Andre Richter
123 lines
3.5 KiB
Rust
123 lines
3.5 KiB
Rust
#![deny(warnings)]
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extern crate arg_parser;
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extern crate extra;
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extern crate termion;
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extern crate userutils;
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use std::env;
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use std::fs::File;
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use std::io::{self, Read, Write};
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use std::os::unix::process::CommandExt;
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use std::process::{exit, Command};
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use std::str;
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use arg_parser::ArgParser;
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use extra::io::fail;
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use extra::option::OptionalExt;
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use termion::input::TermRead;
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use userutils::Passwd;
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const MAN_PAGE: &'static str = /* @MANSTART{su} */ r#"
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NAME
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su - substitute user identity
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SYNOPSIS
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su [ user ]
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su [ -h | --help ]
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DESCRIPTION
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The su utility requests appropriate user credentials via PAM and switches to
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that user ID (the default user is the superuser). A shell is then executed.
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OPTIONS
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-h
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--help
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Display this help and exit.
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AUTHOR
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Written by Jeremy Soller.
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"#;
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const PASSWD_FILE: &'static str = "/etc/passwd";
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pub fn main() {
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let stdin = io::stdin();
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let mut stdin = stdin.lock();
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let stdout = io::stdout();
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let mut stdout = stdout.lock();
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let mut stderr = io::stderr();
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let mut parser = ArgParser::new(1)
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.add_flag(&["h", "help"]);
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parser.parse(env::args());
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// Shows the help
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if parser.found("help") {
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stdout.write_all(MAN_PAGE.as_bytes()).try(&mut stderr);
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stdout.flush().try(&mut stderr);
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exit(0);
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}
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let user = if parser.args.is_empty() {
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String::from("root")
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} else {
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parser.args[0].to_string()
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};
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let uid = userutils::get_uid(&mut stderr);
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let mut passwd_string = String::new();
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let mut passwd_file = match File::open(PASSWD_FILE) {
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Ok(file) => file,
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Err(err) => fail(&format!("su: there was an error opening the passwd file: {}", err), &mut stderr)
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};
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passwd_file.read_to_string(&mut passwd_string).try(&mut stderr);
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let passwd_file_entries = match Passwd::parse_file(&passwd_string) {
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Ok(entries) => entries,
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Err(_) => fail(&format!("su: there was an error parsing the passwd file."), &mut stderr)
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};
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let mut passwd_option = passwd_file_entries.iter()
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.find(|passwd| { user == passwd.user && ("" == passwd.hash || uid == 0) });
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if passwd_option.is_none() {
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stdout.write_all(b"password: ").try(&mut stderr);
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stdout.flush().try(&mut stderr);
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if let Some(password) = stdin.read_passwd(&mut stdout).try(&mut stderr) {
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stdout.write(b"\n").try(&mut stderr);
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stdout.flush().try(&mut stderr);
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passwd_option = passwd_file_entries.iter()
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.find(|passwd| user == passwd.user && passwd.verify(&password));
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}
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}
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if let Some(passwd) = passwd_option {
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let mut command = Command::new(passwd.shell);
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command.uid(passwd.uid);
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command.gid(passwd.gid);
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command.env("USER", &user);
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command.env("UID", format!("{}", passwd.uid));
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command.env("GROUPS", format!("{}", passwd.gid));
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command.env("HOME", passwd.home);
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command.env("SHELL", passwd.shell);
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match command.spawn() {
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Ok(mut child) => match child.wait() {
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Ok(_status) => (),
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Err(err) => fail(&format!("su: failed to wait for '{}': {}", passwd.shell, err), &mut stderr)
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},
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Err(err) => fail(&format!("su: failed to execute '{}': {}", passwd.shell, err), &mut stderr)
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}
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} else {
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stdout.write(b"su: authentication failed\n").try(&mut stderr);
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stdout.flush().try(&mut stderr);
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}
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}
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