luckyimnotanigger/tun2proxy
1
0
Fork 0
mirror of https://github.com/tun2proxy/tun2proxy.git synced 2025-06-10 00:27:46 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Restore /etc/resolv.conf if it was written directly

Browse source
This commit is contained in:
B. Blechschmidt 2023-10-08 13:09:37 +02:00
parent cea0e0fa27
commit 299b51667d
1 changed files with 25 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

30
src/setup.rs
View file

@ -6,6 +6,7 @@ use smoltcp::wire::IpCidr;
use std::{
convert::TryFrom,
ffi::OsStr,
fs,
io::BufRead,
net::{IpAddr, Ipv4Addr, Ipv6Addr},
os::unix::io::RawFd,
@ -22,6 +23,8 @@ pub struct Setup {
set_up: bool,
delete_proxy_route: bool,
child: libc::pid_t,
unmount_resolvconf: bool,
restore_resolvconf_data: Option<Vec<u8>>,
}
pub fn get_default_cidrs() -> [IpCidr; 4] {
@ -86,6 +89,8 @@ impl Setup {
set_up: false,
delete_proxy_route: false,
child: 0,
unmount_resolvconf: false,
restore_resolvconf_data: None,
}
}
@ -155,8 +160,7 @@ impl Setup {
Ok(false)
}
fn write_nameserver(fd: RawFd) -> Result<(), Error> {
let data = "nameserver 198.18.0.1\n".as_bytes();
fn write_buffer_to_fd(fd: RawFd, data: &[u8]) -> Result<(), Error> {
let mut written = 0;
loop {
if written >= data.len() {
@ -164,11 +168,17 @@ impl Setup {
}
written += nix::unistd::write(fd, &data[written..])?;
}
Ok(())
}
fn write_nameserver(fd: RawFd) -> Result<(), Error> {
let data = "nameserver 198.18.0.1\n".as_bytes();
Self::write_buffer_to_fd(fd, data)?;
nix::sys::stat::fchmod(fd, nix::sys::stat::Mode::from_bits(0o444).unwrap())?;
Ok(())
}
fn setup_resolv_conf() -> Result<(), Error> {
fn setup_resolv_conf(&mut self) -> Result<(), Error> {
let mut fd = nix::fcntl::open(
"/tmp/tun2proxy-resolv.conf",
nix::fcntl::OFlag::O_RDWR | nix::fcntl::OFlag::O_CLOEXEC | nix::fcntl::OFlag::O_CREAT,
@ -187,12 +197,17 @@ impl Setup {
{
log::warn!("failed to bind mount custom resolv.conf onto /etc/resolv.conf, resorting to direct write");
nix::unistd::close(fd)?;
self.restore_resolvconf_data = Some(fs::read("/etc/resolv.conf")?);
fd = nix::fcntl::open(
"/etc/resolv.conf",
nix::fcntl::OFlag::O_WRONLY | nix::fcntl::OFlag::O_CLOEXEC | nix::fcntl::OFlag::O_TRUNC,
nix::sys::stat::Mode::from_bits(0o644).unwrap(),
)?;
Self::write_nameserver(fd)?;
} else {
self.unmount_resolvconf = true;
}
nix::unistd::close(fd)?;
Ok(())
@ -225,7 +240,12 @@ impl Setup {
.args(["route", "del", self.tunnel_bypass_addr.to_string().as_str()])
.output();
}
nix::mount::umount("/etc/resolv.conf")?;
if self.unmount_resolvconf {
nix::mount::umount("/etc/resolv.conf")?;
}
if let Some(data) = &self.restore_resolvconf_data {
fs::write("/etc/resolv.conf", data)?;
}
Ok(())
}
@ -250,7 +270,7 @@ impl Setup {
let delete_proxy_route = self.route_proxy_address()?;
self.delete_proxy_route = delete_proxy_route;
Self::setup_resolv_conf()?;
self.setup_resolv_conf()?;
self.add_tunnel_routes()?;
// Signal to child that we are done setting up everything.