ic-auth 0.20.0

Portable authentication, delegation proof verification and local session machinery
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160

//! One typed credential boundary over the complete portable proof verifiers.
//! The host selects enrollment independently of the submitted proof variant.

use crate::{admission_budget::SessionAdmissionBudget, portable::VerifiedPortableClaims};
use ic_auth_protocol_types::{PortableCredential, PortableProof};
use thiserror::Error;

/// Protected enrolled verifier selection. Only compiled capabilities can be
/// selected; the request cannot choose a key or enable a different mechanism.
pub enum PortableVerificationContext<'a> {
    #[cfg(feature = "portable-signature-verification")]
    Ed25519 {
        claims: &'a crate::portable::PortableClaimsContext<'a>,
        public_key: &'a [u8; 32],
    },
    #[cfg(feature = "certified-proof-verification")]
    Certified(&'a crate::portable_certified::PortableCertifiedContext<'a>),
}
impl<'ctx> PortableVerificationContext<'ctx> {
    /// The exact protected claims context used by the selected complete verifier.
    #[cfg(feature = "sessions")]
    pub(crate) fn claims(&self) -> &crate::portable::PortableClaimsContext<'ctx> {
        match self {
            #[cfg(feature = "portable-signature-verification")]
            Self::Ed25519 { claims, .. } => claims,
            #[cfg(feature = "certified-proof-verification")]
            Self::Certified(context) => &context.claims,
        }
    }
}

/// A transport or complete proof refusal, never session authorization.
#[derive(Debug, Error, Eq, PartialEq)]
pub enum PortableCredentialError {
    #[error("credential proof does not match the protected enrolled mechanism")]
    MechanismMismatch,
    #[cfg(feature = "portable-signature-verification")]
    #[error(transparent)]
    Ed25519(#[from] crate::portable_signature::PortableSignatureError),
    #[cfg(feature = "certified-proof-verification")]
    #[error(transparent)]
    Certified(#[from] crate::portable_certified::PortableCertifiedError),
}

/// Verify the envelope using the host-selected mechanism and the retained shared
/// budget. Mismatched variants fail before cryptography or budget consumption.
/// Claims, proof bounds, time and key checks remain owned by the complete verifier.
/// Outer transport decoding needs a host allocation/instruction limit separately.
/// Session admission owns verification and reuses its canonical decode. This
/// entry point independently decodes a standalone credential.
pub fn verify_credential(
    budget: &mut SessionAdmissionBudget,
    credential: &PortableCredential,
    context: &PortableVerificationContext<'_>,
) -> Result<VerifiedPortableClaims, PortableCredentialError> {
    match (context, &credential.proof) {
        #[cfg(feature = "portable-signature-verification")]
        (
            PortableVerificationContext::Ed25519 { claims, public_key },
            PortableProof::Ed25519 { signature },
        ) => Ok(crate::portable_signature::verify_ed25519_claims(
            budget,
            &credential.claims,
            signature,
            claims,
            public_key,
        )?),
        #[cfg(feature = "certified-proof-verification")]
        (
            PortableVerificationContext::Certified(context),
            PortableProof::Certified {
                delegation,
                issuer_signature,
            },
        ) => Ok(crate::portable_certified::verify_certified_claims(
            budget,
            &credential.claims,
            delegation,
            issuer_signature,
            context,
        )?),
        _ => Err(PortableCredentialError::MechanismMismatch),
    }
}

/// Prepared only inside one serialized engine call. The factory binds the
/// checked claims to the exact verifier selection used after cheap store checks.
#[cfg(feature = "sessions")]
pub(crate) struct PreparedCredential<'a, 'ctx> {
    claims: crate::portable::ContextualClaims<'a, 'ctx>,
    verification: &'a PortableVerificationContext<'ctx>,
    #[cfg(feature = "certified-proof-verification")]
    encoded_len: usize,
}

#[cfg(feature = "sessions")]
impl<'ctx> PortableVerificationContext<'ctx> {
    pub(crate) fn prepare<'a>(
        &'a self,
        decoded: crate::portable::DecodedPortableClaims,
    ) -> Result<PreparedCredential<'a, 'ctx>, crate::portable::PortableClaimsError> {
        #[cfg(feature = "certified-proof-verification")]
        let encoded_len = decoded.encoded_len;
        Ok(PreparedCredential {
            claims: decoded.validate_context(self.claims())?,
            verification: self,
            #[cfg(feature = "certified-proof-verification")]
            encoded_len,
        })
    }
}

#[cfg(feature = "sessions")]
impl PreparedCredential<'_, '_> {
    pub(crate) fn decoded(&self) -> &crate::portable::DecodedPortableClaims {
        self.claims.decoded()
    }

    pub(crate) fn verify(
        self,
        budget: &mut SessionAdmissionBudget,
        proof: &PortableProof,
    ) -> Result<VerifiedPortableClaims, PortableCredentialError> {
        match (self.verification, proof) {
            #[cfg(feature = "portable-signature-verification")]
            (
                PortableVerificationContext::Ed25519 { public_key, .. },
                PortableProof::Ed25519 { signature },
            ) => Ok(crate::portable_signature::verify_prepared(
                budget,
                self.claims,
                signature,
                public_key,
            )?),
            #[cfg(feature = "certified-proof-verification")]
            (
                PortableVerificationContext::Certified(context),
                PortableProof::Certified {
                    delegation,
                    issuer_signature,
                },
            ) => {
                crate::portable_certified::check_bounds(
                    self.encoded_len,
                    delegation,
                    issuer_signature,
                    context,
                )?;
                Ok(crate::portable_certified::verify_prepared(
                    budget,
                    self.claims,
                    delegation,
                    issuer_signature,
                    context,
                )?)
            }
            _ => Err(PortableCredentialError::MechanismMismatch),
        }
    }
}