mirror of
https://github.com/topjohnwu/Magisk.git
synced 2024-11-24 10:35:26 +00:00
339 lines
9.1 KiB
C++
339 lines
9.1 KiB
C++
#include <unistd.h>
|
|
#include <fcntl.h>
|
|
#include <pwd.h>
|
|
#include <sys/socket.h>
|
|
#include <sys/wait.h>
|
|
#include <sys/mount.h>
|
|
|
|
#include <daemon.hpp>
|
|
#include <magisk.hpp>
|
|
#include <utils.hpp>
|
|
#include <selinux.hpp>
|
|
#include <db.hpp>
|
|
|
|
#include "su.hpp"
|
|
#include "pts.hpp"
|
|
|
|
using namespace std;
|
|
|
|
static pthread_mutex_t cache_lock = PTHREAD_MUTEX_INITIALIZER;
|
|
static shared_ptr<su_info> cached;
|
|
|
|
su_info::su_info(unsigned uid) :
|
|
uid(uid), access(DEFAULT_SU_ACCESS), mgr_st({}),
|
|
timestamp(0), _lock(PTHREAD_MUTEX_INITIALIZER) {}
|
|
|
|
su_info::~su_info() {
|
|
pthread_mutex_destroy(&_lock);
|
|
}
|
|
|
|
mutex_guard su_info::lock() {
|
|
return mutex_guard(_lock);
|
|
}
|
|
|
|
bool su_info::is_fresh() {
|
|
timespec ts;
|
|
clock_gettime(CLOCK_MONOTONIC, &ts);
|
|
long current = ts.tv_sec * 1000L + ts.tv_nsec / 1000000L;
|
|
return current - timestamp < 3000; /* 3 seconds */
|
|
}
|
|
|
|
void su_info::refresh() {
|
|
timespec ts;
|
|
clock_gettime(CLOCK_MONOTONIC, &ts);
|
|
timestamp = ts.tv_sec * 1000L + ts.tv_nsec / 1000000L;
|
|
}
|
|
|
|
static void database_check(const shared_ptr<su_info> &info) {
|
|
int uid = info->uid;
|
|
get_db_settings(info->cfg);
|
|
|
|
// Check multiuser settings
|
|
switch (info->cfg[SU_MULTIUSER_MODE]) {
|
|
case MULTIUSER_MODE_OWNER_ONLY:
|
|
if (to_user_id(uid) != 0) {
|
|
uid = -1;
|
|
info->access = NO_SU_ACCESS;
|
|
}
|
|
break;
|
|
case MULTIUSER_MODE_OWNER_MANAGED:
|
|
uid = to_app_id(uid);
|
|
break;
|
|
case MULTIUSER_MODE_USER:
|
|
default:
|
|
break;
|
|
}
|
|
|
|
if (uid > 0)
|
|
get_uid_policy(info->access, uid);
|
|
|
|
// We need to check our manager
|
|
if (info->access.log || info->access.notify)
|
|
get_manager(to_user_id(uid), &info->mgr_pkg, &info->mgr_st);
|
|
}
|
|
|
|
static shared_ptr<su_info> get_su_info(unsigned uid) {
|
|
LOGD("su: request from uid=[%d]\n", uid);
|
|
|
|
shared_ptr<su_info> info;
|
|
|
|
{
|
|
mutex_guard lock(cache_lock);
|
|
if (!cached || cached->uid != uid || !cached->is_fresh())
|
|
cached = make_shared<su_info>(uid);
|
|
cached->refresh();
|
|
info = cached;
|
|
}
|
|
|
|
mutex_guard lock = info->lock();
|
|
|
|
if (info->access.policy == QUERY) {
|
|
// Not cached, get data from database
|
|
database_check(info);
|
|
|
|
// If it's root or the manager, allow it silently
|
|
if (info->uid == UID_ROOT || to_app_id(info->uid) == to_app_id(info->mgr_st.st_uid)) {
|
|
info->access = SILENT_SU_ACCESS;
|
|
return info;
|
|
}
|
|
|
|
// Check su access settings
|
|
switch (info->cfg[ROOT_ACCESS]) {
|
|
case ROOT_ACCESS_DISABLED:
|
|
LOGW("Root access is disabled!\n");
|
|
info->access = NO_SU_ACCESS;
|
|
break;
|
|
case ROOT_ACCESS_ADB_ONLY:
|
|
if (info->uid != UID_SHELL) {
|
|
LOGW("Root access limited to ADB only!\n");
|
|
info->access = NO_SU_ACCESS;
|
|
}
|
|
break;
|
|
case ROOT_ACCESS_APPS_ONLY:
|
|
if (info->uid == UID_SHELL) {
|
|
LOGW("Root access is disabled for ADB!\n");
|
|
info->access = NO_SU_ACCESS;
|
|
}
|
|
break;
|
|
case ROOT_ACCESS_APPS_AND_ADB:
|
|
default:
|
|
break;
|
|
}
|
|
|
|
if (info->access.policy != QUERY)
|
|
return info;
|
|
|
|
// If still not determined, check if manager exists
|
|
if (info->mgr_pkg.empty()) {
|
|
info->access = NO_SU_ACCESS;
|
|
return info;
|
|
}
|
|
} else {
|
|
return info;
|
|
}
|
|
|
|
// If still not determined, ask manager
|
|
int fd = app_request(info);
|
|
if (fd < 0) {
|
|
info->access.policy = DENY;
|
|
} else {
|
|
int ret = read_int_be(fd);
|
|
info->access.policy = ret < 0 ? DENY : static_cast<policy_t>(ret);
|
|
close(fd);
|
|
}
|
|
|
|
return info;
|
|
}
|
|
|
|
// Set effective uid back to root, otherwise setres[ug]id will fail if uid isn't root
|
|
static void set_identity(unsigned uid) {
|
|
if (seteuid(0)) {
|
|
PLOGE("seteuid (root)");
|
|
}
|
|
if (setresgid(uid, uid, uid)) {
|
|
PLOGE("setresgid (%u)", uid);
|
|
}
|
|
if (setresuid(uid, uid, uid)) {
|
|
PLOGE("setresuid (%u)", uid);
|
|
}
|
|
}
|
|
|
|
void su_daemon_handler(int client, const sock_cred *cred) {
|
|
LOGD("su: request from pid=[%d], client=[%d]\n", cred->pid, client);
|
|
|
|
su_context ctx = {
|
|
.info = get_su_info(cred->uid),
|
|
.req = su_request(),
|
|
.pid = cred->pid
|
|
};
|
|
|
|
// Read su_request
|
|
xxread(client, &ctx.req, sizeof(su_req_base));
|
|
read_string(client, ctx.req.shell);
|
|
read_string(client, ctx.req.command);
|
|
|
|
if (ctx.info->access.log)
|
|
app_log(ctx);
|
|
else if (ctx.info->access.notify)
|
|
app_notify(ctx);
|
|
|
|
// Fail fast
|
|
if (ctx.info->access.policy == DENY) {
|
|
LOGW("su: request rejected (%u)\n", ctx.info->uid);
|
|
ctx.info.reset();
|
|
write_int(client, DENY);
|
|
close(client);
|
|
return;
|
|
}
|
|
|
|
// Fork a child root process
|
|
//
|
|
// The child process will need to setsid, open a pseudo-terminal
|
|
// if needed, and eventually exec shell.
|
|
// The parent process will wait for the result and
|
|
// send the return code back to our client.
|
|
|
|
if (int child = xfork(); child) {
|
|
ctx.info.reset();
|
|
|
|
// Wait result
|
|
LOGD("su: waiting child pid=[%d]\n", child);
|
|
int status, code;
|
|
|
|
if (waitpid(child, &status, 0) > 0)
|
|
code = WEXITSTATUS(status);
|
|
else
|
|
code = -1;
|
|
|
|
LOGD("su: return code=[%d]\n", code);
|
|
write(client, &code, sizeof(code));
|
|
close(client);
|
|
return;
|
|
}
|
|
|
|
LOGD("su: fork handler\n");
|
|
|
|
// Abort upon any error occurred
|
|
log_cb.ex = exit;
|
|
|
|
// ack
|
|
write_int(client, 0);
|
|
|
|
// Become session leader
|
|
xsetsid();
|
|
|
|
// The FDs for each of the streams
|
|
int infd = recv_fd(client);
|
|
int outfd = recv_fd(client);
|
|
int errfd = recv_fd(client);
|
|
|
|
// App need a PTY
|
|
if (read_int(client)) {
|
|
string pts;
|
|
string ptmx;
|
|
auto magiskpts = MAGISKTMP + "/" SHELLPTS;
|
|
if (access(magiskpts.data(), F_OK)) {
|
|
pts = "/dev/pts";
|
|
ptmx = "/dev/ptmx";
|
|
} else {
|
|
pts = magiskpts;
|
|
ptmx = magiskpts + "/ptmx";
|
|
}
|
|
int ptmx_fd = xopen(ptmx.data(), O_RDWR);
|
|
int unlock = 0;
|
|
ioctl(ptmx_fd, TIOCSPTLCK, &unlock);
|
|
send_fd(client, ptmx_fd);
|
|
int pty_num = get_pty_num(ptmx_fd);
|
|
close(ptmx_fd);
|
|
|
|
string pts_slave = pts + "/" + to_string(pty_num);
|
|
LOGD("su: pts_slave=[%s]\n", pts_slave.data());
|
|
|
|
// Opening the TTY has to occur after the
|
|
// fork() and setsid() so that it becomes
|
|
// our controlling TTY and not the daemon's
|
|
int ptsfd = xopen(pts_slave.data(), O_RDWR);
|
|
|
|
if (infd < 0)
|
|
infd = ptsfd;
|
|
if (outfd < 0)
|
|
outfd = ptsfd;
|
|
if (errfd < 0)
|
|
errfd = ptsfd;
|
|
}
|
|
|
|
// Swap out stdin, stdout, stderr
|
|
xdup2(infd, STDIN_FILENO);
|
|
xdup2(outfd, STDOUT_FILENO);
|
|
xdup2(errfd, STDERR_FILENO);
|
|
|
|
close(infd);
|
|
close(outfd);
|
|
close(errfd);
|
|
close(client);
|
|
|
|
// Handle namespaces
|
|
if (ctx.req.mount_master)
|
|
ctx.info->cfg[SU_MNT_NS] = NAMESPACE_MODE_GLOBAL;
|
|
switch (ctx.info->cfg[SU_MNT_NS]) {
|
|
case NAMESPACE_MODE_GLOBAL:
|
|
LOGD("su: use global namespace\n");
|
|
break;
|
|
case NAMESPACE_MODE_REQUESTER:
|
|
LOGD("su: use namespace of pid=[%d]\n", ctx.pid);
|
|
if (switch_mnt_ns(ctx.pid))
|
|
LOGD("su: setns failed, fallback to global\n");
|
|
break;
|
|
case NAMESPACE_MODE_ISOLATE:
|
|
LOGD("su: use new isolated namespace\n");
|
|
switch_mnt_ns(ctx.pid);
|
|
xunshare(CLONE_NEWNS);
|
|
xmount(nullptr, "/", nullptr, MS_PRIVATE | MS_REC, nullptr);
|
|
break;
|
|
}
|
|
|
|
const char *argv[4] = { nullptr };
|
|
|
|
argv[0] = ctx.req.login ? "-" : ctx.req.shell.data();
|
|
|
|
if (!ctx.req.command.empty()) {
|
|
argv[1] = "-c";
|
|
argv[2] = ctx.req.command.data();
|
|
}
|
|
|
|
// Setup environment
|
|
umask(022);
|
|
char path[32];
|
|
snprintf(path, sizeof(path), "/proc/%d/cwd", ctx.pid);
|
|
chdir(path);
|
|
snprintf(path, sizeof(path), "/proc/%d/environ", ctx.pid);
|
|
char buf[4096] = { 0 };
|
|
int fd = xopen(path, O_RDONLY);
|
|
read(fd, buf, sizeof(buf));
|
|
close(fd);
|
|
clearenv();
|
|
for (size_t pos = 0; buf[pos];) {
|
|
putenv(buf + pos);
|
|
pos += strlen(buf + pos) + 1;
|
|
}
|
|
if (!ctx.req.keepenv) {
|
|
struct passwd *pw;
|
|
pw = getpwuid(ctx.req.uid);
|
|
if (pw) {
|
|
setenv("HOME", pw->pw_dir, 1);
|
|
setenv("USER", pw->pw_name, 1);
|
|
setenv("LOGNAME", pw->pw_name, 1);
|
|
setenv("SHELL", ctx.req.shell.data(), 1);
|
|
}
|
|
}
|
|
|
|
// Unblock all signals
|
|
sigset_t block_set;
|
|
sigemptyset(&block_set);
|
|
sigprocmask(SIG_SETMASK, &block_set, nullptr);
|
|
set_identity(ctx.req.uid);
|
|
execvp(ctx.req.shell.data(), (char **) argv);
|
|
fprintf(stderr, "Cannot execute %s: %s\n", ctx.req.shell.data(), strerror(errno));
|
|
PLOGE("exec");
|
|
}
|