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platform_system_core/init/property_service.cpp
Nick Kralevich 9ca898fff8 Avoid leaking property values into logs on error 
The purpose of having fine grain read/write control over the property
space is to help ensure the confidentiality of data stored in
properties. Leaking property values into the dmesg buffer on errors
exposes the value outside of the access control rules specified by
policy.

(arguably this is also true for the property name, not just the value.
However, property names are exposed in other places now, so the
incentive to fix this is lower. It would also take away a valuable
debugging tool.)

Test: compiles
Change-Id: I4a0634b8b5e4fd2edf718eaf7343940df627366d
2019-04-04 10:15:25 -07:00

1012 lines
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/*
* 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 "property_service.h"
#include <android/api-level.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <limits.h>
#include <netinet/in.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/poll.h>
#include <sys/select.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>
#include <wchar.h>
#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#include <sys/_system_properties.h>
#include <map>
#include <memory>
#include <queue>
#include <vector>
#include <android-base/chrono_utils.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <property_info_parser/property_info_parser.h>
#include <property_info_serializer/property_info_serializer.h>
#include <selinux/android.h>
#include <selinux/label.h>
#include <selinux/selinux.h>
#include "epoll.h"
#include "init.h"
#include "persistent_properties.h"
#include "property_type.h"
#include "selinux.h"
#include "subcontext.h"
#include "util.h"
using namespace std::literals;
using android::base::GetProperty;
using android::base::ReadFileToString;
using android::base::Split;
using android::base::StartsWith;
using android::base::StringPrintf;
using android::base::Timer;
using android::base::Trim;
using android::base::WriteStringToFile;
using android::properties::BuildTrie;
using android::properties::ParsePropertyInfoFile;
using android::properties::PropertyInfoAreaFile;
using android::properties::PropertyInfoEntry;
namespace android {
namespace init {
static bool persistent_properties_loaded = false;
static int property_set_fd = -1;
static PropertyInfoAreaFile property_info_area;
uint32_t InitPropertySet(const std::string& name, const std::string& value);
uint32_t (*property_set)(const std::string& name, const std::string& value) = InitPropertySet;
void CreateSerializedPropertyInfo();
struct PropertyAuditData {
const ucred* cr;
const char* name;
};
void property_init() {
mkdir("/dev/__properties__", S_IRWXU | S_IXGRP | S_IXOTH);
CreateSerializedPropertyInfo();
if (__system_property_area_init()) {
LOG(FATAL) << "Failed to initialize property area";
}
if (!property_info_area.LoadDefaultPath()) {
LOG(FATAL) << "Failed to load serialized property info file";
}
}
bool CanReadProperty(const std::string& source_context, const std::string& name) {
const char* target_context = nullptr;
property_info_area->GetPropertyInfo(name.c_str(), &target_context, nullptr);
PropertyAuditData audit_data;
audit_data.name = name.c_str();
ucred cr = {.pid = 0, .uid = 0, .gid = 0};
audit_data.cr = &cr;
return selinux_check_access(source_context.c_str(), target_context, "file", "read",
&audit_data) == 0;
}
static bool CheckMacPerms(const std::string& name, const char* target_context,
const char* source_context, const ucred& cr) {
if (!target_context || !source_context) {
return false;
}
PropertyAuditData audit_data;
audit_data.name = name.c_str();
audit_data.cr = &cr;
bool has_access = (selinux_check_access(source_context, target_context, "property_service",
"set", &audit_data) == 0);
return has_access;
}
static uint32_t PropertySet(const std::string& name, const std::string& value, std::string* error) {
size_t valuelen = value.size();
if (!IsLegalPropertyName(name)) {
*error = "Illegal property name";
return PROP_ERROR_INVALID_NAME;
}
if (valuelen >= PROP_VALUE_MAX && !StartsWith(name, "ro.")) {
*error = "Property value too long";
return PROP_ERROR_INVALID_VALUE;
}
if (mbstowcs(nullptr, value.data(), 0) == static_cast<std::size_t>(-1)) {
*error = "Value is not a UTF8 encoded string";
return PROP_ERROR_INVALID_VALUE;
}
prop_info* pi = (prop_info*) __system_property_find(name.c_str());
if (pi != nullptr) {
// ro.* properties are actually "write-once".
if (StartsWith(name, "ro.")) {
*error = "Read-only property was already set";
return PROP_ERROR_READ_ONLY_PROPERTY;
}
__system_property_update(pi, value.c_str(), valuelen);
} else {
int rc = __system_property_add(name.c_str(), name.size(), value.c_str(), valuelen);
if (rc < 0) {
*error = "__system_property_add failed";
return PROP_ERROR_SET_FAILED;
}
}
// Don't write properties to disk until after we have read all default
// properties to prevent them from being overwritten by default values.
if (persistent_properties_loaded && StartsWith(name, "persist.")) {
WritePersistentProperty(name, value);
}
property_changed(name, value);
return PROP_SUCCESS;
}
typedef int (*PropertyAsyncFunc)(const std::string&, const std::string&);
struct PropertyChildInfo {
pid_t pid;
PropertyAsyncFunc func;
std::string name;
std::string value;
};
static std::queue<PropertyChildInfo> property_children;
static void PropertyChildLaunch() {
auto& info = property_children.front();
pid_t pid = fork();
if (pid < 0) {
LOG(ERROR) << "Failed to fork for property_set_async";
while (!property_children.empty()) {
property_children.pop();
}
return;
}
if (pid != 0) {
info.pid = pid;
} else {
if (info.func(info.name, info.value) != 0) {
LOG(ERROR) << "property_set_async(\"" << info.name << "\", \"" << info.value
<< "\") failed";
}
_exit(0);
}
}
bool PropertyChildReap(pid_t pid) {
if (property_children.empty()) {
return false;
}
auto& info = property_children.front();
if (info.pid != pid) {
return false;
}
std::string error;
if (PropertySet(info.name, info.value, &error) != PROP_SUCCESS) {
LOG(ERROR) << "Failed to set async property " << info.name << " to " << info.value << ": "
<< error;
}
property_children.pop();
if (!property_children.empty()) {
PropertyChildLaunch();
}
return true;
}
static uint32_t PropertySetAsync(const std::string& name, const std::string& value,
PropertyAsyncFunc func, std::string* error) {
if (value.empty()) {
return PropertySet(name, value, error);
}
PropertyChildInfo info;
info.func = func;
info.name = name;
info.value = value;
property_children.push(info);
if (property_children.size() == 1) {
PropertyChildLaunch();
}
return PROP_SUCCESS;
}
static int RestoreconRecursiveAsync(const std::string& name, const std::string& value) {
return selinux_android_restorecon(value.c_str(), SELINUX_ANDROID_RESTORECON_RECURSE);
}
uint32_t InitPropertySet(const std::string& name, const std::string& value) {
if (StartsWith(name, "ctl.")) {
LOG(ERROR) << "InitPropertySet: Do not set ctl. properties from init; call the Service "
"functions directly";
return PROP_ERROR_INVALID_NAME;
}
if (name == "selinux.restorecon_recursive") {
LOG(ERROR) << "InitPropertySet: Do not set selinux.restorecon_recursive from init; use the "
"restorecon builtin directly";
return PROP_ERROR_INVALID_NAME;
}
uint32_t result = 0;
ucred cr = {.pid = 1, .uid = 0, .gid = 0};
std::string error;
result = HandlePropertySet(name, value, kInitContext.c_str(), cr, &error);
if (result != PROP_SUCCESS) {
LOG(ERROR) << "Init cannot set '" << name << "' to '" << value << "': " << error;
}
return result;
}
class SocketConnection {
public:
SocketConnection(int socket, const ucred& cred) : socket_(socket), cred_(cred) {}
~SocketConnection() { close(socket_); }
bool RecvUint32(uint32_t* value, uint32_t* timeout_ms) {
return RecvFully(value, sizeof(*value), timeout_ms);
}
bool RecvChars(char* chars, size_t size, uint32_t* timeout_ms) {
return RecvFully(chars, size, timeout_ms);
}
bool RecvString(std::string* value, uint32_t* timeout_ms) {
uint32_t len = 0;
if (!RecvUint32(&len, timeout_ms)) {
return false;
}
if (len == 0) {
*value = "";
return true;
}
// http://b/35166374: don't allow init to make arbitrarily large allocations.
if (len > 0xffff) {
LOG(ERROR) << "sys_prop: RecvString asked to read huge string: " << len;
errno = ENOMEM;
return false;
}
std::vector<char> chars(len);
if (!RecvChars(&chars[0], len, timeout_ms)) {
return false;
}
*value = std::string(&chars[0], len);
return true;
}
bool SendUint32(uint32_t value) {
int result = TEMP_FAILURE_RETRY(send(socket_, &value, sizeof(value), 0));
return result == sizeof(value);
}
int socket() { return socket_; }
const ucred& cred() { return cred_; }
std::string source_context() const {
char* source_context = nullptr;
getpeercon(socket_, &source_context);
std::string result = source_context;
freecon(source_context);
return result;
}
private:
bool PollIn(uint32_t* timeout_ms) {
struct pollfd ufds[1];
ufds[0].fd = socket_;
ufds[0].events = POLLIN;
ufds[0].revents = 0;
while (*timeout_ms > 0) {
auto start_time = std::chrono::steady_clock::now();
int nr = poll(ufds, 1, *timeout_ms);
auto now = std::chrono::steady_clock::now();
auto time_elapsed =
std::chrono::duration_cast<std::chrono::milliseconds>(now - start_time);
uint64_t millis = time_elapsed.count();
*timeout_ms = (millis > *timeout_ms) ? 0 : *timeout_ms - millis;
if (nr > 0) {
return true;
}
if (nr == 0) {
// Timeout
break;
}
if (nr < 0 && errno != EINTR) {
PLOG(ERROR) << "sys_prop: error waiting for uid " << cred_.uid
<< " to send property message";
return false;
} else { // errno == EINTR
// Timer rounds milliseconds down in case of EINTR we want it to be rounded up
// to avoid slowing init down by causing EINTR with under millisecond timeout.
if (*timeout_ms > 0) {
--(*timeout_ms);
}
}
}
LOG(ERROR) << "sys_prop: timeout waiting for uid " << cred_.uid
<< " to send property message.";
return false;
}
bool RecvFully(void* data_ptr, size_t size, uint32_t* timeout_ms) {
size_t bytes_left = size;
char* data = static_cast<char*>(data_ptr);
while (*timeout_ms > 0 && bytes_left > 0) {
if (!PollIn(timeout_ms)) {
return false;
}
int result = TEMP_FAILURE_RETRY(recv(socket_, data, bytes_left, MSG_DONTWAIT));
if (result <= 0) {
PLOG(ERROR) << "sys_prop: recv error";
return false;
}
bytes_left -= result;
data += result;
}
if (bytes_left != 0) {
LOG(ERROR) << "sys_prop: recv data is not properly obtained.";
}
return bytes_left == 0;
}
int socket_;
ucred cred_;
DISALLOW_IMPLICIT_CONSTRUCTORS(SocketConnection);
};
bool CheckControlPropertyPerms(const std::string& name, const std::string& value,
const std::string& source_context, const ucred& cr) {
// We check the legacy method first but these properties are dontaudit, so we only log an audit
// if the newer method fails as well. We only do this with the legacy ctl. properties.
if (name == "ctl.start" || name == "ctl.stop" || name == "ctl.restart") {
// The legacy permissions model is that ctl. properties have their name ctl.<action> and
// their value is the name of the service to apply that action to. Permissions for these
// actions are based on the service, so we must create a fake name of ctl.<service> to
// check permissions.
auto control_string_legacy = "ctl." + value;
const char* target_context_legacy = nullptr;
const char* type_legacy = nullptr;
property_info_area->GetPropertyInfo(control_string_legacy.c_str(), &target_context_legacy,
&type_legacy);
if (CheckMacPerms(control_string_legacy, target_context_legacy, source_context.c_str(), cr)) {
return true;
}
}
auto control_string_full = name + "$" + value;
const char* target_context_full = nullptr;
const char* type_full = nullptr;
property_info_area->GetPropertyInfo(control_string_full.c_str(), &target_context_full,
&type_full);
return CheckMacPerms(control_string_full, target_context_full, source_context.c_str(), cr);
}
// This returns one of the enum of PROP_SUCCESS or PROP_ERROR*.
uint32_t CheckPermissions(const std::string& name, const std::string& value,
const std::string& source_context, const ucred& cr, std::string* error) {
if (!IsLegalPropertyName(name)) {
*error = "Illegal property name";
return PROP_ERROR_INVALID_NAME;
}
if (StartsWith(name, "ctl.")) {
if (!CheckControlPropertyPerms(name, value, source_context, cr)) {
*error = StringPrintf("Invalid permissions to perform '%s' on '%s'", name.c_str() + 4,
value.c_str());
return PROP_ERROR_HANDLE_CONTROL_MESSAGE;
}
return PROP_SUCCESS;
}
const char* target_context = nullptr;
const char* type = nullptr;
property_info_area->GetPropertyInfo(name.c_str(), &target_context, &type);
if (!CheckMacPerms(name, target_context, source_context.c_str(), cr)) {
*error = "SELinux permission check failed";
return PROP_ERROR_PERMISSION_DENIED;
}
if (type == nullptr || !CheckType(type, value)) {
*error = StringPrintf("Property type check failed, value doesn't match expected type '%s'",
(type ?: "(null)"));
return PROP_ERROR_INVALID_VALUE;
}
return PROP_SUCCESS;
}
// This returns one of the enum of PROP_SUCCESS or PROP_ERROR*.
uint32_t HandlePropertySet(const std::string& name, const std::string& value,
const std::string& source_context, const ucred& cr, std::string* error) {
if (auto ret = CheckPermissions(name, value, source_context, cr, error); ret != PROP_SUCCESS) {
return ret;
}
if (StartsWith(name, "ctl.")) {
HandleControlMessage(name.c_str() + 4, value, cr.pid);
return PROP_SUCCESS;
}
// sys.powerctl is a special property that is used to make the device reboot. We want to log
// any process that sets this property to be able to accurately blame the cause of a shutdown.
if (name == "sys.powerctl") {
std::string cmdline_path = StringPrintf("proc/%d/cmdline", cr.pid);
std::string process_cmdline;
std::string process_log_string;
if (ReadFileToString(cmdline_path, &process_cmdline)) {
// Since cmdline is null deliminated, .c_str() conveniently gives us just the process
// path.
process_log_string = StringPrintf(" (%s)", process_cmdline.c_str());
}
LOG(INFO) << "Received sys.powerctl='" << value << "' from pid: " << cr.pid
<< process_log_string;
}
if (name == "selinux.restorecon_recursive") {
return PropertySetAsync(name, value, RestoreconRecursiveAsync, error);
}
return PropertySet(name, value, error);
}
static void handle_property_set_fd() {
static constexpr uint32_t kDefaultSocketTimeout = 2000; /* ms */
int s = accept4(property_set_fd, nullptr, nullptr, SOCK_CLOEXEC);
if (s == -1) {
return;
}
ucred cr;
socklen_t cr_size = sizeof(cr);
if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, &cr, &cr_size) < 0) {
close(s);
PLOG(ERROR) << "sys_prop: unable to get SO_PEERCRED";
return;
}
SocketConnection socket(s, cr);
uint32_t timeout_ms = kDefaultSocketTimeout;
uint32_t cmd = 0;
if (!socket.RecvUint32(&cmd, &timeout_ms)) {
PLOG(ERROR) << "sys_prop: error while reading command from the socket";
socket.SendUint32(PROP_ERROR_READ_CMD);
return;
}
switch (cmd) {
case PROP_MSG_SETPROP: {
char prop_name[PROP_NAME_MAX];
char prop_value[PROP_VALUE_MAX];
if (!socket.RecvChars(prop_name, PROP_NAME_MAX, &timeout_ms) ||
!socket.RecvChars(prop_value, PROP_VALUE_MAX, &timeout_ms)) {
PLOG(ERROR) << "sys_prop(PROP_MSG_SETPROP): error while reading name/value from the socket";
return;
}
prop_name[PROP_NAME_MAX-1] = 0;
prop_value[PROP_VALUE_MAX-1] = 0;
const auto& cr = socket.cred();
std::string error;
uint32_t result =
HandlePropertySet(prop_name, prop_value, socket.source_context(), cr, &error);
if (result != PROP_SUCCESS) {
LOG(ERROR) << "Unable to set property '" << prop_name << "' from uid:" << cr.uid
<< " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;
}
break;
}
case PROP_MSG_SETPROP2: {
std::string name;
std::string value;
if (!socket.RecvString(&name, &timeout_ms) ||
!socket.RecvString(&value, &timeout_ms)) {
PLOG(ERROR) << "sys_prop(PROP_MSG_SETPROP2): error while reading name/value from the socket";
socket.SendUint32(PROP_ERROR_READ_DATA);
return;
}
const auto& cr = socket.cred();
std::string error;
uint32_t result = HandlePropertySet(name, value, socket.source_context(), cr, &error);
if (result != PROP_SUCCESS) {
LOG(ERROR) << "Unable to set property '" << name << "' from uid:" << cr.uid
<< " gid:" << cr.gid << " pid:" << cr.pid << ": " << error;
}
socket.SendUint32(result);
break;
}
default:
LOG(ERROR) << "sys_prop: invalid command " << cmd;
socket.SendUint32(PROP_ERROR_INVALID_CMD);
break;
}
}
static bool load_properties_from_file(const char*, const char*,
std::map<std::string, std::string>*);
/*
* Filter is used to decide which properties to load: NULL loads all keys,
* "ro.foo.*" is a prefix match, and "ro.foo.bar" is an exact match.
*/
static void LoadProperties(char* data, const char* filter, const char* filename,
std::map<std::string, std::string>* properties) {
char *key, *value, *eol, *sol, *tmp, *fn;
size_t flen = 0;
const char* context = kInitContext.c_str();
if (SelinuxGetVendorAndroidVersion() >= __ANDROID_API_P__) {
for (const auto& [path_prefix, secontext] : paths_and_secontexts) {
if (StartsWith(filename, path_prefix)) {
context = secontext;
}
}
}
if (filter) {
flen = strlen(filter);
}
sol = data;
while ((eol = strchr(sol, '\n'))) {
key = sol;
*eol++ = 0;
sol = eol;
while (isspace(*key)) key++;
if (*key == '#') continue;
tmp = eol - 2;
while ((tmp > key) && isspace(*tmp)) *tmp-- = 0;
if (!strncmp(key, "import ", 7) && flen == 0) {
fn = key + 7;
while (isspace(*fn)) fn++;
key = strchr(fn, ' ');
if (key) {
*key++ = 0;
while (isspace(*key)) key++;
}
load_properties_from_file(fn, key, properties);
} else {
value = strchr(key, '=');
if (!value) continue;
*value++ = 0;
tmp = value - 2;
while ((tmp > key) && isspace(*tmp)) *tmp-- = 0;
while (isspace(*value)) value++;
if (flen > 0) {
if (filter[flen - 1] == '*') {
if (strncmp(key, filter, flen - 1)) continue;
} else {
if (strcmp(key, filter)) continue;
}
}
if (StartsWith(key, "ctl.") || key == "sys.powerctl"s ||
key == "selinux.restorecon_recursive"s) {
LOG(ERROR) << "Ignoring disallowed property '" << key
<< "' with special meaning in prop file '" << filename << "'";
continue;
}
ucred cr = {.pid = 1, .uid = 0, .gid = 0};
std::string error;
if (CheckPermissions(key, value, context, cr, &error) == PROP_SUCCESS) {
auto it = properties->find(key);
if (it == properties->end()) {
(*properties)[key] = value;
} else if (it->second != value) {
LOG(WARNING) << "Overriding previous 'ro.' property '" << key << "':'"
<< it->second << "' with new value '" << value << "'";
it->second = value;
}
} else {
LOG(ERROR) << "Do not have permissions to set '" << key << "' to '" << value
<< "' in property file '" << filename << "': " << error;
}
}
}
}
// Filter is used to decide which properties to load: NULL loads all keys,
// "ro.foo.*" is a prefix match, and "ro.foo.bar" is an exact match.
static bool load_properties_from_file(const char* filename, const char* filter,
std::map<std::string, std::string>* properties) {
Timer t;
auto file_contents = ReadFile(filename);
if (!file_contents) {
PLOG(WARNING) << "Couldn't load property file '" << filename
<< "': " << file_contents.error();
return false;
}
file_contents->push_back('\n');
LoadProperties(file_contents->data(), filter, filename, properties);
LOG(VERBOSE) << "(Loading properties from " << filename << " took " << t << ".)";
return true;
}
// persist.sys.usb.config values can't be combined on build-time when property
// files are split into each partition.
// So we need to apply the same rule of build/make/tools/post_process_props.py
// on runtime.
static void update_sys_usb_config() {
bool is_debuggable = android::base::GetBoolProperty("ro.debuggable", false);
std::string config = android::base::GetProperty("persist.sys.usb.config", "");
if (config.empty()) {
property_set("persist.sys.usb.config", is_debuggable ? "adb" : "none");
} else if (is_debuggable && config.find("adb") == std::string::npos &&
config.length() + 4 < PROP_VALUE_MAX) {
config.append(",adb");
property_set("persist.sys.usb.config", config);
}
}
static void load_override_properties() {
if (ALLOW_LOCAL_PROP_OVERRIDE) {
std::map<std::string, std::string> properties;
load_properties_from_file("/data/local.prop", nullptr, &properties);
for (const auto& [name, value] : properties) {
std::string error;
if (PropertySet(name, value, &error) != PROP_SUCCESS) {
LOG(ERROR) << "Could not set '" << name << "' to '" << value
<< "' in /data/local.prop: " << error;
}
}
}
}
/* 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) {
// Devices with FDE have load_persist_props called twice; the first time when the temporary
// /data partition is mounted and then again once /data is truly mounted. We do not want to
// read persistent properties from the temporary /data partition or mark persistent properties
// as having been loaded during the first call, so we return in that case.
std::string crypto_state = android::base::GetProperty("ro.crypto.state", "");
std::string crypto_type = android::base::GetProperty("ro.crypto.type", "");
if (crypto_state == "encrypted" && crypto_type == "block") {
static size_t num_calls = 0;
if (++num_calls == 1) return;
}
load_override_properties();
/* Read persistent properties after all default values have been loaded. */
auto persistent_properties = LoadPersistentProperties();
for (const auto& persistent_property_record : persistent_properties.properties()) {
property_set(persistent_property_record.name(), persistent_property_record.value());
}
persistent_properties_loaded = true;
property_set("ro.persistent_properties.ready", "true");
}
// If the ro.product.[brand|device|manufacturer|model|name] properties have not been explicitly
// set, derive them from ro.product.${partition}.* properties
static void property_initialize_ro_product_props() {
const char* RO_PRODUCT_PROPS_PREFIX = "ro.product.";
const char* RO_PRODUCT_PROPS[] = {
"brand", "device", "manufacturer", "model", "name",
};
const char* RO_PRODUCT_PROPS_ALLOWED_SOURCES[] = {
"odm", "product", "product_services", "system", "vendor",
};
const char* RO_PRODUCT_PROPS_DEFAULT_SOURCE_ORDER =
"product,product_services,odm,vendor,system";
const std::string EMPTY = "";
std::string ro_product_props_source_order =
GetProperty("ro.product.property_source_order", EMPTY);
if (!ro_product_props_source_order.empty()) {
// Verify that all specified sources are valid
for (const auto& source : Split(ro_product_props_source_order, ",")) {
// Verify that the specified source is valid
bool is_allowed_source = false;
for (const auto& allowed_source : RO_PRODUCT_PROPS_ALLOWED_SOURCES) {
if (source == allowed_source) {
is_allowed_source = true;
break;
}
}
if (!is_allowed_source) {
LOG(ERROR) << "Found unexpected source in ro.product.property_source_order; "
"using the default property source order";
ro_product_props_source_order = RO_PRODUCT_PROPS_DEFAULT_SOURCE_ORDER;
break;
}
}
} else {
ro_product_props_source_order = RO_PRODUCT_PROPS_DEFAULT_SOURCE_ORDER;
}
for (const auto& ro_product_prop : RO_PRODUCT_PROPS) {
std::string base_prop(RO_PRODUCT_PROPS_PREFIX);
base_prop += ro_product_prop;
std::string base_prop_val = GetProperty(base_prop, EMPTY);
if (!base_prop_val.empty()) {
continue;
}
for (const auto& source : Split(ro_product_props_source_order, ",")) {
std::string target_prop(RO_PRODUCT_PROPS_PREFIX);
target_prop += source;
target_prop += '.';
target_prop += ro_product_prop;
std::string target_prop_val = GetProperty(target_prop, EMPTY);
if (!target_prop_val.empty()) {
LOG(INFO) << "Setting product property " << base_prop << " to '" << target_prop_val
<< "' (from " << target_prop << ")";
std::string error;
uint32_t res = PropertySet(base_prop, target_prop_val, &error);
if (res != PROP_SUCCESS) {
LOG(ERROR) << "Error setting product property " << base_prop << ": err=" << res
<< " (" << error << ")";
}
break;
}
}
}
}
// If the ro.build.fingerprint property has not been set, derive it from constituent pieces
static void property_derive_build_fingerprint() {
std::string build_fingerprint = GetProperty("ro.build.fingerprint", "");
if (!build_fingerprint.empty()) {
return;
}
const std::string UNKNOWN = "unknown";
build_fingerprint = GetProperty("ro.product.brand", UNKNOWN);
build_fingerprint += '/';
build_fingerprint += GetProperty("ro.product.name", UNKNOWN);
build_fingerprint += '/';
build_fingerprint += GetProperty("ro.product.device", UNKNOWN);
build_fingerprint += ':';
build_fingerprint += GetProperty("ro.build.version.release", UNKNOWN);
build_fingerprint += '/';
build_fingerprint += GetProperty("ro.build.id", UNKNOWN);
build_fingerprint += '/';
build_fingerprint += GetProperty("ro.build.version.incremental", UNKNOWN);
build_fingerprint += ':';
build_fingerprint += GetProperty("ro.build.type", UNKNOWN);
build_fingerprint += '/';
build_fingerprint += GetProperty("ro.build.tags", UNKNOWN);
LOG(INFO) << "Setting property 'ro.build.fingerprint' to '" << build_fingerprint << "'";
std::string error;
uint32_t res = PropertySet("ro.build.fingerprint", build_fingerprint, &error);
if (res != PROP_SUCCESS) {
LOG(ERROR) << "Error setting property 'ro.build.fingerprint': err=" << res << " (" << error
<< ")";
}
}
void property_load_boot_defaults(bool load_debug_prop) {
// TODO(b/117892318): merge prop.default and build.prop files into one
// We read the properties and their values into a map, in order to always allow properties
// loaded in the later property files to override the properties in loaded in the earlier
// property files, regardless of if they are "ro." properties or not.
std::map<std::string, std::string> properties;
if (!load_properties_from_file("/system/etc/prop.default", nullptr, &properties)) {
// Try recovery path
if (!load_properties_from_file("/prop.default", nullptr, &properties)) {
// Try legacy path
load_properties_from_file("/default.prop", nullptr, &properties);
}
}
load_properties_from_file("/system/build.prop", nullptr, &properties);
load_properties_from_file("/vendor/default.prop", nullptr, &properties);
load_properties_from_file("/vendor/build.prop", nullptr, &properties);
load_properties_from_file("/odm/default.prop", nullptr, &properties);
load_properties_from_file("/odm/build.prop", nullptr, &properties);
load_properties_from_file("/product/build.prop", nullptr, &properties);
load_properties_from_file("/product_services/build.prop", nullptr, &properties);
load_properties_from_file("/factory/factory.prop", "ro.*", &properties);
if (load_debug_prop) {
constexpr static const char kAdbDebugProp[] = "/system/etc/adb_debug.prop";
LOG(INFO) << "Loading " << kAdbDebugProp;
load_properties_from_file(kAdbDebugProp, nullptr, &properties);
}
for (const auto& [name, value] : properties) {
std::string error;
if (PropertySet(name, value, &error) != PROP_SUCCESS) {
LOG(ERROR) << "Could not set '" << name << "' to '" << value
<< "' while loading .prop files" << error;
}
}
property_initialize_ro_product_props();
property_derive_build_fingerprint();
update_sys_usb_config();
}
static int SelinuxAuditCallback(void* data, security_class_t /*cls*/, char* buf, size_t len) {
auto* d = reinterpret_cast<PropertyAuditData*>(data);
if (!d || !d->name || !d->cr) {
LOG(ERROR) << "AuditCallback invoked with null data arguments!";
return 0;
}
snprintf(buf, len, "property=%s pid=%d uid=%d gid=%d", d->name, d->cr->pid, d->cr->uid,
d->cr->gid);
return 0;
}
bool LoadPropertyInfoFromFile(const std::string& filename,
std::vector<PropertyInfoEntry>* property_infos) {
auto file_contents = std::string();
if (!ReadFileToString(filename, &file_contents)) {
PLOG(ERROR) << "Could not read properties from '" << filename << "'";
return false;
}
auto errors = std::vector<std::string>{};
ParsePropertyInfoFile(file_contents, property_infos, &errors);
// Individual parsing errors are reported but do not cause a failed boot, which is what
// returning false would do here.
for (const auto& error : errors) {
LOG(ERROR) << "Could not read line from '" << filename << "': " << error;
}
return true;
}
void CreateSerializedPropertyInfo() {
auto property_infos = std::vector<PropertyInfoEntry>();
if (access("/system/etc/selinux/plat_property_contexts", R_OK) != -1) {
if (!LoadPropertyInfoFromFile("/system/etc/selinux/plat_property_contexts",
&property_infos)) {
return;
}
// Don't check for failure here, so we always have a sane list of properties.
// E.g. In case of recovery, the vendor partition will not have mounted and we
// still need the system / platform properties to function.
if (!LoadPropertyInfoFromFile("/vendor/etc/selinux/vendor_property_contexts",
&property_infos)) {
// Fallback to nonplat_* if vendor_* doesn't exist.
LoadPropertyInfoFromFile("/vendor/etc/selinux/nonplat_property_contexts",
&property_infos);
}
if (access("/product/etc/selinux/product_property_contexts", R_OK) != -1) {
LoadPropertyInfoFromFile("/product/etc/selinux/product_property_contexts",
&property_infos);
}
if (access("/odm/etc/selinux/odm_property_contexts", R_OK) != -1) {
LoadPropertyInfoFromFile("/odm/etc/selinux/odm_property_contexts", &property_infos);
}
} else {
if (!LoadPropertyInfoFromFile("/plat_property_contexts", &property_infos)) {
return;
}
if (!LoadPropertyInfoFromFile("/vendor_property_contexts", &property_infos)) {
// Fallback to nonplat_* if vendor_* doesn't exist.
LoadPropertyInfoFromFile("/nonplat_property_contexts", &property_infos);
}
LoadPropertyInfoFromFile("/product_property_contexts", &property_infos);
LoadPropertyInfoFromFile("/odm_property_contexts", &property_infos);
}
auto serialized_contexts = std::string();
auto error = std::string();
if (!BuildTrie(property_infos, "u:object_r:default_prop:s0", "string", &serialized_contexts,
&error)) {
LOG(ERROR) << "Unable to serialize property contexts: " << error;
return;
}
constexpr static const char kPropertyInfosPath[] = "/dev/__properties__/property_info";
if (!WriteStringToFile(serialized_contexts, kPropertyInfosPath, 0444, 0, 0, false)) {
PLOG(ERROR) << "Unable to write serialized property infos to file";
}
selinux_android_restorecon(kPropertyInfosPath, 0);
}
void StartPropertyService(Epoll* epoll) {
selinux_callback cb;
cb.func_audit = SelinuxAuditCallback;
selinux_set_callback(SELINUX_CB_AUDIT, cb);
property_set("ro.property_service.version", "2");
property_set_fd = CreateSocket(PROP_SERVICE_NAME, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
false, 0666, 0, 0, nullptr);
if (property_set_fd == -1) {
PLOG(FATAL) << "start_property_service socket creation failed";
}
listen(property_set_fd, 8);
if (auto result = epoll->RegisterHandler(property_set_fd, handle_property_set_fd); !result) {
PLOG(FATAL) << result.error();
}
}
} // namespace init
} // namespace android
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