crtxcr/raou
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also set dumpable to 0, minor improvements

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This commit is contained in:
Albert S. 2019-08-22 13:08:50 +02:00
bovenliggende f445ce7b1f
commit bb8de3b6c7
2 gewijzigde bestanden met toevoegingen van 32 en 49 verwijderingen
Statistieken weergeven Download Patch-bestand Download Diff-bestand Expand all files Collapse all files

2
Cargo.lock gegenereerd
Bestand weergeven

@ -1,3 +1,5 @@
# This file is automatically @generated by Cargo.
# It is not intended for manual editing.
[[package]]
name = "libc"
version = "0.2.43"

79
src/main.rs
Bestand weergeven

@ -1,10 +1,10 @@
use std::env::Args;
use std::io::{Error, ErrorKind};
use std::fs::File;
use std::io::BufReader;
use std::io::BufRead;
use std::ffi::CString;
use std::ffi::CStr;
use std::ffi::CString;
use std::fs::File;
use std::io::BufRead;
use std::io::BufReader;
use std::io::{Error, ErrorKind};
extern crate libc;
use libc::passwd;
@ -35,7 +35,6 @@ impl Entry {
}
}
struct Passwd {
pw_name: String,
pw_passwd: String,
@ -46,15 +45,11 @@ struct Passwd {
pw_shell: String,
}
fn initgroups(user: &str, group: libc::gid_t) -> std::io::Result<()> {
let userarg = CString::new(user);
return errnowrapper(unsafe {
libc::initgroups(userarg.unwrap().as_ptr(), group)
});
return errnowrapper(unsafe { libc::initgroups(userarg.unwrap().as_ptr(), group) });
}
fn errnowrapper(ret: libc::c_int) -> std::io::Result<()> {
if ret != 0 {
return Err(Error::last_os_error());
@ -95,7 +90,6 @@ fn getpwnam(username: &str) -> std::io::Result<Passwd> {
pw_shell: getstr((*pwnamresult).pw_shell),
})
}
}
fn ensure_allowed(userid: libc::uid_t, entry: &Entry) -> std::io::Result<()> {
@ -119,7 +113,6 @@ fn ensure_allowed(userid: libc::uid_t, entry: &Entry) -> std::io::Result<()> {
));
}
fn usage() {
println!("Usage: raou ENRTYNAME");
}
@ -141,13 +134,12 @@ fn assign(entry: &mut Entry, key: &str, value: &str) {
"env_vars" => add_multi(&mut entry.inherit_envs, val),
"argv0" => entry.argv0 = val,
"target_user" => entry.dest_user = val,
"allow_args" => entry.arbitrary_args = (val == "1" || val == "true"),
"allow_args" => entry.arbitrary_args = val == "1" || val == "true",
"args" => entry.args = val,
"no_new_privs" => entry.no_new_privs = (val == "1" || val == "true"),
"no_new_privs" => entry.no_new_privs = val == "1" || val == "true",
_ => {
eprintln!("Ignoring invalid key {}", key);
}
}
}
fn assign_from_line(entry: &mut Entry, line: &str) {
@ -159,7 +151,6 @@ fn assign_from_line(entry: &mut Entry, line: &str) {
return;
}
assign(entry, key.unwrap(), value.unwrap())
}
fn create_entry_from_file(filepath: &str) -> std::io::Result<Entry> {
let mut entry: Entry = Entry::new();
@ -179,7 +170,8 @@ fn clearenv() -> std::io::Result<()> {
}
//TODO: AsRef for envs?
fn setup_environment(passwd: &Passwd, envs: &[String]) -> std::io::Result<()> {
let saved_envs: Vec<String> = envs.iter()
let saved_envs: Vec<String> = envs
.iter()
.map(|s| std::env::var(s).expect("No such var"))
.collect();
clearenv()?;
@ -194,7 +186,6 @@ fn setup_environment(passwd: &Passwd, envs: &[String]) -> std::io::Result<()> {
std::env::set_var(&envs[i], item);
}
Ok(())
}
fn become_user(passwd: &Passwd) -> std::io::Result<()> {
@ -204,13 +195,12 @@ fn become_user(passwd: &Passwd) -> std::io::Result<()> {
std::env::set_current_dir(&passwd.pw_dir)?;
Ok(())
}
fn init_sandbox(entry: &Entry) -> std::io::Result<()> {
if (entry.no_new_privs) {
errnowrapper(unsafe {
libc::prctl(libc::PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)
})?;
}
fn drop_privs(entry: &Entry) -> std::io::Result<()> {
if entry.no_new_privs {
errnowrapper(unsafe { libc::prctl(libc::PR_SET_DUMPABLE, 0) })?;
errnowrapper(unsafe { libc::prctl(libc::PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) })?;
}
Ok(())
}
@ -220,8 +210,6 @@ fn to_cstring<T: AsRef<str>>(s: T) -> *const libc::c_char {
}
fn create_execv_args(entry: &Entry, cmdargs: &Vec<String>) -> Vec<*const libc::c_char> {
let mut args: Vec<*const libc::c_char>;
if entry.arbitrary_args && cmdargs.len() > 2 {
args = cmdargs.iter().skip(2).map(to_cstring).collect();
@ -256,11 +244,8 @@ fn exec(entryname: &str, cmdargs: &Vec<String>) -> std::io::Result<()> {
let destuserpasswd: Passwd = getpwnam(&entry.dest_user)?;
let currentuser: u32 = geteuid();
let args = create_execv_args(&entry, &cmdargs);
ensure_allowed(currentuser, &entry)?;
become_user(&destuserpasswd).or_else(|e| {
return Err(Error::new(
@ -268,39 +253,35 @@ fn exec(entryname: &str, cmdargs: &Vec<String>) -> std::io::Result<()> {
"Failed to switch user: ".to_owned() + &e.to_string(),
));
})?;
setup_environment(&destuserpasswd, &entry.inherit_envs)
.or_else(|e| {
return Err(Error::new(
ErrorKind::Other,
"Environment setup failure: ".to_owned() + &e.to_string(),
));
})?;
init_sandbox(&entry).or_else(|e| {
setup_environment(&destuserpasswd, &entry.inherit_envs).or_else(|e| {
return Err(Error::new(
ErrorKind::Other,
"Sandbox init failure: ".to_owned() + &e.to_string(),
"Environment setup failure: ".to_owned() + &e.to_string(),
));
})?;
drop_privs(&entry).or_else(|e| {
return Err(Error::new(
ErrorKind::Other,
"Failed to drop priviliges: ".to_owned() + &e.to_string(),
));
})?;
unsafe {
errnowrapper(libc::execv(to_cstring(entry.cmd), args.as_ptr()))
.or_else(|e| {
return Err(Error::new(
ErrorKind::Other,
"execv failed: ".to_owned() + &e.to_string(),
));
})?;
errnowrapper(libc::execv(to_cstring(entry.cmd), args.as_ptr())).or_else(|e| {
return Err(Error::new(
ErrorKind::Other,
"execv failed: ".to_owned() + &e.to_string(),
));
})?;
}
std::process::exit(0);
Ok(())
}
fn main() -> Result<(), std::io::Error> {
let argv: Args = std::env::args();
let cmdargs: Vec<String> = argv.collect();
let entryname = cmdargs.get(1);
if entryname.is_some() {
match exec(&entryname.unwrap(), &cmdargs) {
Err(e) => {
eprintln!("The following error ocurred:");