Start the user API

src/api.rs

@@ -1,3 +1,9 @@
+use std::rc::Rc;
+use std::cell::RefCell;
+use std::ops::Deref;
+
+use slog::Logger;
+
 use std::sync::Arc;
 
 use capnp::capability::{Params, Results, Promise};
@@ -21,15 +27,19 @@ use users::Users;
 
 // TODO Session restoration by making the Bootstrap cap a SturdyRef
 pub struct Bootstrap {
-    session: Arc<Session>,
+    log: Logger,
+
     db: Databases,
     nw: Arc<Network>,
+
+    session: Rc<RefCell<Option<Session>>>,
 }
 
 impl Bootstrap {
-    pub fn new(session: Arc<Session>, db: Databases, nw: Arc<Network>) -> Self {
-        info!(session.log, "Created Bootstrap");
-        Self { session, db, nw }
+    pub fn new(log: Logger, db: Databases, nw: Arc<Network>) -> Self {
+        info!(log, "Created Bootstrap");
+        let session = Rc::new(RefCell::new(None));
+        Self { session, db, nw, log }
     }
 }
 
@@ -43,7 +53,15 @@ impl connection_capnp::bootstrap::Server for Bootstrap {
         // TODO: When should we allow multiple auth and how do me make sure that does not leak
         // priviledges (e.g. due to previously issues caps)?
 
-        res.get().set_authentication_system(capnp_rpc::new_client(auth::Auth::new(self.db.clone(), self.session.clone())));
+        // If this Rc has a strong count of 1 then there's no other cap issued yet meaning we can
+        // safely transform the inner session with an auth.
+        if Rc::strong_count(&self.session) == 1 {
+            let session = Rc::clone(&self.session);
+            let db = self.db.clone();
+            res.get().set_authentication_system(capnp_rpc::new_client(
+                    auth::Auth::new(self.log.new(o!()), db, session))
+            );
+        }
 
         Promise::ok(())
     }
@@ -52,32 +70,19 @@ impl connection_capnp::bootstrap::Server for Bootstrap {
         _: MachineSystemParams,
         mut res: MachineSystemResults
     ) -> Promise<(), capnp::Error> {
-        let session = self.session.clone();
-        let accessdb = self.db.access.clone();
-        let nw = self.nw.clone();
-        let f = async move {
-            // Ensure the lock is dropped as soon as possible
-            if let Some(user) = { session.user.lock().await.clone() } {
-                let perms = accessdb.collect_permrules(&user.data)
-                    .map_err(|e| capnp::Error::failed(format!("AccessDB lookup failed: {}", e)))?;
-
-                debug!(session.log, "Giving MachineSystem cap to user {} with perms:", user.id);
-                for r in perms.iter() {
+        if let Some(session) = self.session.borrow().deref() {
+            debug!(self.log, "Giving MachineSystem cap to user {} with perms:", session.authzid);
+            for r in session.perms.iter() {
                 debug!(session.log, "   {}", r);
             }
 
             // TODO actual permission check and stuff
             //      Right now we only check that the user has authenticated at all.
-                let c = capnp_rpc::new_client(Machines::new(user.id, perms, nw));
+            let c = capnp_rpc::new_client(Machines::new(Rc::clone(&self.session), self.nw.clone()));
             res.get().set_machine_system(c);
         }
 
-            // Promise is Ok either way, just the machine system may not be set, indicating as
-            // usual a lack of permission.
-            Ok(())
-        };
-
-        Promise::from_future(f)
+        Promise::ok(())
     }
 
     fn user_system(
@@ -85,25 +90,13 @@ impl connection_capnp::bootstrap::Server for Bootstrap {
         _: UserSystemParams,
         mut results: UserSystemResults
     ) -> Promise<(), capnp::Error> {
-        let session = self.session.clone();
-        let accessdb = self.db.access.clone();
-        let f = async move {
-            // Ensure the lock is dropped as soon as possible
-            if let Some(user) = { session.user.lock().await.clone() } {
-                let perms = accessdb.collect_permrules(&user.data)
-                    .map_err(|e| capnp::Error::failed(format!("AccessDB lookup failed: {}", e)))?;
-
+        if self.session.borrow().is_some() {
             // TODO actual permission check and stuff
             //      Right now we only check that the user has authenticated at all.
-                let c = capnp_rpc::new_client(Users::new(perms));
+            let c = capnp_rpc::new_client(Users::new(Rc::clone(&self.session), self.db.userdb.clone()));
             results.get().set_user_system(c);
         }
 
-            // Promise is Ok either way, just the machine system may not be set, indicating as
-            // usual a lack of permission.
-            Ok(())
-        };
-
-        Promise::from_future(f)
+        Promise::ok(())
     }
 }

src/api/auth.rs

@@ -4,6 +4,11 @@
 //! Authentication using SASL
 
 use std::sync::Arc;
+use std::rc::Rc;
+use std::cell::RefCell;
+use std::ops::Deref;
+
+use slog::Logger;
 
 use rsasl::{
     SASL,
@@ -24,14 +29,15 @@ use crate::api::Session;
 pub use crate::schema::authenticationsystem_capnp as auth_system;
 use crate::db::Databases;
 use crate::db::pass::PassDB;
-use crate::db::user::{Internal as UserDB};
+use crate::db::user::{Internal as UserDB, UserId, User};
+use crate::db::access::AccessControl as AccessDB;
 
 pub struct AppData {
     passdb: Arc<PassDB>,
     userdb: Arc<UserDB>,
 }
 pub struct SessionData {
-    session: Arc<Session>,
+    authz: Option<User>,
 }
 
 struct CB;
@@ -45,7 +51,6 @@ impl Callback<AppData, SessionData> for CB {
             Property::GSASL_VALIDATE_SIMPLE => {
                 // FIXME: get_property and retrieve_mut can't be used interleaved but that's
                 // technically safe.
-                let cap_session = session.retrieve_mut().map(|sd| sd.session.clone());
 
                 let authid: &str = session
                     .get_property(Property::GSASL_AUTHID)
@@ -60,27 +65,14 @@ impl Callback<AppData, SessionData> for CB {
 
 
                 if let Some(appdata) = sasl.retrieve_mut() {
-                    if let Ok(Some(b)) = appdata.passdb.check(authid, pass.to_bytes()) {
-                        if b {
-                            if let Some(s) = cap_session {
-                                if let Ok(Some(user)) = appdata.userdb.get_user(authid) {
-                                    // FIXME: This should set the userid outside the callback
-                                    s.user.try_lock().unwrap().replace(user);
+                    if let Ok(Some(user)) = appdata.userdb.login(authid, pass.to_bytes()) {
+                        session.retrieve_mut().unwrap().authz.replace(user);
+                        return Ok(());
                     }
                 }
 
-                            // Early return, implicitly returns GSASL_OK
-                            return Ok(());
-                        } else {
                 ReturnCode::GSASL_AUTHENTICATION_ERROR
             }
-                    } else {
-                        ReturnCode::GSASL_AUTHENTICATION_ERROR
-                    }
-                } else {
-                    ReturnCode::GSASL_AUTHENTICATION_ERROR
-                }
-            }
             p => {
                 println!("Callback called with property {:?}", p);
                 ReturnCode::GSASL_NO_CALLBACK 
@@ -90,29 +82,28 @@ impl Callback<AppData, SessionData> for CB {
     }
 }
 
-pub struct Auth {
+pub struct Auth<'a> {
     pub ctx: RSASL<AppData, SessionData>,
-    session: Arc<Session>,
+    session: Rc<RefCell<Option<Session>>>,
+    access: Arc<AccessDB>,
+    log: Logger,
 }
 
-impl Auth {
-    pub fn new(dbs: Databases, session: Arc<Session>) -> Self {
+impl<'a> Auth<'a> {
+    pub fn new(log: Logger, dbs: Databases, session: Rc<RefCell<Option<Session>>>) -> Self {
         let mut ctx = SASL::new().unwrap();
 
         let appdata = Box::new(AppData { passdb: dbs.passdb.clone(), userdb: dbs.userdb.clone() });
 
         ctx.store(appdata);
-
         ctx.install_callback::<CB>();
 
-        info!(session.log, "Auth created");
-
-        Self { ctx, session }
+        Self { log, ctx, session, access: dbs.access.clone() }
     }
 }
 
 use crate::schema::authenticationsystem_capnp::*;
-impl authentication_system::Server for Auth {
+impl<'a> authentication_system::Server for Auth<'a> {
     fn mechanisms(&mut self, 
         _: authentication_system::MechanismsParams,
         mut res: authentication_system::MechanismsResults
@@ -166,7 +157,7 @@ impl authentication_system::Server for Auth {
                 }),
         };
 
-        session.store(Box::new(SessionData { session: self.session.clone() }));
+        session.store(Box::new(SessionData { authz: None }));
 
         // If the client has provided initial data go use that
         use request::initial_response::Which;
@@ -188,12 +179,28 @@ impl authentication_system::Server for Auth {
 
         // The step may either return an error, a success or the need for more data
         // TODO: Set the session user. Needs a lookup though <.>
+        use response::Result as Resres;
         match step_res {
             Ok(Step::Done(b)) => {
-                use response::Result;
+                let user = session
+                    .retrieve_mut()
+                    .and_then(|data| {
+                        data.authz.take()
+                    })
+                    .expect("Authentication returned OK but didn't set user id");
+
+                let perms = pry!(self.access.collect_permrules(&user.data)
+                    .map_err(|e| capnp::Error::failed(format!("AccessDB lookup failed: {}", e))));
+                self.session.replace(Session::new(
+                    self.log.new(o!()),
+                    user.id,
+                    "".to_string(),
+                    user.data.roles.into_boxed_slice(),
+                    perms.into_boxed_slice()
+                ));
 
                 let mut outcome = pry!(res.get().get_response()).init_outcome();
-                outcome.reborrow().set_result(Result::Successful);
+                outcome.reborrow().set_result(Resres::Successful);
                 if b.len() != 0 {
                     outcome.init_additional_data().set_additional(&b);
                 }
@@ -204,11 +211,13 @@ impl authentication_system::Server for Auth {
                 Promise::ok(())
             }
             // TODO: This should really be an outcome because this is failed auth just as much atm.
-            Err(e) => 
-                return Promise::err(capnp::Error {
-                    kind: capnp::ErrorKind::Failed,
-                    description: format!("SASL error: {}", e),
-                }),
+            Err(e) => {
+                let mut outcome = pry!(res.get().get_response()).init_outcome();
+                outcome.reborrow().set_result(Resres::Failed);
+                let text = format!("{}", e);
+                outcome.set_help_text(&text);
+                Promise::ok(())
+            }
         }
 
     }

src/api/machines.rs

@@ -1,4 +1,7 @@
 use std::sync::Arc;
+use std::cell::RefCell;
+use std::rc::Rc;
+use std::ops::Deref;
 
 use capnp::capability::Promise;
 use capnp::Error;
@@ -11,18 +14,18 @@ use crate::schema::machinesystem_capnp::machine_system::info as machines;
 use crate::network::Network;
 use crate::db::user::UserId;
 use crate::db::access::{PermRule, admin_perm};
+use crate::connection::Session;
 
 /// An implementation of the `Machines` API
 #[derive(Clone)]
 pub struct Machines {
-    user: UserId,
-    permissions: Vec<PermRule>,
+    session: Rc<RefCell<Option<Session>>>,
     network: Arc<Network>,
 }
 
 impl Machines {
-    pub fn new(user: UserId, permissions: Vec<PermRule>, network: Arc<Network>) -> Self {
-        Self { user, permissions, network }
+    pub fn new(session: Rc<RefCell<Option<Session>>>, network: Arc<Network>) -> Self {
+        Self { session, network }
     }
 }
 
@@ -44,10 +47,13 @@ impl machines::Server for Machines {
         mut results: machines::GetMachineListResults)
         -> Promise<(), Error>
     {
+        let session = Rc::clone(&self.session);
+        let session = session.borrow();
+        if let Some(session) = session.deref() {
             let v: Vec<(String, crate::machine::Machine)> = self.network.machines.iter()
                 .filter(|(_name, machine)| {
                     let required_disclose = &machine.desc.privs.disclose;
-                for perm_rule in self.permissions.iter() {
+                    for perm_rule in session.perms.iter() {
                         if perm_rule.match_perm(required_disclose) {
                             return true;
                         }
@@ -58,8 +64,8 @@ impl machines::Server for Machines {
                 .map(|(n,m)| (n.clone(), m.clone()))
                 .collect();
 
-        let permissions = self.permissions.clone();
-        let user = self.user.clone();
+            let permissions = &session.perms;
+            let user = &session.authzid;
 
             let f = async move {
                 let mut machines = results.get().init_machine_list(v.len() as u32);
@@ -103,21 +109,24 @@ impl machines::Server for Machines {
             };
 
             Promise::from_future(f)
+        } else {
+            Promise::ok(())
+        }
     }
 
     fn get_machine(&mut self,
         params: machines::GetMachineParams,
         mut results: machines::GetMachineResults
         ) -> Promise<(), capnp::Error> {
-
+        if let Some(session) = self.session.borrow().deref() {
             let name = {
                 let params = pry!(params.get());
                 pry!(params.get_name()).to_string()
             };
 
             let network = self.network.clone();
-        let user = self.user.clone();
-        let permissions = self.permissions.clone();
+            let user = session.authzid;
+            let permissions = session.perms;
 
             let f = async move {
                 if let Some(machine) = network.machines.get(&name) {
@@ -158,5 +167,8 @@ impl machines::Server for Machines {
                 Ok(())
             };
             Promise::from_future(f)
+        } else {
+            Promise::ok(())
+        }
     }
 }

src/api/user.rs

@@ -1,27 +1,42 @@
-use crate::db::access::PermRule;
+use std::rc::Rc;
+use std::cell::RefCell;
+use std::ops::Deref;
+
+use crate::connection::Session;
 use crate::db::user as db;
 use crate::schema::user_capnp::user::*;
 
 #[derive(Clone)]
 pub struct User {
-    user: db::User,
-    perms: Vec<PermRule>,
+    session: Rc<RefCell<Option<Session>>>,
 }
 
 impl User {
-    pub fn new(user: db::User, perms: Vec<PermRule>) -> Self {
-        Self { user, perms }
+    pub fn new(session: Rc<RefCell<Option<Session>>>) -> Self {
+        Self { session }
     }
 
-    pub fn fill(&self, builder: &mut Builder) {
-        builder.set_username(&self.user.id.uid);
-        if let Some(ref realm) = &self.user.id.realm {
+    pub fn fill_self(&self, builder: &mut Builder) {
+        if let Some(session) = self.session.borrow().deref() {
+            self.fill_userid(builder, &session.authzid);
+        }
+    }
+
+    pub fn fill_with(&self, builder: &mut Builder, user: db::User) {
+        self.fill_userid(builder, &user.id)
+    }
+
+    pub fn fill_userid(&self, builder: &mut Builder, uid: &db::UserId) {
+        builder.set_username(&uid.uid);
+        if let Some(ref realm) = &uid.realm {
             let mut space = builder.reborrow().init_space();
             space.set_name(&realm);
         }
     }
 }
 
-impl info::Server for User {}
+impl info::Server for User {
+
+}
 impl manage::Server for User {}
 impl admin::Server for User {}

src/api/users.rs

@@ -1,17 +1,27 @@
+use std::cell::RefCell;
+use std::rc::Rc;
+use std::sync::Arc;
+use std::ops::Deref;
+
 use capnp::capability::Promise;
 
+use crate::api::user::User;
+use crate::connection::Session;
 use crate::db::access::{PermRule, Permission};
+use crate::db::user::{UserId, Internal as UserDB};
 use crate::schema::usersystem_capnp::user_system;
 use crate::schema::usersystem_capnp::user_system::{info, manage};
+use crate::error;
 
 #[derive(Clone, Debug)]
 pub struct Users {
-    perms: Vec<PermRule>,
+    session: Rc<RefCell<Option<Session>>>,
+    userdb: Arc<UserDB>,
 }
 
 impl Users {
-    pub fn new(perms: Vec<PermRule>) -> Self {
-        Self { perms }
+    pub fn new(session: Rc<RefCell<Option<Session>>>, userdb: Arc<UserDB>) -> Self {
+        Self { session, userdb }
     }
 }
 
@@ -31,11 +41,13 @@ impl user_system::Server for Users {
         mut results: user_system::ManageResults,
     ) -> Promise<(), capnp::Error> {
         let perm: &Permission = Permission::new("bffh.users.manage");
-        if self.perms.iter().any(|rule| rule.match_perm(perm)) {
+        if let Some(session) = self.session.borrow().deref() {
+            if session.perms.iter().any(|rule| rule.match_perm(perm)) {
                 results
                     .get()
                     .set_manage(capnp_rpc::new_client(self.clone()));
             }
+        }
 
         Promise::ok(())
     }
@@ -47,8 +59,48 @@ impl info::Server for Users {
         _: info::GetUserSelfParams,
         mut results: info::GetUserSelfResults,
     ) -> Promise<(), capnp::Error> {
+        let user = User::new(Rc::clone(&self.session));
+        let mut builder = results.get().init_user();
+        user.fill_self(&mut builder);
         Promise::ok(())
     }
 }
 
-impl manage::Server for Users {}
+impl manage::Server for Users {
+    fn get_user_list(
+        &mut self,
+        _: manage::GetUserListParams,
+        mut results: manage::GetUserListResults,
+    ) -> Promise<(), capnp::Error> {
+        let result: Result<(), error::Error> = 
+            self.userdb.list_users()
+                .and_then(|users| {
+                    let builder = results.get().init_user_list(users.len() as u32);
+                    let u = User::new(Rc::clone(&self.session));
+                    for (i, user) in users.into_iter().enumerate() {
+                        let mut b = builder.reborrow().get(i as u32);
+                        u.fill_with(&mut b, user);
+                    }
+                    Ok(())
+                });
+
+        match result {
+            Ok(()) => Promise::ok(()),
+            Err(e) => Promise::err(capnp::Error::failed("User lookup failed: {}".to_string())),
+        }
+    }
+
+    /*fn add_user(
+        &mut self,
+        params: manage::AddUserParams,
+        mut results: manage::AddUserResults,
+    ) -> Promise<(), capnp::Error> {
+    }
+
+    fn remove_user(
+        &mut self,
+        _: manage::RemoveUserParams,
+        mut results: manage::RemoveUserResults,
+    ) -> Promise<(), capnp::Error> {
+    }*/
+}

src/connection.rs

@@ -1,22 +1,22 @@
-use std::sync::Arc;
-use std::future::Future;
 use futures::FutureExt;
+use std::future::Future;
+use std::sync::Arc;
 
 use slog::Logger;
 
 use smol::lock::Mutex;
 use smol::net::TcpStream;
 
-use crate::error::Result;
 use crate::api::Bootstrap;
+use crate::error::Result;
 
-use capnp_rpc::{twoparty, rpc_twoparty_capnp};
+use capnp_rpc::{rpc_twoparty_capnp, twoparty};
 
 use crate::schema::connection_capnp;
 
+use crate::db::access::{AccessControl, PermRule, RoleIdentifier};
+use crate::db::user::UserId;
 use crate::db::Databases;
-use crate::db::access::{AccessControl, Permission};
-use crate::db::user::User;
 use crate::network::Network;
 
 #[derive(Debug)]
@@ -25,15 +25,42 @@ use crate::network::Network;
 pub struct Session {
     // Session-spezific log
     pub log: Logger,
-    pub user: Mutex<Option<User>>,
-    pub accessdb: Arc<AccessControl>,
+
+    /// User this session has been authorized as.
+    ///
+    /// Slightly different than the authnid which indicates as what this session has been
+    /// authenticated as (e.g. using EXTERNAL auth the authnid would be the CN of the client
+    /// certificate, but the authzid would be an user)
+    pub authzid: UserId,
+
+    pub authnid: String,
+
+    /// Roles this session has been assigned via group memberships, direct role assignment or
+    /// authentication types
+    pub roles: Box<[RoleIdentifier]>,
+
+    /// Permissions this session has.
+    ///
+    /// This is a snapshot of the permissions the underlying user has
+    /// take at time of creation (i.e. session establishment)
+    pub perms: Box<[PermRule]>,
 }
 
 impl Session {
-    pub fn new(log: Logger, accessdb: Arc<AccessControl>) -> Self {
-        let user = Mutex::new(None);
-
-        Session { log, user, accessdb }
+    pub fn new(
+        log: Logger,
+        authzid: UserId,
+        authnid: String,
+        roles: Box<[RoleIdentifier]>,
+        perms: Box<[PermRule]>,
+    ) -> Self {
+        Session {
+            log,
+            authzid,
+            authnid,
+            roles,
+            perms,
+        }
     }
 }
 
@@ -48,14 +75,17 @@ impl ConnectionHandler {
         Self { log, db, network }
     }
 
-    pub fn handle(&mut self, stream: TcpStream) -> impl Future<Output=Result<()>> {
+    pub fn handle(&mut self, stream: TcpStream) -> impl Future<Output = Result<()>> {
         info!(self.log, "New connection from on {:?}", stream);
-        let session = Arc::new(Session::new(self.log.new(o!()), self.db.access.clone()));
-        let boots = Bootstrap::new(session, self.db.clone(), self.network.clone());
+        let boots = Bootstrap::new(self.log.new(o!()), self.db.clone(), self.network.clone());
         let rpc: connection_capnp::bootstrap::Client = capnp_rpc::new_client(boots);
 
-        let network = twoparty::VatNetwork::new(stream.clone(), stream,
-            rpc_twoparty_capnp::Side::Server, Default::default());
+        let network = twoparty::VatNetwork::new(
+            stream.clone(),
+            stream,
+            rpc_twoparty_capnp::Side::Server,
+            Default::default(),
+        );
         let rpc_system = capnp_rpc::RpcSystem::new(Box::new(network), Some(rpc.client));
 
         // Convert the error type to one of our errors

src/db/user.rs

@@ -89,6 +89,10 @@ pub struct UserData {
     /// The higher, the higher the priority. Higher priority users overwrite lower priority ones.
     pub priority: u64,
 
+    #[serde(skip_serializing_if = "Option::is_none")]
+    #[serde(default)]
+    pub passwd: Option<String>,
+
     /// Additional data storage
     #[serde(flatten, skip_serializing_if = "HashMap::is_empty")]
     kv: HashMap<String, String>,
@@ -96,11 +100,7 @@ pub struct UserData {
 
 impl UserData {
     pub fn new(roles: Vec<RoleIdentifier>, priority: u64) -> Self {
-        Self { 
-            roles: roles,
-            priority: priority,
-            kv: HashMap::new(),
-        }
+        Self { roles, priority, kv: HashMap::new(), passwd: None }
     }
 }
 
@@ -124,30 +124,8 @@ pub fn load_file<P: AsRef<Path>>(path: P) -> Result<HashMap<String, User>> {
 
 pub fn init(log: Logger, _config: &Config, env: Arc<lmdb::Environment>) -> Result<Internal> {
     let mut flags = lmdb::DatabaseFlags::empty();
-    flags.set(lmdb::DatabaseFlags::INTEGER_KEY, true);
-    let db = env.create_db(Some("users"), flags)?;
+    let db = env.create_db(Some("userdb"), flags)?;
     debug!(&log, "Opened user db successfully.");
 
     Ok(Internal::new(log, env, db))
 }
-
-#[cfg(test_DISABLED)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn format_uid_test() {
-        let uid = "testuser".to_string();
-        let suid = "testsuid".to_string();
-        let realm = "testloc".to_string();
-
-        assert_eq!("testuser", 
-            format!("{}", UserIdentifier::new(uid.clone(), None, None)));
-        assert_eq!("testuser+testsuid", 
-            format!("{}", UserIdentifier::new(uid.clone(), Some(suid.clone()), None)));
-        assert_eq!("testuser+testsuid", 
-            format!("{}", UserIdentifier::new(uid.clone(), Some(suid.clone()), None)));
-        assert_eq!("testuser+testsuid@testloc", 
-            format!("{}", UserIdentifier::new(uid, Some(suid), Some(realm))));
-    }
-}

src/db/user/internal.rs

@@ -1,7 +1,7 @@
 use std::sync::Arc;
 
 use slog::Logger;
-use lmdb::{Environment, Transaction, RwTransaction};
+use lmdb::{Environment, Transaction, RwTransaction, Cursor};
 
 use crate::error::Result;
 
@@ -46,4 +46,25 @@ impl Internal {
 
         Ok(())
     }
+
+    pub fn list_users(&self) -> Result<Vec<User>> {
+        let txn = self.env.begin_ro_txn()?;
+        Ok(self.list_users_txn(&txn)?.collect())
+    }
+    pub fn list_users_txn<T: Transaction>(&self, txn: &T) -> Result<impl Iterator<Item=User>> {
+       let mut cursor = txn.open_ro_cursor(self.db)?;
+       Ok(cursor.iter_start().map(|buf| {
+           let (_kbuf, vbuf) = buf.unwrap();
+           flexbuffers::from_slice(vbuf).unwrap()
+       }))
+    }
+
+    pub fn login(&self, uid: &str, password: &[u8]) -> Result<Option<User>> {
+        let txn = self.env.begin_ro_txn()?;
+        Ok(self.get_user_txn(&txn, uid)?
+            .filter(|user| {
+                user.data.passwd.is_some()
+                && argon2::verify_encoded(user.data.passwd.as_ref().unwrap(), password).unwrap_or(false)
+            }))
+    }
 }