routing/bedrock/
with_rights.rs

1// Copyright 2024 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5use crate::bedrock::request_metadata::Metadata;
6use crate::error::RoutingError;
7use crate::rights::{Rights, RightsWalker};
8use crate::walk_state::WalkStateUnit;
9use async_trait::async_trait;
10use fidl_fuchsia_component_sandbox as fsandbox;
11use moniker::ExtendedMoniker;
12use router_error::RouterError;
13use sandbox::{CapabilityBound, Request, Routable, Router, RouterResponse};
14
15struct RightsRouter<T: CapabilityBound> {
16    router: Router<T>,
17    rights: Rights,
18    moniker: ExtendedMoniker,
19}
20
21#[async_trait]
22impl<T: CapabilityBound> Routable<T> for RightsRouter<T> {
23    async fn route(
24        &self,
25        request: Option<Request>,
26        debug: bool,
27    ) -> Result<RouterResponse<T>, router_error::RouterError> {
28        let request = request.ok_or_else(|| RouterError::InvalidArgs)?;
29        let RightsRouter { router, rights, moniker } = self;
30        let request_rights: Rights =
31            request.metadata.get_metadata().ok_or(fsandbox::RouterError::InvalidArgs)?;
32        let request_rights = RightsWalker::new(request_rights, moniker.clone());
33        let router_rights = RightsWalker::new(*rights, moniker.clone());
34        // The rights of the request must be compatible with the
35        // rights of this step of the route.
36        match request_rights.validate_next(&router_rights) {
37            Ok(()) => router.route(Some(request), debug).await,
38            Err(e) => Err(RoutingError::from(e).into()),
39        }
40    }
41}
42
43pub trait WithRights {
44    /// Returns a router that ensures the capability request does not request
45    /// greater rights than provided at this stage of the route.
46    fn with_rights(self, moniker: impl Into<ExtendedMoniker>, rights: Rights) -> Self;
47}
48
49impl<T: CapabilityBound> WithRights for Router<T> {
50    fn with_rights(self, moniker: impl Into<ExtendedMoniker>, rights: Rights) -> Self {
51        Router::<T>::new(RightsRouter { rights, router: self, moniker: moniker.into() })
52    }
53}
54
55#[cfg(test)]
56mod tests {
57    use super::*;
58    use assert_matches::assert_matches;
59    use fidl_fuchsia_io as fio;
60    use router_error::{DowncastErrorForTest, RouterError};
61    use sandbox::{Data, Dict, WeakInstanceToken};
62    use std::sync::Arc;
63
64    #[derive(Debug)]
65    struct FakeComponentToken {}
66
67    impl FakeComponentToken {
68        fn new() -> WeakInstanceToken {
69            WeakInstanceToken { inner: Arc::new(FakeComponentToken {}) }
70        }
71    }
72
73    impl sandbox::WeakInstanceTokenAny for FakeComponentToken {
74        fn as_any(&self) -> &dyn std::any::Any {
75            self
76        }
77    }
78
79    #[fuchsia::test]
80    async fn rights_good() {
81        let source = Data::String("hello".to_string());
82        let base = Router::<Data>::new_ok(source);
83        let proxy = base.with_rights(ExtendedMoniker::ComponentManager, fio::RW_STAR_DIR.into());
84        let metadata = Dict::new();
85        metadata.set_metadata(Into::<Rights>::into(fio::R_STAR_DIR));
86        let capability = proxy
87            .route(Some(Request { target: FakeComponentToken::new(), metadata }), false)
88            .await
89            .unwrap();
90        let capability = match capability {
91            RouterResponse::<Data>::Capability(d) => d,
92            c => panic!("Bad enum {:#?}", c),
93        };
94        assert_eq!(capability, Data::String("hello".to_string()));
95    }
96
97    #[fuchsia::test]
98    async fn rights_bad() {
99        let source = Data::String("hello".to_string());
100        let base = Router::<Data>::new_ok(source);
101        let proxy = base.with_rights(ExtendedMoniker::ComponentManager, fio::R_STAR_DIR.into());
102        let metadata = Dict::new();
103        metadata.set_metadata(Into::<Rights>::into(fio::RW_STAR_DIR));
104        let error = proxy
105            .route(Some(Request { target: FakeComponentToken::new(), metadata }), false)
106            .await
107            .unwrap_err();
108        assert_matches!(
109            error,
110            RouterError::NotFound(err)
111            if matches!(
112                err.downcast_for_test::<RoutingError>(),
113                RoutingError::RightsRoutingError(
114                    crate::error::RightsRoutingError::Invalid { moniker: ExtendedMoniker::ComponentManager, requested, provided }
115                ) if *requested == <fio::Operations as Into<Rights>>::into(fio::RW_STAR_DIR) && *provided == <fio::Operations as Into<Rights>>::into(fio::R_STAR_DIR)
116            )
117        );
118    }
119}
routing/bedrock/with_rights.rs

routing/bedrock/
with_rights.rs
