CSRF -> XSRF (I use the XSRF abbreviation more myself)

This commit is contained in:
Olivier 'reivilibre' 2024-01-20 22:03:33 +00:00
parent 5a5dfe36b9
commit adfc1b1cf6
6 changed files with 47 additions and 47 deletions

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@ -1,6 +1,6 @@
{ {
"db_name": "PostgreSQL", "db_name": "PostgreSQL",
"query": "\n SELECT user_name, user_id, login_session_id, csrf_secret\n FROM login_sessions INNER JOIN users USING (user_id)\n WHERE login_session_token_hash = $1\n ", "query": "\n SELECT user_name, user_id, login_session_id, xsrf_secret\n FROM login_sessions INNER JOIN users USING (user_id)\n WHERE login_session_token_hash = $1\n ",
"describe": { "describe": {
"columns": [ "columns": [
{ {
@ -20,7 +20,7 @@
}, },
{ {
"ordinal": 3, "ordinal": 3,
"name": "csrf_secret", "name": "xsrf_secret",
"type_info": "Bytea" "type_info": "Bytea"
} }
], ],
@ -36,5 +36,5 @@
false false
] ]
}, },
"hash": "d6b173d90cd227a65bfc4a47ed3ba7b19650ed4d3dc44c1519775a6d0c9026b7" "hash": "125d60c302bfc35fa7edc71b4c23c1a4fd81060df92388ccbfd43dd8c5771031"
} }

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@ -1,6 +1,6 @@
{ {
"db_name": "PostgreSQL", "db_name": "PostgreSQL",
"query": "INSERT INTO login_sessions (login_session_token_hash, user_id, started_at_utc, csrf_secret)\n VALUES ($1, $2, NOW(), $3)", "query": "INSERT INTO login_sessions (login_session_token_hash, user_id, started_at_utc, xsrf_secret)\n VALUES ($1, $2, NOW(), $3)",
"describe": { "describe": {
"columns": [], "columns": [],
"parameters": { "parameters": {
@ -12,5 +12,5 @@
}, },
"nullable": [] "nullable": []
}, },
"hash": "2633347de5bc78129d60926bbeab5571eddce6f76d80db323622db9648d918c3" "hash": "cfc3e3102493b5b385bcab8eb8d4ea73d38cfb32cdf5c34b6cc76738669490fd"
} }

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@ -5,7 +5,7 @@ CREATE TABLE login_sessions (
login_session_token_hash BYTEA NOT NULL UNIQUE, login_session_token_hash BYTEA NOT NULL UNIQUE,
user_id UUID NOT NULL REFERENCES users(user_id), user_id UUID NOT NULL REFERENCES users(user_id),
started_at_utc TIMESTAMP NOT NULL, started_at_utc TIMESTAMP NOT NULL,
csrf_secret BYTEA NOT NULL xsrf_secret BYTEA NOT NULL
); );
CREATE INDEX ON login_sessions (user_id); CREATE INDEX ON login_sessions (user_id);
@ -20,4 +20,4 @@ COMMENT ON COLUMN login_sessions.user_id IS 'ID of the user that this login sess
COMMENT ON COLUMN login_sessions.started_at_utc IS 'Timestamp in UTC when the session was started.'; COMMENT ON COLUMN login_sessions.started_at_utc IS 'Timestamp in UTC when the session was started.';
COMMENT ON COLUMN login_sessions.csrf_secret IS 'Key for a Blake2sMac256 which is used to prevent Cross-Site Request Forgery.'; COMMENT ON COLUMN login_sessions.xsrf_secret IS 'Key for a Blake2sMac256 which is used to prevent Cross-Site Request Forgery.';

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@ -8,7 +8,7 @@ use sqlx::{types::Uuid, Connection, PgPool, Postgres, Transaction};
use tracing::error; use tracing::error;
use crate::web::login::{ use crate::web::login::{
LoginSession, LOGIN_SESSION_CSRF_SECRET_BYTES, LOGIN_SESSION_TOKEN_HASH_BYTES, LoginSession, LOGIN_SESSION_TOKEN_HASH_BYTES, LOGIN_SESSION_XSRF_SECRET_BYTES,
}; };
/// Postgres-backed storage for IdCoop /// Postgres-backed storage for IdCoop
@ -239,12 +239,12 @@ impl<'a, 'txn> IdCoopStoreTxn<'a, 'txn> {
&mut self, &mut self,
login_session_token_hash: &[u8; LOGIN_SESSION_TOKEN_HASH_BYTES], login_session_token_hash: &[u8; LOGIN_SESSION_TOKEN_HASH_BYTES],
user_id: Uuid, user_id: Uuid,
csrf_secret: &[u8; LOGIN_SESSION_CSRF_SECRET_BYTES], xsrf_secret: &[u8; LOGIN_SESSION_XSRF_SECRET_BYTES],
) -> eyre::Result<()> { ) -> eyre::Result<()> {
sqlx::query!( sqlx::query!(
"INSERT INTO login_sessions (login_session_token_hash, user_id, started_at_utc, csrf_secret) "INSERT INTO login_sessions (login_session_token_hash, user_id, started_at_utc, xsrf_secret)
VALUES ($1, $2, NOW(), $3)", VALUES ($1, $2, NOW(), $3)",
login_session_token_hash, user_id, csrf_secret login_session_token_hash, user_id, xsrf_secret
) )
.execute(&mut **self.txn) .execute(&mut **self.txn)
.await .await
@ -258,7 +258,7 @@ impl<'a, 'txn> IdCoopStoreTxn<'a, 'txn> {
) -> eyre::Result<Option<LoginSession>> { ) -> eyre::Result<Option<LoginSession>> {
let row_opt = sqlx::query!( let row_opt = sqlx::query!(
" "
SELECT user_name, user_id, login_session_id, csrf_secret SELECT user_name, user_id, login_session_id, xsrf_secret
FROM login_sessions INNER JOIN users USING (user_id) FROM login_sessions INNER JOIN users USING (user_id)
WHERE login_session_token_hash = $1 WHERE login_session_token_hash = $1
", ",
@ -274,10 +274,10 @@ impl<'a, 'txn> IdCoopStoreTxn<'a, 'txn> {
user_name: row.user_name, user_name: row.user_name,
user_id: row.user_id, user_id: row.user_id,
login_session_id: row.login_session_id, login_session_id: row.login_session_id,
csrf_secret: row xsrf_secret: row
.csrf_secret .xsrf_secret
.try_into() .try_into()
.map_err(|_| eyre!("cannot retrieve login session: has invalid CSRF token"))?, .map_err(|_| eyre!("cannot retrieve login session: has invalid XSRF token"))?,
})) }))
} }
} }

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@ -32,28 +32,28 @@ pub const LOGIN_SESSION_TOKEN_BYTES: usize = 32;
/// Size of a Blake2s hash of the login token (which is what we store in the database) /// Size of a Blake2s hash of the login token (which is what we store in the database)
pub const LOGIN_SESSION_TOKEN_HASH_BYTES: usize = 32; pub const LOGIN_SESSION_TOKEN_HASH_BYTES: usize = 32;
/// Size of the CSRF secret in bytes; this is a Blake2sMac256 salt size. /// Size of the XSRF secret in bytes; this is a Blake2sMac256 salt size.
/// TODO the Blake2sMac256 also has a 'personal' item which might give us more bytes to play with and /// TODO the Blake2sMac256 also has a 'personal' item which might give us more bytes to play with and
/// perhaps we should be using that too. /// perhaps we should be using that too.
pub const LOGIN_SESSION_CSRF_SECRET_BYTES: usize = 8; pub const LOGIN_SESSION_XSRF_SECRET_BYTES: usize = 8;
pub struct LoginSession { pub struct LoginSession {
pub user_name: String, pub user_name: String,
pub user_id: Uuid, pub user_id: Uuid,
pub login_session_id: i32, pub login_session_id: i32,
pub csrf_secret: [u8; LOGIN_SESSION_CSRF_SECRET_BYTES], pub xsrf_secret: [u8; LOGIN_SESSION_XSRF_SECRET_BYTES],
} }
/// CSRF token expiry time is 1 week. /// XSRF token expiry time is 1 week.
pub const CSRF_TOKEN_EXPIRY_TIME: Duration = Duration::milliseconds(1000 * 86400 * 7); pub const XSRF_TOKEN_EXPIRY_TIME: Duration = Duration::milliseconds(1000 * 86400 * 7);
impl LoginSession { impl LoginSession {
/// Generates a CSRF token which is bound to this session and expires 1 week in the future. /// Generates a XSRF token which is bound to this session and expires 1 week in the future.
pub fn generate_csrf_token(&self, now: DateTime<Utc>) -> eyre::Result<String> { pub fn generate_xsrf_token(&self, now: DateTime<Utc>) -> eyre::Result<String> {
let now_timestamp = now.timestamp(); let now_timestamp = now.timestamp();
let now_8bytes = now_timestamp.to_be_bytes(); let now_8bytes = now_timestamp.to_be_bytes();
let mac_tag_bytes = Blake2sMac256::new_with_salt_and_personal(&self.csrf_secret, &[], &[])? let mac_tag_bytes = Blake2sMac256::new_with_salt_and_personal(&self.xsrf_secret, &[], &[])?
.chain_update(&now_8bytes) .chain_update(&now_8bytes)
.finalize() .finalize()
.into_bytes(); .into_bytes();
@ -62,34 +62,34 @@ impl LoginSession {
Ok(format!("{now_timestamp}.{mac_b64}")) Ok(format!("{now_timestamp}.{mac_b64}"))
} }
/// Validates a CSRF token to check it is bound to this session and hasn't expired (is less than a week old). /// Validates a XSRF token to check it is bound to this session and hasn't expired (is less than a week old).
pub fn validate_csrf_token(&self, token: &str, now: DateTime<Utc>) -> eyre::Result<()> { pub fn validate_xsrf_token(&self, token: &str, now: DateTime<Utc>) -> eyre::Result<()> {
let (timestamp_str, mac_b64) = token let (timestamp_str, mac_b64) = token
.split_once('.') .split_once('.')
.context("CSRF token in wrong format")?; .context("XSRF token in wrong format")?;
let timestamp: i64 = timestamp_str let timestamp: i64 = timestamp_str
.parse() .parse()
.context("timestamp in CSRF token is wrong")?; .context("timestamp in XSRF token is wrong")?;
let mac_tag_bytes: Vec<u8> = BASE64_URL_SAFE_NO_PAD let mac_tag_bytes: Vec<u8> = BASE64_URL_SAFE_NO_PAD
.decode(mac_b64) .decode(mac_b64)
.context("failed to b64decode the MAC in CSRF token")?; .context("failed to b64decode the MAC in XSRF token")?;
let timestamp_8bytes = timestamp.to_be_bytes(); let timestamp_8bytes = timestamp.to_be_bytes();
Blake2sMac256::new_with_salt_and_personal(&self.csrf_secret, &[], &[])? Blake2sMac256::new_with_salt_and_personal(&self.xsrf_secret, &[], &[])?
.chain_update(&timestamp_8bytes) .chain_update(&timestamp_8bytes)
.verify_slice(&mac_tag_bytes) .verify_slice(&mac_tag_bytes)
.context("bad MAC in CSRF token")?; .context("bad MAC in XSRF token")?;
// At this point, the MAC is correct. All that's left is to check that the timestamp isn't too old. // At this point, the MAC is correct. All that's left is to check that the timestamp isn't too old.
if now.signed_duration_since( if now.signed_duration_since(
Utc.timestamp_opt(timestamp, 0) Utc.timestamp_opt(timestamp, 0)
.earliest() .earliest()
.context("CSRF timestamp not valid")?, .context("XSRF timestamp not valid")?,
) > CSRF_TOKEN_EXPIRY_TIME ) > XSRF_TOKEN_EXPIRY_TIME
{ {
bail!("CSRF token expired."); bail!("XSRF token expired.");
} }
Ok(()) Ok(())
@ -162,8 +162,8 @@ pub async fn get_login(
match current_session { match current_session {
Some(_session) => make_post_login_redirect(query.then), Some(_session) => make_post_login_redirect(query.then),
None => { None => {
let csrf_token = sessionless_xsrf::get_token(&cookies); let xsrf_token = sessionless_xsrf::get_token(&cookies);
Html(format!("<form method='POST'>UN<input type='text' name='username'> PW<input type='password' name='password'> <input type='hidden' name='csrf' value='{}'><button type='submit'>click here to login</button> (temporary form)</form>", csrf_token)).into_response() Html(format!("<form method='POST'>UN<input type='text' name='username'> PW<input type='password' name='password'> <input type='hidden' name='xsrf' value='{}'><button type='submit'>click here to login</button> (temporary form)</form>", xsrf_token)).into_response()
} }
} }
} }
@ -172,7 +172,7 @@ pub async fn get_login(
pub struct PostLoginForm { pub struct PostLoginForm {
username: String, username: String,
password: String, password: String,
csrf: String, xsrf: String,
} }
fn dummy_password_hash( fn dummy_password_hash(
@ -197,8 +197,8 @@ pub async fn post_login(
Extension(config): Extension<Arc<Configuration>>, Extension(config): Extension<Arc<Configuration>>,
Form(form): Form<PostLoginForm>, Form(form): Form<PostLoginForm>,
) -> WebResult<Response> { ) -> WebResult<Response> {
if !sessionless_xsrf::check_token(&cookies, &form.csrf) { if !sessionless_xsrf::check_token(&cookies, &form.xsrf) {
// Invalid CSRF token: try again // Invalid XSRF token: try again
return Ok(get_login(None, Query(query), cookies).await); return Ok(get_login(None, Query(query), cookies).await);
} }
@ -240,13 +240,13 @@ pub async fn post_login(
let login_session_token_b64 = BASE64_URL_SAFE_NO_PAD.encode(login_session_token); let login_session_token_b64 = BASE64_URL_SAFE_NO_PAD.encode(login_session_token);
let login_session_token_hash: [u8; LOGIN_SESSION_TOKEN_HASH_BYTES] = let login_session_token_hash: [u8; LOGIN_SESSION_TOKEN_HASH_BYTES] =
Blake2s256::digest(&login_session_token).into(); Blake2s256::digest(&login_session_token).into();
let csrf_secret = thread_rng().gen::<[u8; LOGIN_SESSION_CSRF_SECRET_BYTES]>(); let xsrf_secret = thread_rng().gen::<[u8; LOGIN_SESSION_XSRF_SECRET_BYTES]>();
// store session in the database // store session in the database
store store
.txn(|mut txn| { .txn(|mut txn| {
Box::pin(async move { Box::pin(async move {
txn.create_login_session(&login_session_token_hash, user.user_id, &csrf_secret) txn.create_login_session(&login_session_token_hash, user.user_id, &xsrf_secret)
.await .await
}) })
}) })

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@ -106,7 +106,7 @@ pub async fn oidc_authorisation(
#[derive(Deserialize)] #[derive(Deserialize)]
pub struct PostConsentForm { pub struct PostConsentForm {
action: String, action: String,
csrf: String, xsrf: String,
} }
pub async fn post_oidc_authorisation_consent( pub async fn post_oidc_authorisation_consent(
@ -128,7 +128,7 @@ pub async fn post_oidc_authorisation_consent(
}; };
if login_session if login_session
.validate_csrf_token(&form.csrf, Utc::now()) .validate_xsrf_token(&form.xsrf, Utc::now())
.is_err() .is_err()
{ {
// XSRF token is not valid, so show the consent form again... // XSRF token is not valid, so show the consent form again...
@ -212,12 +212,12 @@ async fn show_consent_page(
client_config: &OidcClientConfiguration, client_config: &OidcClientConfiguration,
_config: &Configuration, _config: &Configuration,
) -> Response { ) -> Response {
let csrf_token = login_session let xsrf_token = login_session
.generate_csrf_token(Utc::now()) .generate_xsrf_token(Utc::now())
.expect("must be able to create a CSRF token"); .expect("must be able to create a XSRF token");
Html(format!( Html(format!(
"hi <u>{}</u>, consent to <u>{}</u>? <form method='POST'><input type='hidden' name='csrf' value='{}'><button type='submit' name='action' value='accept'>Accept</button> <button type='submit' name='action' value='deny'>Deny</button></form>", "hi <u>{}</u>, consent to <u>{}</u>? <form method='POST'><input type='hidden' name='xsrf' value='{}'><button type='submit' name='action' value='accept'>Accept</button> <button type='submit' name='action' value='deny'>Deny</button></form>",
login_session.user_name, client_config.name, csrf_token login_session.user_name, client_config.name, xsrf_token
)) ))
.into_response() .into_response()
} }