policy.rs 95.2%

418 of 439 lines run, 75 of 95 functions · run #356 on main · run missed

//! The trust policy (spec §14.5): who may update which references, signed
//! by a threshold of root keys. A repository without a policy is unverified.
//!
//! Encoding: `{0: version, 1: repo, 2: serial, 3: {0: root keys, 1: threshold},
//! 4: [rule], 5: [identity bytes], 6: [revoked], 7: expires}`; a rule is
//! `{0: pattern, 1: keys, 2: threshold, 3: require, 4: allow_conflicts}` with
//! `require` 0 = signed, 1 = sealed, 2 = any.

use crate::cbor::{self, Value};
use crate::hash::{hash_object, KeyId, ObjectRef, ObjectType};
use crate::identity::{self, Domain, Identity, Signature};
use crate::objects::{
    array, bytes, check_version, field, map, oref, text, uint, ObjectError, FORMAT_VERSION,
};
use std::collections::BTreeMap;

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum Require {
    Signed,
    Sealed,
    Any,
}

impl Require {
    fn tag(self) -> u64 {
        match self {
            Require::Signed => 0,
            Require::Sealed => 1,
            Require::Any => 2,
        }
    }
    fn from_tag(t: u64) -> Result<Require, ObjectError> {
        Ok(match t {
            0 => Require::Signed,
            1 => Require::Sealed,
            2 => Require::Any,
            _ => return Err(ObjectError::Schema(format!("unknown require {t}"))),
        })
    }
    pub fn name(self) -> &'static str {
        match self {
            Require::Signed => "signed",
            Require::Sealed => "sealed",
            Require::Any => "any",
        }
    }
}

#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Rule {
    /// Glob over reference names; `*` matches any run of characters.
    pub pattern: String,
    pub keys: Vec<KeyId>,
    pub threshold: u32,
    pub require: Require,
    pub allow_conflicts: bool,
    /// Who else may sign, by what an issuer certified (§14.7): a short-lived
    /// key whose certificate is the issuer's, for a subject the pattern
    /// matches, counts as one signer within the scope given.
    pub subjects: Vec<SubjectGrant>,
}

/// A rule's grant to the holders of certificates an issuer gives (§14.7):
/// `repo:andy/demo:bookmark:main`, `agent:claude@andy`, with `*` as in
/// reference patterns.
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct SubjectGrant {
    pub pattern: String,
    pub issuer: KeyId,
    pub scope: identity::Scope,
}

impl SubjectGrant {
    fn to_value(&self) -> Value {
        Value::map([
            (0, Value::Text(self.pattern.clone())),
            (1, Value::Bytes(self.issuer.0.to_vec())),
            (
                2,
                Value::Array(
                    self.scope
                        .names()
                        .into_iter()
                        .map(|n| Value::Text(n.to_string()))
                        .collect(),
                ),
            ),
        ])
    }

    fn from_value(v: &Value) -> Result<SubjectGrant, ObjectError> {
        let m = map(v, "subject")?;
        let mut scope = identity::Scope::NONE;
        for n in array(field(m, 2, "subject scope")?, "subject scope")? {
            let n = text(n, "subject scope")?;
            scope = scope
                | identity::Scope::named(n)
                    .ok_or_else(|| ObjectError::Schema(format!("subject: unknown scope {n:?}")))?;
        }
        Ok(SubjectGrant {
            pattern: text(field(m, 0, "subject pattern")?, "subject pattern")?.to_owned(),
            issuer: oref(field(m, 1, "subject issuer")?, "subject issuer")?,
            scope,
        })
    }
}

#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Policy {
    pub repo: [u8; 16],
    pub serial: u64,
    pub roots: Vec<KeyId>,
    pub root_threshold: u32,
    pub rules: Vec<Rule>,
    /// Embedded so verification needs no fetch.
    pub identities: Vec<Identity>,
    pub revoked: Vec<KeyId>,
    pub expires: u64,
}

/// `*` matches any run of characters (including `/`); everything else is literal.
pub fn glob_matches(pattern: &str, name: &str) -> bool {
    fn rec(p: &[u8], n: &[u8]) -> bool {
        match p.first() {
            None => n.is_empty(),
            Some(b'*') => (0..=n.len()).any(|i| rec(&p[1..], &n[i..])),
            Some(c) => n.first() == Some(c) && rec(&p[1..], &n[1..]),
        }
    }
    rec(pattern.as_bytes(), name.as_bytes())
}

impl Policy {
    fn keys_value(keys: &[KeyId]) -> Value {
        Value::Array(keys.iter().map(|k| Value::Bytes(k.0.to_vec())).collect())
    }
    fn keys_from(v: &Value, what: &str) -> Result<Vec<KeyId>, ObjectError> {
        let mut ks = array(v, what)?
            .iter()
            .map(|k| oref(k, what))
            .collect::<Result<Vec<_>, _>>()?;
        ks.sort();
        ks.dedup();
        Ok(ks)
    }

    pub fn to_value(&self) -> Value {
        Value::map([
            (0, Value::Uint(FORMAT_VERSION)),
            (1, Value::Bytes(self.repo.to_vec())),
            (2, Value::Uint(self.serial)),
            (
                3,
                Value::map([
                    (0, Self::keys_value(&self.roots)),
                    (1, Value::Uint(self.root_threshold as u64)),
                ]),
            ),
            (
                4,
                Value::Array(
                    self.rules
                        .iter()
                        .map(|r| {
                            let mut v = Value::map([
                                (0, Value::Text(r.pattern.clone())),
                                (1, Self::keys_value(&r.keys)),
                                (2, Value::Uint(r.threshold as u64)),
                                (3, Value::Uint(r.require.tag())),
                                (4, Value::Bool(r.allow_conflicts)),
                            ]);
                            // Only when there are any, so a policy without
                            // them encodes, and hashes, as before.
                            if !r.subjects.is_empty() {
                                if let Value::Map(m) = &mut v {
                                    m.insert(
                                        5,
                                        Value::Array(
                                            r.subjects.iter().map(SubjectGrant::to_value).collect(),
                                        ),
                                    );
                                }
                            }
                            v
                        })
                        .collect(),
                ),
            ),
            (
                5,
                Value::Array(
                    self.identities
                        .iter()
                        .map(|i| Value::Bytes(i.encode()))
                        .collect(),
                ),
            ),
            (6, Self::keys_value(&self.revoked)),
            (7, Value::Uint(self.expires)),
        ])
    }

    pub fn encode(&self) -> Vec<u8> {
        cbor::encode(&self.to_value())
    }

    pub fn hash(&self) -> ObjectRef {
        hash_object(ObjectType::Policy, &self.encode())
    }

    pub fn decode(b: &[u8]) -> Result<Policy, ObjectError> {
        let v = cbor::decode(b)?;
        let m = map(&v, "policy")?;
        check_version(m)?;
        let roots = map(field(m, 3, "roots")?, "roots")?;
        let mut rules = Vec::new();
        for r in array(field(m, 4, "rules")?, "rules")? {
            let rm = map(r, "rule")?;
            rules.push(Rule {
                pattern: text(field(rm, 0, "pattern")?, "pattern")?.to_owned(),
                keys: Self::keys_from(field(rm, 1, "rule keys")?, "rule keys")?,
                threshold: uint(field(rm, 2, "threshold")?, "threshold")? as u32,
                require: Require::from_tag(uint(field(rm, 3, "require")?, "require")?)?,
                allow_conflicts: field(rm, 4, "allow_conflicts")?
                    .as_bool()
                    .ok_or_else(|| ObjectError::Schema("allow_conflicts: expected bool".into()))?,
                subjects: match rm.get(&5) {
                    None => vec![],
                    Some(v) => array(v, "subjects")?
                        .iter()
                        .map(SubjectGrant::from_value)
                        .collect::<Result<_, _>>()?,
                },
            });
        }
        let identities = array(field(m, 5, "identities")?, "identities")?
            .iter()
            .map(|i| Identity::decode(bytes(i, "identity")?))
            .collect::<Result<Vec<_>, _>>()?;
        let p = Policy {
            repo: bytes(field(m, 1, "repo")?, "repo")?
                .try_into()
                .map_err(|_| ObjectError::Schema("repo: expected 16 bytes".into()))?,
            serial: uint(field(m, 2, "serial")?, "serial")?,
            roots: Self::keys_from(field(roots, 0, "root keys")?, "root keys")?,
            root_threshold: uint(field(roots, 1, "root threshold")?, "root threshold")? as u32,
            rules,
            identities,
            revoked: Self::keys_from(field(m, 6, "revoked")?, "revoked")?,
            expires: uint(field(m, 7, "expires")?, "expires")?,
        };
        if p.root_threshold == 0 || p.root_threshold as usize > p.roots.len() {
            return Err(ObjectError::Schema(
                "root threshold must be between 1 and the number of root keys".into(),
            ));
        }
        for r in &p.rules {
            if r.threshold == 0 || r.threshold as usize > r.keys.len() + r.subjects.len() {
                return Err(ObjectError::Schema(format!(
                    "rule {:?}: threshold must be between 1 and the number of keys and subjects",
                    r.pattern
                )));
            }
        }
        Ok(p)
    }

    pub fn identity(&self, key: &KeyId) -> Option<&Identity> {
        self.identities.iter().find(|i| i.hash() == *key)
    }

    pub fn is_revoked(&self, key: &KeyId) -> bool {
        self.revoked.contains(key)
    }

    pub fn is_expired(&self, now_ms: u64) -> bool {
        now_ms > self.expires
    }

    /// The first rule whose pattern matches `reference`.
    pub fn rule_for(&self, reference: &str) -> Option<&Rule> {
        self.rules
            .iter()
            .find(|r| glob_matches(&r.pattern, reference))
    }

    /// Whether the rule for `reference` lets a certificate from `issuer`
    /// for `subject` sign within `scope` (§14.7). The certificate itself,
    /// and the time it is checked at, are the caller's to verify.
    pub fn subject_grant(
        &self,
        reference: &str,
        issuer: &KeyId,
        subject: &str,
        scope: identity::Scope,
    ) -> bool {
        !self.is_revoked(issuer)
            && self.rule_for(reference).is_some_and(|r| {
                r.subjects.iter().any(|g| {
                    g.issuer == *issuer && g.scope.has(scope) && glob_matches(&g.pattern, subject)
                })
            })
    }

    /// Whether `key` may update `reference`: listed in the matching rule and not revoked.
    pub fn authorizes(&self, key: &KeyId, reference: &str) -> bool {
        !self.is_revoked(key)
            && self
                .rule_for(reference)
                .is_some_and(|r| r.keys.contains(key))
    }

    /// Verify that `sigs` over this policy's hash meet `trusted`'s root
    /// threshold (`trusted` is the previous policy, or this one when
    /// bootstrapping). Returns the signing root keys.
    pub fn verify_signatures(
        &self,
        sigs: &[Signature],
        trusted: &Policy,
    ) -> Result<Vec<KeyId>, String> {
        let target = self.hash();
        let mut signers = Vec::new();
        for sig in sigs {
            if !trusted.roots.contains(&sig.key) || trusted.is_revoked(&sig.key) {
                continue;
            }
            let Some(id) = trusted
                .identity(&sig.key)
                .or_else(|| self.identity(&sig.key))
            else {
                continue;
            };
            if identity::verify(id, sig, Domain::Policy, &target).is_ok()
                && !signers.contains(&sig.key)
            {
                signers.push(sig.key);
            }
        }
        if (signers.len() as u32) < trusted.root_threshold {
            return Err(format!(
                "policy needs {} root signature(s), has {}",
                trusted.root_threshold,
                signers.len()
            ));
        }
        Ok(signers)
    }

    /// Bootstrap check for the first policy a repository sees (trust on
    /// first use): at least one valid signature by one of its own roots.
    /// The full threshold applies only to updates from a trusted policy,
    /// whose signers are the previous roots and need not be the new ones.
    pub fn verify_bootstrap(&self, sigs: &[Signature]) -> Result<KeyId, String> {
        let target = self.hash();
        for sig in sigs {
            if !self.roots.contains(&sig.key) || self.is_revoked(&sig.key) {
                continue;
            }
            if let Some(id) = self.identity(&sig.key) {
                if identity::verify(id, sig, Domain::Policy, &target).is_ok() {
                    return Ok(sig.key);
                }
            }
        }
        Err("policy carries no valid signature by one of its own root keys".into())
    }

    /// A single-root policy letting `root` do everything on every reference.
    pub fn single_root(repo: [u8; 16], root: Identity, expires: u64) -> Policy {
        let key = root.hash();
        Policy {
            repo,
            serial: 1,
            roots: vec![key],
            root_threshold: 1,
            rules: vec![Rule {
                pattern: "*".into(),
                keys: vec![key],
                threshold: 1,
                require: Require::Any,
                allow_conflicts: true,
                subjects: vec![],
            }],
            identities: vec![root],
            revoked: vec![],
            expires,
        }
    }

    /// Whether `key` appears anywhere in the policy (roots, rules, identities).
    pub fn mentions(&self, key: &KeyId) -> bool {
        self.roots.contains(key)
            || self.rules.iter().any(|r| r.keys.contains(key))
            || self.identity(key).is_some()
    }

    /// Whether `key` is `rule_key` or one of its predecessors in the
    /// rotation chain (`previous` links, spec §14.2), so that changes signed
    /// before a rotation remain authorized. Revoked keys never qualify.
    pub fn succeeds(&self, rule_key: &KeyId, key: &KeyId) -> bool {
        if self.is_revoked(key) {
            return false;
        }
        let mut cur = Some(*rule_key);
        for _ in 0..32 {
            match cur {
                Some(k) if k == *key => return true,
                Some(k) => cur = self.identity(&k).and_then(|i| i.previous),
                None => return false,
            }
        }
        false
    }

    /// Replace `old` by `new` in the roots and every rule and embed `new`'s
    /// identity (a rotation, spec §14.2). The old identity stays embedded so
    /// signatures made before the rotation still verify; it is superseded,
    /// not revoked.
    pub fn substitute_key(&mut self, old: &KeyId, new: Identity) {
        let nk = new.hash();
        for k in self
            .roots
            .iter_mut()
            .chain(self.rules.iter_mut().flat_map(|r| r.keys.iter_mut()))
        {
            if k == old {
                *k = nk;
            }
        }
        for r in &mut self.rules {
            r.keys.sort();
            r.keys.dedup();
        }
        self.roots.sort();
        self.roots.dedup();
        if self.identity(&nk).is_none() {
            self.identities.push(new);
        }
    }

    /// Identities keyed by KeyId.
    pub fn identity_map(&self) -> BTreeMap<KeyId, &Identity> {
        self.identities.iter().map(|i| (i.hash(), i)).collect()
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::identity::SecretKey;

    fn sk(n: u8) -> SecretKey {
        SecretKey {
            ed_seed: [n; 32],
            ml_seed: [n + 100; 32],
        }
    }

    #[test]
    fn globs() {
        assert!(glob_matches("*", "main"));
        assert!(glob_matches("release/*", "release/1.0"));
        assert!(!glob_matches("release/*", "main"));
        assert!(glob_matches("main", "main"));
        assert!(!glob_matches("main", "main2"));
        assert!(glob_matches("*-rc*", "1.0-rc2"));
        assert!(glob_matches("", ""));
    }

    /// Subjects an issuer certifies (oxygenhub#241): kept through
    /// encoding, absent from a policy without them, and granted only for
    /// their issuer, pattern and scope, and not when the issuer is revoked.
    #[test]
    fn a_rule_grants_certified_subjects() {
        use crate::identity::Scope;
        let root = sk(1).identity("Root", "r@x", 0);
        let hub = sk(3).identity("Hub", "h@x", 0);
        let mut p = Policy::single_root([9; 16], root.clone(), 10);
        let plain = p.encode();
        p.rules[0].subjects.push(SubjectGrant {
            pattern: "repo:andy/demo:bookmark:main".into(),
            issuer: hub.hash(),
            scope: Scope::REFS | Scope::CHANGES,
        });
        p.rules[0].subjects.push(SubjectGrant {
            pattern: "agent:*@andy".into(),
            issuer: hub.hash(),
            scope: Scope::CHANGES,
        });
        let back = Policy::decode(&p.encode()).unwrap();
        assert_eq!(back, p);
        let mut again = back.clone();
        again.rules[0].subjects.clear();
        assert_eq!(
            again.encode(),
            plain,
            "no subjects, the same bytes as before"
        );

        let main = "repo:andy/demo:bookmark:main";
        assert!(p.subject_grant("main", &hub.hash(), main, Scope::REFS));
        assert!(p.subject_grant("main", &hub.hash(), "agent:claude@andy", Scope::CHANGES));
        assert!(
            !p.subject_grant("main", &hub.hash(), "agent:claude@andy", Scope::REFS),
            "not its scope"
        );
        assert!(
            !p.subject_grant(
                "main",
                &hub.hash(),
                "repo:andy/demo:bookmark:dev",
                Scope::REFS
            ),
            "not its pattern"
        );
        assert!(
            !p.subject_grant("main", &root.hash(), main, Scope::REFS),
            "not its issuer"
        );
        p.revoked.push(hub.hash());
        assert!(
            !p.subject_grant("main", &hub.hash(), main, Scope::REFS),
            "a revoked issuer grants nothing"
        );

        // A rule of subjects alone is a rule.
        let mut only = Policy::single_root([9; 16], root, 10);
        only.rules[0].keys.clear();
        only.rules[0].subjects.push(SubjectGrant {
            pattern: "*".into(),
            issuer: hub.hash(),
            scope: Scope::REFS,
        });
        assert!(Policy::decode(&only.encode()).is_ok());
        only.rules[0].subjects.clear();
        assert!(Policy::decode(&only.encode()).is_err(), "nobody to sign");
    }

    #[test]
    fn round_trip_and_rules() {
        let root = sk(1).identity("Root", "r@x", 0);
        let dev = sk(2).identity("Dev", "d@x", 0);
        let mut p = Policy::single_root([9; 16], root.clone(), 10);
        p.rules.insert(
            0,
            Rule {
                pattern: "release/*".into(),
                keys: vec![root.hash()],
                threshold: 1,
                require: Require::Signed,
                allow_conflicts: false,
                subjects: vec![],
            },
        );
        p.rules[1].keys.push(dev.hash());
        p.identities.push(dev.clone());
        p.revoked.push(ObjectRef([7; 32]));
        let d = Policy::decode(&p.encode()).unwrap();
        assert_eq!(d.rules.len(), 2);
        assert_eq!(d.rules[0].require, Require::Signed);
        assert_eq!(d.identity(&dev.hash()), Some(&dev));
        assert!(d.authorizes(&dev.hash(), "main"));
        assert!(!d.authorizes(&dev.hash(), "release/1"));
        assert!(d.authorizes(&root.hash(), "release/1"));
        assert!(d.is_expired(11) && !d.is_expired(10));
        assert_eq!(d.hash(), p.hash());

        let mut bad = p.clone();
        bad.root_threshold = 5;
        assert!(Policy::decode(&bad.encode()).is_err());
    }

    #[test]
    fn signatures_need_root_threshold() {
        let r1 = sk(1);
        let r2 = sk(2);
        let i1 = r1.identity("a", "a", 0);
        let i2 = r2.identity("b", "b", 0);
        let mut p = Policy::single_root([1; 16], i1.clone(), 100);
        p.roots.push(i2.hash());
        p.roots.sort();
        p.root_threshold = 2;
        p.identities.push(i2.clone());
        let h = p.hash();
        let s1 = r1.sign(Domain::Policy, &i1.hash(), &h);
        let s2 = r2.sign(Domain::Policy, &i2.hash(), &h);
        assert!(p.verify_signatures(std::slice::from_ref(&s1), &p).is_err());
        assert_eq!(
            p.verify_signatures(&[s1.clone(), s2.clone()], &p)
                .unwrap()
                .len(),
            2
        );
        // Duplicates do not count twice; a non-root signer does not count.
        assert!(p.verify_signatures(&[s1.clone(), s1.clone()], &p).is_err());
        let stranger = sk(3);
        let si = stranger.identity("s", "s", 0);
        let s3 = stranger.sign(Domain::Policy, &si.hash(), &h);
        assert!(p.verify_signatures(&[s1.clone(), s3], &p).is_err());
        // A successor policy is verified against the previous roots.
        let mut next = p.clone();
        next.serial = 2;
        next.revoked.push(i2.hash());
        let nh = next.hash();
        let n1 = r1.sign(Domain::Policy, &i1.hash(), &nh);
        let n2 = r2.sign(Domain::Policy, &i2.hash(), &nh);
        assert_eq!(next.verify_signatures(&[n1, n2], &p).unwrap().len(), 2);
    }
}

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1		//! The trust policy (spec §14.5): who may update which references, signed
2		//! by a threshold of root keys. A repository without a policy is unverified.
3		//!
4		//! Encoding: `{0: version, 1: repo, 2: serial, 3: {0: root keys, 1: threshold},
5		//! 4: [rule], 5: [identity bytes], 6: [revoked], 7: expires}`; a rule is
6		//! `{0: pattern, 1: keys, 2: threshold, 3: require, 4: allow_conflicts}` with
7		//! `require` 0 = signed, 1 = sealed, 2 = any.
8
9		use crate::cbor::{self, Value};
10		use crate::hash::{hash_object, KeyId, ObjectRef, ObjectType};
11		use crate::identity::{self, Domain, Identity, Signature};
12		use crate::objects::{
13		array, bytes, check_version, field, map, oref, text, uint, ObjectError, FORMAT_VERSION,
14		};
15		use std::collections::BTreeMap;
16
17		#[derive(Clone, Copy, Debug, PartialEq, Eq)]
18		pub enum Require {
19		Signed,
20		Sealed,
21		Any,
22		}
23
24		impl Require {
25	282×	fn tag(self) -> u64 {
26	282×	match self {
27	4×	Require::Signed => 0,
28	0×	Require::Sealed => 1,
29	278×	Require::Any => 2,
30		}
31	282×	}
32	698×	fn from_tag(t: u64) -> Result<Require, ObjectError> {
33	698×	Ok(match t {
34	2×	0 => Require::Signed,
35	0×	1 => Require::Sealed,
36	696×	2 => Require::Any,
37	0×	_ => return Err(ObjectError::Schema(format!("unknown require {t}"))),
38		})
39	698×	}
40	2×	pub fn name(self) -> &'static str {
41	2×	match self {
42	0×	Require::Signed => "signed",
43	0×	Require::Sealed => "sealed",
44	2×	Require::Any => "any",
45		}
46	2×	}
47		}
48
49		#[derive(Clone, Debug, PartialEq, Eq)]
50		pub struct Rule {
51		/// Glob over reference names; `*` matches any run of characters.
52		pub pattern: String,
53		pub keys: Vec<KeyId>,
54		pub threshold: u32,
55		pub require: Require,
56		pub allow_conflicts: bool,
57		/// Who else may sign, by what an issuer certified (§14.7): a short-lived
58		/// key whose certificate is the issuer's, for a subject the pattern
59		/// matches, counts as one signer within the scope given.
60		pub subjects: Vec<SubjectGrant>,
61		}
62
63		/// A rule's grant to the holders of certificates an issuer gives (§14.7):
64		/// `repo:andy/demo:bookmark:main`, `agent:claude@andy`, with `*` as in
65		/// reference patterns.
66		#[derive(Clone, Debug, PartialEq, Eq)]
67		pub struct SubjectGrant {
68		pub pattern: String,
69		pub issuer: KeyId,
70		pub scope: identity::Scope,
71		}
72
73		impl SubjectGrant {
74	48×	fn to_value(&self) -> Value {
75	48×	Value::map([
76	48×	(0, Value::Text(self.pattern.clone())),
77	48×	(1, Value::Bytes(self.issuer.0.to_vec())),
78		(
79		2,
80		Value::Array(
81	48×	self.scope
82	48×	.names()
83	48×	.into_iter()
84	91×	.map(\|n\| Value::Text(n.to_string()))
85	48×	.collect(),
86		),
87		),
88		])
89	48×	}
90
91	149×	fn from_value(v: &Value) -> Result<SubjectGrant, ObjectError> {
92	149×	let m = map(v, "subject")?;
93	149×	let mut scope = identity::Scope::NONE;
94	295×	for n in array(field(m, 2, "subject scope")?, "subject scope")? {
95	295×	let n = text(n, "subject scope")?;
96	295×	scope = scope
97	295×	\| identity::Scope::named(n)
98	295×	.ok_or_else(\|\| ObjectError::Schema(format!("subject: unknown scope {n:?}")))?;
99		}
100		Ok(SubjectGrant {
101	149×	pattern: text(field(m, 0, "subject pattern")?, "subject pattern")?.to_owned(),
102	149×	issuer: oref(field(m, 1, "subject issuer")?, "subject issuer")?,
103	149×	scope,
104		})
105	149×	}
106		}
107
108		#[derive(Clone, Debug, PartialEq, Eq)]
109		pub struct Policy {
110		pub repo: [u8; 16],
111		pub serial: u64,
112		pub roots: Vec<KeyId>,
113		pub root_threshold: u32,
114		pub rules: Vec<Rule>,
115		/// Embedded so verification needs no fetch.
116		pub identities: Vec<Identity>,
117		pub revoked: Vec<KeyId>,
118		pub expires: u64,
119		}
120
121		/// `*` matches any run of characters (including `/`); everything else is literal.
122	238×	pub fn glob_matches(pattern: &str, name: &str) -> bool {
123	1813×	fn rec(p: &[u8], n: &[u8]) -> bool {
124	1813×	match p.first() {
125	1180×	None => n.is_empty(),
126	1167×	Some(b'*') => (0..=n.len()).any(\|i\| rec(&p[1..], &n[i..])),
127	423×	Some(c) => n.first() == Some(c) && rec(&p[1..], &n[1..]),
128		}
129	1813×	}
130	238×	rec(pattern.as_bytes(), name.as_bytes())
131	238×	}
132
133		impl Policy {
134	838×	fn keys_value(keys: &[KeyId]) -> Value {
135	838×	Value::Array(keys.iter().map(\|k\| Value::Bytes(k.0.to_vec())).collect())
136	838×	}
137	2090×	fn keys_from(v: &Value, what: &str) -> Result<Vec<KeyId>, ObjectError> {
138	2090×	let mut ks = array(v, what)?
139	2090×	.iter()
140	2090×	.map(\|k\| oref(k, what))
141	2090×	.collect::<Result<Vec<_>, _>>()?;
142	2090×	ks.sort();
143	2090×	ks.dedup();
144	2090×	Ok(ks)
145	2090×	}
146
147	278×	pub fn to_value(&self) -> Value {
148	278×	Value::map([
149	278×	(0, Value::Uint(FORMAT_VERSION)),
150	278×	(1, Value::Bytes(self.repo.to_vec())),
151	278×	(2, Value::Uint(self.serial)),
152	278×	(
153	278×	3,
154	278×	Value::map([
155	278×	(0, Self::keys_value(&self.roots)),
156	278×	(1, Value::Uint(self.root_threshold as u64)),
157	278×	]),
158	278×	),
159		(
160		4,
161		Value::Array(
162	278×	self.rules
163	278×	.iter()
164	282×	.map(\|r\| {
165	282×	let mut v = Value::map([
166	282×	(0, Value::Text(r.pattern.clone())),
167	282×	(1, Self::keys_value(&r.keys)),
168	282×	(2, Value::Uint(r.threshold as u64)),
169	282×	(3, Value::Uint(r.require.tag())),
170	282×	(4, Value::Bool(r.allow_conflicts)),
171	282×	]);
172		// Only when there are any, so a policy without
173		// them encodes, and hashes, as before.
174	282×	if !r.subjects.is_empty() {
175	47×	if let Value::Map(m) = &mut v {
176	47×	m.insert(
177	47×	5,
178	47×	Value::Array(
179	47×	r.subjects.iter().map(SubjectGrant::to_value).collect(),
180	47×	),
181	47×	);
182	47×	}
183	235×	}
184	282×	v
185	282×	})
186	278×	.collect(),
187		),
188		),
189		(
190		5,
191		Value::Array(
192	278×	self.identities
193	278×	.iter()
194	565×	.map(\|i\| Value::Bytes(i.encode()))
195	278×	.collect(),
196		),
197		),
198	278×	(6, Self::keys_value(&self.revoked)),
199	278×	(7, Value::Uint(self.expires)),
200		])
201	278×	}
202
203	278×	pub fn encode(&self) -> Vec<u8> {
204	278×	cbor::encode(&self.to_value())
205	278×	}
206
207	160×	pub fn hash(&self) -> ObjectRef {
208	160×	hash_object(ObjectType::Policy, &self.encode())
209	160×	}
210
211	696×	pub fn decode(b: &[u8]) -> Result<Policy, ObjectError> {
212	696×	let v = cbor::decode(b)?;
213	696×	let m = map(&v, "policy")?;
214	696×	check_version(m)?;
215	696×	let roots = map(field(m, 3, "roots")?, "roots")?;
216	696×	let mut rules = Vec::new();
217	698×	for r in array(field(m, 4, "rules")?, "rules")? {
218	698×	let rm = map(r, "rule")?;
219	698×	rules.push(Rule {
220	698×	pattern: text(field(rm, 0, "pattern")?, "pattern")?.to_owned(),
221	698×	keys: Self::keys_from(field(rm, 1, "rule keys")?, "rule keys")?,
222	698×	threshold: uint(field(rm, 2, "threshold")?, "threshold")? as u32,
223	698×	require: Require::from_tag(uint(field(rm, 3, "require")?, "require")?)?,
224	698×	allow_conflicts: field(rm, 4, "allow_conflicts")?
225	698×	.as_bool()
226	698×	.ok_or_else(\|\| ObjectError::Schema("allow_conflicts: expected bool".into()))?,
227	698×	subjects: match rm.get(&5) {
228	550×	None => vec![],
229	148×	Some(v) => array(v, "subjects")?
230	148×	.iter()
231	148×	.map(SubjectGrant::from_value)
232	148×	.collect::<Result<_, _>>()?,
233		},
234		});
235		}
236	696×	let identities = array(field(m, 5, "identities")?, "identities")?
237	696×	.iter()
238	1360×	.map(\|i\| Identity::decode(bytes(i, "identity")?))
239	696×	.collect::<Result<Vec<_>, _>>()?;
240	696×	let p = Policy {
241	696×	repo: bytes(field(m, 1, "repo")?, "repo")?
242	696×	.try_into()
243	696×	.map_err(\|_\| ObjectError::Schema("repo: expected 16 bytes".into()))?,
244	696×	serial: uint(field(m, 2, "serial")?, "serial")?,
245	696×	roots: Self::keys_from(field(roots, 0, "root keys")?, "root keys")?,
246	696×	root_threshold: uint(field(roots, 1, "root threshold")?, "root threshold")? as u32,
247	696×	rules,
248	696×	identities,
249	696×	revoked: Self::keys_from(field(m, 6, "revoked")?, "revoked")?,
250	696×	expires: uint(field(m, 7, "expires")?, "expires")?,
251		};
252	696×	if p.root_threshold == 0 \|\| p.root_threshold as usize > p.roots.len() {
253	1×	return Err(ObjectError::Schema(
254	1×	"root threshold must be between 1 and the number of root keys".into(),
255	1×	));
256	695×	}
257	696×	for r in &p.rules {
258	696×	if r.threshold == 0 \|\| r.threshold as usize > r.keys.len() + r.subjects.len() {
259	1×	return Err(ObjectError::Schema(format!(
260	1×	"rule {:?}: threshold must be between 1 and the number of keys and subjects",
261	1×	r.pattern
262	1×	)));
263	695×	}
264		}
265	694×	Ok(p)
266	696×	}
267
268	226×	pub fn identity(&self, key: &KeyId) -> Option<&Identity> {
269	367×	self.identities.iter().find(\|i\| i.hash() == *key)
270	226×	}
271
272	446×	pub fn is_revoked(&self, key: &KeyId) -> bool {
273	446×	self.revoked.contains(key)
274	446×	}
275
276	7×	pub fn is_expired(&self, now_ms: u64) -> bool {
277	7×	now_ms > self.expires
278	7×	}
279
280		/// The first rule whose pattern matches `reference`.
281	205×	pub fn rule_for(&self, reference: &str) -> Option<&Rule> {
282	205×	self.rules
283	205×	.iter()
284	206×	.find(\|r\| glob_matches(&r.pattern, reference))
285	205×	}
286
287		/// Whether the rule for `reference` lets a certificate from `issuer`
288		/// for `subject` sign within `scope` (§14.7). The certificate itself,
289		/// and the time it is checked at, are the caller's to verify.
290	26×	pub fn subject_grant(
291	26×	&self,
292	26×	reference: &str,
293	26×	issuer: &KeyId,
294	26×	subject: &str,
295	26×	scope: identity::Scope,
296	26×	) -> bool {
297	26×	!self.is_revoked(issuer)
298	25×	&& self.rule_for(reference).is_some_and(\|r\| {
299	29×	r.subjects.iter().any(\|g\| {
300	29×	g.issuer == *issuer && g.scope.has(scope) && glob_matches(&g.pattern, subject)
301	29×	})
302	25×	})
303	26×	}
304
305		/// Whether `key` may update `reference`: listed in the matching rule and not revoked.
306	79×	pub fn authorizes(&self, key: &KeyId, reference: &str) -> bool {
307	79×	!self.is_revoked(key)
308	78×	&& self
309	78×	.rule_for(reference)
310	78×	.is_some_and(\|r\| r.keys.contains(key))
311	79×	}
312
313		/// Verify that `sigs` over this policy's hash meet `trusted`'s root
314		/// threshold (`trusted` is the previous policy, or this one when
315		/// bootstrapping). Returns the signing root keys.
316	81×	pub fn verify_signatures(
317	81×	&self,
318	81×	sigs: &[Signature],
319	81×	trusted: &Policy,
320	81×	) -> Result<Vec<KeyId>, String> {
321	81×	let target = self.hash();
322	81×	let mut signers = Vec::new();
323	112×	for sig in sigs {
324	112×	if !trusted.roots.contains(&sig.key) \|\| trusted.is_revoked(&sig.key) {
325	25×	continue;
326	87×	}
327	87×	let Some(id) = trusted
328	87×	.identity(&sig.key)
329	87×	.or_else(\|\| self.identity(&sig.key))
330		else {
331	0×	continue;
332		};
333	87×	if identity::verify(id, sig, Domain::Policy, &target).is_ok()
334	87×	&& !signers.contains(&sig.key)
335	86×	{
336	86×	signers.push(sig.key);
337	86×	}
338		}
339	81×	if (signers.len() as u32) < trusted.root_threshold {
340	6×	return Err(format!(
341	6×	"policy needs {} root signature(s), has {}",
342	6×	trusted.root_threshold,
343	6×	signers.len()
344	6×	));
345	75×	}
346	75×	Ok(signers)
347	81×	}
348
349		/// Bootstrap check for the first policy a repository sees (trust on
350		/// first use): at least one valid signature by one of its own roots.
351		/// The full threshold applies only to updates from a trusted policy,
352		/// whose signers are the previous roots and need not be the new ones.
353	26×	pub fn verify_bootstrap(&self, sigs: &[Signature]) -> Result<KeyId, String> {
354	26×	let target = self.hash();
355	26×	for sig in sigs {
356	26×	if !self.roots.contains(&sig.key) \|\| self.is_revoked(&sig.key) {
357	0×	continue;
358	26×	}
359	26×	if let Some(id) = self.identity(&sig.key) {
360	26×	if identity::verify(id, sig, Domain::Policy, &target).is_ok() {
361	26×	return Ok(sig.key);
362	0×	}
363	0×	}
364		}
365	0×	Err("policy carries no valid signature by one of its own root keys".into())
366	26×	}
367
368		/// A single-root policy letting `root` do everything on every reference.
369	20×	pub fn single_root(repo: [u8; 16], root: Identity, expires: u64) -> Policy {
370	20×	let key = root.hash();
371	20×	Policy {
372	20×	repo,
373	20×	serial: 1,
374	20×	roots: vec![key],
375	20×	root_threshold: 1,
376	20×	rules: vec![Rule {
377	20×	pattern: "*".into(),
378	20×	keys: vec![key],
379	20×	threshold: 1,
380	20×	require: Require::Any,
381	20×	allow_conflicts: true,
382	20×	subjects: vec![],
383	20×	}],
384	20×	identities: vec![root],
385	20×	revoked: vec![],
386	20×	expires,
387	20×	}
388	20×	}
389
390		/// Whether `key` appears anywhere in the policy (roots, rules, identities).
391	10×	pub fn mentions(&self, key: &KeyId) -> bool {
392	10×	self.roots.contains(key)
393	1×	\|\| self.rules.iter().any(\|r\| r.keys.contains(key))
394	0×	\|\| self.identity(key).is_some()
395	10×	}
396
397		/// Whether `key` is `rule_key` or one of its predecessors in the
398		/// rotation chain (`previous` links, spec §14.2), so that changes signed
399		/// before a rotation remain authorized. Revoked keys never qualify.
400	37×	pub fn succeeds(&self, rule_key: &KeyId, key: &KeyId) -> bool {
401	37×	if self.is_revoked(key) {
402	0×	return false;
403	37×	}
404	37×	let mut cur = Some(*rule_key);
405	37×	for _ in 0..32 {
406	48×	match cur {
407	48×	Some(k) if k == *key => return true,
408	23×	Some(k) => cur = self.identity(&k).and_then(\|i\| i.previous),
409	12×	None => return false,
410		}
411		}
412	0×	false
413	37×	}
414
415		/// Replace `old` by `new` in the roots and every rule and embed `new`'s
416		/// identity (a rotation, spec §14.2). The old identity stays embedded so
417		/// signatures made before the rotation still verify; it is superseded,
418		/// not revoked.
419	9×	pub fn substitute_key(&mut self, old: &KeyId, new: Identity) {
420	9×	let nk = new.hash();
421	18×	for k in self
422	9×	.roots
423	9×	.iter_mut()
424	9×	.chain(self.rules.iter_mut().flat_map(\|r\| r.keys.iter_mut()))
425		{
426	18×	if k == old {
427	18×	*k = nk;
428	18×	}
429		}
430	9×	for r in &mut self.rules {
431	9×	r.keys.sort();
432	9×	r.keys.dedup();
433	9×	}
434	9×	self.roots.sort();
435	9×	self.roots.dedup();
436	9×	if self.identity(&nk).is_none() {
437	9×	self.identities.push(new);
438	9×	}
439	9×	}
440
441		/// Identities keyed by KeyId.
442	0×	pub fn identity_map(&self) -> BTreeMap<KeyId, &Identity> {
443	0×	self.identities.iter().map(\|i\| (i.hash(), i)).collect()
444	0×	}
445		}
446
447		#[cfg(test)]
448		mod tests {
449		use super::*;
450		use crate::identity::SecretKey;
451
452	7×	fn sk(n: u8) -> SecretKey {
453	7×	SecretKey {
454	7×	ed_seed: [n; 32],
455	7×	ml_seed: [n + 100; 32],
456	7×	}
457	7×	}
458
459		#[test]
460	1×	fn globs() {
461	1×	assert!(glob_matches("*", "main"));
462	1×	assert!(glob_matches("release/*", "release/1.0"));
463	1×	assert!(!glob_matches("release/*", "main"));
464	1×	assert!(glob_matches("main", "main"));
465	1×	assert!(!glob_matches("main", "main2"));
466	1×	assert!(glob_matches("-rc", "1.0-rc2"));
467	1×	assert!(glob_matches("", ""));
468	1×	}
469
470		/// Subjects an issuer certifies (oxygenhub#241): kept through
471		/// encoding, absent from a policy without them, and granted only for
472		/// their issuer, pattern and scope, and not when the issuer is revoked.
473		#[test]
474	1×	fn a_rule_grants_certified_subjects() {
475		use crate::identity::Scope;
476	1×	let root = sk(1).identity("Root", "r@x", 0);
477	1×	let hub = sk(3).identity("Hub", "h@x", 0);
478	1×	let mut p = Policy::single_root([9; 16], root.clone(), 10);
479	1×	let plain = p.encode();
480	1×	p.rules[0].subjects.push(SubjectGrant {
481	1×	pattern: "repo:andy/demo:bookmark:main".into(),
482	1×	issuer: hub.hash(),
483	1×	scope: Scope::REFS \| Scope::CHANGES,
484	1×	});
485	1×	p.rules[0].subjects.push(SubjectGrant {
486	1×	pattern: "agent:*@andy".into(),
487	1×	issuer: hub.hash(),
488	1×	scope: Scope::CHANGES,
489	1×	});
490	1×	let back = Policy::decode(&p.encode()).unwrap();
491	1×	assert_eq!(back, p);
492	1×	let mut again = back.clone();
493	1×	again.rules[0].subjects.clear();
494	1×	assert_eq!(
495	1×	again.encode(),
496		plain,
497		"no subjects, the same bytes as before"
498		);
499
500	1×	let main = "repo:andy/demo:bookmark:main";
501	1×	assert!(p.subject_grant("main", &hub.hash(), main, Scope::REFS));
502	1×	assert!(p.subject_grant("main", &hub.hash(), "agent:claude@andy", Scope::CHANGES));
503	1×	assert!(
504	1×	!p.subject_grant("main", &hub.hash(), "agent:claude@andy", Scope::REFS),
505		"not its scope"
506		);
507	1×	assert!(
508	1×	!p.subject_grant(
509	1×	"main",
510	1×	&hub.hash(),
511	1×	"repo:andy/demo:bookmark:dev",
512	1×	Scope::REFS
513	1×	),
514		"not its pattern"
515		);
516	1×	assert!(
517	1×	!p.subject_grant("main", &root.hash(), main, Scope::REFS),
518		"not its issuer"
519		);
520	1×	p.revoked.push(hub.hash());
521	1×	assert!(
522	1×	!p.subject_grant("main", &hub.hash(), main, Scope::REFS),
523		"a revoked issuer grants nothing"
524		);
525
526		// A rule of subjects alone is a rule.
527	1×	let mut only = Policy::single_root([9; 16], root, 10);
528	1×	only.rules[0].keys.clear();
529	1×	only.rules[0].subjects.push(SubjectGrant {
530	1×	pattern: "*".into(),
531	1×	issuer: hub.hash(),
532	1×	scope: Scope::REFS,
533	1×	});
534	1×	assert!(Policy::decode(&only.encode()).is_ok());
535	1×	only.rules[0].subjects.clear();
536	1×	assert!(Policy::decode(&only.encode()).is_err(), "nobody to sign");
537	1×	}
538
539		#[test]
540	1×	fn round_trip_and_rules() {
541	1×	let root = sk(1).identity("Root", "r@x", 0);
542	1×	let dev = sk(2).identity("Dev", "d@x", 0);
543	1×	let mut p = Policy::single_root([9; 16], root.clone(), 10);
544	1×	p.rules.insert(
545		0,
546	1×	Rule {
547	1×	pattern: "release/*".into(),
548	1×	keys: vec![root.hash()],
549	1×	threshold: 1,
550	1×	require: Require::Signed,
551	1×	allow_conflicts: false,
552	1×	subjects: vec![],
553	1×	},
554		);
555	1×	p.rules[1].keys.push(dev.hash());
556	1×	p.identities.push(dev.clone());
557	1×	p.revoked.push(ObjectRef([7; 32]));
558	1×	let d = Policy::decode(&p.encode()).unwrap();
559	1×	assert_eq!(d.rules.len(), 2);
560	1×	assert_eq!(d.rules[0].require, Require::Signed);
561	1×	assert_eq!(d.identity(&dev.hash()), Some(&dev));
562	1×	assert!(d.authorizes(&dev.hash(), "main"));
563	1×	assert!(!d.authorizes(&dev.hash(), "release/1"));
564	1×	assert!(d.authorizes(&root.hash(), "release/1"));
565	1×	assert!(d.is_expired(11) && !d.is_expired(10));
566	1×	assert_eq!(d.hash(), p.hash());
567
568	1×	let mut bad = p.clone();
569	1×	bad.root_threshold = 5;
570	1×	assert!(Policy::decode(&bad.encode()).is_err());
571	1×	}
572
573		#[test]
574	1×	fn signatures_need_root_threshold() {
575	1×	let r1 = sk(1);
576	1×	let r2 = sk(2);
577	1×	let i1 = r1.identity("a", "a", 0);
578	1×	let i2 = r2.identity("b", "b", 0);
579	1×	let mut p = Policy::single_root([1; 16], i1.clone(), 100);
580	1×	p.roots.push(i2.hash());
581	1×	p.roots.sort();
582	1×	p.root_threshold = 2;
583	1×	p.identities.push(i2.clone());
584	1×	let h = p.hash();
585	1×	let s1 = r1.sign(Domain::Policy, &i1.hash(), &h);
586	1×	let s2 = r2.sign(Domain::Policy, &i2.hash(), &h);
587	1×	assert!(p.verify_signatures(std::slice::from_ref(&s1), &p).is_err());
588	1×	assert_eq!(
589	1×	p.verify_signatures(&[s1.clone(), s2.clone()], &p)
590	1×	.unwrap()
591	1×	.len(),
592		2
593		);
594		// Duplicates do not count twice; a non-root signer does not count.
595	1×	assert!(p.verify_signatures(&[s1.clone(), s1.clone()], &p).is_err());
596	1×	let stranger = sk(3);
597	1×	let si = stranger.identity("s", "s", 0);
598	1×	let s3 = stranger.sign(Domain::Policy, &si.hash(), &h);
599	1×	assert!(p.verify_signatures(&[s1.clone(), s3], &p).is_err());
600		// A successor policy is verified against the previous roots.
601	1×	let mut next = p.clone();
602	1×	next.serial = 2;
603	1×	next.revoked.push(i2.hash());
604	1×	let nh = next.hash();
605	1×	let n1 = r1.sign(Domain::Policy, &i1.hash(), &nh);
606	1×	let n2 = r2.sign(Domain::Policy, &i2.hash(), &nh);
607	1×	assert_eq!(next.verify_signatures(&[n1, n2], &p).unwrap().len(), 2);
608	1×	}
609		}

Coverage / crates/oxy-core/src/policy.rs 95.2%

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