Add protocol for authenticating a unix socket

This commit is contained in:
Oystein Kristoffer Tveit 2024-08-09 19:08:48 +02:00
parent dc29dd274a
commit 20e60ca5c7
Signed by: oysteikt
GPG Key ID: 9F2F7D8250F35146
4 changed files with 548 additions and 5 deletions

89
Cargo.lock generated
View File

@ -99,6 +99,21 @@ version = "1.0.82"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "f538837af36e6f6a9be0faa67f9a314f8119e4e4b5867c6ab40ed60360142519" checksum = "f538837af36e6f6a9be0faa67f9a314f8119e4e4b5867c6ab40ed60360142519"
[[package]]
name = "async-bincode"
version = "0.7.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "21849a990d47109757e820904d7c0b569a8013f6595bf14d911884634d58795f"
dependencies = [
"bincode",
"byteorder",
"bytes",
"futures-core",
"futures-sink",
"serde",
"tokio",
]
[[package]] [[package]]
name = "atoi" name = "atoi"
version = "2.0.0" version = "2.0.0"
@ -141,6 +156,15 @@ version = "1.6.0"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "8c3c1a368f70d6cf7302d78f8f7093da241fb8e8807c05cc9e51a125895a6d5b" checksum = "8c3c1a368f70d6cf7302d78f8f7093da241fb8e8807c05cc9e51a125895a6d5b"
[[package]]
name = "bincode"
version = "1.3.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b1f45e9417d87227c7a56d22e471c6206462cba514c7590c09aff4cf6d1ddcad"
dependencies = [
"serde",
]
[[package]] [[package]]
name = "bitflags" name = "bitflags"
version = "1.3.2" version = "1.3.2"
@ -555,6 +579,21 @@ dependencies = [
"percent-encoding", "percent-encoding",
] ]
[[package]]
name = "futures"
version = "0.3.30"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "645c6916888f6cb6350d2550b80fb63e734897a8498abe35cfb732b6487804b0"
dependencies = [
"futures-channel",
"futures-core",
"futures-executor",
"futures-io",
"futures-sink",
"futures-task",
"futures-util",
]
[[package]] [[package]]
name = "futures-channel" name = "futures-channel"
version = "0.3.30" version = "0.3.30"
@ -599,6 +638,17 @@ version = "0.3.30"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "a44623e20b9681a318efdd71c299b6b222ed6f231972bfe2f224ebad6311f0c1" checksum = "a44623e20b9681a318efdd71c299b6b222ed6f231972bfe2f224ebad6311f0c1"
[[package]]
name = "futures-macro"
version = "0.3.30"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "87750cf4b7a4c0625b1529e4c543c2182106e4dedc60a2a6455e00d212c489ac"
dependencies = [
"proc-macro2",
"quote",
"syn 2.0.60",
]
[[package]] [[package]]
name = "futures-sink" name = "futures-sink"
version = "0.3.30" version = "0.3.30"
@ -617,8 +667,10 @@ version = "0.3.30"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "3d6401deb83407ab3da39eba7e33987a73c3df0c82b4bb5813ee871c19c41d48" checksum = "3d6401deb83407ab3da39eba7e33987a73c3df0c82b4bb5813ee871c19c41d48"
dependencies = [ dependencies = [
"futures-channel",
"futures-core", "futures-core",
"futures-io", "futures-io",
"futures-macro",
"futures-sink", "futures-sink",
"futures-task", "futures-task",
"memchr", "memchr",
@ -906,20 +958,27 @@ name = "mysqladm-rs"
version = "0.1.0" version = "0.1.0"
dependencies = [ dependencies = [
"anyhow", "anyhow",
"async-bincode",
"bincode",
"clap", "clap",
"dialoguer", "dialoguer",
"env_logger", "env_logger",
"futures",
"indoc", "indoc",
"itertools", "itertools",
"log", "log",
"nix", "nix",
"prettytable", "prettytable",
"rand",
"ratatui", "ratatui",
"serde", "serde",
"serde_json", "serde_json",
"sqlx", "sqlx",
"thiserror",
"tokio", "tokio",
"tokio-util",
"toml", "toml",
"uuid",
] ]
[[package]] [[package]]
@ -1812,18 +1871,18 @@ dependencies = [
[[package]] [[package]]
name = "thiserror" name = "thiserror"
version = "1.0.58" version = "1.0.63"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "03468839009160513471e86a034bb2c5c0e4baae3b43f79ffc55c4a5427b3297" checksum = "c0342370b38b6a11b6cc11d6a805569958d54cfa061a29969c3b5ce2ea405724"
dependencies = [ dependencies = [
"thiserror-impl", "thiserror-impl",
] ]
[[package]] [[package]]
name = "thiserror-impl" name = "thiserror-impl"
version = "1.0.58" version = "1.0.63"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "c61f3ba182994efc43764a46c018c347bc492c79f024e705f46567b418f6d4f7" checksum = "a4558b58466b9ad7ca0f102865eccc95938dca1a74a856f2b57b6629050da261"
dependencies = [ dependencies = [
"proc-macro2", "proc-macro2",
"quote", "quote",
@ -1883,6 +1942,19 @@ dependencies = [
"tokio", "tokio",
] ]
[[package]]
name = "tokio-util"
version = "0.7.11"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "9cf6b47b3771c49ac75ad09a6162f53ad4b8088b76ac60e8ec1455b31a189fe1"
dependencies = [
"bytes",
"futures-core",
"futures-sink",
"pin-project-lite",
"tokio",
]
[[package]] [[package]]
name = "toml" name = "toml"
version = "0.8.12" version = "0.8.12"
@ -2023,6 +2095,15 @@ version = "0.2.1"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "711b9620af191e0cdc7468a8d14e709c3dcdb115b36f838e601583af800a370a" checksum = "711b9620af191e0cdc7468a8d14e709c3dcdb115b36f838e601583af800a370a"
[[package]]
name = "uuid"
version = "1.10.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "81dfa00651efa65069b0b6b651f4aaa31ba9e3c3ce0137aaad053604ee7e0314"
dependencies = [
"getrandom",
]
[[package]] [[package]]
name = "vcpkg" name = "vcpkg"
version = "0.2.15" version = "0.2.15"

View File

@ -5,20 +5,27 @@ edition = "2021"
[dependencies] [dependencies]
anyhow = "1.0.82" anyhow = "1.0.82"
async-bincode = "0.7.2"
bincode = "1.3.3"
clap = { version = "4.5.4", features = ["derive"] } clap = { version = "4.5.4", features = ["derive"] }
dialoguer = "0.11.0" dialoguer = "0.11.0"
env_logger = "0.11.3" env_logger = "0.11.3"
futures = "0.3.30"
indoc = "2.0.5" indoc = "2.0.5"
itertools = "0.12.1" itertools = "0.12.1"
log = "0.4.21" log = "0.4.21"
nix = { version = "0.28.0", features = ["user"] } nix = { version = "0.28.0", features = ["fs", "user"] }
prettytable = "0.10.0" prettytable = "0.10.0"
rand = "0.8.5"
ratatui = { version = "0.26.2", optional = true } ratatui = { version = "0.26.2", optional = true }
serde = "1.0.198" serde = "1.0.198"
serde_json = { version = "1.0.116", features = ["preserve_order"] } serde_json = { version = "1.0.116", features = ["preserve_order"] }
sqlx = { version = "0.7.4", features = ["runtime-tokio", "mysql", "tls-rustls"] } sqlx = { version = "0.7.4", features = ["runtime-tokio", "mysql", "tls-rustls"] }
thiserror = "1.0.63"
tokio = { version = "1.37.0", features = ["rt", "macros"] } tokio = { version = "1.37.0", features = ["rt", "macros"] }
tokio-util = "0.7.11"
toml = "0.8.12" toml = "0.8.12"
uuid = { version = "1.10.0", features = ["v4"] }
[features] [features]
default = ["mysql-admutils-compatibility"] default = ["mysql-admutils-compatibility"]

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@ -0,0 +1,454 @@
//! This module provides a way to authenticate a client uid to a server over a Unix socket.
//! This is needed so that the server can trust the client's uid, which it depends on to
//! make modifications for that user in the database. It is crucial that the server can trust
//! that the client is the unix user it claims to be.
//!
//! This works by having the client respond to a challenge on a socket that is verifiably owned
//! by the client. In more detailed steps, the following should happen:
//!
//! 1. Before initializing it's request, the client should open an "authentication" socket with permissions 644
//! and owned by the uid of the current user.
//! 2. The client opens a request to the server on the "normal" socket where the server is listening,
//! In this request, the client should include the following:
//! - The address of it's authentication socket
//! - The uid of the user currently using the client
//! - A challenge string that has been randomly generated
//! 3. The server validates the following:
//! - The address of the auth socket is valid
//! - The owner of the auth socket address is the same as the uid
//! 4. Server connects to the auth socket address and receives another challenge string.
//! The server should close the connection after receiving the challenge string.
//! 5. Server verifies that the challenge is the same as the one it originally received.
//! It responds to the client with an "Authenticated" message if the challenge matches,
//! or an error message if it does not.
//! 6. Client closes the authentication socket. Normal socket is used for communication.
//!
//! Note that the server can at any point in the process send an error message to the client
//! over it's initial connection, and the client should respond by closing the authentication
//! socket, it's connection to the normal socket, and reporting the error to the user.
//!
//! Also note that it is essential that the client does not send any sensitive information
//! over it's authentication socket, since it is readable by any user on the system.
use std::os::unix::io::AsRawFd;
use std::path::PathBuf;
use async_bincode::{tokio::AsyncBincodeStream, AsyncDestination};
use futures::{SinkExt, StreamExt};
use nix::{sys::stat, unistd::Uid};
use rand::distributions::Alphanumeric;
use rand::Rng;
use serde::{Deserialize, Serialize};
use tokio::net::{UnixListener, UnixStream};
use tokio_util::sync::CancellationToken;
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub enum ClientRequest {
Initialize {
uid: u32,
challenge: u64,
auth_socket: String,
},
Cancel,
}
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub enum ServerResponse {
Authenticated,
ChallengeDidNotMatch,
ServerError(ServerError),
}
// TODO: wrap more data into the errors
#[derive(Debug, PartialEq, Serialize, Deserialize, Clone)]
pub enum ServerError {
InvalidRequest,
UnableToReadPermissionsFromAuthSocket,
CouldNotConnectToAuthSocket,
AuthSocketClosedEarly,
UidMismatch,
ChallengeMismatch,
InvalidChallenge,
}
#[derive(Debug, PartialEq)]
pub enum ClientError {
UnableToConnectToServer,
UnableToOpenAuthSocket,
UnableToConfigureAuthSocket,
AuthSocketClosedEarly,
UnableToCloseAuthSocket,
AuthenticationError,
InvalidServerResponse(ServerResponse),
UnableToParseServerResponse,
NoServerResponse,
ServerError(ServerError),
}
async fn create_auth_socket(socket_addr: &str) -> Result<UnixListener, ClientError> {
let auth_socket =
UnixListener::bind(socket_addr).map_err(|_err| ClientError::UnableToOpenAuthSocket)?;
stat::fchmod(
auth_socket.as_raw_fd(),
stat::Mode::S_IRUSR | stat::Mode::S_IWUSR | stat::Mode::S_IRGRP,
)
.map_err(|_err| ClientError::UnableToConfigureAuthSocket)?;
Ok(auth_socket)
}
type ClientToServerStream<'a> =
AsyncBincodeStream<&'a mut UnixStream, ServerResponse, ClientRequest, AsyncDestination>;
type ServerToClientStream<'a> =
AsyncBincodeStream<&'a mut UnixStream, ClientRequest, ServerResponse, AsyncDestination>;
// TODO: make the challenge constant size and use socket directly, this is overkill
type AuthStream<'a> = AsyncBincodeStream<&'a mut UnixStream, u64, u64, AsyncDestination>;
// TODO: add timeout
const AUTH_SOCKET_NAME: &str = "mysqladm-rs-cli-auth.sock";
pub async fn client_authenticate(
normal_socket: &mut UnixStream,
#[cfg(not(test))] auth_socket_dir: Option<PathBuf>,
#[cfg(test)] auth_socket_file: Option<PathBuf>,
) -> Result<(), ClientError> {
let random_prefix: String = rand::thread_rng()
.sample_iter(&Alphanumeric)
.take(16)
.map(char::from)
.collect();
let socket_name = format!("{}-{}", random_prefix, AUTH_SOCKET_NAME);
#[cfg(not(test))]
let auth_socket_address = match auth_socket_dir {
Some(dir) => dir.join(socket_name).to_str().unwrap().to_string(),
None => std::env::temp_dir()
.join(socket_name)
.to_str()
.unwrap()
.to_string(),
};
#[cfg(test)]
let auth_socket_address = match auth_socket_file {
Some(file) => file.to_str().unwrap().to_string(),
None => std::env::temp_dir()
.join(socket_name)
.to_str()
.unwrap()
.to_string(),
};
client_authenticate_with_auth_socket_address(normal_socket, &auth_socket_address).await
}
async fn client_authenticate_with_auth_socket_address(
normal_socket: &mut UnixStream,
auth_socket_address: &str,
) -> Result<(), ClientError> {
let auth_socket = create_auth_socket(auth_socket_address).await?;
let result =
client_authenticate_with_auth_socket(normal_socket, auth_socket, auth_socket_address).await;
std::fs::remove_file(auth_socket_address)
.map_err(|_err| ClientError::UnableToCloseAuthSocket)?;
result
}
async fn client_authenticate_with_auth_socket(
normal_socket: &mut UnixStream,
auth_socket: UnixListener,
auth_socket_address: &str,
) -> Result<(), ClientError> {
let challenge = rand::random::<u64>();
let uid = nix::unistd::getuid();
let mut normal_socket: ClientToServerStream =
AsyncBincodeStream::from(normal_socket).for_async();
let challenge_replier_cancellation_token = CancellationToken::new();
let challenge_replier_cancellation_token_clone = challenge_replier_cancellation_token.clone();
let challenge_replier_handle = tokio::spawn(async move {
loop {
tokio::select! {
socket = auth_socket.accept() =>
{
match socket {
Ok((mut conn, _addr)) => {
let mut stream: AuthStream = AsyncBincodeStream::from(&mut conn).for_async();
stream.send(challenge).await.ok();
stream.close().await.ok();
}
Err(_err) => return Err(ClientError::AuthSocketClosedEarly),
}
}
_ = challenge_replier_cancellation_token_clone.cancelled() => {
break Ok(());
}
}
}
});
let client_hello = ClientRequest::Initialize {
uid: uid.into(),
challenge,
auth_socket: auth_socket_address.to_string(),
};
normal_socket
.send(client_hello)
.await
.map_err(|err| match *err {
bincode::ErrorKind::Io(_err) => ClientError::UnableToConnectToServer,
_ => ClientError::NoServerResponse,
})?;
match normal_socket.next().await {
Some(Ok(ServerResponse::Authenticated)) => {}
Some(Ok(ServerResponse::ChallengeDidNotMatch)) => {
return Err(ClientError::AuthenticationError)
}
Some(Ok(ServerResponse::ServerError(err))) => return Err(ClientError::ServerError(err)),
Some(Err(err)) => match *err {
bincode::ErrorKind::Io(_err) => return Err(ClientError::NoServerResponse),
_ => return Err(ClientError::UnableToParseServerResponse),
},
None => return Err(ClientError::NoServerResponse),
}
challenge_replier_cancellation_token.cancel();
challenge_replier_handle.await.ok();
Ok(())
}
macro_rules! report_server_error_and_return {
($normal_socket:expr, $err:expr) => {{
$normal_socket
.send(ServerResponse::ServerError($err))
.await
.ok();
return Err($err);
}};
}
async fn server_authenticate(
normal_socket: &mut UnixStream,
#[cfg(test)] unix_user_uid: Option<u32>,
) -> Result<Uid, ServerError> {
let mut normal_socket: ServerToClientStream =
AsyncBincodeStream::from(normal_socket).for_async();
let (uid, challenge, auth_socket) = match normal_socket.next().await {
Some(Ok(ClientRequest::Initialize {
uid,
challenge,
auth_socket,
})) => (uid, challenge, auth_socket),
// TODO: more granular errros
_ => report_server_error_and_return!(normal_socket, ServerError::InvalidRequest),
};
#[cfg(test)]
let auth_socket_uid = match unix_user_uid {
Some(uid) => uid,
None => report_server_error_and_return!(
normal_socket,
ServerError::UnableToReadPermissionsFromAuthSocket
),
};
#[cfg(not(test))]
let auth_socket_uid = match stat::stat(auth_socket.as_str()) {
Ok(stat) => stat.st_uid,
Err(_err) => report_server_error_and_return!(
normal_socket,
ServerError::UnableToReadPermissionsFromAuthSocket
),
};
if uid != auth_socket_uid {
report_server_error_and_return!(normal_socket, ServerError::UidMismatch);
}
let mut authenticated_unix_socket = match UnixStream::connect(auth_socket).await {
Ok(socket) => socket,
Err(_err) => {
report_server_error_and_return!(normal_socket, ServerError::CouldNotConnectToAuthSocket)
}
};
let mut authenticated_unix_socket: AuthStream =
AsyncBincodeStream::from(&mut authenticated_unix_socket).for_async();
let challenge_2 = match authenticated_unix_socket.next().await {
Some(Ok(challenge)) => challenge,
Some(Err(_)) => {
report_server_error_and_return!(normal_socket, ServerError::InvalidChallenge)
}
None => report_server_error_and_return!(normal_socket, ServerError::AuthSocketClosedEarly),
};
authenticated_unix_socket.close().await.ok();
if challenge != challenge_2 {
normal_socket
.send(ServerResponse::ChallengeDidNotMatch)
.await
.ok();
return Err(ServerError::ChallengeMismatch);
}
normal_socket.send(ServerResponse::Authenticated).await.ok();
Ok(Uid::from_raw(uid))
}
#[cfg(test)]
mod test {
use super::*;
use std::time::Duration;
use tokio::time::sleep;
#[tokio::test]
async fn test_valid_authentication() {
let (mut client, mut server) = UnixStream::pair().unwrap();
let client_handle =
tokio::spawn(async move { client_authenticate(&mut client, None).await });
let server_handle = tokio::spawn(async move {
let uid = nix::unistd::getuid().into();
server_authenticate(&mut server, Some(uid)).await
});
client_handle.await.unwrap().unwrap();
server_handle.await.unwrap().unwrap();
}
#[tokio::test]
async fn test_ensure_auth_socket_does_not_exist() {
let (mut client, mut server) = UnixStream::pair().unwrap();
let client_handle = tokio::spawn(async move {
client_authenticate_with_auth_socket_address(
&mut client,
"/tmp/test_auth_socket_does_not_exist.sock",
)
.await
});
let server_handle = tokio::spawn(async move {
let uid = nix::unistd::getuid().into();
server_authenticate(&mut server, Some(uid)).await
});
client_handle.await.unwrap().unwrap();
server_handle.await.unwrap().unwrap();
}
#[tokio::test]
async fn test_uid_mismatch() {
let (mut client, mut server) = UnixStream::pair().unwrap();
let client_handle = tokio::spawn(async move {
let err = client_authenticate(&mut client, None).await;
assert_eq!(err, Err(ClientError::ServerError(ServerError::UidMismatch)));
});
let server_handle = tokio::spawn(async move {
let uid: u32 = nix::unistd::getuid().into();
let err = server_authenticate(&mut server, Some(uid + 1)).await;
assert_eq!(err, Err(ServerError::UidMismatch));
});
client_handle.await.unwrap();
server_handle.await.unwrap();
}
#[tokio::test]
async fn test_snooping_connection() {
let (mut client, mut server) = UnixStream::pair().unwrap();
let socket_path = std::env::temp_dir().join("socket_to_snoop.sock");
let socket_path_clone = socket_path.clone();
let client_handle =
tokio::spawn(
async move { client_authenticate(&mut client, Some(socket_path_clone)).await },
);
while !socket_path.exists() {
sleep(std::time::Duration::from_millis(10)).await;
}
let mut snooper = UnixStream::connect(socket_path.clone()).await.unwrap();
let mut snooper: AuthStream = AsyncBincodeStream::from(&mut snooper).for_async();
let message = snooper.next().await.unwrap().unwrap();
let mut other_snooper = UnixStream::connect(socket_path.clone()).await.unwrap();
let mut other_snooper: AuthStream =
AsyncBincodeStream::from(&mut other_snooper).for_async();
let other_message = other_snooper.next().await.unwrap().unwrap();
assert_eq!(message, other_message);
let third_snooper_handle = tokio::spawn(async move {
let mut third_snooper = UnixStream::connect(socket_path.clone()).await.unwrap();
let mut third_snooper: AuthStream =
AsyncBincodeStream::from(&mut third_snooper).for_async();
// NOTE: Should hang
third_snooper.send(1234).await.unwrap()
});
sleep(Duration::from_millis(10)).await;
let server_handle = tokio::spawn(async move {
let uid: u32 = nix::unistd::getuid().into();
server_authenticate(&mut server, Some(uid)).await
});
client_handle.await.unwrap().unwrap();
server_handle.await.unwrap().unwrap();
third_snooper_handle.abort();
}
#[tokio::test]
async fn test_dead_server() {
let (mut client, server) = UnixStream::pair().unwrap();
std::mem::drop(server);
let client_handle = tokio::spawn(async move {
let err = client_authenticate(&mut client, None).await;
assert_eq!(err, Err(ClientError::UnableToConnectToServer));
});
client_handle.await.unwrap();
}
#[tokio::test]
async fn test_no_response_from_server() {
let (mut client, server) = UnixStream::pair().unwrap();
let client_handle = tokio::spawn(async move {
let err = client_authenticate(&mut client, None).await;
assert_eq!(err, Err(ClientError::NoServerResponse));
});
sleep(Duration::from_millis(200)).await;
std::mem::drop(server);
client_handle.await.unwrap();
}
// TODO: Test challenge mismatch
// TODO: Test invoking server with junk data
}

View File

@ -10,6 +10,7 @@ use crate::cli::mysql_admutils_compatibility::{mysql_dbadm, mysql_useradm};
use clap::Parser; use clap::Parser;
mod authenticated_unix_socket;
mod cli; mod cli;
mod core; mod core;