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platform_system_core/init/init.cpp
Alex Klyubin 16696e201b Use split SELinux policy at boot, if available 
This modifies init's loading of SELinux policy into the kernel to
load the split (platform/system vs non-platform/vendor) policy if it's
present. If the split policy is not present, the usual monolithic
policy is loaded into the kernel, same as before.

Split policy is loaded by first compiling it from CIL form using
secilc compiler into the conventional monolithic/compiled form which
is then loaded into the kernel.

The build system has not yet been modified to place split policy onto
devices. Thus, this commit currently has no effect. For testing split
policy, build plat_sepolicy.cil, nonplat_sepolicy.cil, and
mapping_sepolicy.cil, and place them into the root directory of the
device.

The following tests were performed for a device with monolithic policy
and for the same device with split policy.

Test: Device boots, no new denials
Test: Play Movies plays back movies
Test: Load ip6.me im Chrome
Bug: 31363362
Change-Id: I9a75a48ac88f3392abc36669f91b0803e88cd147
2017-03-01 14:07:40 -08:00

1193 lines
40 KiB
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/*
* Copyright (C) 2008 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 <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <libgen.h>
#include <paths.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/mount.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <unistd.h>
#include <selinux/selinux.h>
#include <selinux/label.h>
#include <selinux/android.h>
#include <android-base/file.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <cutils/fs.h>
#include <cutils/iosched_policy.h>
#include <cutils/list.h>
#include <cutils/sockets.h>
#include <libavb/libavb.h>
#include <private/android_filesystem_config.h>
#include <fstream>
#include <memory>
#include "action.h"
#include "bootchart.h"
#include "devices.h"
#include "fs_mgr.h"
#include "import_parser.h"
#include "init.h"
#include "init_parser.h"
#include "keychords.h"
#include "log.h"
#include "property_service.h"
#include "service.h"
#include "signal_handler.h"
#include "ueventd.h"
#include "util.h"
#include "watchdogd.h"
using android::base::StringPrintf;
struct selabel_handle *sehandle;
struct selabel_handle *sehandle_prop;
static int property_triggers_enabled = 0;
static char qemu[32];
std::string default_console = "/dev/console";
static time_t process_needs_restart_at;
const char *ENV[32];
static std::unique_ptr<Timer> waiting_for_exec(nullptr);
static int epoll_fd = -1;
static std::unique_ptr<Timer> waiting_for_prop(nullptr);
static std::string wait_prop_name;
static std::string wait_prop_value;
void register_epoll_handler(int fd, void (*fn)()) {
epoll_event ev;
ev.events = EPOLLIN;
ev.data.ptr = reinterpret_cast<void*>(fn);
if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd, &ev) == -1) {
PLOG(ERROR) << "epoll_ctl failed";
}
}
/* add_environment - add "key=value" to the current environment */
int add_environment(const char *key, const char *val)
{
size_t n;
size_t key_len = strlen(key);
/* The last environment entry is reserved to terminate the list */
for (n = 0; n < (arraysize(ENV) - 1); n++) {
/* Delete any existing entry for this key */
if (ENV[n] != NULL) {
size_t entry_key_len = strcspn(ENV[n], "=");
if ((entry_key_len == key_len) && (strncmp(ENV[n], key, entry_key_len) == 0)) {
free((char*)ENV[n]);
ENV[n] = NULL;
}
}
/* Add entry if a free slot is available */
if (ENV[n] == NULL) {
char* entry;
asprintf(&entry, "%s=%s", key, val);
ENV[n] = entry;
return 0;
}
}
LOG(ERROR) << "No env. room to store: '" << key << "':'" << val << "'";
return -1;
}
bool start_waiting_for_exec()
{
if (waiting_for_exec) {
return false;
}
waiting_for_exec.reset(new Timer());
return true;
}
void stop_waiting_for_exec()
{
if (waiting_for_exec) {
LOG(INFO) << "Wait for exec took " << *waiting_for_exec;
waiting_for_exec.reset();
}
}
bool start_waiting_for_property(const char *name, const char *value)
{
if (waiting_for_prop) {
return false;
}
if (property_get(name) != value) {
// Current property value is not equal to expected value
wait_prop_name = name;
wait_prop_value = value;
waiting_for_prop.reset(new Timer());
} else {
LOG(INFO) << "start_waiting_for_property(\""
<< name << "\", \"" << value << "\"): already set";
}
return true;
}
void property_changed(const char *name, const char *value)
{
if (property_triggers_enabled)
ActionManager::GetInstance().QueuePropertyTrigger(name, value);
if (waiting_for_prop) {
if (wait_prop_name == name && wait_prop_value == value) {
wait_prop_name.clear();
wait_prop_value.clear();
LOG(INFO) << "Wait for property took " << *waiting_for_prop;
waiting_for_prop.reset();
}
}
}
static void restart_processes()
{
process_needs_restart_at = 0;
ServiceManager::GetInstance().ForEachServiceWithFlags(SVC_RESTARTING, [](Service* s) {
s->RestartIfNeeded(&process_needs_restart_at);
});
}
void handle_control_message(const std::string& msg, const std::string& name) {
Service* svc = ServiceManager::GetInstance().FindServiceByName(name);
if (svc == nullptr) {
LOG(ERROR) << "no such service '" << name << "'";
return;
}
if (msg == "start") {
svc->Start();
} else if (msg == "stop") {
svc->Stop();
} else if (msg == "restart") {
svc->Restart();
} else {
LOG(ERROR) << "unknown control msg '" << msg << "'";
}
}
static int wait_for_coldboot_done_action(const std::vector<std::string>& args) {
Timer t;
LOG(VERBOSE) << "Waiting for " COLDBOOT_DONE "...";
// Historically we had a 1s timeout here because we weren't otherwise
// tracking boot time, and many OEMs made their sepolicy regular
// expressions too expensive (http://b/19899875).
// Now we're tracking boot time, just log the time taken to a system
// property. We still panic if it takes more than a minute though,
// because any build that slow isn't likely to boot at all, and we'd
// rather any test lab devices fail back to the bootloader.
if (wait_for_file(COLDBOOT_DONE, 60s) < 0) {
LOG(ERROR) << "Timed out waiting for " COLDBOOT_DONE;
panic();
}
property_set("ro.boottime.init.cold_boot_wait", std::to_string(t.duration_ms()).c_str());
return 0;
}
/*
* Writes 512 bytes of output from Hardware RNG (/dev/hw_random, backed
* by Linux kernel's hw_random framework) into Linux RNG's via /dev/urandom.
* Does nothing if Hardware RNG is not present.
*
* Since we don't yet trust the quality of Hardware RNG, these bytes are not
* mixed into the primary pool of Linux RNG and the entropy estimate is left
* unmodified.
*
* If the HW RNG device /dev/hw_random is present, we require that at least
* 512 bytes read from it are written into Linux RNG. QA is expected to catch
* devices/configurations where these I/O operations are blocking for a long
* time. We do not reboot or halt on failures, as this is a best-effort
* attempt.
*/
static int mix_hwrng_into_linux_rng_action(const std::vector<std::string>& args)
{
int result = -1;
int hwrandom_fd = -1;
int urandom_fd = -1;
char buf[512];
ssize_t chunk_size;
size_t total_bytes_written = 0;
hwrandom_fd = TEMP_FAILURE_RETRY(
open("/dev/hw_random", O_RDONLY | O_NOFOLLOW | O_CLOEXEC));
if (hwrandom_fd == -1) {
if (errno == ENOENT) {
LOG(ERROR) << "/dev/hw_random not found";
// It's not an error to not have a Hardware RNG.
result = 0;
} else {
PLOG(ERROR) << "Failed to open /dev/hw_random";
}
goto ret;
}
urandom_fd = TEMP_FAILURE_RETRY(
open("/dev/urandom", O_WRONLY | O_NOFOLLOW | O_CLOEXEC));
if (urandom_fd == -1) {
PLOG(ERROR) << "Failed to open /dev/urandom";
goto ret;
}
while (total_bytes_written < sizeof(buf)) {
chunk_size = TEMP_FAILURE_RETRY(
read(hwrandom_fd, buf, sizeof(buf) - total_bytes_written));
if (chunk_size == -1) {
PLOG(ERROR) << "Failed to read from /dev/hw_random";
goto ret;
} else if (chunk_size == 0) {
LOG(ERROR) << "Failed to read from /dev/hw_random: EOF";
goto ret;
}
chunk_size = TEMP_FAILURE_RETRY(write(urandom_fd, buf, chunk_size));
if (chunk_size == -1) {
PLOG(ERROR) << "Failed to write to /dev/urandom";
goto ret;
}
total_bytes_written += chunk_size;
}
LOG(INFO) << "Mixed " << total_bytes_written << " bytes from /dev/hw_random into /dev/urandom";
result = 0;
ret:
if (hwrandom_fd != -1) {
close(hwrandom_fd);
}
if (urandom_fd != -1) {
close(urandom_fd);
}
return result;
}
static void security_failure() {
LOG(ERROR) << "Security failure...";
panic();
}
static bool set_highest_available_option_value(std::string path, int min, int max)
{
std::ifstream inf(path, std::fstream::in);
if (!inf) {
LOG(ERROR) << "Cannot open for reading: " << path;
return false;
}
int current = max;
while (current >= min) {
// try to write out new value
std::string str_val = std::to_string(current);
std::ofstream of(path, std::fstream::out);
if (!of) {
LOG(ERROR) << "Cannot open for writing: " << path;
return false;
}
of << str_val << std::endl;
of.close();
// check to make sure it was recorded
inf.seekg(0);
std::string str_rec;
inf >> str_rec;
if (str_val.compare(str_rec) == 0) {
break;
}
current--;
}
inf.close();
if (current < min) {
LOG(ERROR) << "Unable to set minimum option value " << min << " in " << path;
return false;
}
return true;
}
#define MMAP_RND_PATH "/proc/sys/vm/mmap_rnd_bits"
#define MMAP_RND_COMPAT_PATH "/proc/sys/vm/mmap_rnd_compat_bits"
/* __attribute__((unused)) due to lack of mips support: see mips block
* in set_mmap_rnd_bits_action */
static bool __attribute__((unused)) set_mmap_rnd_bits_min(int start, int min, bool compat) {
std::string path;
if (compat) {
path = MMAP_RND_COMPAT_PATH;
} else {
path = MMAP_RND_PATH;
}
return set_highest_available_option_value(path, min, start);
}
/*
* Set /proc/sys/vm/mmap_rnd_bits and potentially
* /proc/sys/vm/mmap_rnd_compat_bits to the maximum supported values.
* Returns -1 if unable to set these to an acceptable value.
*
* To support this sysctl, the following upstream commits are needed:
*
* d07e22597d1d mm: mmap: add new /proc tunable for mmap_base ASLR
* e0c25d958f78 arm: mm: support ARCH_MMAP_RND_BITS
* 8f0d3aa9de57 arm64: mm: support ARCH_MMAP_RND_BITS
* 9e08f57d684a x86: mm: support ARCH_MMAP_RND_BITS
* ec9ee4acd97c drivers: char: random: add get_random_long()
* 5ef11c35ce86 mm: ASLR: use get_random_long()
*/
static int set_mmap_rnd_bits_action(const std::vector<std::string>& args)
{
int ret = -1;
/* values are arch-dependent */
#if defined(__aarch64__)
/* arm64 supports 18 - 33 bits depending on pagesize and VA_SIZE */
if (set_mmap_rnd_bits_min(33, 24, false)
&& set_mmap_rnd_bits_min(16, 16, true)) {
ret = 0;
}
#elif defined(__x86_64__)
/* x86_64 supports 28 - 32 bits */
if (set_mmap_rnd_bits_min(32, 32, false)
&& set_mmap_rnd_bits_min(16, 16, true)) {
ret = 0;
}
#elif defined(__arm__) || defined(__i386__)
/* check to see if we're running on 64-bit kernel */
bool h64 = !access(MMAP_RND_COMPAT_PATH, F_OK);
/* supported 32-bit architecture must have 16 bits set */
if (set_mmap_rnd_bits_min(16, 16, h64)) {
ret = 0;
}
#elif defined(__mips__) || defined(__mips64__)
// TODO: add mips support b/27788820
ret = 0;
#else
LOG(ERROR) << "Unknown architecture";
#endif
if (ret == -1) {
LOG(ERROR) << "Unable to set adequate mmap entropy value!";
security_failure();
}
return ret;
}
#define KPTR_RESTRICT_PATH "/proc/sys/kernel/kptr_restrict"
#define KPTR_RESTRICT_MINVALUE 2
#define KPTR_RESTRICT_MAXVALUE 4
/* Set kptr_restrict to the highest available level.
*
* Aborts if unable to set this to an acceptable value.
*/
static int set_kptr_restrict_action(const std::vector<std::string>& args)
{
std::string path = KPTR_RESTRICT_PATH;
if (!set_highest_available_option_value(path, KPTR_RESTRICT_MINVALUE, KPTR_RESTRICT_MAXVALUE)) {
LOG(ERROR) << "Unable to set adequate kptr_restrict value!";
security_failure();
}
return 0;
}
static int keychord_init_action(const std::vector<std::string>& args)
{
keychord_init();
return 0;
}
static int console_init_action(const std::vector<std::string>& args)
{
std::string console = property_get("ro.boot.console");
if (!console.empty()) {
default_console = "/dev/" + console;
}
return 0;
}
static void import_kernel_nv(const std::string& key, const std::string& value, bool for_emulator) {
if (key.empty()) return;
if (for_emulator) {
// In the emulator, export any kernel option with the "ro.kernel." prefix.
property_set(StringPrintf("ro.kernel.%s", key.c_str()).c_str(), value.c_str());
return;
}
if (key == "qemu") {
strlcpy(qemu, value.c_str(), sizeof(qemu));
} else if (android::base::StartsWith(key, "androidboot.")) {
property_set(StringPrintf("ro.boot.%s", key.c_str() + 12).c_str(), value.c_str());
}
}
static void export_oem_lock_status() {
if (property_get("ro.oem_unlock_supported") != "1") {
return;
}
std::string value = property_get("ro.boot.verifiedbootstate");
if (!value.empty()) {
property_set("ro.boot.flash.locked", value == "orange" ? "0" : "1");
}
}
static void export_kernel_boot_props() {
struct {
const char *src_prop;
const char *dst_prop;
const char *default_value;
} prop_map[] = {
{ "ro.boot.serialno", "ro.serialno", "", },
{ "ro.boot.mode", "ro.bootmode", "unknown", },
{ "ro.boot.baseband", "ro.baseband", "unknown", },
{ "ro.boot.bootloader", "ro.bootloader", "unknown", },
{ "ro.boot.hardware", "ro.hardware", "unknown", },
{ "ro.boot.revision", "ro.revision", "0", },
};
for (size_t i = 0; i < arraysize(prop_map); i++) {
std::string value = property_get(prop_map[i].src_prop);
property_set(prop_map[i].dst_prop, (!value.empty()) ? value.c_str() : prop_map[i].default_value);
}
}
static constexpr char android_dt_dir[] = "/proc/device-tree/firmware/android";
static bool is_dt_compatible() {
std::string dt_value;
std::string file_name = StringPrintf("%s/compatible", android_dt_dir);
if (android::base::ReadFileToString(file_name, &dt_value)) {
// trim the trailing '\0' out, otherwise the comparison
// will produce false-negatives.
dt_value.resize(dt_value.size() - 1);
if (dt_value == "android,firmware") {
return true;
}
}
return false;
}
static bool is_dt_fstab_compatible() {
std::string dt_value;
std::string file_name = StringPrintf("%s/%s/compatible", android_dt_dir, "fstab");
if (android::base::ReadFileToString(file_name, &dt_value)) {
dt_value.resize(dt_value.size() - 1);
if (dt_value == "android,fstab") {
return true;
}
}
return false;
}
static void process_kernel_dt() {
if (!is_dt_compatible()) return;
std::unique_ptr<DIR, int(*)(DIR*)>dir(opendir(android_dt_dir), closedir);
if (!dir) return;
std::string dt_file;
struct dirent *dp;
while ((dp = readdir(dir.get())) != NULL) {
if (dp->d_type != DT_REG || !strcmp(dp->d_name, "compatible") || !strcmp(dp->d_name, "name")) {
continue;
}
std::string file_name = StringPrintf("%s/%s", android_dt_dir, dp->d_name);
android::base::ReadFileToString(file_name, &dt_file);
std::replace(dt_file.begin(), dt_file.end(), ',', '.');
std::string property_name = StringPrintf("ro.boot.%s", dp->d_name);
property_set(property_name.c_str(), dt_file.c_str());
}
}
static void process_kernel_cmdline() {
// The first pass does the common stuff, and finds if we are in qemu.
// The second pass is only necessary for qemu to export all kernel params
// as properties.
import_kernel_cmdline(false, import_kernel_nv);
if (qemu[0]) import_kernel_cmdline(true, import_kernel_nv);
}
static int property_enable_triggers_action(const std::vector<std::string>& args)
{
/* Enable property triggers. */
property_triggers_enabled = 1;
return 0;
}
static int queue_property_triggers_action(const std::vector<std::string>& args)
{
ActionManager::GetInstance().QueueBuiltinAction(property_enable_triggers_action, "enable_property_trigger");
ActionManager::GetInstance().QueueAllPropertyTriggers();
return 0;
}
static void selinux_init_all_handles(void)
{
sehandle = selinux_android_file_context_handle();
selinux_android_set_sehandle(sehandle);
sehandle_prop = selinux_android_prop_context_handle();
}
enum selinux_enforcing_status { SELINUX_PERMISSIVE, SELINUX_ENFORCING };
static selinux_enforcing_status selinux_status_from_cmdline() {
selinux_enforcing_status status = SELINUX_ENFORCING;
import_kernel_cmdline(false, [&](const std::string& key, const std::string& value, bool in_qemu) {
if (key == "androidboot.selinux" && value == "permissive") {
status = SELINUX_PERMISSIVE;
}
});
return status;
}
static bool selinux_is_enforcing(void)
{
if (ALLOW_PERMISSIVE_SELINUX) {
return selinux_status_from_cmdline() == SELINUX_ENFORCING;
}
return true;
}
static int audit_callback(void *data, security_class_t /*cls*/, char *buf, size_t len) {
property_audit_data *d = reinterpret_cast<property_audit_data*>(data);
if (!d || !d->name || !d->cr) {
LOG(ERROR) << "audit_callback 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;
}
/*
* Forks, executes the provided program in the child, and waits for the completion in the parent.
*
* Returns true if the child exited with status code 0, returns false otherwise.
*/
static bool fork_execve_and_wait_for_completion(const char* filename, char* const argv[],
char* const envp[]) {
pid_t child_pid = fork();
if (child_pid == -1) {
PLOG(ERROR) << "Failed to fork for " << filename;
return false;
}
if (child_pid == 0) {
// fork succeeded -- this is executing in the child process
if (execve(filename, argv, envp) == -1) {
PLOG(ERROR) << "Failed to execve " << filename;
return false;
}
// Unreachable because execve will have succeeded and replaced this code
// with child process's code.
_exit(127);
return false;
} else {
// fork succeeded -- this is executing in the original/parent process
int status;
if (TEMP_FAILURE_RETRY(waitpid(child_pid, &status, 0)) != child_pid) {
PLOG(ERROR) << "Failed to wait for " << filename;
return false;
}
if (WIFEXITED(status)) {
int status_code = WEXITSTATUS(status);
if (status_code == 0) {
return true;
} else {
LOG(ERROR) << filename << " exited with status " << status_code;
}
} else if (WIFSIGNALED(status)) {
LOG(ERROR) << filename << " killed by signal " << WTERMSIG(status);
} else if (WIFSTOPPED(status)) {
LOG(ERROR) << filename << " stopped by signal " << WSTOPSIG(status);
} else {
LOG(ERROR) << "waitpid for " << filename << " returned unexpected status: " << status;
}
return false;
}
}
static constexpr const char plat_policy_cil_file[] = "/plat_sepolicy.cil";
static bool selinux_is_split_policy_device() { return access(plat_policy_cil_file, R_OK) != -1; }
/*
* Loads SELinux policy split across platform/system and non-platform/vendor files.
*
* Returns true upon success, false otherwise (failure cause is logged).
*/
static bool selinux_load_split_policy() {
// IMPLEMENTATION NOTE: Split policy consists of three CIL files:
// * platform -- policy needed due to logic contained in the system image,
// * non-platform -- policy needed due to logic contained in the vendor image,
// * mapping -- mapping policy which helps preserve forward-compatibility of non-platform policy
// with newer versions of platform policy.
//
// secilc is invoked to compile the above three policy files into a single monolithic policy
// file. This file is then loaded into the kernel.
LOG(INFO) << "Compiling SELinux policy";
// We store the output of the compilation on /dev because this is the most convenient tmpfs
// storage mount available this early in the boot sequence.
char compiled_sepolicy[] = "/dev/sepolicy.XXXXXX";
android::base::unique_fd compiled_sepolicy_fd(mkostemp(compiled_sepolicy, O_CLOEXEC));
if (compiled_sepolicy_fd < 0) {
PLOG(ERROR) << "Failed to create temporary file " << compiled_sepolicy;
return false;
}
const char* compile_args[] = {"/system/bin/secilc", plat_policy_cil_file, "-M", "true", "-c",
"30", // TODO: pass in SELinux policy version from build system
"/mapping_sepolicy.cil", "/nonplat_sepolicy.cil", "-o",
compiled_sepolicy,
// We don't care about file_contexts output by the compiler
"-f", "/sys/fs/selinux/null", // /dev/null is not yet available
nullptr};
if (!fork_execve_and_wait_for_completion(compile_args[0], (char**)compile_args, (char**)ENV)) {
unlink(compiled_sepolicy);
return false;
}
unlink(compiled_sepolicy);
LOG(INFO) << "Loading compiled SELinux policy";
if (selinux_android_load_policy_from_fd(compiled_sepolicy_fd, compiled_sepolicy) < 0) {
LOG(ERROR) << "Failed to load SELinux policy from " << compiled_sepolicy;
return false;
}
return true;
}
/*
* Loads SELinux policy from a monolithic file.
*
* Returns true upon success, false otherwise (failure cause is logged).
*/
static bool selinux_load_monolithic_policy() {
LOG(VERBOSE) << "Loading SELinux policy from monolithic file";
if (selinux_android_load_policy() < 0) {
PLOG(ERROR) << "Failed to load monolithic SELinux policy";
return false;
}
return true;
}
/*
* Loads SELinux policy into the kernel.
*
* Returns true upon success, false otherwise (failure cause is logged).
*/
static bool selinux_load_policy() {
return selinux_is_split_policy_device() ? selinux_load_split_policy()
: selinux_load_monolithic_policy();
}
static void selinux_initialize(bool in_kernel_domain) {
Timer t;
selinux_callback cb;
cb.func_log = selinux_klog_callback;
selinux_set_callback(SELINUX_CB_LOG, cb);
cb.func_audit = audit_callback;
selinux_set_callback(SELINUX_CB_AUDIT, cb);
if (in_kernel_domain) {
LOG(INFO) << "Loading SELinux policy";
if (!selinux_load_policy()) {
panic();
}
bool kernel_enforcing = (security_getenforce() == 1);
bool is_enforcing = selinux_is_enforcing();
if (kernel_enforcing != is_enforcing) {
if (security_setenforce(is_enforcing)) {
PLOG(ERROR) << "security_setenforce(%s) failed" << (is_enforcing ? "true" : "false");
security_failure();
}
}
if (!write_file("/sys/fs/selinux/checkreqprot", "0")) {
security_failure();
}
// init's first stage can't set properties, so pass the time to the second stage.
setenv("INIT_SELINUX_TOOK", std::to_string(t.duration_ms()).c_str(), 1);
} else {
selinux_init_all_handles();
}
}
// Set the UDC controller for the ConfigFS USB Gadgets.
// Read the UDC controller in use from "/sys/class/udc".
// In case of multiple UDC controllers select the first one.
static void set_usb_controller() {
std::unique_ptr<DIR, decltype(&closedir)>dir(opendir("/sys/class/udc"), closedir);
if (!dir) return;
dirent* dp;
while ((dp = readdir(dir.get())) != nullptr) {
if (dp->d_name[0] == '.') continue;
property_set("sys.usb.controller", dp->d_name);
break;
}
}
static bool early_mount_one(struct fstab_rec* rec) {
if (rec && fs_mgr_is_verified(rec)) {
// setup verity and create the dm-XX block device
// needed to mount this partition
int ret = fs_mgr_setup_verity(rec, false);
if (ret == FS_MGR_SETUP_VERITY_FAIL) {
PLOG(ERROR) << "early_mount: Failed to setup verity for '" << rec->mount_point << "'";
return false;
}
// The exact block device name is added as a mount source by
// fs_mgr_setup_verity() in ->blk_device as "/dev/block/dm-XX"
// We create that device by running coldboot on /sys/block/dm-XX
std::string dm_device(basename(rec->blk_device));
std::string syspath = StringPrintf("/sys/block/%s", dm_device.c_str());
device_init(syspath.c_str(), [&](uevent* uevent) -> coldboot_action_t {
if (uevent->device_name && !strcmp(dm_device.c_str(), uevent->device_name)) {
LOG(VERBOSE) << "early_mount: creating dm-verity device : " << dm_device;
return COLDBOOT_STOP;
}
return COLDBOOT_CONTINUE;
});
}
if (rec && fs_mgr_do_mount_one(rec)) {
PLOG(ERROR) << "early_mount: Failed to mount '" << rec->mount_point << "'";
return false;
}
return true;
}
/* Early mount vendor and ODM partitions. The fstab is read from device-tree. */
static bool early_mount() {
// first check if device tree fstab entries are compatible
if (!is_dt_fstab_compatible()) {
LOG(INFO) << "Early mount skipped (missing/incompatible fstab in device tree)";
return true;
}
std::unique_ptr<fstab, decltype(&fs_mgr_free_fstab)> tab(
fs_mgr_read_fstab_dt(), fs_mgr_free_fstab);
if (!tab) {
LOG(ERROR) << "Early mount failed to read fstab from device tree";
return false;
}
// find out fstab records for odm, system and vendor
// TODO: add std::map<std::string, fstab_rec*> so all required information about
// them can be gathered at once in a single loop
fstab_rec* odm_rec = fs_mgr_get_entry_for_mount_point(tab.get(), "/odm");
fstab_rec* system_rec = fs_mgr_get_entry_for_mount_point(tab.get(), "/system");
fstab_rec* vendor_rec = fs_mgr_get_entry_for_mount_point(tab.get(), "/vendor");
if (!odm_rec && !system_rec && !vendor_rec) {
// nothing to early mount
return true;
}
// don't allow verifyatboot for early mounted partitions
if ((odm_rec && fs_mgr_is_verifyatboot(odm_rec)) ||
(system_rec && fs_mgr_is_verifyatboot(system_rec)) ||
(vendor_rec && fs_mgr_is_verifyatboot(vendor_rec))) {
LOG(ERROR) << "Early mount partitions can't be verified at boot";
return false;
}
// assume A/B device if we find 'slotselect' in any fstab entry
bool is_ab = ((odm_rec && fs_mgr_is_slotselect(odm_rec)) ||
(system_rec && fs_mgr_is_slotselect(system_rec)) ||
(vendor_rec && fs_mgr_is_slotselect(vendor_rec)));
// check for verified partitions
bool need_verity = ((odm_rec && fs_mgr_is_verified(odm_rec)) ||
(system_rec && fs_mgr_is_verified(system_rec)) ||
(vendor_rec && fs_mgr_is_verified(vendor_rec)));
// check if verity metadata is on a separate partition and get partition
// name from the end of the ->verity_loc path. verity state is not partition
// specific, so there must be only 1 additional partition that carries
// verity state.
std::string meta_partition;
if (odm_rec && odm_rec->verity_loc) {
meta_partition = basename(odm_rec->verity_loc);
} else if (system_rec && system_rec->verity_loc) {
meta_partition = basename(system_rec->verity_loc);
} else if (vendor_rec && vendor_rec->verity_loc) {
meta_partition = basename(vendor_rec->verity_loc);
}
bool found_odm = !odm_rec;
bool found_system = !system_rec;
bool found_vendor = !vendor_rec;
bool found_meta = meta_partition.empty();
int count_odm = 0, count_vendor = 0, count_system = 0;
// create the devices we need..
device_init(nullptr, [&](uevent* uevent) -> coldboot_action_t {
if (!strncmp(uevent->subsystem, "firmware", 8)) {
return COLDBOOT_CONTINUE;
}
// we need platform devices to create symlinks
if (!strncmp(uevent->subsystem, "platform", 8)) {
return COLDBOOT_CREATE;
}
// Ignore everything that is not a block device
if (strncmp(uevent->subsystem, "block", 5)) {
return COLDBOOT_CONTINUE;
}
coldboot_action_t ret;
bool create_this_node = false;
if (uevent->partition_name) {
// prefix match partition names so we create device nodes for
// A/B-ed partitions
if (!found_odm && !strncmp(uevent->partition_name, "odm", 3)) {
LOG(VERBOSE) << "early_mount: found (" << uevent->partition_name << ") partition";
// wait twice for A/B-ed partitions
count_odm++;
if (!is_ab || count_odm == 2) {
found_odm = true;
}
create_this_node = true;
} else if (!found_system && !strncmp(uevent->partition_name, "system", 6)) {
LOG(VERBOSE) << "early_mount: found (" << uevent->partition_name << ") partition";
count_system++;
if (!is_ab || count_system == 2) {
found_system = true;
}
create_this_node = true;
} else if (!found_vendor && !strncmp(uevent->partition_name, "vendor", 6)) {
LOG(VERBOSE) << "early_mount: found (" << uevent->partition_name << ") partition";
count_vendor++;
if (!is_ab || count_vendor == 2) {
found_vendor = true;
}
create_this_node = true;
} else if (!found_meta && (meta_partition == uevent->partition_name)) {
LOG(VERBOSE) << "early_mount: found (" << uevent->partition_name << ") partition";
found_meta = true;
create_this_node = true;
}
}
// if we found all other partitions already, create this
// node and stop coldboot. If this is a prefix matched
// partition, create device node and continue. For everything
// else skip the device node
if (found_meta && found_odm && found_system && found_vendor) {
ret = COLDBOOT_STOP;
} else if (create_this_node) {
ret = COLDBOOT_CREATE;
} else {
ret = COLDBOOT_CONTINUE;
}
return ret;
});
if (need_verity) {
// create /dev/device mapper
device_init("/sys/devices/virtual/misc/device-mapper",
[&](uevent* uevent) -> coldboot_action_t { return COLDBOOT_STOP; });
}
bool success = true;
if (odm_rec && !(success = early_mount_one(odm_rec))) goto done;
if (system_rec && !(success = early_mount_one(system_rec))) goto done;
if (vendor_rec && !(success = early_mount_one(vendor_rec))) goto done;
done:
device_close();
return success;
}
int main(int argc, char** argv) {
if (!strcmp(basename(argv[0]), "ueventd")) {
return ueventd_main(argc, argv);
}
if (!strcmp(basename(argv[0]), "watchdogd")) {
return watchdogd_main(argc, argv);
}
boot_clock::time_point start_time = boot_clock::now();
// Clear the umask.
umask(0);
add_environment("PATH", _PATH_DEFPATH);
bool is_first_stage = (getenv("INIT_SECOND_STAGE") == nullptr);
// Don't expose the raw commandline to unprivileged processes.
chmod("/proc/cmdline", 0440);
// Get the basic filesystem setup we need put together in the initramdisk
// on / and then we'll let the rc file figure out the rest.
if (is_first_stage) {
mount("tmpfs", "/dev", "tmpfs", MS_NOSUID, "mode=0755");
mkdir("/dev/pts", 0755);
mkdir("/dev/socket", 0755);
mount("devpts", "/dev/pts", "devpts", 0, NULL);
#define MAKE_STR(x) __STRING(x)
mount("proc", "/proc", "proc", 0, "hidepid=2,gid=" MAKE_STR(AID_READPROC));
gid_t groups[] = { AID_READPROC };
setgroups(arraysize(groups), groups);
mount("sysfs", "/sys", "sysfs", 0, NULL);
mount("selinuxfs", "/sys/fs/selinux", "selinuxfs", 0, NULL);
mknod("/dev/kmsg", S_IFCHR | 0600, makedev(1, 11));
mknod("/dev/random", S_IFCHR | 0666, makedev(1, 8));
mknod("/dev/urandom", S_IFCHR | 0666, makedev(1, 9));
}
// Now that tmpfs is mounted on /dev and we have /dev/kmsg, we can actually
// talk to the outside world...
InitKernelLogging(argv);
LOG(INFO) << "init " << (is_first_stage ? "first" : "second") << " stage started!";
if (is_first_stage) {
if (!early_mount()) {
LOG(ERROR) << "Failed to mount required partitions early ...";
panic();
}
// Set up SELinux, loading the SELinux policy.
selinux_initialize(true);
// We're in the kernel domain, so re-exec init to transition to the init domain now
// that the SELinux policy has been loaded.
if (restorecon("/init") == -1) {
PLOG(ERROR) << "restorecon failed";
security_failure();
}
setenv("INIT_SECOND_STAGE", "true", 1);
static constexpr uint32_t kNanosecondsPerMillisecond = 1e6;
uint64_t start_ms = start_time.time_since_epoch().count() / kNanosecondsPerMillisecond;
setenv("INIT_STARTED_AT", StringPrintf("%" PRIu64, start_ms).c_str(), 1);
char* path = argv[0];
char* args[] = { path, nullptr };
if (execv(path, args) == -1) {
PLOG(ERROR) << "execv(\"" << path << "\") failed";
security_failure();
}
} else {
// Indicate that booting is in progress to background fw loaders, etc.
close(open("/dev/.booting", O_WRONLY | O_CREAT | O_CLOEXEC, 0000));
property_init();
// If arguments are passed both on the command line and in DT,
// properties set in DT always have priority over the command-line ones.
process_kernel_dt();
process_kernel_cmdline();
// Propagate the kernel variables to internal variables
// used by init as well as the current required properties.
export_kernel_boot_props();
// Make the time that init started available for bootstat to log.
property_set("ro.boottime.init", getenv("INIT_STARTED_AT"));
property_set("ro.boottime.init.selinux", getenv("INIT_SELINUX_TOOK"));
// Set libavb version for Framework-only OTA match in Treble build.
property_set("ro.boot.init.avb_version", std::to_string(AVB_MAJOR_VERSION).c_str());
// Clean up our environment.
unsetenv("INIT_SECOND_STAGE");
unsetenv("INIT_STARTED_AT");
unsetenv("INIT_SELINUX_TOOK");
// Now set up SELinux for second stage.
selinux_initialize(false);
}
// These directories were necessarily created before initial policy load
// and therefore need their security context restored to the proper value.
// This must happen before /dev is populated by ueventd.
LOG(INFO) << "Running restorecon...";
restorecon("/dev");
restorecon("/dev/kmsg");
restorecon("/dev/socket");
restorecon("/dev/random");
restorecon("/dev/urandom");
restorecon("/dev/__properties__");
restorecon("/plat_property_contexts");
restorecon("/nonplat_property_contexts");
restorecon("/sys", SELINUX_ANDROID_RESTORECON_RECURSE);
restorecon("/dev/block", SELINUX_ANDROID_RESTORECON_RECURSE);
restorecon("/dev/device-mapper");
epoll_fd = epoll_create1(EPOLL_CLOEXEC);
if (epoll_fd == -1) {
PLOG(ERROR) << "epoll_create1 failed";
exit(1);
}
signal_handler_init();
property_load_boot_defaults();
export_oem_lock_status();
start_property_service();
set_usb_controller();
const BuiltinFunctionMap function_map;
Action::set_function_map(&function_map);
Parser& parser = Parser::GetInstance();
parser.AddSectionParser("service",std::make_unique<ServiceParser>());
parser.AddSectionParser("on", std::make_unique<ActionParser>());
parser.AddSectionParser("import", std::make_unique<ImportParser>());
std::string bootscript = property_get("ro.boot.init_rc");
if (bootscript.empty()) {
parser.ParseConfig("/init.rc");
parser.set_is_system_etc_init_loaded(
parser.ParseConfig("/system/etc/init"));
parser.set_is_vendor_etc_init_loaded(
parser.ParseConfig("/vendor/etc/init"));
parser.set_is_odm_etc_init_loaded(parser.ParseConfig("/odm/etc/init"));
} else {
parser.ParseConfig(bootscript);
parser.set_is_system_etc_init_loaded(true);
parser.set_is_vendor_etc_init_loaded(true);
parser.set_is_odm_etc_init_loaded(true);
}
ActionManager& am = ActionManager::GetInstance();
am.QueueEventTrigger("early-init");
// Queue an action that waits for coldboot done so we know ueventd has set up all of /dev...
am.QueueBuiltinAction(wait_for_coldboot_done_action, "wait_for_coldboot_done");
// ... so that we can start queuing up actions that require stuff from /dev.
am.QueueBuiltinAction(mix_hwrng_into_linux_rng_action, "mix_hwrng_into_linux_rng");
am.QueueBuiltinAction(set_mmap_rnd_bits_action, "set_mmap_rnd_bits");
am.QueueBuiltinAction(set_kptr_restrict_action, "set_kptr_restrict");
am.QueueBuiltinAction(keychord_init_action, "keychord_init");
am.QueueBuiltinAction(console_init_action, "console_init");
// Trigger all the boot actions to get us started.
am.QueueEventTrigger("init");
// Repeat mix_hwrng_into_linux_rng in case /dev/hw_random or /dev/random
// wasn't ready immediately after wait_for_coldboot_done
am.QueueBuiltinAction(mix_hwrng_into_linux_rng_action, "mix_hwrng_into_linux_rng");
// Don't mount filesystems or start core system services in charger mode.
std::string bootmode = property_get("ro.bootmode");
if (bootmode == "charger") {
am.QueueEventTrigger("charger");
} else {
am.QueueEventTrigger("late-init");
}
// Run all property triggers based on current state of the properties.
am.QueueBuiltinAction(queue_property_triggers_action, "queue_property_triggers");
while (true) {
if (!(waiting_for_exec || waiting_for_prop)) {
am.ExecuteOneCommand();
restart_processes();
}
// By default, sleep until something happens.
int epoll_timeout_ms = -1;
// If there's a process that needs restarting, wake up in time for that.
if (process_needs_restart_at != 0) {
epoll_timeout_ms = (process_needs_restart_at - time(nullptr)) * 1000;
if (epoll_timeout_ms < 0) epoll_timeout_ms = 0;
}
// If there's more work to do, wake up again immediately.
if (am.HasMoreCommands()) epoll_timeout_ms = 0;
epoll_event ev;
int nr = TEMP_FAILURE_RETRY(epoll_wait(epoll_fd, &ev, 1, epoll_timeout_ms));
if (nr == -1) {
PLOG(ERROR) << "epoll_wait failed";
} else if (nr == 1) {
((void (*)()) ev.data.ptr)();
}
}
return 0;
}
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