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use std::fs;
use std::{env, os::unix::prelude::PermissionsExt};
use std::process::ExitCode;
use std::time::SystemTime;
use pwd::Passwd;
use nix::{unistd};
use serde_json::Value;
extern crate time;
fn main() -> ExitCode {
let args: Vec<String> = env::args().collect();
if args.len() < 2 {
eprintln!("Invalid argument count.");
return ExitCode::from(0);
}
let config = match config("/etc/crab.conf") {
Some(data) => data,
None => return ExitCode::from(1)
};
let user = match Passwd::current_user() {
Some(data) => data,
None => {
eprintln!("You dont exist.");
return ExitCode::from(2);
}
};
let persist = match allowed(&config, &user.name) {
Some(data) => data,
None => {
eprintln!("Operation Not Permitted. This incidence will be reported.");
return ExitCode::from(3);
}
};
if !validate(&user.name, persist) {
eprintln!("Authentication failed.");
return ExitCode::from(4);
}
if !unistd::setuid(unistd::geteuid()).is_ok() || !unistd::setgid(unistd::getegid()).is_ok() {
eprintln!("Failed to set root permissions");
return ExitCode::from(5);
};
let err = exec::execvp(&args[1], &args[1..]);
println!("Error: {}", err);
ExitCode::from(0)
}
struct Config {
users: Vec<(String, bool)>
}
fn validate(user: &str, persist: bool) -> bool {
if persist && get_persist(user) {
return true;
}
let input = rpassword::prompt_password(format!("crab ({}) password: ", user)).unwrap();
let mut auth = pam::Authenticator::with_password("crab").unwrap();
auth.get_handler().set_credentials(user.to_owned(), input);
if !auth.authenticate().is_ok() || !auth.open_session().is_ok() {
return false;
}
if persist {
set_persist(user);
}
return true;
}
fn allowed(config: &Config, user: &str) -> Option<bool> {
for (name, persist) in &config.users {
if name == user {
return Some(persist.clone());
}
}
None
}
fn config(path: &str) -> Option<Config> {
let file = match std::fs::read_to_string(path) {
Err(e) => {
eprintln!("{}: {}", &path, e);
return None
},
Ok(data) => data
};
let mut users = vec![];
for (line_num, line) in file.split("\n").enumerate() {
let args: Vec<&str> = line.split(" ").collect();
if line.trim() == "" {
continue;
}
if args.len() < 2 {
eprintln!("Error in config at line {}: Not enough arguments", line_num);
continue;
}
let user: String = args[0].to_string();
let persist: bool = match args[1].parse() {
Err(e) => {
eprintln!("Error in config at line {}: {}", line_num, e);
continue;
},
Ok(data) => data
};
users.push((user, persist));
}
Some(Config{users})
}
fn get_terminal_process() -> Option<i32> {
let id: i32 = match std::process::id().try_into() {
Ok(data) => data,
Err(_) => return None
};
let stat = match procinfo::pid::stat(id) {
Ok(data) => data,
Err(_) => return None
};
Some(stat.tty_nr)
}
fn get_terminal_config() -> Option<Value> {
let id = match get_terminal_process() {
Some(data) => data,
None => return None
};
let data = match std::fs::read_to_string(path(&id)) {
Ok(data) => data,
Err(_) => "{}".to_string()
};
let json: Value = match serde_json::from_str(&data) {
Ok(data) => data,
Err(_) => return None
};
Some(json)
}
fn write_terminal_config(id: &i32, data: &str) -> Result<(), Box<dyn std::error::Error>> {
std::fs::write(path(&id), data)?;
unistd::chown(std::path::Path::new(&path(&id)), Some(unistd::Uid::from(0)), Some(unistd::Gid::from(0)))?;
let metadata = std::fs::metadata(path(&id))?;
let mut perms = metadata.permissions();
perms.set_mode(0o0660);
fs::set_permissions(path(&id), perms)?;
Ok(())
}
fn get_persist(user: &str) -> bool {
let json = match get_terminal_config() {
Some(data) => data,
None => return false
};
let timestamp = match json[user].as_u64() {
Some(data) => data,
None => return false
};
return now() - timestamp < 60 * 3;
}
fn set_persist(user: &str) {
let mut json = match get_terminal_config() {
Some(data) => data,
None => return
};
json[user] = Value::from(now());
let id = match get_terminal_process() {
Some(data) => data,
None => return
};
match write_terminal_config(&id, &json.to_string()) {
Ok(_) => {},
Err(e) => {
eprintln!("Internal Error: {}", e)
}
};
}
fn now() -> u64 {
return SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
}
fn path(id: &i32) -> String {
return format!("/tmp/crab-{}", id);
}
|
