ic_auth/
portable.rs

1//! Canonical portable credential claims and explicit protected-context checks.
2//! Encoding, decoding and hashing alone do not verify time or authority.
3//! Context checks do not verify signatures, enrollment provenance or revocation.
4//! No value returned by this module is sufficient for session admission.
5
6#[cfg(any(
7    feature = "sessions",
8    feature = "portable-signature-verification",
9    feature = "token-verification"
10))]
11mod decoded;
12mod revocation;
13mod rules;
14mod verified;
15#[cfg(any(
16    feature = "sessions",
17    feature = "portable-signature-verification",
18    feature = "token-verification"
19))]
20pub use decoded::DecodedPortableClaims;
21pub use revocation::{LoginRevocationChange, LoginRevocationError, MemoryLoginRevocations};
22pub use rules::{PortableClaimsContext, PortableClaimsError, validate_claims_context};
23pub use verified::VerifiedPortableClaims;
24
25use crate::canonical::{CanonicalAuthError, encode_principal, encode_role_grants};
26use crate::certificate_issuance::{GrantValidationError, validate_grants};
27use ic_auth_protocol_types::{
28    AudienceId, CanonicalId, DelegatedRoleGrant, PortableClaims, PortableMechanism, Principal,
29};
30use sha2::{Digest, Sha256};
31use thiserror::Error;
32
33const DOMAIN: &[u8] = b"IC-AUTH-PORTABLE-CREDENTIAL\0";
34const SCHEMA: u16 = 1;
35const MAX_GRANTS: usize = 16;
36const MAX_SCOPES: usize = 32;
37const MAX_LABEL_BYTES: usize = 64;
38
39/// Hard cap on the signed claims blob, independent of outer transport limits.
40pub const MAX_CLAIMS_BYTES: usize = 65_536;
41
42/// Structural codec errors, never proof-verification outcomes.
43#[derive(Debug, Error, PartialEq, Eq)]
44pub enum PortableEncodingError {
45    #[error("portable claims exceed their byte bound")]
46    TooLarge,
47    #[error("truncated portable claims")]
48    Truncated,
49    #[error("wrong portable domain, schema or mechanism")]
50    WrongDomain,
51    #[error("portable claims contain trailing bytes")]
52    TrailingBytes,
53    #[error("invalid portable principal, label or count")]
54    InvalidShape,
55    #[error("anonymous account subject")]
56    AnonymousSubject,
57    #[error(transparent)]
58    Grants(#[from] GrantValidationError),
59    #[error(transparent)]
60    Canonical(#[from] CanonicalAuthError),
61}
62
63/// Encode exactly the frozen 0.6 claims domain. Never sort or normalize input.
64/// Time relationships and protected authority are verification responsibilities.
65pub fn encode_claims(claims: &PortableClaims) -> Result<Vec<u8>, PortableEncodingError> {
66    validate_shape(claims)?;
67    // Validated grant/count/label bounds limit allocation even before the final
68    // whole-blob check. No unbounded extension or caller-selected capacity.
69    let mut out = Vec::new();
70    out.extend_from_slice(DOMAIN);
71    out.extend_from_slice(&SCHEMA.to_be_bytes());
72    out.push(match claims.mechanism {
73        PortableMechanism::Certified => 0,
74        PortableMechanism::Ed25519 => 1,
75    });
76    out.extend_from_slice(claims.audience.canonical_network_id.as_bytes());
77    out.extend_from_slice(claims.audience.fleet_id.as_bytes());
78    encode_principal(&mut out, claims.issuer)?;
79    out.extend_from_slice(&claims.key_binding_id);
80    out.extend_from_slice(&claims.browser_public_key);
81    encode_principal(&mut out, claims.account_subject)?;
82    for time in [
83        claims.login_started_at_ns,
84        claims.login_deadline_ns,
85        claims.issued_at_ns,
86        claims.admission_expires_at_ns,
87    ] {
88        out.extend_from_slice(&time.to_be_bytes());
89    }
90    out.extend_from_slice(&claims.nonce);
91    encode_role_grants(&mut out, &claims.grants)?;
92    if out.len() > MAX_CLAIMS_BYTES {
93        return Err(PortableEncodingError::TooLarge);
94    }
95    Ok(out)
96}
97
98/// Decode bounded canonical claims. Lengths/counts are admitted before allocation;
99/// unknown schema/mechanism, trailing bytes and noncanonical grants are rejected.
100/// This is deliberately not a deserializer for the previous token domain.
101pub fn decode_claims(bytes: &[u8]) -> Result<PortableClaims, PortableEncodingError> {
102    if bytes.len() > MAX_CLAIMS_BYTES {
103        return Err(PortableEncodingError::TooLarge);
104    }
105    let mut input = Reader(bytes);
106    if input.take(DOMAIN.len())? != DOMAIN || input.array::<2>()? != SCHEMA.to_be_bytes() {
107        return Err(PortableEncodingError::WrongDomain);
108    }
109    let mechanism = match input.array::<1>()? {
110        [0] => PortableMechanism::Certified,
111        [1] => PortableMechanism::Ed25519,
112        _ => return Err(PortableEncodingError::WrongDomain),
113    };
114    let audience = AudienceId {
115        canonical_network_id: CanonicalId::from_bytes(input.array()?),
116        fleet_id: CanonicalId::from_bytes(input.array()?),
117    };
118    let issuer = input.principal()?;
119    let key_binding_id = input.array()?;
120    let browser_public_key = input.array()?;
121    let account_subject = input.principal()?;
122    let login_started_at_ns = u64::from_be_bytes(input.array()?);
123    let login_deadline_ns = u64::from_be_bytes(input.array()?);
124    let issued_at_ns = u64::from_be_bytes(input.array()?);
125    let admission_expires_at_ns = u64::from_be_bytes(input.array()?);
126    let nonce = input.array()?;
127    let count = input.count(MAX_GRANTS)?;
128    let mut grants = Vec::with_capacity(count);
129    for _ in 0..count {
130        let target = input
131            .label()?
132            .parse()
133            .map_err(|_| PortableEncodingError::InvalidShape)?;
134        let count = input.count(MAX_SCOPES)?;
135        let mut scopes = Vec::with_capacity(count);
136        for _ in 0..count {
137            scopes.push(input.label()?.to_owned());
138        }
139        grants.push(DelegatedRoleGrant { target, scopes });
140    }
141    if !input.0.is_empty() {
142        return Err(PortableEncodingError::TrailingBytes);
143    }
144    let claims = PortableClaims {
145        mechanism,
146        audience,
147        issuer,
148        key_binding_id,
149        browser_public_key,
150        account_subject,
151        login_started_at_ns,
152        login_deadline_ns,
153        issued_at_ns,
154        admission_expires_at_ns,
155        nonce,
156        grants,
157    };
158    validate_shape(&claims)?;
159    Ok(claims)
160}
161
162/// SHA-256 of the exact canonical signed blob, for signing and replay identity.
163/// The digest authenticates nothing by itself; signature bytes are not included.
164pub fn claims_hash(claims: &PortableClaims) -> Result<[u8; 32], PortableEncodingError> {
165    Ok(Sha256::digest(encode_claims(claims)?).into())
166}
167
168/// Derive the IC sender for a directly authenticated Ed25519 browser key.
169/// Hosts must compare this with the actual ingress caller, not a client field.
170/// This does not validate curve membership or possession of the key.
171pub fn browser_principal(public_key: &[u8; 32]) -> Principal {
172    // RFC 8410 Ed25519 SubjectPublicKeyInfo: SEQUENCE(algorithm OID, BIT STRING).
173    let mut der = [0; 44];
174    der[..12].copy_from_slice(&[
175        0x30, 0x2a, 0x30, 0x05, 0x06, 0x03, 0x2b, 0x65, 0x70, 0x03, 0x21, 0,
176    ]);
177    der[12..].copy_from_slice(public_key);
178    Principal::self_authenticating(der)
179}
180
181fn validate_shape(claims: &PortableClaims) -> Result<(), PortableEncodingError> {
182    if claims.account_subject == Principal::anonymous() {
183        return Err(PortableEncodingError::AnonymousSubject);
184    }
185    validate_grants(&claims.grants, MAX_GRANTS, MAX_SCOPES)?;
186    if claims
187        .grants
188        .iter()
189        .any(|grant| grant.target.as_str().len() > MAX_LABEL_BYTES)
190    {
191        return Err(PortableEncodingError::InvalidShape);
192    }
193    Ok(())
194}
195
196struct Reader<'a>(&'a [u8]);
197
198impl<'a> Reader<'a> {
199    fn take(&mut self, len: usize) -> Result<&'a [u8], PortableEncodingError> {
200        let (head, tail) = self
201            .0
202            .split_at_checked(len)
203            .ok_or(PortableEncodingError::Truncated)?;
204        self.0 = tail;
205        Ok(head)
206    }
207
208    fn array<const N: usize>(&mut self) -> Result<[u8; N], PortableEncodingError> {
209        self.take(N)?
210            .try_into()
211            .map_err(|_| PortableEncodingError::Truncated)
212    }
213
214    fn length(&mut self, max: usize) -> Result<usize, PortableEncodingError> {
215        let len = u32::from_be_bytes(self.array()?);
216        let len = usize::try_from(len).map_err(|_| PortableEncodingError::InvalidShape)?;
217        if len > max {
218            return Err(PortableEncodingError::InvalidShape);
219        }
220        Ok(len)
221    }
222
223    fn count(&mut self, max: usize) -> Result<usize, PortableEncodingError> {
224        let count = self.length(max)?;
225        if count == 0 {
226            return Err(PortableEncodingError::InvalidShape);
227        }
228        Ok(count)
229    }
230
231    fn principal(&mut self) -> Result<Principal, PortableEncodingError> {
232        let len = self.length(29)?;
233        Ok(Principal::from_slice(self.take(len)?))
234    }
235
236    fn label(&mut self) -> Result<&'a str, PortableEncodingError> {
237        let len = self.count(MAX_LABEL_BYTES)?;
238        std::str::from_utf8(self.take(len)?).map_err(|_| PortableEncodingError::InvalidShape)
239    }
240}
ic_auth/portable.rs

ic_auth/
portable.rs
