rewrite it in rust™ (just for fun)

This commit is contained in:
Albert S. 2018-10-07 00:23:26 +02:00
parent dec216580a
commit fe0e531718
3 changed files with 163 additions and 0 deletions

51
rust/Cargo.lock generated Normal file
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@ -0,0 +1,51 @@
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name = "bitflags"
version = "1.0.4"
source = "registry+https://github.com/rust-lang/crates.io-index"
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name = "cc"
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source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "cfg-if"
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source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "libc"
version = "0.2.43"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "nix"
version = "0.11.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
"cc 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
"cfg-if 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
"libc 0.2.43 (registry+https://github.com/rust-lang/crates.io-index)",
"void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "qsni"
version = "0.1.0"
dependencies = [
"nix 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
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source = "registry+https://github.com/rust-lang/crates.io-index"
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7
rust/Cargo.toml Normal file
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[package]
name = "qsni"
version = "0.1.0"
authors = ["Albert S. <mail@quitesimple.org>"]
[dependencies]
nix = "0.11.0"

105
rust/src/main.rs Normal file
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use std::env;
use std::io::BufReader;
use std::io::BufRead;
use std::io::Error;
use std::io::ErrorKind;
use std::io::Write;
use std::ffi::CString;
static PROFILEPATH : &'static str ="/etc/qsni.d/";
static NET_CLS_DIR : &'static str="/sys/fs/cgroup/net_cls/";
extern crate nix;
fn ensure_outside_profile()
{
let fp = std::fs::File::open("/proc/self/cgroup").expect("Error opening cgroups file of process");
let bf = BufReader::new(fp);
for line in bf.lines() {
let currentline = line.expect("Error while reading line");
let splitted : Vec<&str> = currentline.split(':').collect();
if splitted.len() < 3 {
panic!("Misformated line in cgroups file!");
}
if splitted[1] == "net_cls" && splitted[2] != "/" {
panic!("already assigned to a net class, thus you can't use this binary to change that");
}
}
}
fn init_profile(profilepath : &str)
{
use nix::unistd::*;
use nix::sys::wait::*;
match fork()
{
Ok(ForkResult::Parent { child, .. }) => {
let waitresult = waitpid(child, Some(WaitPidFlag::empty())).expect("waitpid failed");
match waitresult
{
WaitStatus::Exited(pid, code) =>
{
if code != 0
{
panic!("profile setup script failed");
}
},
_ => { },
}
}
Ok(ForkResult::Child) => {
unsafe { nix::libc::clearenv(); }
nix::unistd::execv(&CString::new(profilepath).unwrap(), &[CString::new(profilepath).unwrap()]).expect("Faileed execv");},
Err(_) => println!("Fork failed"),
}
}
fn assign_to_profile(profilename : &str)
{
let filename = NET_CLS_DIR.to_owned() + "/" + profilename + "/tasks";
let mut file = std::fs::OpenOptions::new().write(true).append(true).open(filename).expect("Failed to open net class file for writing");
let mypid = nix::unistd::getpid().to_string();
write!(file, "{}", mypid).expect("An error occured while writing the pid");
}
fn main()
{
std::panic::set_hook(Box::new(|pi| {
if let Some(s) = pi.payload().downcast_ref::<String>() {
eprintln!("{}", s);
}
eprintln!("Details:");
eprintln!("{}", pi);
}));
let args : Vec<String> = std::env::args().collect();
if args.len() < 3 {
println!("usage: qsni profile command [arguments...]");
std::process::exit(1);
}
ensure_outside_profile();
let profilename : &str = &args[1];
let profilefilepath = PROFILEPATH.to_owned() + profilename;
if ! std::path::Path::new(&profilefilepath).exists(){
eprintln!("The specified profile {} does not exist", profilename);
std::process::exit(1);
}
let currentuid = nix::unistd::getuid();
let currentgid = nix::unistd::getgid();
nix::unistd::setuid(nix::unistd::Uid::from_raw(0)).expect("Failed to become root");
init_profile(&profilefilepath);
assign_to_profile(&profilename);
nix::unistd::setgid(currentgid).expect("setgid failed during drop");
nix::unistd::setuid(currentuid).expect("setuid failed during drop");
let cmd = &args[2];
let mut execargs : Vec<CString> = args.iter().skip(3).map(|s| { CString::new(s.as_str()).unwrap() }).collect();
execargs.insert(0, CString::new(cmd.as_str()).unwrap());
nix::unistd::execvp(&CString::new(cmd.as_str()).unwrap(), &execargs).expect("execv failed launching your program");
}