Add portal backend impl

Author: A6GibKm

.gitignore

@@ -1,3 +1,4 @@
 /target
+/portal/target
 Cargo.lock
 cli/target

Cargo.toml

@@ -4,4 +4,5 @@ resolver = "2"
 members = [
   "client",
   "cli",
+  "portal-impl",
 ]

portal-impl/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "oo7-portal-impl"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+tokio = { version = "1.17", features = [ "macros", "io-util", "rt-multi-thread" ] }
+futures-util = "0.3"
+futures-channel = "0.3"
+oo7 = { path = "../client", default-features = false, features = ["tokio", "native_crypto"] }
+ring = "0.17.5"
+secrecy = { version = "0.8", features = [ "alloc" ] }
+serde = { version = "1.0", features = ["derive"] }
+tracing = "0.1"
+tracing-subscriber = "0.3"
+zbus = "3.5.0"
+zeroize = { version = "1", features = ["zeroize_derive"] }

portal-impl/data/oo7-portal.portal

@@ -0,0 +1,4 @@
+[portal]
+DBusName=org.freedesktop.impl.portal.desktop.oo7
+Interfaces=org.freedesktop.impl.portal.Secret
+UseIn=gnome

portal-impl/data/oo7-portal.service

@@ -0,0 +1,3 @@
+[D-BUS Service]
+Name=org.freedesktop.impl.portal.Secret
+Exec=@bindir@/oo7-portal

portal-impl/src/main.rs

@@ -0,0 +1,228 @@
+use std::{
+    collections::HashMap,
+    future::pending,
+    os::fd::{AsRawFd, FromRawFd},
+    sync::{Arc, Mutex},
+};
+
+use futures_util::FutureExt;
+use oo7::{
+    dbus::{Algorithm, Service},
+    zbus::{self, dbus_interface, zvariant, zvariant::Type},
+};
+use ring::rand::SecureRandom;
+use serde::Serialize;
+use tokio::io::AsyncWriteExt;
+use zvariant::OwnedObjectPath;
+
+const PORTAL_VERSION: u32 = 1;
+const PORTAL_SECRET_SIZE: usize = 64;
+const PORTAL_NAME: &str = "org.freedesktop.impl.portal.desktop.oo7";
+const PORTAL_PATH: &str = "/org/freedesktop/portal/desktop";
+
+#[derive(Serialize, PartialEq, Eq, Debug, Type)]
+#[doc(hidden)]
+enum ResponseType {
+    Success = 0,
+    Cancelled = 1,
+    Other = 2,
+}
+
+#[derive(zbus::DBusError, Debug)]
+enum Error {
+    Msg(String),
+}
+
+impl Error {
+    fn new(msg: &str) -> Error {
+        Error::Msg(msg.to_string())
+    }
+}
+
+impl From<oo7::dbus::Error> for Error {
+    fn from(err: oo7::dbus::Error) -> Self {
+        Error::new(&err.to_string())
+    }
+}
+
+struct Secret;
+
+#[dbus_interface(name = "org.freedesktop.impl.portal.Secret")]
+impl Secret {
+    #[dbus_interface(property, name = "version")]
+    fn version(&self) -> u32 {
+        PORTAL_VERSION
+    }
+
+    #[dbus_interface(out_args("response", "results"))]
+    async fn retrieve_secret(
+        &self,
+        #[zbus(object_server)] object_server: &zbus::ObjectServer,
+        handle: OwnedObjectPath,
+        app_id: &str,
+        fd: zvariant::Fd,
+        _options: HashMap<&str, zvariant::Value<'_>>,
+    ) -> Result<(ResponseType, HashMap<&str, zvariant::OwnedValue>), Error> {
+        tracing::debug!("Got request from {app_id} with options: {_options:?}");
+
+        let (sender, receiver) = futures_channel::oneshot::channel();
+
+        if let Err(err) = Request::serve(object_server, handle.clone(), sender).await {
+            tracing::error!("Could not register object {handle}: {err}");
+        }
+
+        let fut_1 = async move {
+            let res = match retrieve_secret_inner(app_id, fd).await {
+                Ok(res) => Ok((ResponseType::Success, res)),
+                Err(err) => {
+                    tracing::error!("could not retrieve secret: {err}");
+                    Ok((ResponseType::Other, HashMap::new()))
+                }
+            };
+
+            // We do not accept Close request anymore here.
+            tracing::debug!("Object {handle} handled");
+            object_server
+                .remove::<Request, &zvariant::OwnedObjectPath>(&handle)
+                .await
+                .unwrap();
+
+            res
+        };
+
+        let fut_2 = async move {
+            receiver.await.unwrap();
+            Ok((ResponseType::Cancelled, HashMap::new()))
+        };
+
+        let t1 = fut_1.fuse();
+        let t2 = fut_2.fuse();
+
+        futures_util::pin_mut!(t1, t2);
+
+        futures_util::select! {
+            fut_1_res = t1 => fut_1_res,
+            fut_2_res = t2 => fut_2_res,
+        }
+    }
+}
+
+fn generate_secret() -> Result<zeroize::Zeroizing<Vec<u8>>, Error> {
+    let mut secret = [0; PORTAL_SECRET_SIZE];
+    let rand = ring::rand::SystemRandom::new();
+    rand.fill(&mut secret)
+        .map_err(|err| Error::new(&err.to_string()))?;
+    Ok(zeroize::Zeroizing::new(secret.to_vec()))
+}
+
+async fn retrieve_secret_inner(
+    app_id: &str,
+    fd: zvariant::Fd,
+) -> Result<HashMap<&'static str, zvariant::OwnedValue>, Error> {
+    let service = Service::new(Algorithm::Encrypted)
+        .await
+        .or(Service::new(Algorithm::Plain).await)?;
+    let collection = service.default_collection().await?;
+    let attributes = HashMap::from([("app_id", app_id)]);
+
+    let secret = if let Some(item) = collection
+        .search_items(attributes.clone())
+        .await
+        .map_err(|err| Error::new(&err.to_string()))?
+        .first()
+    {
+        item.secret().await?
+    } else {
+        tracing::debug!("Could not find secret for {app_id}, creating one");
+        let secret = generate_secret()?;
+        collection
+            .create_item(
+                &format!("Secret Portal token for {app_id}"),
+                attributes,
+                &secret,
+                true,
+                // TODO Find a better one.
+                "text/plain",
+            )
+            .await?;
+
+        secret
+    };
+
+    // Write the secret to the FD.
+    let raw_fd = fd.as_raw_fd();
+    let std_stream = unsafe { std::os::unix::net::UnixStream::from_raw_fd(raw_fd) };
+    let mut stream =
+        tokio::net::UnixStream::from_std(std_stream).map_err(|e| Error::new(&e.to_string()))?;
+    stream
+        .write(&secret)
+        .await
+        .map_err(|e| Error::new(&e.to_string()))?;
+
+    Ok(HashMap::new())
+}
+
+#[tokio::main]
+async fn main() -> Result<(), zbus::Error> {
+    tracing_subscriber::fmt::init();
+
+    let backend = Secret;
+    let cnx = zbus::ConnectionBuilder::session()?
+        .serve_at(PORTAL_PATH, backend)?
+        .build()
+        .await?;
+    // NOTE For debugging.
+    let flags = zbus::fdo::RequestNameFlags::ReplaceExisting
+        | zbus::fdo::RequestNameFlags::AllowReplacement;
+    cnx.request_name_with_flags(PORTAL_NAME, flags).await?;
+
+    loop {
+        pending::<()>().await;
+    }
+}
+
+struct Request {
+    handle_path: zvariant::OwnedObjectPath,
+    sender: Arc<Mutex<Option<futures_channel::oneshot::Sender<()>>>>,
+}
+
+#[dbus_interface(name = "org.freedesktop.impl.portal.Request")]
+impl Request {
+    async fn close(
+        &self,
+        #[zbus(object_server)] server: &zbus::ObjectServer,
+    ) -> zbus::fdo::Result<()> {
+        tracing::debug!("Object {} closed", self.handle_path);
+        server
+            .remove::<Self, &zvariant::OwnedObjectPath>(&self.handle_path)
+            .await?;
+
+        if let Ok(mut guard) = self.sender.lock() {
+            if let Some(sender) = (*guard).take() {
+                // This will Err out if the receiver has been dropped.
+                let _ = sender.send(());
+            }
+        }
+
+        Ok(())
+    }
+}
+
+impl Request {
+    async fn serve(
+        object_server: &zbus::ObjectServer,
+        handle_path: OwnedObjectPath,
+        sender: futures_channel::oneshot::Sender<()>,
+    ) -> zbus::fdo::Result<()> {
+        tracing::debug!("Handling object {:?}", handle_path.as_str());
+
+        let iface = Request {
+            handle_path: handle_path.clone(),
+            sender: Arc::new(Mutex::new(Some(sender))),
+        };
+
+        object_server.at(handle_path, iface).await?;
+
+        Ok(())
+    }
+}