Magisk/native/jni/magiskhide/hide_utils.cpp
topjohnwu ab5fedda0b Prevent Magisk database race condition
The database should only be accessed by a single process, which is magiskd.
This means 'magisk --sqlite [SQL]' has to be updated to pass the SQL command to the daemon.
In addition, open the database connection with SQLITE_OPEN_FULLMUTEX to support multithread in magiskd.
2018-11-16 03:20:30 -05:00

311 lines
6.5 KiB
C++

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#include <string.h>
#include <libgen.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "magisk.h"
#include "utils.h"
#include "resetprop.h"
#include "magiskhide.h"
#include "daemon.h"
#include "db.h"
Vector<CharArray> hide_list;
pthread_mutex_t list_lock;
static pthread_t proc_monitor_thread;
static const char *prop_key[] =
{ "ro.boot.vbmeta.device_state", "ro.boot.verifiedbootstate", "ro.boot.flash.locked",
"ro.boot.veritymode", "ro.boot.warranty_bit", "ro.warranty_bit", "ro.debuggable",
"ro.secure", "ro.build.type", "ro.build.tags", "ro.build.selinux", nullptr };
static const char *prop_value[] =
{ "locked", "green", "1",
"enforcing", "0", "0", "0",
"1", "user", "release-keys", "0", nullptr };
struct ps_arg {
const char *name;
uid_t uid;
};
void manage_selinux() {
char val;
int fd = xopen(SELINUX_ENFORCE, O_RDONLY);
xxread(fd, &val, sizeof(val));
close(fd);
// Permissive
if (val == '0') {
chmod(SELINUX_ENFORCE, 0640);
chmod(SELINUX_POLICY, 0440);
}
}
void hide_sensitive_props() {
LOGI("hide_utils: Hiding sensitive props\n");
// Hide all sensitive props
for (int i = 0; prop_key[i]; ++i) {
CharArray value = getprop(prop_key[i]);
if (!value.empty() && value != prop_value[i])
setprop(prop_key[i], prop_value[i], false);
}
}
static void ps(void (*cb)(int, void*), void *arg) {
DIR *dir;
struct dirent *entry;
if (!(dir = xopendir("/proc")))
return;
while ((entry = xreaddir(dir))) {
if (entry->d_type == DT_DIR && is_num(entry->d_name))
cb(atoi(entry->d_name), arg);
}
closedir(dir);
}
static bool check_proc_name(int pid, const char *name) {
char buf[4019];
FILE *f;
sprintf(buf, "/proc/%d/comm", pid);
if ((f = fopen(buf, "r"))) {
fgets(buf, sizeof(buf), f);
if (strcmp(buf, name) == 0)
return true;
} else {
// The PID is already killed
return false;
}
fclose(f);
sprintf(buf, "/proc/%d/cmdline", pid);
if ((f = fopen(buf, "r"))) {
fgets(buf, sizeof(buf), f);
if (strcmp(basename(buf), name) == 0)
return true;
} else {
// The PID is already killed
return false;
}
fclose(f);
sprintf(buf, "/proc/%d/exe", pid);
if (access(buf, F_OK) != 0)
return false;
xreadlink(buf, buf, sizeof(buf));
return strcmp(basename(buf), name) == 0;
}
static void kill_proc_cb(int pid, void *v) {
ps_arg *args = static_cast<ps_arg *>(v);
if (check_proc_name(pid, args->name))
kill(pid, SIGTERM);
else if (args->uid > 0) {
char buf[64];
struct stat st;
sprintf(buf, "/proc/%d", pid);
stat(buf, &st);
if (args->uid == st.st_uid)
kill(pid, SIGTERM);
}
}
static void kill_process(const char *name) {
ps_arg args = { .name = name };
struct stat st;
int fd = xopen("/data/data", O_RDONLY | O_CLOEXEC);
if (fstatat(fd, name, &st, 0) == 0)
args.uid = st.st_uid;
else
args.uid = 0;
close(fd);
ps(kill_proc_cb, &args);
}
void clean_magisk_props() {
LOGD("hide_utils: Cleaning magisk props\n");
getprop([](const char *name, auto, auto) -> void {
if (strstr(name, "magisk"))
deleteprop(name);
}, nullptr, false);
}
int add_list(const char *proc) {
for (auto &s : hide_list) {
// They should be unique
if (s == proc)
return HIDE_ITEM_EXIST;
}
LOGI("hide_list add: [%s]\n", proc);
// Add to database
char sql[4096];
snprintf(sql, sizeof(sql), "INSERT INTO hidelist (process) VALUES('%s')", proc);
char *err = db_exec(sql);
db_err_cmd(err, return DAEMON_ERROR);
// Critical region
pthread_mutex_lock(&list_lock);
hide_list.push_back(proc);
kill_process(proc);
pthread_mutex_unlock(&list_lock);
return DAEMON_SUCCESS;
}
int add_list(int client) {
char *proc = read_string(client);
int ret = add_list(proc);
free(proc);
return ret;
}
static int rm_list(const char *proc) {
// Update list in critical region
bool do_rm = false;
pthread_mutex_lock(&list_lock);
for (auto it = hide_list.begin(); it != hide_list.end(); ++it) {
if (*it == proc) {
do_rm = true;
LOGI("hide_list rm: [%s]\n", proc);
hide_list.erase(it);
kill_process(proc);
break;
}
}
pthread_mutex_unlock(&list_lock);
if (do_rm) {
char sql[4096];
snprintf(sql, sizeof(sql), "DELETE FROM hidelist WHERE process='%s'", proc);
char *err = db_exec(sql);
db_err(err);
return DAEMON_SUCCESS;
} else {
return HIDE_ITEM_NOT_EXIST;
}
}
int rm_list(int client) {
char *proc = read_string(client);
int ret = rm_list(proc);
free(proc);
return ret;
}
#define LEGACY_LIST MOUNTPOINT "/.core/hidelist"
static int collect_list(void *, int, char **data, char**) {
LOGI("hide_list: [%s]\n", data[0]);
hide_list.push_back(data[0]);
return 0;
}
bool init_list() {
LOGD("hide_list: initialize\n");
char *err = db_exec("SELECT process FROM hidelist", collect_list);
db_err_cmd(err, return false);
// Migrate old hide list into database
if (access(LEGACY_LIST, R_OK) == 0) {
Vector<CharArray> tmp;
file_to_vector(LEGACY_LIST, tmp);
for (auto &s : tmp)
add_list(s);
unlink(LEGACY_LIST);
}
return true;
}
void ls_list(int client) {
FILE *out = fdopen(recv_fd(client), "a");
for (auto &s : hide_list)
fprintf(out, "%s\n", s.c_str());
fclose(out);
write_int(client, DAEMON_SUCCESS);
close(client);
}
static void set_hide_config() {
char sql[64];
sprintf(sql, "REPLACE INTO settings (key,value) VALUES('%s',%d)",
DB_SETTING_KEYS[HIDE_CONFIG], hide_enabled);
char *err = db_exec(sql);
db_err(err);
}
int launch_magiskhide(int client) {
if (hide_enabled)
return HIDE_IS_ENABLED;
if (!log_daemon_started)
return LOGCAT_DISABLED;
hide_enabled = true;
set_hide_config();
LOGI("* Starting MagiskHide\n");
hide_sensitive_props();
// Initialize the mutex lock
pthread_mutex_init(&list_lock, nullptr);
// Initialize the hide list
if (!init_list())
goto error;
// Add SafetyNet by default
add_list("com.google.android.gms.unstable");
// Get thread reference
proc_monitor_thread = pthread_self();
if (client >= 0) {
write_int(client, DAEMON_SUCCESS);
close(client);
}
// Start monitoring
proc_monitor();
error:
hide_enabled = false;
return DAEMON_ERROR;
}
int stop_magiskhide() {
LOGI("* Stopping MagiskHide\n");
hide_enabled = false;
set_hide_config();
pthread_kill(proc_monitor_thread, TERM_THREAD);
return DAEMON_SUCCESS;
}
void auto_start_magiskhide() {
if (!start_log_daemon())
return;
db_settings dbs;
get_db_settings(&dbs, HIDE_CONFIG);
if (dbs[HIDE_CONFIG]) {
pthread_t thread;
xpthread_create(&thread, nullptr, [](void*) -> void* {
launch_magiskhide(-1);
return nullptr;
}, nullptr);
pthread_detach(thread);
}
}