kanidm unixd mfa capabilities (#2672)

Improve the support for the resolver to support MFA options with pam. This enables async task spawning and cancelation via the resolver backend as well. 

Co-authored-by: David Mulder <dmulder@samba.org>

server/core/src/https/v1.rs

@@ -3181,7 +3181,12 @@ pub(crate) fn route_setup(state: ServerState) -> Router<ServerState> {
         .route("/v1/group/:id/_unix/_token", get(group_id_unix_token_get))
         .route("/v1/group/:id/_unix", post(group_id_unix_post))
         .route("/v1/group", get(group_get).post(group_post))
-        .route("/v1/group/:id", get(group_id_get).patch(group_id_patch).delete(group_id_delete))
+        .route(
+            "/v1/group/:id",
+            get(group_id_get)
+                .patch(group_id_patch)
+                .delete(group_id_delete),
+        )
         .route(
             "/v1/group/:id/_attr/:attr",
             delete(group_id_attr_delete)

unix_integration/pam_kanidm/src/pam/mod.rs

@@ -53,6 +53,9 @@ use tracing_subscriber::filter::LevelFilter;
 use tracing_subscriber::fmt;
 use tracing_subscriber::prelude::*;
 
+use std::thread;
+use std::time::Duration;
+
 pub fn get_cfg() -> Result<KanidmUnixdConfig, PamResultCode> {
     KanidmUnixdConfig::new()
         .read_options_from_optional_config(DEFAULT_CONFIG_PATH)
@@ -106,6 +109,38 @@ pub struct PamKanidm;
 
 pam_hooks!(PamKanidm);
 
+macro_rules! match_sm_auth_client_response {
+    ($expr:expr, $opts:ident, $($pat:pat => $result:expr),*) => {
+        match $expr {
+            Ok(r) => match r {
+                $($pat => $result),*
+                ClientResponse::PamAuthenticateStepResponse(PamAuthResponse::Success) => {
+                    return PamResultCode::PAM_SUCCESS;
+                }
+                ClientResponse::PamAuthenticateStepResponse(PamAuthResponse::Denied) => {
+                    return PamResultCode::PAM_AUTH_ERR;
+                }
+                ClientResponse::PamAuthenticateStepResponse(PamAuthResponse::Unknown) => {
+                    if $opts.ignore_unknown_user {
+                        return PamResultCode::PAM_IGNORE;
+                    } else {
+                        return PamResultCode::PAM_USER_UNKNOWN;
+                    }
+                }
+                _ => {
+                    // unexpected response.
+                    error!(err = ?r, "PAM_IGNORE, unexpected resolver response");
+                    return PamResultCode::PAM_IGNORE;
+                }
+            },
+            Err(err) => {
+                error!(?err, "PAM_IGNORE");
+                return PamResultCode::PAM_IGNORE;
+            }
+        }
+    }
+}
+
 impl PamHooks for PamKanidm {
     fn acct_mgmt(pamh: &PamHandle, args: Vec<&CStr>, _flags: PamFlag) -> PamResultCode {
         let opts = match Options::try_from(&args) {
@@ -241,21 +276,7 @@ impl PamHooks for PamKanidm {
         let mut req = ClientRequest::PamAuthenticateInit(account_id);
 
         loop {
-            match daemon_client.call_and_wait(&req, timeout) {
-                Ok(r) => match r {
-                    ClientResponse::PamAuthenticateStepResponse(PamAuthResponse::Success) => {
-                        return PamResultCode::PAM_SUCCESS;
-                    }
-                    ClientResponse::PamAuthenticateStepResponse(PamAuthResponse::Denied) => {
-                        return PamResultCode::PAM_AUTH_ERR;
-                    }
-                    ClientResponse::PamAuthenticateStepResponse(PamAuthResponse::Unknown) => {
-                        if opts.ignore_unknown_user {
-                            return PamResultCode::PAM_IGNORE;
-                        } else {
-                            return PamResultCode::PAM_USER_UNKNOWN;
-                        }
-                    }
+            match_sm_auth_client_response!(daemon_client.call_and_wait(&req, timeout), opts,
                 ClientResponse::PamAuthenticateStepResponse(PamAuthResponse::Password) => {
                     let mut consume_authtok = None;
                     // Swap the authtok out with a None, so it can only be consumed once.
@@ -284,7 +305,7 @@ impl PamHooks for PamKanidm {
                     timeout = cfg.unix_sock_timeout;
                     req = ClientRequest::PamAuthenticateStep(PamAuthRequest::Password { cred });
                     continue;
-                    }
+                },
                 ClientResponse::PamAuthenticateStepResponse(
                     PamAuthResponse::DeviceAuthorizationGrant { data },
                 ) => {
@@ -308,18 +329,76 @@ impl PamHooks for PamKanidm {
                         PamAuthRequest::DeviceAuthorizationGrant { data },
                     );
                     continue;
+                },
+                ClientResponse::PamAuthenticateStepResponse(PamAuthResponse::MFACode {
+                    msg,
+                }) => {
+                    match conv.send(PAM_TEXT_INFO, &msg) {
+                        Ok(_) => {}
+                        Err(err) => {
+                            if opts.debug {
+                                println!("Message prompt failed");
                             }
-                    _ => {
-                        // unexpected response.
-                        error!(err = ?r, "PAM_IGNORE, unexpected resolver response");
-                        return PamResultCode::PAM_IGNORE;
+                            return err;
+                        }
+                    }
+                    let cred = match conv.send(PAM_PROMPT_ECHO_OFF, "Code") {
+                        Ok(password) => match password {
+                            Some(cred) => cred,
+                            None => {
+                                debug!("no mfa code");
+                                return PamResultCode::PAM_CRED_INSUFFICIENT;
                             }
                         },
                         Err(err) => {
-                    error!(?err, "PAM_IGNORE");
-                    return PamResultCode::PAM_IGNORE;
+                            debug!("unable to get mfa code");
+                            return err;
+                        }
+                    };
+
+                    // Now setup the request for the next loop.
+                    timeout = cfg.unix_sock_timeout;
+                    req = ClientRequest::PamAuthenticateStep(PamAuthRequest::MFACode {
+                        cred,
+                    });
+                    continue;
+                },
+                ClientResponse::PamAuthenticateStepResponse(PamAuthResponse::MFAPoll {
+                    msg,
+                    polling_interval,
+                }) => {
+                    match conv.send(PAM_TEXT_INFO, &msg) {
+                        Ok(_) => {}
+                        Err(err) => {
+                            if opts.debug {
+                                println!("Message prompt failed");
+                            }
+                            return err;
                         }
                     }
+
+                    loop {
+                        thread::sleep(Duration::from_secs(polling_interval.into()));
+                        timeout = cfg.unix_sock_timeout;
+                        req = ClientRequest::PamAuthenticateStep(PamAuthRequest::MFAPoll);
+
+                        // Counter intuitive, but we don't need a max poll attempts here because
+                        // if the resolver goes away, then this will error on the sock and
+                        // will shutdown. This allows the resolver to dynamically extend the
+                        // timeout if needed, and removes logic from the front end.
+                        match_sm_auth_client_response!(
+                            daemon_client.call_and_wait(&req, timeout), opts,
+                            ClientResponse::PamAuthenticateStepResponse(
+                                    PamAuthResponse::MFAPollWait,
+                            ) => {
+                                // Continue polling if the daemon says to wait
+                                continue;
+                            }
+                        );
+
+                    }
+                }
+            );
         } // while true, continue calling PamAuthenticateStep until we get a decision.
     }
 

unix_integration/src/daemon.rs

@@ -202,6 +202,10 @@ async fn handle_client(
     let mut reqs = Framed::new(sock, ClientCodec);
     let mut pam_auth_session_state = None;
 
+    // Setup a broadcast channel so that if we have an unexpected disconnection, we can
+    // tell consumers to stop work.
+    let (shutdown_tx, _shutdown_rx) = broadcast::channel(1);
+
     trace!("Waiting for requests ...");
     while let Some(Ok(req)) = reqs.next().await {
         let resp = match req {
@@ -295,7 +299,10 @@ async fn handle_client(
                     }
                     None => {
                         match cachelayer
-                            .pam_account_authenticate_init(account_id.as_str())
+                            .pam_account_authenticate_init(
+                                account_id.as_str(),
+                                shutdown_tx.subscribe(),
+                            )
                             .await
                         {
                             Ok((auth_session, pam_auth_response)) => {
@@ -407,6 +414,14 @@ async fn handle_client(
         debug!("flushed response!");
     }
 
+    // Signal any tasks that they need to stop.
+    if let Err(shutdown_err) = shutdown_tx.send(()) {
+        warn!(
+            ?shutdown_err,
+            "Unable to signal tasks to stop, they will naturally timeout instead."
+        )
+    }
+
     // Disconnect them
     debug!("Disconnecting client ...");
     Ok(())

unix_integration/src/idprovider/interface.rs

@@ -2,6 +2,7 @@ use crate::db::KeyStoreTxn;
 use crate::unix_proto::{DeviceAuthorizationResponse, PamAuthRequest, PamAuthResponse};
 use async_trait::async_trait;
 use serde::{Deserialize, Serialize};
+use tokio::sync::broadcast;
 use uuid::Uuid;
 
 pub use kanidm_hsm_crypto as tpm;
@@ -63,11 +64,35 @@ pub struct UserToken {
 pub enum AuthCredHandler {
     Password,
     DeviceAuthorizationGrant,
+    /// Additional data required by the provider to complete the
+    /// authentication, but not required by PAM
+    ///
+    /// Sadly due to how this is passed around we can't make this a
+    /// generic associated type, else it would have to leak up to the
+    /// daemon.
+    ///
+    /// ⚠️  TODO: Optimally this should actually be a tokio oneshot receiver
+    /// with the decision from a task that is spawned.
+    MFA {
+        data: Vec<String>,
+    },
 }
 
 pub enum AuthRequest {
     Password,
-    DeviceAuthorizationGrant { data: DeviceAuthorizationResponse },
+    DeviceAuthorizationGrant {
+        data: DeviceAuthorizationResponse,
+    },
+    MFACode {
+        msg: String,
+    },
+    MFAPoll {
+        /// Message to display to the user.
+        msg: String,
+        /// Interval in seconds between poll attemts.
+        polling_interval: u32,
+    },
+    MFAPollWait,
 }
 
 #[allow(clippy::from_over_into)]
@@ -78,6 +103,15 @@ impl Into<PamAuthResponse> for AuthRequest {
             AuthRequest::DeviceAuthorizationGrant { data } => {
                 PamAuthResponse::DeviceAuthorizationGrant { data }
             }
+            AuthRequest::MFACode { msg } => PamAuthResponse::MFACode { msg },
+            AuthRequest::MFAPoll {
+                msg,
+                polling_interval,
+            } => PamAuthResponse::MFAPoll {
+                msg,
+                polling_interval,
+            },
+            AuthRequest::MFAPollWait => PamAuthResponse::MFAPollWait,
         }
     }
 }
@@ -133,6 +167,7 @@ pub trait IdProvider {
         _token: Option<&UserToken>,
         _tpm: &mut tpm::BoxedDynTpm,
         _machine_key: &tpm::MachineKey,
+        _shutdown_rx: &broadcast::Receiver<()>,
     ) -> Result<(AuthRequest, AuthCredHandler), IdpError>;
 
     async fn unix_user_online_auth_step<D: KeyStoreTxn + Send>(
@@ -143,6 +178,7 @@ pub trait IdProvider {
         _keystore: &mut D,
         _tpm: &mut tpm::BoxedDynTpm,
         _machine_key: &tpm::MachineKey,
+        _shutdown_rx: &broadcast::Receiver<()>,
     ) -> Result<(AuthResult, AuthCacheAction), IdpError>;
 
     async fn unix_user_offline_auth_init(

unix_integration/src/idprovider/kanidm.rs

@@ -3,7 +3,7 @@ use async_trait::async_trait;
 use kanidm_client::{ClientError, KanidmClient, StatusCode};
 use kanidm_proto::internal::OperationError;
 use kanidm_proto::v1::{UnixGroupToken, UnixUserToken};
-use tokio::sync::RwLock;
+use tokio::sync::{broadcast, RwLock};
 
 use super::interface::{
     // KeyStore,
@@ -197,6 +197,7 @@ impl IdProvider for KanidmProvider {
         _token: Option<&UserToken>,
         _tpm: &mut tpm::BoxedDynTpm,
         _machine_key: &tpm::MachineKey,
+        _shutdown_rx: &broadcast::Receiver<()>,
     ) -> Result<(AuthRequest, AuthCredHandler), IdpError> {
         // Not sure that I need to do much here?
         Ok((AuthRequest::Password, AuthCredHandler::Password))
@@ -210,6 +211,7 @@ impl IdProvider for KanidmProvider {
         _keystore: &mut D,
         _tpm: &mut tpm::BoxedDynTpm,
         _machine_key: &tpm::MachineKey,
+        _shutdown_rx: &broadcast::Receiver<()>,
     ) -> Result<(AuthResult, AuthCacheAction), IdpError> {
         match (cred_handler, pam_next_req) {
             (AuthCredHandler::Password, PamAuthRequest::Password { cred }) => {

unix_integration/src/resolver.rs

@@ -28,6 +28,8 @@ use crate::unix_proto::{HomeDirectoryInfo, NssGroup, NssUser, PamAuthRequest, Pa
 
 use kanidm_hsm_crypto::{BoxedDynTpm, HmacKey, MachineKey, Tpm};
 
+use tokio::sync::broadcast;
+
 const NXCACHE_SIZE: NonZeroUsize = unsafe { NonZeroUsize::new_unchecked(128) };
 
 #[derive(Debug, Clone)]
@@ -44,9 +46,12 @@ pub enum AuthSession {
         id: Id,
         token: Option<Box<UserToken>>,
         online_at_init: bool,
-        // cred_type: AuthCredType,
-        // next_cred: AuthNextCred,
         cred_handler: AuthCredHandler,
+        /// Some authentication operations may need to spawn background tasks. These tasks need
+        /// to know when to stop as the caller has disconnected. This reciever allows that, so
+        /// that tasks which .resubscribe() to this channel can then select! on it and be notified
+        /// when they need to stop.
+        shutdown_rx: broadcast::Receiver<()>,
     },
     Success,
     Denied,
@@ -867,6 +872,7 @@ where
     pub async fn pam_account_authenticate_init(
         &self,
         account_id: &str,
+        shutdown_rx: broadcast::Receiver<()>,
     ) -> Result<(AuthSession, PamAuthResponse), ()> {
         // Setup an auth session. If possible bring the resolver online.
         // Further steps won't attempt to bring the cache online to prevent
@@ -893,6 +899,7 @@ where
                     token.as_ref(),
                     hsm_lock.deref_mut(),
                     &self.machine_key,
+                    &shutdown_rx,
                 )
                 .await
         } else {
@@ -910,6 +917,7 @@ where
                     token: token.map(Box::new),
                     online_at_init,
                     cred_handler,
+                    shutdown_rx,
                 };
 
                 // Now identify what credentials are needed next. The auth session tells
@@ -945,6 +953,7 @@ where
                     token: _,
                     online_at_init: true,
                     ref mut cred_handler,
+                    ref shutdown_rx,
                 },
                 CacheState::Online,
             ) => {
@@ -960,6 +969,7 @@ where
                         &mut dbtxn,
                         hsm_lock.deref_mut(),
                         &self.machine_key,
+                        shutdown_rx,
                     )
                     .await;
 
@@ -1008,6 +1018,8 @@ where
                     token: Some(ref token),
                     online_at_init: _,
                     ref mut cred_handler,
+                    // Only need in online auth.
+                    shutdown_rx: _,
                 },
                 _,
             ) => {
@@ -1038,6 +1050,10 @@ where
                         // AuthCredHandler::DeviceAuthorizationGrant is invalid for offline auth
                         return Err(());
                     }
+                    (AuthCredHandler::MFA { .. }, _) => {
+                        // AuthCredHandler::MFA is invalid for offline auth
+                        return Err(());
+                    }
                 }
 
                 /*
@@ -1102,7 +1118,12 @@ where
         account_id: &str,
         password: &str,
     ) -> Result<Option<bool>, ()> {
-        let mut auth_session = match self.pam_account_authenticate_init(account_id).await? {
+        let (_shutdown_tx, shutdown_rx) = broadcast::channel(1);
+
+        let mut auth_session = match self
+            .pam_account_authenticate_init(account_id, shutdown_rx)
+            .await?
+        {
             (auth_session, PamAuthResponse::Password) => {
                 // Can continue!
                 auth_session
@@ -1111,6 +1132,18 @@ where
                 // Can continue!
                 auth_session
             }
+            (auth_session, PamAuthResponse::MFACode { .. }) => {
+                // Can continue!
+                auth_session
+            }
+            (auth_session, PamAuthResponse::MFAPoll { .. }) => {
+                // Can continue!
+                auth_session
+            }
+            (auth_session, PamAuthResponse::MFAPollWait) => {
+                // Can continue!
+                auth_session
+            }
             (_, PamAuthResponse::Unknown) => return Ok(None),
             (_, PamAuthResponse::Denied) => return Ok(Some(false)),
             (_, PamAuthResponse::Success) => {

unix_integration/src/unix_proto.rs

@@ -36,22 +36,30 @@ pub enum PamAuthResponse {
     Success,
     Denied,
     Password,
-    DeviceAuthorizationGrant { data: DeviceAuthorizationResponse },
-    /*
-    MFACode {
+    DeviceAuthorizationGrant {
+        data: DeviceAuthorizationResponse,
     },
-    */
+    /// PAM must prompt for an authentication code
+    MFACode {
+        msg: String,
+    },
+    /// PAM will poll for an external response
+    MFAPoll {
+        /// Initial message to display as the polling begins.
+        msg: String,
+        /// Seconds between polling attempts.
+        polling_interval: u32,
+    },
+    MFAPollWait,
     // CTAP2
 }
 
 #[derive(Serialize, Deserialize, Debug)]
 pub enum PamAuthRequest {
     Password { cred: String },
-    DeviceAuthorizationGrant { data: DeviceAuthorizationResponse }, /*
-                                                                    MFACode {
-                                                                        cred: Option<PamCred>
-                                                                    }
-                                                                    */
+    DeviceAuthorizationGrant { data: DeviceAuthorizationResponse },
+    MFACode { cred: String },
+    MFAPoll,
 }
 
 #[derive(Serialize, Deserialize, Debug)]