Files
SukiSU-Ultra/userspace/ksud/src/ksu.rs
2023-04-04 16:41:57 +08:00

285 lines
7.7 KiB
Rust

use anyhow::{Ok, Result};
#[cfg(unix)]
use anyhow::ensure;
use getopts::Options;
#[cfg(unix)]
use std::os::unix::process::CommandExt;
use std::{ffi::CStr, process::Command};
use crate::{
defs,
utils::{self, umask},
};
pub const KERNEL_SU_OPTION: u32 = 0xDEAD_BEEF;
const CMD_GRANT_ROOT: u64 = 0;
// const CMD_BECOME_MANAGER: u64 = 1;
const CMD_GET_VERSION: u64 = 2;
// const CMD_ALLOW_SU: u64 = 3;
// const CMD_DENY_SU: u64 = 4;
// const CMD_GET_ALLOW_LIST: u64 = 5;
// const CMD_GET_DENY_LIST: u64 = 6;
const CMD_REPORT_EVENT: u64 = 7;
pub const CMD_SET_SEPOLICY: u64 = 8;
pub const CMD_CHECK_SAFEMODE: u64 = 9;
const EVENT_POST_FS_DATA: u64 = 1;
const EVENT_BOOT_COMPLETED: u64 = 2;
#[cfg(any(target_os = "linux", target_os = "android"))]
pub fn grant_root() -> Result<()> {
let mut result: u32 = 0;
unsafe {
#[allow(clippy::cast_possible_wrap)]
libc::prctl(
KERNEL_SU_OPTION as i32, // supposed to overflow
CMD_GRANT_ROOT,
0,
0,
std::ptr::addr_of_mut!(result).cast::<libc::c_void>(),
);
}
ensure!(result == KERNEL_SU_OPTION, "grant root failed");
Err(std::process::Command::new("sh").exec().into())
}
#[cfg(not(any(target_os = "linux", target_os = "android")))]
pub fn grant_root() -> Result<()> {
unimplemented!("grant_root is only available on android");
}
fn print_usage(program: &str, opts: Options) {
let brief = format!("KernelSU\n\nUsage: {program} [options] [-] [user [argument...]]");
print!("{}", opts.usage(&brief));
}
fn set_identity(uid: u32) {
#[cfg(any(target_os = "linux", target_os = "android"))]
unsafe {
libc::seteuid(uid);
libc::setresgid(uid, uid, uid);
libc::setresuid(uid, uid, uid);
}
}
#[cfg(not(unix))]
pub fn root_shell() -> Result<()> {
unimplemented!()
}
#[cfg(unix)]
pub fn root_shell() -> Result<()> {
// we are root now, this was set in kernel!
let args: Vec<String> = std::env::args().collect();
let program = args[0].clone();
let mut opts = Options::new();
opts.optopt(
"c",
"command",
"pass COMMAND to the invoked shell",
"COMMAND",
);
opts.optflag("h", "help", "display this help message and exit");
opts.optflag("l", "login", "force run in the global mount namespace");
opts.optflag(
"p",
"preserve-environment",
"preserve the entire environment",
);
opts.optflag(
"s",
"shell",
"use SHELL instead of the default /system/bin/sh",
);
opts.optflag("v", "version", "display version number and exit");
opts.optflag("V", "", "display version code and exit");
opts.optflag(
"M",
"mount-master",
"force run in the global mount namespace",
);
// Replace -cn with -z, -mm with -M for supporting getopt_long
let args = args
.into_iter()
.map(|e| {
if e == "-mm" {
"-M".to_string()
} else if e == "-cn" {
"-z".to_string()
} else {
e
}
})
.collect::<Vec<String>>();
let matches = match opts.parse(&args[1..]) {
std::result::Result::Ok(m) => m,
Err(f) => {
println!("{f}");
print_usage(&program, opts);
std::process::exit(-1);
}
};
if matches.opt_present("h") {
print_usage(&program, opts);
return Ok(());
}
if matches.opt_present("v") {
println!("{}:KernelSU", defs::VERSION_NAME);
return Ok(());
}
if matches.opt_present("V") {
println!("{}", defs::VERSION_CODE);
return Ok(());
}
let shell = matches.opt_str("s").unwrap_or("/system/bin/sh".to_string());
let mut is_login = matches.opt_present("l");
let preserve_env = matches.opt_present("p");
let mount_master = matches.opt_present("M");
let mut free_idx = 0;
let command = matches.opt_str("c").map(|cmd| {
free_idx = matches.free.len();
let mut cmds = vec![];
cmds.push(cmd);
cmds.extend(matches.free.clone());
cmds
});
let mut args = vec![];
if let Some(cmd) = command {
args.push("-c".to_string());
args.push(cmd.join(" "));
};
if free_idx < matches.free.len() && matches.free[free_idx] == "-" {
is_login = true;
free_idx += 1;
}
let mut uid = 0; // default uid = 0(root)
if free_idx < matches.free.len() {
let name = &matches.free[free_idx];
uid = unsafe {
#[cfg(target_arch = "aarch64")]
let pw = libc::getpwnam(name.as_ptr() as *const u8).as_ref();
#[cfg(target_arch = "x86_64")]
let pw = libc::getpwnam(name.as_ptr() as *const i8).as_ref();
match pw {
Some(pw) => pw.pw_uid,
None => name.parse::<u32>().unwrap_or(0),
}
}
}
// https://github.com/topjohnwu/Magisk/blob/master/native/src/su/su_daemon.cpp#L408
let arg0 = if is_login { "-" } else { &shell };
let mut command = &mut Command::new(&shell);
if !preserve_env {
// This is actually incorrect, i don't know why.
// command = command.env_clear();
let pw = unsafe { libc::getpwuid(uid).as_ref() };
if let Some(pw) = pw {
let home = unsafe { CStr::from_ptr(pw.pw_dir) };
let pw_name = unsafe { CStr::from_ptr(pw.pw_name) };
let home = home.to_string_lossy();
let pw_name = pw_name.to_string_lossy();
command = command
.env("HOME", home.as_ref())
.env("USER", pw_name.as_ref())
.env("LOGNAME", pw_name.as_ref())
.env("SHELL", &shell);
}
}
// escape from the current cgroup and become session leader
// WARNING!!! This cause some root shell hang forever!
// command = command.process_group(0);
command = unsafe {
command.pre_exec(move || {
umask(0o22);
utils::switch_cgroups();
// switch to global mount namespace
#[cfg(any(target_os = "linux", target_os = "android"))]
if mount_master {
let _ = utils::switch_mnt_ns(1);
let _ = utils::unshare_mnt_ns();
}
set_identity(uid);
std::result::Result::Ok(())
})
};
command = command.args(args).arg0(arg0);
Err(command.exec().into())
}
pub fn get_version() -> i32 {
let mut result: i32 = 0;
#[cfg(any(target_os = "linux", target_os = "android"))]
unsafe {
#[allow(clippy::cast_possible_wrap)]
libc::prctl(
KERNEL_SU_OPTION as i32, // supposed to overflow
CMD_GET_VERSION,
std::ptr::addr_of_mut!(result).cast::<libc::c_void>(),
);
}
result
}
fn report_event(event: u64) {
#[cfg(any(target_os = "linux", target_os = "android"))]
unsafe {
#[allow(clippy::cast_possible_wrap)]
libc::prctl(
KERNEL_SU_OPTION as i32, // supposed to overflow
CMD_REPORT_EVENT,
event,
);
}
}
pub fn check_kernel_safemode() -> bool {
let mut result: i32 = 0;
#[cfg(any(target_os = "linux", target_os = "android"))]
unsafe {
#[allow(clippy::cast_possible_wrap)]
libc::prctl(
KERNEL_SU_OPTION as i32, // supposed to overflow
CMD_CHECK_SAFEMODE,
0,
0,
std::ptr::addr_of_mut!(result).cast::<libc::c_void>(),
);
}
result == KERNEL_SU_OPTION as i32
}
pub fn report_post_fs_data() {
report_event(EVENT_POST_FS_DATA);
}
pub fn report_boot_complete() {
report_event(EVENT_BOOT_COMPLETED);
}