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Magisk
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Magisk/native/jni/core/daemon.cpp

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9.3 KiB
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#include <fcntl.h>
#include <pthread.h>
#include <csignal>
#include <libgen.h>
#include <sys/un.h>
#include <sys/types.h>
#include <sys/mount.h>
#include <android/log.h>
#include <magisk.hpp>
#include <utils.hpp>
#include <daemon.hpp>
#include <selinux.hpp>
#include <db.hpp>
#include <resetprop.hpp>
#include <flags.hpp>
#include <stream.hpp>
#include "core.hpp"
using namespace std;
int SDK_INT = -1;
string MAGISKTMP;
bool RECOVERY_MODE = false;
int DAEMON_STATE = STATE_NONE;
static struct stat self_st;
static bool verify_client(pid_t pid) {
// Verify caller is the same as server
char path[32];
sprintf(path, "/proc/%d/exe", pid);
struct stat st;
return !(stat(path, &st) || st.st_dev != self_st.st_dev || st.st_ino != self_st.st_ino);
}
static bool check_zygote(pid_t pid) {
char buf[32];
sprintf(buf, "/proc/%d/attr/current", pid);
auto fp = open_file(buf, "r");
if (!fp)
return false;
fscanf(fp.get(), "%s", buf);
return buf == "u:r:zygote:s0"sv;
}
static void request_handler(int client, int req_code, ucred cred) {
switch (req_code) {
case MAGISKHIDE:
magiskhide_handler(client, &cred);
break;
case SUPERUSER:
su_daemon_handler(client, &cred);
break;
case POST_FS_DATA:
post_fs_data(client);
break;
case LATE_START:
late_start(client);
break;
case BOOT_COMPLETE:
boot_complete(client);
break;
case SQLITE_CMD:
exec_sql(client);
break;
case REMOVE_MODULES:
remove_modules();
write_int(client, 0);
close(client);
reboot();
break;
default:
close(client);
break;
}
}
static void handle_request(int client) {
int req_code;
// Verify client credentials
ucred cred;
get_client_cred(client, &cred);
bool is_root = cred.uid == 0;
bool is_zygote = check_zygote(cred.pid);
bool is_client = verify_client(cred.pid);
if (!is_root && !is_zygote && !is_client)
goto shortcut;
req_code = read_int(client);
if (req_code < 0 || req_code >= DAEMON_CODE_END)
goto shortcut;
// Check client permissions
switch (req_code) {
case POST_FS_DATA:
case LATE_START:
case BOOT_COMPLETE:
case SQLITE_CMD:
case GET_PATH:
if (!is_root) {
write_int(client, ROOT_REQUIRED);
goto shortcut;
}
break;
case REMOVE_MODULES:
if (cred.uid != UID_SHELL && cred.uid != UID_ROOT) {
write_int(client, 1);
goto shortcut;
}
break;
case MAGISKHIDE: // accept hide request from zygote
if (!is_root && !is_zygote) {
write_int(client, ROOT_REQUIRED);
goto shortcut;
}
break;
}
// Simple requests
switch (req_code) {
case CHECK_VERSION:
write_string(client, MAGISK_VERSION ":MAGISK");
goto shortcut;
case CHECK_VERSION_CODE:
write_int(client, MAGISK_VER_CODE);
goto shortcut;
case GET_PATH:
write_string(client, MAGISKTMP.data());
goto shortcut;
case START_DAEMON:
setup_logfile(true);
goto shortcut;
}
// Create new thread to handle complex requests
new_daemon_thread([=] { return request_handler(client, req_code, cred); });
return;
shortcut:
close(client);
}
static void magisk_logging();
static void daemon_entry(int ppid) {
magisk_logging();
int fd = xopen("/dev/null", O_WRONLY);
xdup2(fd, STDOUT_FILENO);
xdup2(fd, STDERR_FILENO);
if (fd > STDERR_FILENO)
close(fd);
fd = xopen("/dev/zero", O_RDONLY);
xdup2(fd, STDIN_FILENO);
if (fd > STDERR_FILENO)
close(fd);
setsid();
setcon("u:r:" SEPOL_PROC_DOMAIN ":s0");
LOGI(NAME_WITH_VER(Magisk) " daemon started\n");
// Make sure ppid is not in acct
char src[64], dest[64];
sprintf(src, "/acct/uid_0/pid_%d", ppid);
if (access(src, F_OK) == 0) {
sprintf(dest, "/acct/uid_0/pid_%d", getpid());
rename(src, dest);
}
sprintf(src, "/sys/fs/cgroup/uid_0/pid_%d", ppid);
if (access(src, F_OK) == 0) {
sprintf(dest, "/sys/fs/cgroup/uid_0/pid_%d", getpid());
rename(src, dest);
}
// Get self stat
xreadlink("/proc/self/exe", src, sizeof(src));
MAGISKTMP = dirname(src);
xstat("/proc/self/exe", &self_st);
// Get API level
parse_prop_file("/system/build.prop", [](auto key, auto val) -> bool {
if (key == "ro.build.version.sdk") {
SDK_INT = parse_int(val);
return false;
}
return true;
});
if (SDK_INT < 0) {
// In case some devices do not store this info in build.prop, fallback to getprop
auto sdk = getprop("ro.build.version.sdk");
if (!sdk.empty()) {
SDK_INT = parse_int(sdk);
}
}
LOGI("* Device API level: %d\n", SDK_INT);
restore_tmpcon();
// SAR cleanups
auto mount_list = MAGISKTMP + "/" ROOTMNT;
if (access(mount_list.data(), F_OK) == 0) {
file_readline(true, mount_list.data(), [](string_view line) -> bool {
umount2(line.data(), MNT_DETACH);
return true;
});
}
unlink("/dev/.se");
// Load config status
auto config = MAGISKTMP + "/" INTLROOT "/config";
parse_prop_file(config.data(), [](auto key, auto val) -> bool {
if (key == "RECOVERYMODE" && val == "true")
RECOVERY_MODE = true;
return true;
});
struct sockaddr_un sun;
socklen_t len = setup_sockaddr(&sun, MAIN_SOCKET);
fd = xsocket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
if (xbind(fd, (struct sockaddr*) &sun, len))
exit(1);
xlisten(fd, 10);
// Change process name
set_nice_name("magiskd");
// Block all signals
sigset_t block_set;
sigfillset(&block_set);
pthread_sigmask(SIG_SETMASK, &block_set, nullptr);
// Loop forever to listen for requests
for (;;) {
int client = xaccept4(fd, nullptr, nullptr, SOCK_CLOEXEC);
handle_request(client);
}
}
int connect_daemon(bool create) {
sockaddr_un sun;
socklen_t len = setup_sockaddr(&sun, MAIN_SOCKET);
int fd = xsocket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
if (connect(fd, (struct sockaddr*) &sun, len)) {
if (!create || getuid() != UID_ROOT || getgid() != UID_ROOT) {
LOGE("No daemon is currently running!\n");
exit(1);
}
int ppid = getpid();
LOGD("client: launching new main daemon process\n");
if (fork_dont_care() == 0) {
close(fd);
daemon_entry(ppid);
}
while (connect(fd, (struct sockaddr*) &sun, len))
usleep(10000);
}
return fd;
}
#define TMP_LOGFILE "/dev/.magisk.log"
namespace {
class fd_holder {
public:
explicit fd_holder(int fd) : fd(fd) {}
~fd_holder() { close(fd); }
FILE *get_fp() { auto fp = fdopen(fd, "a"); setbuf(fp, nullptr); return fp; }
private:
int fd;
};
}
static shared_ptr<fd_holder> g_log_file;
void setup_logfile(bool reset) {
static atomic_flag has_setup = ATOMIC_FLAG_INIT;
if (has_setup.test_and_set(memory_order_relaxed))
return;
if (reset)
rename(LOGFILE, LOGFILE ".bak");
g_log_file.reset();
int fd = open(LOGFILE, O_WRONLY | O_APPEND | O_CREAT | O_CLOEXEC, 0644);
if (fd < 0)
return;
if (int old = open(TMP_LOGFILE, O_RDONLY | O_CLOEXEC); old >= 0) {
char buf[4096];
int sz;
while ((sz = xread(old, buf, sizeof(buf))) > 0) {
xwrite(fd, buf, sz);
}
close(old);
}
unlink(TMP_LOGFILE);
g_log_file = make_shared<fd_holder>(fd);
}
static int magisk_log(int prio, const char *fmt, va_list ap) {
// Block all signals temporarily
sigset_t block_set, old_set;
sigfillset(&block_set);
pthread_sigmask(SIG_SETMASK, &block_set, &old_set);
run_finally fin([set = &old_set] { pthread_sigmask(SIG_SETMASK, set, nullptr); });
va_list args;
va_copy(args, ap);
// Log to logcat
__android_log_vprint(prio, "Magisk", fmt, ap);
// Create local copy to prevent race condition
auto log_file = g_log_file;
if (!log_file)
return 0;
char buf[4096];
char type;
switch (prio) {
case ANDROID_LOG_DEBUG:
type = 'D';
break;
case ANDROID_LOG_INFO:
type = 'I';
break;
case ANDROID_LOG_WARN:
type = 'W';
break;
default:
type = 'E';
break;
}
timeval tv;
tm tm;
gettimeofday(&tv, nullptr);
localtime_r(&tv.tv_sec, &tm);
size_t len = strftime(buf, sizeof(buf), "%m-%d %T", &tm);
int ms = tv.tv_usec / 1000;
len += sprintf(buf + len, ".%03d %*d %*d %c : ", ms, 5, getpid(), 5, gettid(), type);
strcpy(buf + len, fmt);
return vfprintf(log_file->get_fp(), buf, args);
}
#define mlog(prio) [](auto fmt, auto ap){ return magisk_log(ANDROID_LOG_##prio, fmt, ap); }
static void magisk_logging() {
if (int fd = open(TMP_LOGFILE, O_WRONLY | O_APPEND | O_CREAT | O_CLOEXEC, 0644); fd >= 0) {
g_log_file = make_shared<fd_holder>(fd);
}
log_cb.d = mlog(DEBUG);
log_cb.i = mlog(INFO);
log_cb.w = mlog(WARN);
log_cb.e = mlog(ERROR);
log_cb.ex = nop_ex;
}
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