cratestack_axum/headers/
verified_signer.rs

1//! Carrying the envelope's verified signer from the request extensions into
2//! the handler's `CratestackContext` (maintainer decision D2 on
3//! cratestack#1006).
4//!
5//! The envelope layer runs before any context exists, so it can only leave
6//! the fact on the request, as a `cratestack_core::VerifiedSigner`
7//! extension. Generated handlers build their context from the
8//! `AuthProvider`'s answer and then call [`enrich_context_from_envelope`],
9//! next to [`super::enrich_context_from_headers`]. A separate function, not a
10//! new parameter on that one, so its public signature does not change.
11//!
12//! This is a recorded fact, **not an authentication**:
13//! `CratestackContext::record_verified_signer` leaves `is_authenticated()`
14//! and the principal alone. Who the caller is stays the `AuthProvider`'s
15//! call (the signer-to-principal adapter is cratestack#1077). The helper is
16//! compiled with or without the `cose` feature, so generated code does not
17//! depend on it; without the layer nothing ever inserts the extension and
18//! this is a no-op.
19
20use cratestack_core::{CratestackContext, VerifiedSigner};
21
22/// Record the `VerifiedSigner` the envelope layer left in `extensions`, if
23/// any, on `ctx`. `extensions` is the request's (generated handlers pass
24/// `ClientIpContext::extensions`, a clone of them).
25///
26/// Extensions are in-process only, so nothing on the wire can put one
27/// there: a signer is present only when an in-process layer (the envelope
28/// layer, or one the application trusts as much) inserted it.
29pub fn enrich_context_from_envelope(
30    mut ctx: CratestackContext,
31    extensions: &http::Extensions,
32) -> CratestackContext {
33    if let Some(signer) = extensions.get::<VerifiedSigner>() {
34        ctx.record_verified_signer(signer.clone());
35    }
36    ctx
37}
38
39#[cfg(test)]
40mod tests {
41    use cratestack_core::{CratestackContext, VerifiedSigner};
42
43    use super::enrich_context_from_envelope;
44
45    #[test]
46    fn a_signer_in_the_extensions_is_recorded_but_does_not_authenticate() {
47        let mut extensions = http::Extensions::new();
48        extensions.insert(VerifiedSigner::new(vec![1; 8], [7; 32], -19));
49        let ctx = enrich_context_from_envelope(CratestackContext::anonymous(), &extensions);
50        let signer = ctx.verified_signer().expect("recorded");
51        assert_eq!(signer.thumbprint(), &[7; 32]);
52        assert!(!ctx.is_authenticated());
53    }
54
55    #[test]
56    fn without_one_the_context_is_unchanged() {
57        let ctx =
58            enrich_context_from_envelope(CratestackContext::anonymous(), &http::Extensions::new());
59        assert!(ctx.verified_signer().is_none());
60    }
61}
cratestack_axum/headers/verified_signer.rs

cratestack_axum/headers/
verified_signer.rs
