h>
57 #include <android-base/result.h>
58 #include <android-base/stringprintf.h>
59 #include <android-base/strings.h>
60 #include <property_info_parser/property_info_parser.h>
61 #include <property_info_serializer/property_info_serializer.h>
62 #include <selinux/android.h>
63 #include <selinux/label.h>
64 #include <selinux/selinux.h>
65
66 #include "debug_ramdisk.h"
67 #include "epoll.h"
68 #include "init.h"
69 #include "persistent_properties.h"
70 #include "property_type.h"
71 #include "proto_utils.h"
72 #include "second_stage_resources.h"
73 #include "selinux.h"
74 #include "subcontext.h"
75 #include "system/core/init/property_service.pb.h"
76 #include "util.h"
77
78 using namespace std::literals;
79
80 using android::base::ErrnoError;
81 using android::base::Error;
82 using android::base::GetProperty;
83 using android::base::ParseInt;
84 using android::base::ReadFileToString;
85 using android::base::Result;
86 using android::base::Split;
87 using android::base::StartsWith;
88 using android::base::StringPrintf;
89 using android::base::Timer;
90 using android::base::Trim;
91 using android::base::unique_fd;
92 using android::base::WriteStringToFile;
93 using android::properties::BuildTrie;
94 using android::properties::ParsePropertyInfoFile;
95 using android::properties::PropertyInfoAreaFile;
96 using android::properties::PropertyInfoEntry;
97 using android::sysprop::InitProperties::is_userspace_reboot_supported;
98
99 namespace android {
100 namespace init {
101
102 class PersistWriteThread;
103
104 constexpr auto FINGERPRINT_PROP = "ro.build.fingerprint";
105 constexpr auto LEGACY_FINGERPRINT_PROP = "ro.build.legacy.fingerprint";
106 constexpr auto ID_PROP = "ro.build.id";
107 constexpr auto LEGACY_ID_PROP = "ro.build.legacy.id";
108 constexpr auto VBMETA_DIGEST_PROP = "ro.boot.vbmeta.digest";
109 constexpr auto DIGEST_SIZE_USED = 8;
110 constexpr auto API_LEVEL_CURRENT = 10000;
111
112 static bool persistent_properties_loaded = false;
113
114 static int property_set_fd = -1;
115 static int from_init_socket = -1;
116 static int init_socket = -1;
117 static bool accept_messages = false;
118 static std::mutex accept_messages_lock;
119 static std::thread property_service_thread;
120
121 static std::unique_ptr<PersistWriteThread> persist_write_thread;
122
123 static PropertyInfoAreaFile property_info_area;
124
125 struct PropertyAuditData {
126 const ucred* cr;
127 const char* name;
128 };
129
PropertyAuditCallback(void * data,security_class_t,char * buf,size_t len)130 static int PropertyAuditCallback(void* data, security_class_t /*cls*/, char* buf, size_t len) {
131 auto* d = reinterpret_cast<PropertyAuditData*>(data);
132
133 if (!d || !d->name || !d->cr) {
134 LOG(ERROR) << "AuditCallback invoked with null data arguments!";
135 return 0;
136 }
137
138 snprintf(buf, len, "property=%s pid=%d uid=%d gid=%d", d->name, d->cr->pid, d->cr->uid,
139 d->cr->gid);
140 return 0;
141 }
142
StartSendingMessages()143 void StartSendingMessages() {
144 auto lock = std::lock_guard{accept_messages_lock};
145 accept_messages = true;
146 }
147
StopSendingMessages()148 void StopSendingMessages() {
149 auto lock = std::lock_guard{accept_messages_lock};
150 accept_messages = false;
151 }
152
CanReadProperty(const std::string & source_context,const std::string & name)153 bool CanReadProperty(const std::string& source_context, const std::string& name) {
154 const char* target_context = nullptr;
155 property_info_area->GetPropertyInfo(name.c_str(), &target_context, nullptr);
156
157 PropertyAuditData audit_data;
158
159 audit_data.name = name.c_str();
160
161 ucred cr = {.pid = 0, .uid = 0, .gid = 0};
162 audit_data.cr = &cr;
163
164 return selinux_check_access(source_context.c_str(), target_context, "file", "read",
165 &audit_data) == 0;
166 }
167
CheckMacPerms(const std::string & name,const char * target_context,const char * source_context,const ucred & cr)168 static bool CheckMacPerms(const std::string& name, const char* target_context,
169 const char* source_context, const ucred& cr) {
170 if (!target_context || !source_context) {
171 return false;
172 }
173
174 PropertyAuditData audit_data;
175
176 audit_data.name = name.c_str();
177 audit_data.cr = &cr;
178
179 bool has_access = (selinux_check_access(source_context, target_context, "property_service",
180 "set", &audit_data) == 0);
181
182 return has_access;
183 }
184
NotifyPropertyChange(const std::string & name,const std::string & value)185 void NotifyPropertyChange(const std::string& name, const std::string& value) {
186 // If init hasn't started its main loop, then it won't be handling property changed messages
187 // anyway, so there's no need to try to send them.
188 auto lock = std::lock_guard{accept_messages_lock};
189 if (accept_messages) {
190 PropertyChanged(name, value);
191 }
192 }
193
194 class AsyncRestorecon {
195 public:
TriggerRestorecon(const std::string & path)196 void TriggerRestorecon(const std::string& path) {
197 auto guard = std::lock_guard{mutex_};
198 paths_.emplace(path);
199
200 if (!thread_started_) {
201 thread_started_ = true;
202 std::thread{&AsyncRestorecon::ThreadFunction, this}.detach();
203 }
204 }
205
206 private:
ThreadFunction()207 void ThreadFunction() {
208 auto lock = std::unique_lock{mutex_};
209
210 while (!paths_.empty()) {
211 auto path = paths_.front();
212 paths_.pop();
213
214 lock.unlock();
215 if (selinux_android_restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_RECURSE) != 0) {
216 LOG(ERROR) << "Asynchronous restorecon of '" << path << "' failed'";
217 }
218 android::base::SetProperty(kRestoreconProperty, path);
219 lock.lock();
220 }
221
222 thread_started_ = false;
223 }
224
225 std::mutex mutex_;
226 std::queue<std::string> paths_;
227 bool thread_started_ = false;
228 };
229
230 class SocketConnection {
231 public:
232 SocketConnection() = default;
SocketConnection(int socket,const ucred & cred)233 SocketConnection(int socket, const ucred& cred) : socket_(socket), cred_(cred) {}
234 SocketConnection(SocketConnection&&) = default;
235
RecvUint32(uint32_t * value,uint32_t * timeout_ms)236 bool RecvUint32(uint32_t* value, uint32_t* timeout_ms) {
237 return RecvFully(value, sizeof(*value), timeout_ms);
238 }
239
RecvChars(char * chars,size_t size,uint32_t * timeout_ms)240 bool RecvChars(char* chars, size_t size, uint32_t* timeout_ms) {
241 return RecvFully(chars, size, timeout_ms);
242 }
243
RecvString(std::string * value,uint32_t * timeout_ms)244 bool RecvString(std::string* value, uint32_t* timeout_ms) {
245 uint32_t len = 0;
246 if (!RecvUint32(&len, timeout_ms)) {
247 return false;
248 }
249
250 if (len == 0) {
251 *value = "";
252 return true;
253 }
254
255 // http://b/35166374: don't allow init to make arbitrarily large allocations.
256 if (len > 0xffff) {
257 LOG(ERROR) << "sys_prop: RecvString asked to read huge string: " << len;
258 errno = ENOMEM;
259 return false;
260 }
261
262 std::vector<char> chars(len);
263 if (!RecvChars(&chars[0], len, timeout_ms)) {
264 return false;
265 }
266
267 *value = std::string(&chars[0], len);
268 return true;
269 }
270
SendUint32(uint32_t value)271 bool SendUint32(uint32_t value) {
272 if (!socket_.ok()) {
273 return true;
274 }
275 int result = TEMP_FAILURE_RETRY(send(socket_.get(), &value, sizeof(value), 0));
276 return result == sizeof(value);
277 }
278
GetSourceContext(std::string * source_context) const279 bool GetSourceContext(std::string* source_context) const {
280 char* c_source_context = nullptr;
281 if (getpeercon(socket_.get(), &c_source_context) != 0) {
282 return false;
283 }
284 *source_context = c_source_context;
285 freecon(c_source_context);
286 return true;
287 }
288
Release()289 [[nodiscard]] int Release() { return socket_.release(); }
290
cred()291 const ucred& cred() { return cred_; }
292
293 SocketConnection& operator=(SocketConnection&&) = default;
294
295 private:
PollIn(uint32_t * timeout_ms)296 bool PollIn(uint32_t* timeout_ms) {
297 struct pollfd ufd = {
298 .fd = socket_.get(),
299 .events = POLLIN,
300 };
301 while (*timeout_ms > 0) {
302 auto start_time = std::chrono::steady_clock::now();
303 int nr = poll(&ufd, 1, *timeout_ms);
304 auto now = std::chrono::steady_clock::now();
305 auto time_elapsed =
306 std::chrono::duration_cast<std::chrono::milliseconds>(now - start_time);
307 uint64_t millis = time_elapsed.count();
308 *timeout_ms = (millis > *timeout_ms) ? 0 : *timeout_ms - millis;
309
310 if (nr > 0) {
311 return true;
312 }
313
314 if (nr == 0) {
315 // Timeout
316 break;
317 }
318
319 if (nr < 0 && errno != EINTR) {
320 PLOG(ERROR) << "sys_prop: error waiting for uid " << cred_.uid
321 << " to send property message";
322 return false;
323 } else { // errno == EINTR
324 // Timer rounds milliseconds down in case of EINTR we want it to be rounded up
325 // to avoid slowing init down by causing EINTR with under millisecond timeout.
326 if (*timeout_ms > 0) {
327 --(*timeout_ms);
328 }
329 }
330 }
331
332 LOG(ERROR) << "sys_prop: timeout waiting for uid " << cred_.uid
333 << " to send property message.";
334 return false;
335 }
336
RecvFully(void * data_ptr,size_t size,uint32_t * timeout_ms)337 bool RecvFully(void* data_ptr, size_t size, uint32_t* timeout_ms) {
338 size_t bytes_left = size;
339 char* data = static_cast<char*>(data_ptr);
340 while (*timeout_ms > 0 && bytes_left > 0) {
341 if (!PollIn(timeout_ms)) {
342 return false;
343 }
344
345 int result = TEMP_FAILURE_RETRY(recv(socket_.get(), data, bytes_left, MSG_DONTWAIT));
346 if (result <= 0) {
347 PLOG(ERROR) << "sys_prop: recv error";
348 return false;
349 }
350
351 bytes_left -= result;
352 data += result;
353 }
354
355 if (bytes_left != 0) {
356 LOG(ERROR) << "sys_prop: recv data is not properly obtained.";
357 }
358
359 return bytes_left == 0;
360 }
361
362 unique_fd socket_;
363 ucred cred_;
364
365 DISALLOW_COPY_AND_ASSIGN(SocketConnection);
366 };
367
368 class PersistWriteThread {
369 public:
370 PersistWriteThread();
371 void Write(std::string name, std::string value, SocketConnection socket);
372
373 private:
374 void Work();
375
376 private:
377 std::thread thread_;
378 std::mutex mutex_;
379 std::condition_variable cv_;
380 std::deque<std::tuple<std::string, std::string, SocketConnection>> work_;
381 };
382
PropertySet(const std::string & name,const std::string & value,SocketConnection * socket,std::string * error)383 static std::optional<uint32_t> PropertySet(const std::string& name, const std::string& value,
384 SocketConnection* socket, std::string* error) {
385 size_t valuelen = value.size();
386
387 if (!IsLegalPropertyName(name)) {
388 *error = "Illegal property name";
389 return {PROP_ERROR_INVALID_NAME};
390 }
391
392 if (auto result = IsLegalPropertyValue(name, value); !result.ok()) {
393 *error = result.error().message();
394 return {PROP_ERROR_INVALID_VALUE};
395 }
396
397 prop_info* pi = (prop_info*)__system_property_find(name.c_str());
398 if (pi != nullptr) {
399 // ro.* properties are actually "write-once".
400 if (StartsWith(name, "ro.")) {
401 *error = "Read-only property was already set";
402 return {PROP_ERROR_READ_ONLY_PROPERTY};
403 }
404
405 __system_property_update(pi, value.c_str(), valuelen);
406 } else {
407 int rc = __system_property_add(name.c_str(), name.size(), value.c_str(), valuelen);
408 if (rc < 0) {
409 *error = "__system_property_add failed";
410 return {PROP_ERROR_SET_FAILED};
411 }
412 }
413
414 // Don't write properties to disk until after we have read all default
415 // properties to prevent them from being overwritten by default values.
416 if (socket && persistent_properties_loaded && StartsWith(name, "persist.")) {
417 if (persist_write_thread) {
418 persist_write_thread->Write(name, value, std::move(*socket));
419 return {};
420 }
421 WritePersistentProperty(name, value);
422 }
423
424 NotifyPropertyChange(name, value);
425 return {PROP_SUCCESS};
426 }
427
428 // Helper for PropertySet, for the case where no socket is used, and therefore an asynchronous
429 // return is not possible.
PropertySetNoSocket(const std::string & name,const std::string & value,std::string * error)430 static uint32_t PropertySetNoSocket(const std::string& name, const std::string& value,
431 std::string* error) {
432 auto ret = PropertySet(name, value, nullptr, error);
433 CHECK(ret.has_value());
434 return *ret;
435 }
436
SendControlMessage(const std::string & msg,const std::string & name,pid_t pid,SocketConnection * socket,std::string * error)437 static uint32_t SendControlMessage(const std::string& msg, const std::string& name, pid_t pid,
438 SocketConnection* socket, std::string* error) {
439 auto lock = std::lock_guard{accept_messages_lock};
440 if (!accept_messages) {
441 *error = "Received control message after shutdown, ignoring";
442 return PROP_ERROR_HANDLE_CONTROL_MESSAGE;
443 }
444
445 // We must release the fd before sending it to init, otherwise there will be a race with init.
446 // If init calls close() before Release(), then fdsan will see the wrong tag and abort().
447 int fd = -1;
448 if (socket != nullptr && SelinuxGetVendorAndroidVersion() > __ANDROID_API_Q__) {
449 fd = socket->Release();
450 }
451
452 bool queue_success = QueueControlMessage(msg, name, pid, fd);
453 if (!queue_success && fd != -1) {
454 uint32_t response = PROP_ERROR_HANDLE_CONTROL_MESSAGE;
455 TEMP_FAILURE_RETRY(send(fd, &response, sizeof(response), 0));
456 close(fd);
457 }
458
459 return PROP_SUCCESS;
460 }
461
CheckControlPropertyPerms(const std::string & name,const std::string & value,const std::string & source_context,const ucred & cr)462 bool CheckControlPropertyPerms(const std::string& name, const std::string& value,
463 const std::string& source_context, const ucred& cr) {
464 // We check the legacy method first but these properties are dontaudit, so we only log an audit
465 // if the newer method fails as well. We only do this with the legacy ctl. properties.
466 if (name == "ctl.start" || name == "ctl.stop" || name == "ctl.restart") {
467 // The legacy permissions model is that ctl. properties have their name ctl.<action> and
468 // their value is the name of the service to apply that action to. Permissions for these
469 // actions are based on the service, so we must create a fake name of ctl.<service> to
470 // check permissions.
471 auto control_string_legacy = "ctl." + value;
472 const char* target_context_legacy = nullptr;
473 const char* type_legacy = nullptr;
474 property_info_area->GetPropertyInfo(control_string_legacy.c_str(), &target_context_legacy,
475 &type_legacy);
476
477 if (CheckMacPerms(control_string_legacy, target_context_legacy, source_context.c_str(), cr)) {
478 return true;
479 }
480 }
481
482 auto control_string_full = name + "$" + value;
483 const char* target_context_full = nullptr;
484 const char* type_full = nullptr;
485 property_info_area->GetPropertyInfo(control_string_full.c_str(), &target_context_full,
486 &type_full);
487
488 return CheckMacPerms(control_string_full, target_context_full, source_context.c_str(), cr);
489 }
490
491 // This returns one of the enum of PROP_SUCCESS or PROP_ERROR*.
CheckPermissions(const std::string & name,const std::string & value,const std::string & source_context,const ucred & cr,std::string * error)492 uint32_t CheckPermissions(const std::string& name, const std::string& value,
493 const std::string& source_context, const ucred& cr, std::string* error) {
494 if (!IsLegalPropertyName(name)) {
495 *error = "Illegal property name";
496 return PROP_ERROR_INVALID_NAME;
497 }
498
499 if (StartsWith(name, "ctl.")) {
500 if (!CheckControlPropertyPerms(name, value, source_context, cr)) {
501 *error = StringPrintf("Invalid permissions to perform '%s' on '%s'", name.c_str() + 4,
502 value.c_str());
503 return PROP_ERROR_HANDLE_CONTROL_MESSAGE;
504 }
505
506 return PROP_SUCCESS;
507 }
508
509 const char* target_context = nullptr;
510 const char* type = nullptr;
511 property_info_area->GetPropertyInfo(name.c_str(), &target_context, &type);
512
513 if (!CheckMacPerms(name, target_context, source_context.c_str(), cr)) {
514 *error = "SELinux permission check failed";
515 return PROP_ERROR_PERMISSION_DENIED;
516 }
517
518 if (!CheckType(type, value)) {
519 *error = StringPrintf("Property type check failed, value doesn't match expected type '%s'",
520 (type ?: "(null)"));
521 return PROP_ERROR_INVALID_VALUE;
522 }
523
524 return PROP_SUCCESS;
525 }
526
527 // This returns one of the enum of PROP_SUCCESS or PROP_ERROR*, or std::nullopt
528 // if asynchronous.
HandlePropertySet(const std::string & name,const std::string & value,const std::string & source_context,const ucred & cr,SocketConnection * socket,std::string * error)529 std::optional<uint32_t> HandlePropertySet(const std::string& name, const std::string& value,
530 const std::string& source_context, const ucred& cr,
531 SocketConnection* socket, std::string* error) {
532 if (auto ret = CheckPermissions(name, value, source_context, cr, error); ret != PROP_SUCCESS) {
533 return {ret};
534 }
535
536 if (StartsWith(name, "ctl.")) {
537 return {SendControlMessage(name.c_str() + 4, value, cr.pid, socket, error)};
538 }
539
540 // sys.powerctl is a special property that is used to make the device reboot. We want to log
541 // any process that sets this property to be able to accurately blame the cause of a shutdown.
542 if (name == "sys.powerctl") {
543 std::string cmdline_path = StringPrintf("proc/%d/cmdline", cr.pid);
544 std::string process_cmdline;
545 std::string process_log_string;
546 if (ReadFileToString(cmdline_path, &process_cmdline)) {
547 // Since cmdline is null deliminated, .c_str() conveniently gives us just the process
548 // path.
549 process_log_string = StringPrintf(" (%s)", process_cmdline.c_str());
550 }
551 LOG(INFO) << "Received sys.powerctl='" << value << "' from pid: " << cr.pid
552 << process_log_string;
553 if (value == "reboot,userspace" && !is_userspace_reboot_supported().value_or(false)) {
554 *error = "Userspace reboot is not supported by this device";
555 return {PROP_ERROR_INVALID_VALUE};
556 }
557 }
558
559 // If a process other than init is writing a non-empty value, it means that process is
560 // requesting that init performs a restorecon operation on the path specified by 'value'.
561 // We use a thread to do this restorecon operation to prevent holding up init, as it may take
562 // a long time to complete.
563 if (name == kRestoreconProperty && cr.pid != 1 && !value.empty()) {
564 static AsyncRestorecon async_restorecon;
565 async_restorecon.TriggerRestorecon(value);
566 return {PROP_SUCCESS};
567 }
568
569 return PropertySet(name, value, socket, error);
570 }
571
572 // Helper for HandlePropertySet, for the case where no socket is used, and
573 // therefore an asynchronous return is not possible.
HandlePropertySetNoSocket(const std::string & name,const std::string & value,const std::string & source_context,const ucred & cr,std::string * error)574 uint32_t HandlePropertySetNoSocket(const std::string& name, const std::string& value,
575 const std::string& source_context, const ucred& cr,
576 std::string* error) {
577 auto ret = HandlePropertySet(name, value, source_context, cr, nullptr, error);
578 CHECK(ret.has_value());
579 return *ret;
580 }
581
handle_property_set_fd()582 static void handle_property_set_fd() {
583 static constexpr uint32_t kDefaultSocketTimeout = 2000; /* ms */
584
585 int s = accept4(property_set_fd, nullptr, nullptr, SOCK_CLOEXEC);
586 if (s == -1) {
587 return;
588 }
589
590 ucred cr;
591 socklen_t cr_size = sizeof(cr);
592 if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, &cr, &cr_size) < 0) {
593 close(s);
594 PLOG(ERROR) << "sys_prop: unable to get SO_PEERCRED";
595 return;
596 }
597
598 SocketConnection socket(s, cr);
599 uint32_t timeout_ms = kDefaultSocketTimeout;
600
601 uint32_t cmd = 0;
602 if (!socket.RecvUint32(&cmd, &timeout_ms)) {
603 PLOG(ERROR) << "sys_prop: error while reading command from the socket";
604 socket.SendUint32(PROP_ERROR_READ_CMD);
605 return;
606 }
607
608 switch (cmd) {
609 case PROP_MSG_SETPROP: {
610 char prop_name[PROP_NAME_MAX];
611 char prop_value[PROP_VALUE_MAX];
612
613 if (!socket.RecvChars(prop_name, PROP_NAME_MAX, &timeout_ms) ||
614 !socket.RecvChars(prop_value, PROP_VALUE_MAX, &timeout_ms)) {
615 PLOG(ERROR) << "sys_prop(PROP_MSG_SETPROP): error while reading name/value from the socket";
616 return;
617 }
618
619 prop_name[PROP_NAME_MAX-1] = 0;
620 prop_value[PROP_VALUE_MAX-1] = 0;
621
622 std::string source_context;
623 if (!socket.GetSourceContext(&source_context)) {
624 PLOG(ERROR) << "Unable to set property '" << prop_name << "': getpeercon() failed";
625 return;
626 }
627
628 const auto& cr = socket.cred();
629 std::string error;
630 auto result = HandlePropertySetNoSocket(prop_name, prop_value, source_context, cr, &error);
631 if (result != PROP_SUCCESS) {
632 LOG(ERROR) << "Unable to set property '" << prop_name << "' from uid:" << cr.uid
633 << " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;
634 }
635
636 break;
637 }
638
639 case PROP_MSG_SETPROP2: {
640 std::string name;
641 std::string value;
642 if (!socket.RecvString(&name, &timeout_ms) ||
643 !socket.RecvString(&value, &timeout_ms)) {
644 PLOG(ERROR) << "sys_prop(PROP_MSG_SETPROP2): error while reading name/value from the socket";
645 socket.SendUint32(PROP_ERROR_READ_DATA);
646 return;
647 }
648
649 std::string source_context;
650 if (!socket.GetSourceContext(&source_context)) {
651 PLOG(ERROR) << "Unable to set property '" << name << "': getpeercon() failed";
652 socket.SendUint32(PROP_ERROR_PERMISSION_DENIED);
653 return;
654 }
655
656 // HandlePropertySet takes ownership of the socket if the set is handled asynchronously.
657 const auto& cr = socket.cred();
658 std::string error;
659 auto result = HandlePropertySet(name, value, source_context, cr, &socket, &error);
660 if (!result) {
661 // Result will be sent after completion.
662 return;
663 }
664 if (*result != PROP_SUCCESS) {
665 LOG(ERROR) << "Unable to set property '" << name << "' from uid:" << cr.uid
666 << " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;
667 }
668 socket.SendUint32(*result);
669 break;
670 }
671
672 default:
673 LOG(ERROR) << "sys_prop: invalid command " << cmd;
674 socket.SendUint32(PROP_ERROR_INVALID_CMD);
675 break;
676 }
677 }
678
InitPropertySet(const std::string & name,const std::string & value)679 uint32_t InitPropertySet(const std::string& name, const std::string& value) {
680 ucred cr = {.pid = 1, .uid = 0, .gid = 0};
681 std::string error;
682 auto result = HandlePropertySetNoSocket(name, value, kInitContext, cr, &error);
683 if (result != PROP_SUCCESS) {
684 LOG(ERROR) << "Init cannot set '" << name << "' to '" << value << "': " << error;
685 }
686
687 return result;
688 }
689
690 static Result<void> load_properties_from_file(const char*, const char*,
691 std::map<std::string, std::string>*);
692
693 /*
694 * Filter is used to decide which properties to load: NULL loads all keys,
695 * "ro.foo.*" is a prefix match, and "ro.foo.bar" is an exact match.
696 */
LoadProperties(char * data,const char * filter,const char * filename,std::map<std::string,std::string> * properties)697 static void LoadProperties(char* data, const char* filter, const char* filename,
698 std::map<std::string, std::string>* properties) {
699 char *key, *value, *eol, *sol, *tmp, *fn;
700 size_t flen = 0;
701
702 static constexpr const char* const kVendorPathPrefixes[4] = {
703 "/vendor",
704 "/odm",
705 "/vendor_dlkm",
706 "/odm_dlkm",
707 };
708
709 const char* context = kInitContext;
710 if (SelinuxGetVendorAndroidVersion() >= __ANDROID_API_P__) {
711 for (const auto& vendor_path_prefix : kVendorPathPrefixes) {
712 if (StartsWith(filename, vendor_path_prefix)) {
713 context = kVendorContext;
714 }
715 }
716 }
717
718 if (filter) {
719 flen = strlen(filter);
720 }
721
722 sol = data;
723 while ((eol = strchr(sol, '\n'))) {
724 key = sol;
725 *eol++ = 0;
726 sol = eol;
727
728 while (isspace(*key)) key++;
729 if (*key == '#') continue;
730
731 tmp = eol - 2;
732 while ((tmp > key) && isspace(*tmp)) *tmp-- = 0;
733
734 if (!strncmp(key, "import ", 7) && flen == 0) {
735 fn = key + 7;
736 while (isspace(*fn)) fn++;
737
738 key = strchr(fn, ' ');
739 if (key) {
740 *key++ = 0;
741 while (isspace(*key)) key++;
742 }
743
744 std::string raw_filename(fn);
745 auto expanded_filename = ExpandProps(raw_filename);
746
747 if (!expanded_filename.ok()) {
748 LOG(ERROR) << "Could not expand filename ': " << expanded_filename.error();
749 continue;
750 }
751
752 if (auto res = load_properties_from_file(expanded_filename->c_str(), key, properties);
753 !res.ok()) {
754 LOG(WARNING) << res.error();
755 }
756 } else {
757 value = strchr(key, '=');
758 if (!value) continue;
759 *value++ = 0;
760
761 tmp = value - 2;
762 while ((tmp > key) && isspace(*tmp)) *tmp-- = 0;
763
764 while (isspace(*value)) value++;
765
766 if (flen > 0) {
767 if (filter[flen - 1] == '*') {
768 if (strncmp(key, filter, flen - 1) != 0) continue;
769 } else {
770 if (strcmp(key, filter) != 0) continue;
771 }
772 }
773
774 if (StartsWith(key, "ctl.") || key == "sys.powerctl"s ||
775 std::string{key} == kRestoreconProperty) {
776 LOG(ERROR) << "Ignoring disallowed property '" << key
777 << "' with special meaning in prop file '" << filename << "'";
778 continue;
779 }
780
781 ucred cr = {.pid = 1, .uid = 0, .gid = 0};
782 std::string error;
783 if (CheckPermissions(key, value, context, cr, &error) == PROP_SUCCESS) {
784 auto it = properties->find(key);
785 if (it == properties->end()) {
786 (*properties)[key] = value;
787 } else if (it->second != value) {
788 LOG(WARNING) << "Overriding previous property '" << key << "':'" << it->second
789 << "' with new value '" << value << "'";
790 it->second = value;
791 }
792 } else {
793 LOG(ERROR) << "Do not have permissions to set '" << key << "' to '" << value
794 << "' in property file '" << filename << "': " << error;
795 }
796 }
797 }
798 }
799
800 // Filter is used to decide which properties to load: NULL loads all keys,
801 // "ro.foo.*" is a prefix match, and "ro.foo.bar" is an exact match.
load_properties_from_file(const char * filename,const char * filter,std::map<std::string,std::string> * properties)802 static Result<void> load_properties_from_file(const char* filename, const char* filter,
803 std::map<std::string, std::string>* properties) {
804 Timer t;
805 auto file_contents = ReadFile(filename);
806 if (!file_contents.ok()) {
807 return Error() << "Couldn't load property file '" << filename
808 << "': " << file_contents.error();
809 }
810 file_contents->push_back('\n');
811
812 LoadProperties(file_contents->data(), filter, filename, properties);
813 LOG(VERBOSE) << "(Loading properties from " << filename << " took " << t << ".)";
814 return {};
815 }
816
LoadPropertiesFromSecondStageRes(std::map<std::string,std::string> * properties)817 static void LoadPropertiesFromSecondStageRes(std::map<std::string, std::string>* properties) {
818 std::string prop = GetRamdiskPropForSecondStage();
819 if (access(prop.c_str(), R_OK) != 0) {
820 CHECK(errno == ENOENT) << "Cannot access " << prop << ": " << strerror(errno);
821 return;
822 }
823 if (auto res = load_properties_from_file(prop.c_str(), nullptr, properties); !res.ok()) {
824 LOG(WARNING) << res.error();
825 }
826 }
827
828 // persist.sys.usb.config values can't be combined on build-time when property
829 // files are split into each partition.
830 // So we need to apply the same rule of build/make/tools/post_process_props.py
831 // on runtime.
update_sys_usb_config()832 static void update_sys_usb_config() {
833 bool is_debuggable = android::base::GetBoolProperty("ro.debuggable", false);
834 std::string config = android::base::GetProperty("persist.sys.usb.config", "");
835 // b/150130503, add (config == "none") condition here to prevent appending
836 // ",adb" if "none" is explicitly defined in default prop.
837 if (config.empty() || config == "none") {
838 InitPropertySet("persist.sys.usb.config", is_debuggable ? "adb" : "none");
839 } else if (is_debuggable && config.find("adb") == std::string::npos &&
840 config.length() + 4 < PROP_VALUE_MAX) {
841 config.append(",adb");
842 InitPropertySet("persist.sys.usb.config", config);
843 }
844 }
845
load_override_properties()846 static void load_override_properties() {
847 if (ALLOW_LOCAL_PROP_OVERRIDE) {
848 std::map<std::string, std::string> properties;
849 load_properties_from_file("/data/local.prop", nullptr, &properties);
850 for (const auto& [name, value] : properties) {
851 std::string error;
852 if (PropertySetNoSocket(name, value, &error) != PROP_SUCCESS) {
853 LOG(ERROR) << "Could not set '" << name << "' to '" << value
854 << "' in /data/local.prop: " << error;
855 }
856 }
857 }
858 }
859
860 // If the ro.product.[brand|device|manufacturer|model|name] properties have not been explicitly
861 // set, derive them from ro.product.${partition}.* properties
property_initialize_ro_product_props()862 static void property_initialize_ro_product_props() {
863 const char* RO_PRODUCT_PROPS_PREFIX = "ro.product.";
864 const char* RO_PRODUCT_PROPS[] = {
865 "brand", "device", "manufacturer", "model", "name",
866 };
867 const char* RO_PRODUCT_PROPS_ALLOWED_SOURCES[] = {
868 "odm", "product", "system_ext", "system", "vendor",
869 };
870 const char* RO_PRODUCT_PROPS_DEFAULT_SOURCE_ORDER = "product,odm,vendor,system_ext,system";
871 const std::string EMPTY = "";
872
873 std::string ro_product_props_source_order =
874 GetProperty("ro.product.property_source_order", EMPTY);
875
876 if (!ro_product_props_source_order.empty()) {
877 // Verify that all specified sources are valid
878 for (const auto& source : Split(ro_product_props_source_order, ",")) {
879 // Verify that the specified source is valid
880 bool is_allowed_source = false;
881 for (const auto& allowed_source : RO_PRODUCT_PROPS_ALLOWED_SOURCES) {
882 if (source == allowed_source) {
883 is_allowed_source = true;
884 break;
885 }
886 }
887 if (!is_allowed_source) {
888 LOG(ERROR) << "Found unexpected source in ro.product.property_source_order; "
889 "using the default property source order";
890 ro_product_props_source_order = RO_PRODUCT_PROPS_DEFAULT_SOURCE_ORDER;
891 break;
892 }
893 }
894 } else {
895 ro_product_props_source_order = RO_PRODUCT_PROPS_DEFAULT_SOURCE_ORDER;
896 }
897
898 for (const auto& ro_product_prop : RO_PRODUCT_PROPS) {
899 std::string base_prop(RO_PRODUCT_PROPS_PREFIX);
900 base_prop += ro_product_prop;
901
902 std::string base_prop_val = GetProperty(base_prop, EMPTY);
903 if (!base_prop_val.empty()) {
904 continue;
905 }
906
907 for (const auto& source : Split(ro_product_props_source_order, ",")) {
908 std::string target_prop(RO_PRODUCT_PROPS_PREFIX);
909 target_prop += source;
910 target_prop += '.';
911 target_prop += ro_product_prop;
912
913 std::string target_prop_val = GetProperty(target_prop, EMPTY);
914 if (!target_prop_val.empty()) {
915 LOG(INFO) << "Setting product property " << base_prop << " to '" << target_prop_val
916 << "' (from " << target_prop << ")";
917 std::string error;
918 auto res = PropertySetNoSocket(base_prop, target_prop_val, &error);
919 if (res != PROP_SUCCESS) {
920 LOG(ERROR) << "Error setting product property " << base_prop << ": err=" << res
921 << " (" << error << ")";
922 }
923 break;
924 }
925 }
926 }
927 }
928
property_initialize_build_id()929 static void property_initialize_build_id() {
930 std::string build_id = GetProperty(ID_PROP, "");
931 if (!build_id.empty()) {
932 return;
933 }
934
935 std::string legacy_build_id = GetProperty(LEGACY_ID_PROP, "");
936 std::string vbmeta_digest = GetProperty(VBMETA_DIGEST_PROP, "");
937 if (vbmeta_digest.size() < DIGEST_SIZE_USED) {
938 LOG(ERROR) << "vbmeta digest size too small " << vbmeta_digest;
939 // Still try to set the id field in the unexpected case.
940 build_id = legacy_build_id;
941 } else {
942 // Derive the ro.build.id by appending the vbmeta digest to the base value.
943 build_id = legacy_build_id + "." + vbmeta_digest.substr(0, DIGEST_SIZE_USED);
944 }
945
946 std::string error;
947 auto res = PropertySetNoSocket(ID_PROP, build_id, &error);
948 if (res != PROP_SUCCESS) {
949 LOG(ERROR) << "Failed to set " << ID_PROP << " to " << build_id;
950 }
951 }
952
ConstructBuildFingerprint(bool legacy)953 static std::string ConstructBuildFingerprint(bool legacy) {
954 const std::string UNKNOWN = "unknown";
955 std::string build_fingerprint = GetProperty("ro.product.brand", UNKNOWN);
956 build_fingerprint += '/';
957 build_fingerprint += GetProperty("ro.product.name", UNKNOWN);
958 build_fingerprint += '/';
959 build_fingerprint += GetProperty("ro.product.device", UNKNOWN);
960 build_fingerprint += ':';
961 build_fingerprint += GetProperty("ro.build.version.release_or_codename", UNKNOWN);
962 build_fingerprint += '/';
963
964 std::string build_id =
965 legacy ? GetProperty(LEGACY_ID_PROP, UNKNOWN) : GetProperty(ID_PROP, UNKNOWN);
966 build_fingerprint += build_id;
967 build_fingerprint += '/';
968 build_fingerprint += GetProperty("ro.build.version.incremental", UNKNOWN);
969 build_fingerprint += ':';
970 build_fingerprint += GetProperty("ro.build.type", UNKNOWN);
971 build_fingerprint += '/';
972 build_fingerprint += GetProperty("ro.build.tags", UNKNOWN);
973
974 return build_fingerprint;
975 }
976
977 // Derive the legacy build fingerprint if we overwrite the build id at runtime.
property_derive_legacy_build_fingerprint()978 static void property_derive_legacy_build_fingerprint() {
979 std::string legacy_build_fingerprint = GetProperty(LEGACY_FINGERPRINT_PROP, "");
980 if (!legacy_build_fingerprint.empty()) {
981 return;
982 }
983
984 // The device doesn't have a legacy build id, skipping the legacy fingerprint.
985 std::string legacy_build_id = GetProperty(LEGACY_ID_PROP, "");
986 if (legacy_build_id.empty()) {
987 return;
988 }
989
990 legacy_build_fingerprint = ConstructBuildFingerprint(true /* legacy fingerprint */);
991 LOG(INFO) << "Setting property '" << LEGACY_FINGERPRINT_PROP << "' to '"
992 << legacy_build_fingerprint << "'";
993
994 std::string error;
995 auto res = PropertySetNoSocket(LEGACY_FINGERPRINT_PROP, legacy_build_fingerprint, &error);
996 if (res != PROP_SUCCESS) {
997 LOG(ERROR) << "Error setting property '" << LEGACY_FINGERPRINT_PROP << "': err=" << res
998 << " (" << error << ")";
999 }
1000 }
1001
1002 // If the ro.build.fingerprint property has not been set, derive it from constituent pieces
property_derive_build_fingerprint()1003 static void property_derive_build_fingerprint() {
1004 std::string build_fingerprint = GetProperty("ro.build.fingerprint", "");
1005 if (!build_fingerprint.empty()) {
1006 return;
1007 }
1008
1009 build_fingerprint = ConstructBuildFingerprint(false /* legacy fingerprint */);
1010 LOG(INFO) << "Setting property '" << FINGERPRINT_PROP << "' to '" << build_fingerprint << "'";
1011
1012 std::string error;
1013 auto res = PropertySetNoSocket(FINGERPRINT_PROP, build_fingerprint, &error);
1014 if (res != PROP_SUCCESS) {
1015 LOG(ERROR) << "Error setting property '" << FINGERPRINT_PROP << "': err=" << res << " ("
1016 << error << ")";
1017 }
1018 }
1019
1020 // If the ro.product.cpu.abilist* properties have not been explicitly
1021 // set, derive them from ro.${partition}.product.cpu.abilist* properties.
property_initialize_ro_cpu_abilist()1022 static void property_initialize_ro_cpu_abilist() {
1023 // From high to low priority.
1024 const char* kAbilistSources[] = {
1025 "product",
1026 "odm",
1027 "vendor",
1028 "system",
1029 };
1030 const std::string EMPTY = "";
1031 const char* kAbilistProp = "ro.product.cpu.abilist";
1032 const char* kAbilist32Prop = "ro.product.cpu.abilist32";
1033 const char* kAbilist64Prop = "ro.product.cpu.abilist64";
1034
1035 // If the properties are defined explicitly, just use them.
1036 if (GetProperty(kAbilistProp, EMPTY) != EMPTY) {
1037 return;
1038 }
1039
1040 // Find the first source defining these properties by order.
1041 std::string abilist32_prop_val;
1042 std::string abilist64_prop_val;
1043 for (const auto& source : kAbilistSources) {
1044 const auto abilist32_prop = std::string("ro.") + source + ".product.cpu.abilist32";
1045 const auto abilist64_prop = std::string("ro.") + source + ".product.cpu.abilist64";
1046 abilist32_prop_val = GetProperty(abilist32_prop, EMPTY);
1047 abilist64_prop_val = GetProperty(abilist64_prop, EMPTY);
1048 // The properties could be empty on 32-bit-only or 64-bit-only devices,
1049 // but we cannot identify a property is empty or undefined by GetProperty().
1050 // So, we assume both of these 2 properties are empty as undefined.
1051 if (abilist32_prop_val != EMPTY || abilist64_prop_val != EMPTY) {
1052 break;
1053 }
1054 }
1055
1056 // Merge ABI lists for ro.product.cpu.abilist
1057 auto abilist_prop_val = abilist64_prop_val;
1058 if (abilist32_prop_val != EMPTY) {
1059 if (abilist_prop_val != EMPTY) {
1060 abilist_prop_val += ",";
1061 }
1062 abilist_prop_val += abilist32_prop_val;
1063 }
1064
1065 // Set these properties
1066 const std::pair<const char*, const std::string&> set_prop_list[] = {
1067 {kAbilistProp, abilist_prop_val},
1068 {kAbilist32Prop, abilist32_prop_val},
1069 {kAbilist64Prop, abilist64_prop_val},
1070 };
1071 for (const auto& [prop, prop_val] : set_prop_list) {
1072 LOG(INFO) << "Setting property '" << prop << "' to '" << prop_val << "'";
1073
1074 std::string error;
1075 auto res = PropertySetNoSocket(prop, prop_val, &error);
1076 if (res != PROP_SUCCESS) {
1077 LOG(ERROR) << "Error setting property '" << prop << "': err=" << res << " (" << error
1078 << ")";
1079 }
1080 }
1081 }
1082
read_api_level_props(const std::vector<std::string> & api_level_props)1083 static int read_api_level_props(const std::vector<std::string>& api_level_props) {
1084 int api_level = API_LEVEL_CURRENT;
1085 for (const auto& api_level_prop : api_level_props) {
1086 api_level = android::base::GetIntProperty(api_level_prop, API_LEVEL_CURRENT);
1087 if (api_level != API_LEVEL_CURRENT) {
1088 break;
1089 }
1090 }
1091 return api_level;
1092 }
1093
property_initialize_ro_vendor_api_level()1094 static void property_initialize_ro_vendor_api_level() {
1095 // ro.vendor.api_level shows the api_level that the vendor images (vendor, odm, ...) are
1096 // required to support.
1097 constexpr auto VENDOR_API_LEVEL_PROP = "ro.vendor.api_level";
1098
1099 // Api level properties of the board. The order of the properties must be kept.
1100 std::vector<std::string> BOARD_API_LEVEL_PROPS = {"ro.board.api_level",
1101 "ro.board.first_api_level"};
1102 // Api level properties of the device. The order of the properties must be kept.
1103 std::vector<std::string> DEVICE_API_LEVEL_PROPS = {"ro.product.first_api_level",
1104 "ro.build.version.sdk"};
1105
1106 int api_level = std::min(read_api_level_props(BOARD_API_LEVEL_PROPS),
1107 read_api_level_props(DEVICE_API_LEVEL_PROPS));
1108 std::string error;
1109 auto res = PropertySetNoSocket(VENDOR_API_LEVEL_PROP, std::to_string(api_level), &error);
1110 if (res != PROP_SUCCESS) {
1111 LOG(ERROR) << "Failed to set " << VENDOR_API_LEVEL_PROP << " with " << api_level << ": "
1112 << error << "(" << res << ")";
1113 }
1114 }
1115
PropertyLoadBootDefaults()1116 void PropertyLoadBootDefaults() {
1117 // We read the properties and their values into a map, in order to always allow properties
1118 // loaded in the later property files to override the properties in loaded in the earlier
1119 // property files, regardless of if they are "ro." properties or not.
1120 std::map<std::string, std::string> properties;
1121
1122 if (IsRecoveryMode()) {
1123 if (auto res = load_properties_from_file("/prop.default", nullptr, &properties);
1124 !res.ok()) {
1125 LOG(ERROR) << res.error();
1126 }
1127 }
1128
1129 // /<part>/etc/build.prop is the canonical location of the build-time properties since S.
1130 // Falling back to /<part>/defalt.prop and /<part>/build.prop only when legacy path has to
1131 // be supported, which is controlled by the support_legacy_path_until argument.
1132 const auto load_properties_from_partition = [&properties](const std::string& partition,
1133 int support_legacy_path_until) {
1134 auto path = "/" + partition + "/etc/build.prop";
1135 if (load_properties_from_file(path.c_str(), nullptr, &properties).ok()) {
1136 return;
1137 }
1138 // To read ro.<partition>.build.version.sdk, temporarily load the legacy paths into a
1139 // separate map. Then by comparing its value with legacy_version, we know that if the
1140 // partition is old enough so that we need to respect the legacy paths.
1141 std::map<std::string, std::string> temp;
1142 auto legacy_path1 = "/" + partition + "/default.prop";
1143 auto legacy_path2 = "/" + partition + "/build.prop";
1144 load_properties_from_file(legacy_path1.c_str(), nullptr, &temp);
1145 load_properties_from_file(legacy_path2.c_str(), nullptr, &temp);
1146 bool support_legacy_path = false;
1147 auto version_prop_name = "ro." + partition + ".build.version.sdk";
1148 auto it = temp.find(version_prop_name);
1149 if (it == temp.end()) {
1150 // This is embarassing. Without the prop, we can't determine how old the partition is.
1151 // Let's be conservative by assuming it is very very old.
1152 support_legacy_path = true;
1153 } else if (int value;
1154 ParseInt(it->second.c_str(), &value) && value <= support_legacy_path_until) {
1155 support_legacy_path = true;
1156 }
1157 if (support_legacy_path) {
1158 // We don't update temp into properties directly as it might skip any (future) logic
1159 // for resolving duplicates implemented in load_properties_from_file. Instead, read
1160 // the files again into the properties map.
1161 load_properties_from_file(legacy_path1.c_str(), nullptr, &properties);
1162 load_properties_from_file(legacy_path2.c_str(), nullptr, &properties);
1163 } else {
1164 LOG(FATAL) << legacy_path1 << " and " << legacy_path2 << " were not loaded "
1165 << "because " << version_prop_name << "(" << it->second << ") is newer "
1166 << "than " << support_legacy_path_until;
1167 }
1168 };
1169
1170 // Order matters here. The more the partition is specific to a product, the higher its
1171 // precedence is.
1172 LoadPropertiesFromSecondStageRes(&properties);
1173
1174 // system should have build.prop, unlike the other partitions
1175 if (auto res = load_properties_from_file("/system/build.prop", nullptr, &properties);
1176 !res.ok()) {
1177 LOG(WARNING) << res.error();
1178 }
1179
1180 load_properties_from_partition("system_ext", /* support_legacy_path_until */ 30);
1181 load_properties_from_file("/system_dlkm/etc/build.prop", nullptr, &properties);
1182 // TODO(b/117892318): uncomment the following condition when vendor.imgs for aosp_* targets are
1183 // all updated.
1184 // if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_R__) {
1185 load_properties_from_file("/vendor/default.prop", nullptr, &properties);
1186 // }
1187 load_properties_from_file("/vendor/build.prop", nullptr, &properties);
1188 load_properties_from_file("/vendor_dlkm/etc/build.prop", nullptr, &properties);
1189 load_properties_from_file("/odm_dlkm/etc/build.prop", nullptr, &properties);
1190 load_properties_from_partition("odm", /* support_legacy_path_until */ 28);
1191 load_properties_from_partition("product", /* support_legacy_path_until */ 30);
1192
1193 if (access(kDebugRamdiskProp, R_OK) == 0) {
1194 LOG(INFO) << "Loading " << kDebugRamdiskProp;
1195 if (auto res = load_properties_from_file(kDebugRamdiskProp, nullptr, &properties);
1196 !res.ok()) {
1197 LOG(WARNING) << res.error();
1198 }
1199 }
1200
1201 for (const auto& [name, value] : properties) {
1202 std::string error;
1203 if (PropertySetNoSocket(name, value, &error) != PROP_SUCCESS) {
1204 LOG(ERROR) << "Could not set '" << name << "' to '" << value
1205 << "' while loading .prop files" << error;
1206 }
1207 }
1208
1209 property_initialize_ro_product_props();
1210 property_initialize_build_id();
1211 property_derive_build_fingerprint();
1212 property_derive_legacy_build_fingerprint();
1213 property_initialize_ro_cpu_abilist();
1214 property_initialize_ro_vendor_api_level();
1215
1216 update_sys_usb_config();
1217 }
1218
LoadPropertyInfoFromFile(const std::string & filename,std::vector<PropertyInfoEntry> * property_infos)1219 bool LoadPropertyInfoFromFile(const std::string& filename,
1220 std::vector<PropertyInfoEntry>* property_infos) {
1221 auto file_contents = std::string();
1222 if (!ReadFileToString(filename, &file_contents)) {
1223 PLOG(ERROR) << "Could not read properties from '" << filename << "'";
1224 return false;
1225 }
1226
1227 auto errors = std::vector<std::string>{};
1228 bool require_prefix_or_exact = SelinuxGetVendorAndroidVersion() >= __ANDROID_API_R__;
1229 ParsePropertyInfoFile(file_contents, require_prefix_or_exact, property_infos, &errors);
1230 // Individual parsing errors are reported but do not cause a failed boot, which is what
1231 // returning false would do here.
1232 for (const auto& error : errors) {
1233 LOG(ERROR) << "Could not read line from '" << filename << "': " << error;
1234 }
1235
1236 return true;
1237 }
1238
CreateSerializedPropertyInfo()1239 void CreateSerializedPropertyInfo() {
1240 auto property_infos = std::vector<PropertyInfoEntry>();
1241 if (access("/system/etc/selinux/plat_property_contexts", R_OK) != -1) {
1242 if (!LoadPropertyInfoFromFile("/system/etc/selinux/plat_property_contexts",
1243 &property_infos)) {
1244 return;
1245 }
1246 // Don't check for failure here, since we don't always have all of these partitions.
1247 // E.g. In case of recovery, the vendor partition will not have mounted and we
1248 // still need the system / platform properties to function.
1249 if (access("/dev/selinux/apex_property_contexts", R_OK) != -1) {
1250 LoadPropertyInfoFromFile("/dev/selinux/apex_property_contexts", &property_infos);
1251 }
1252 if (access("/system_ext/etc/selinux/system_ext_property_contexts", R_OK) != -1) {
1253 LoadPropertyInfoFromFile("/system_ext/etc/selinux/system_ext_property_contexts",
1254 &property_infos);
1255 }
1256 if (access("/vendor/etc/selinux/vendor_property_contexts", R_OK) != -1) {
1257 LoadPropertyInfoFromFile("/vendor/etc/selinux/vendor_property_contexts",
1258 &property_infos);
1259 }
1260 if (access("/product/etc/selinux/product_property_contexts", R_OK) != -1) {
1261 LoadPropertyInfoFromFile("/product/etc/selinux/product_property_contexts",
1262 &property_infos);
1263 }
1264 if (access("/odm/etc/selinux/odm_property_contexts", R_OK) != -1) {
1265 LoadPropertyInfoFromFile("/odm/etc/selinux/odm_property_contexts", &property_infos);
1266 }
1267 } else {
1268 if (!LoadPropertyInfoFromFile("/plat_property_contexts", &property_infos)) {
1269 return;
1270 }
1271 LoadPropertyInfoFromFile("/system_ext_property_contexts", &property_infos);
1272 LoadPropertyInfoFromFile("/vendor_property_contexts", &property_infos);
1273 LoadPropertyInfoFromFile("/product_property_contexts", &property_infos);
1274 LoadPropertyInfoFromFile("/odm_property_contexts", &property_infos);
1275 LoadPropertyInfoFromFile("/dev/selinux/apex_property_contexts", &property_infos);
1276 }
1277
1278 auto serialized_contexts = std::string();
1279 auto error = std::string();
1280 if (!BuildTrie(property_infos, "u:object_r:default_prop:s0", "string", &serialized_contexts,
1281 &error)) {
1282 LOG(ERROR) << "Unable to serialize property contexts: " << error;
1283 return;
1284 }
1285
1286 constexpr static const char kPropertyInfosPath[] = "/dev/__properties__/property_info";
1287 if (!WriteStringToFile(serialized_contexts, kPropertyInfosPath, 0444, 0, 0, false)) {
1288 PLOG(ERROR) << "Unable to write serialized property infos to file";
1289 }
1290 selinux_android_restorecon(kPropertyInfosPath, 0);
1291 }
1292
ExportKernelBootProps()1293 static void ExportKernelBootProps() {
1294 constexpr const char* UNSET = "";
1295 struct {
1296 const char* src_prop;
1297 const char* dst_prop;
1298 const char* default_value;
1299 } prop_map[] = {
1300 // clang-format off
1301 { "ro.boot.serialno", "ro.serialno", UNSET, },
1302 { "ro.boot.mode", "ro.bootmode", "unknown", },
1303 { "ro.boot.baseband", "ro.baseband", "unknown", },
1304 { "ro.boot.bootloader", "ro.bootloader", "unknown", },
1305 { "ro.boot.hardware", "ro.hardware", "unknown", },
1306 { "ro.boot.revision", "ro.revision", "0", },
1307 // clang-format on
1308 };
1309 for (const auto& prop : prop_map) {
1310 std::string value = GetProperty(prop.src_prop, prop.default_value);
1311 if (value != UNSET) InitPropertySet(prop.dst_prop, value);
1312 }
1313 }
1314
ProcessKernelDt()1315 static void ProcessKernelDt() {
1316 if (!is_android_dt_value_expected("compatible", "android,firmware")) {
1317 return;
1318 }
1319
1320 std::unique_ptr<DIR, int (*)(DIR*)> dir(opendir(get_android_dt_dir().c_str()), closedir);
1321 if (!dir) return;
1322
1323 std::string dt_file;
1324 struct dirent* dp;
1325 while ((dp = readdir(dir.get())) != NULL) {
1326 if (dp->d_type != DT_REG || !strcmp(dp->d_name, "compatible") ||
1327 !strcmp(dp->d_name, "name")) {
1328 continue;
1329 }
1330
1331 std::string file_name = get_android_dt_dir() + dp->d_name;
1332
1333 android::base::ReadFileToString(file_name, &dt_file);
1334 std::replace(dt_file.begin(), dt_file.end(), ',', '.');
1335
1336 InitPropertySet("ro.boot."s + dp->d_name, dt_file);
1337 }
1338 }
1339
1340 constexpr auto ANDROIDBOOT_PREFIX = "androidboot."sv;
1341
ProcessKernelCmdline()1342 static void ProcessKernelCmdline() {
1343 ImportKernelCmdline([&](const std::string& key, const std::string& value) {
1344 if (StartsWith(key, ANDROIDBOOT_PREFIX)) {
1345 InitPropertySet("ro.boot." + key.substr(ANDROIDBOOT_PREFIX.size()), value);
1346 }
1347 });
1348 }
1349
1350
ProcessBootconfig()1351 static void ProcessBootconfig() {
1352 ImportBootconfig([&](const std::string& key, const std::string& value) {
1353 if (StartsWith(key, ANDROIDBOOT_PREFIX)) {
1354 InitPropertySet("ro.boot." + key.substr(ANDROIDBOOT_PREFIX.size()), value);
1355 }
1356 });
1357 }
1358
PropertyInit()1359 void PropertyInit() {
1360 selinux_callback cb;
1361 cb.func_audit = PropertyAuditCallback;
1362 selinux_set_callback(SELINUX_CB_AUDIT, cb);
1363
1364 mkdir("/dev/__properties__", S_IRWXU | S_IXGRP | S_IXOTH);
1365 CreateSerializedPropertyInfo();
1366 if (__system_property_area_init()) {
1367 LOG(FATAL) << "Failed to initialize property area";
1368 }
1369 if (!property_info_area.LoadDefaultPath()) {
1370 LOG(FATAL) << "Failed to load serialized property info file";
1371 }
1372
1373 // If arguments are passed both on the command line and in DT,
1374 // properties set in DT always have priority over the command-line ones.
1375 ProcessKernelDt();
1376 ProcessKernelCmdline();
1377 ProcessBootconfig();
1378
1379 // Propagate the kernel variables to internal variables
1380 // used by init as well as the current required properties.
1381 ExportKernelBootProps();
1382
1383 PropertyLoadBootDefaults();
1384 }
1385
HandleInitSocket()1386 static void HandleInitSocket() {
1387 auto message = ReadMessage(init_socket);
1388 if (!message.ok()) {
1389 LOG(ERROR) << "Could not read message from init_dedicated_recv_socket: " << message.error();
1390 return;
1391 }
1392
1393 auto init_message = InitMessage{};
1394 if (!init_message.ParseFromString(*message)) {
1395 LOG(ERROR) << "Could not parse message from init";
1396 return;
1397 }
1398
1399 switch (init_message.msg_case()) {
1400 case InitMessage::kLoadPersistentProperties: {
1401 load_override_properties();
1402 // Read persistent properties after all default values have been loaded.
1403 auto persistent_properties = LoadPersistentProperties();
1404 for (const auto& persistent_property_record : persistent_properties.properties()) {
1405 InitPropertySet(persistent_property_record.name(),
1406 persistent_property_record.value());
1407 }
1408 // Apply debug ramdisk special settings after persistent properties are loaded.
1409 if (android::base::GetBoolProperty("ro.force.debuggable", false)) {
1410 // Always enable usb adb if device is booted with debug ramdisk.
1411 update_sys_usb_config();
1412 }
1413 InitPropertySet("ro.persistent_properties.ready", "true");
1414 persistent_properties_loaded = true;
1415 break;
1416 }
1417 default:
1418 LOG(ERROR) << "Unknown message type from init: " << init_message.msg_case();
1419 }
1420 }
1421
PropertyServiceThread()1422 static void PropertyServiceThread() {
1423 Epoll epoll;
1424 if (auto result = epoll.Open(); !result.ok()) {
1425 LOG(FATAL) << result.error();
1426 }
1427
1428 if (auto result = epoll.RegisterHandler(property_set_fd, handle_property_set_fd);
1429 !result.ok()) {
1430 LOG(FATAL) << result.error();
1431 }
1432
1433 if (auto result = epoll.RegisterHandler(init_socket, HandleInitSocket); !result.ok()) {
1434 LOG(FATAL) << result.error();
1435 }
1436
1437 while (true) {
1438 auto epoll_result = epoll.Wait(std::nullopt);
1439 if (!epoll_result.ok()) {
1440 LOG(ERROR) << epoll_result.error();
1441 }
1442 }
1443 }
1444
PersistWriteThread()1445 PersistWriteThread::PersistWriteThread() {
1446 auto new_thread = std::thread([this]() -> void { Work(); });
1447 thread_.swap(new_thread);
1448 }
1449
Work()1450 void PersistWriteThread::Work() {
1451 while (true) {
1452 std::tuple<std::string, std::string, SocketConnection> item;
1453
1454 // Grab the next item within the lock.
1455 {
1456 std::unique_lock<std::mutex> lock(mutex_);
1457
1458 while (work_.empty()) {
1459 cv_.wait(lock);
1460 }
1461
1462 item = std::move(work_.front());
1463 work_.pop_front();
1464 }
1465
1466 std::this_thread::sleep_for(1s);
1467
1468 // Perform write/fsync outside the lock.
1469 WritePersistentProperty(std::get<0>(item), std::get<1>(item));
1470 NotifyPropertyChange(std::get<0>(item), std::get<1>(item));
1471
1472 SocketConnection& socket = std::get<2>(item);
1473 socket.SendUint32(PROP_SUCCESS);
1474 }
1475 }
1476
Write(std::string name,std::string value,SocketConnection socket)1477 void PersistWriteThread::Write(std::string name, std::string value, SocketConnection socket) {
1478 {
1479 std::unique_lock<std::mutex> lock(mutex_);
1480 work_.emplace_back(std::move(name), std::move(value), std::move(socket));
1481 }
1482 cv_.notify_all();
1483 }
1484
StartPropertyService(int * epoll_socket)1485 void StartPropertyService(int* epoll_socket) {
1486 InitPropertySet("ro.property_service.version", "2");
1487
1488 int sockets[2];
1489 if (socketpair(AF_UNIX, SOCK_SEQPACKET | SOCK_CLOEXEC, 0, sockets) != 0) {
1490 PLOG(FATAL) << "Failed to socketpair() between property_service and init";
1491 }
1492 *epoll_socket = from_init_socket = sockets[0];
1493 init_socket = sockets[1];
1494 StartSendingMessages();
1495
1496 if (auto result = CreateSocket(PROP_SERVICE_NAME, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
1497 /*passcred=*/false, /*should_listen=*/false, 0666, /*uid=*/0,
1498 /*gid=*/0, /*socketcon=*/{});
1499 result.ok()) {
1500 property_set_fd = *result;
1501 } else {
1502 LOG(FATAL) << "start_property_service socket creation failed: " << result.error();
1503 }
1504
1505 listen(property_set_fd, 8);
1506
1507 auto new_thread = std::thread{PropertyServiceThread};
1508 property_service_thread.swap(new_thread);
1509
1510 auto async_persist_writes =
1511 android::base::GetBoolProperty("ro.property_service.async_persist_writes", false);
1512
1513 if (async_persist_writes) {
1514 persist_write_thread = std::make_unique<PersistWriteThread>();
1515 }
1516 }
1517
1518 } // namespace init
1519 } // namespace android
1520