policy.rs 92.7%

307 of 331 lines run, 65 of 80 functions · run #285 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,
}

#[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| {
                            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)),
                            ])
                        })
                        .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()))?,
            });
        }
        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() {
                return Err(ObjectError::Schema(format!(
                    "rule {:?}: threshold must be between 1 and the number of keys",
                    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 `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,
            }],
            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("", ""));
    }

    #[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,
            },
        );
        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	153×	fn tag(self) -> u64 {
26	153×	match self {
27	4×	Require::Signed => 0,
28	0×	Require::Sealed => 1,
29	149×	Require::Any => 2,
30		}
31	153×	}
32	377×	fn from_tag(t: u64) -> Result<Require, ObjectError> {
33	377×	Ok(match t {
34	2×	0 => Require::Signed,
35	0×	1 => Require::Sealed,
36	375×	2 => Require::Any,
37	0×	_ => return Err(ObjectError::Schema(format!("unknown require {t}"))),
38		})
39	377×	}
40	1×	pub fn name(self) -> &'static str {
41	1×	match self {
42	0×	Require::Signed => "signed",
43	0×	Require::Sealed => "sealed",
44	1×	Require::Any => "any",
45		}
46	1×	}
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		}
58
59		#[derive(Clone, Debug, PartialEq, Eq)]
60		pub struct Policy {
61		pub repo: [u8; 16],
62		pub serial: u64,
63		pub roots: Vec<KeyId>,
64		pub root_threshold: u32,
65		pub rules: Vec<Rule>,
66		/// Embedded so verification needs no fetch.
67		pub identities: Vec<Identity>,
68		pub revoked: Vec<KeyId>,
69		pub expires: u64,
70		}
71
72		/// `*` matches any run of characters (including `/`); everything else is literal.
73	86×	pub fn glob_matches(pattern: &str, name: &str) -> bool {
74	523×	fn rec(p: &[u8], n: &[u8]) -> bool {
75	523×	match p.first() {
76	401×	None => n.is_empty(),
77	402×	Some(b'*') => (0..=n.len()).any(\|i\| rec(&p[1..], &n[i..])),
78	40×	Some(c) => n.first() == Some(c) && rec(&p[1..], &n[1..]),
79		}
80	523×	}
81	86×	rec(pattern.as_bytes(), name.as_bytes())
82	86×	}
83
84		impl Policy {
85	451×	fn keys_value(keys: &[KeyId]) -> Value {
86	451×	Value::Array(keys.iter().map(\|k\| Value::Bytes(k.0.to_vec())).collect())
87	451×	}
88	1127×	fn keys_from(v: &Value, what: &str) -> Result<Vec<KeyId>, ObjectError> {
89	1127×	let mut ks = array(v, what)?
90	1127×	.iter()
91	1127×	.map(\|k\| oref(k, what))
92	1127×	.collect::<Result<Vec<_>, _>>()?;
93	1127×	ks.sort();
94	1127×	ks.dedup();
95	1127×	Ok(ks)
96	1127×	}
97
98	149×	pub fn to_value(&self) -> Value {
99	149×	Value::map([
100	149×	(0, Value::Uint(FORMAT_VERSION)),
101	149×	(1, Value::Bytes(self.repo.to_vec())),
102	149×	(2, Value::Uint(self.serial)),
103	149×	(
104	149×	3,
105	149×	Value::map([
106	149×	(0, Self::keys_value(&self.roots)),
107	149×	(1, Value::Uint(self.root_threshold as u64)),
108	149×	]),
109	149×	),
110		(
111		4,
112		Value::Array(
113	149×	self.rules
114	149×	.iter()
115	153×	.map(\|r\| {
116	153×	Value::map([
117	153×	(0, Value::Text(r.pattern.clone())),
118	153×	(1, Self::keys_value(&r.keys)),
119	153×	(2, Value::Uint(r.threshold as u64)),
120	153×	(3, Value::Uint(r.require.tag())),
121	153×	(4, Value::Bool(r.allow_conflicts)),
122	153×	])
123	153×	})
124	149×	.collect(),
125		),
126		),
127		(
128		5,
129		Value::Array(
130	149×	self.identities
131	149×	.iter()
132	370×	.map(\|i\| Value::Bytes(i.encode()))
133	149×	.collect(),
134		),
135		),
136	149×	(6, Self::keys_value(&self.revoked)),
137	149×	(7, Value::Uint(self.expires)),
138		])
139	149×	}
140
141	149×	pub fn encode(&self) -> Vec<u8> {
142	149×	cbor::encode(&self.to_value())
143	149×	}
144
145	89×	pub fn hash(&self) -> ObjectRef {
146	89×	hash_object(ObjectType::Policy, &self.encode())
147	89×	}
148
149	375×	pub fn decode(b: &[u8]) -> Result<Policy, ObjectError> {
150	375×	let v = cbor::decode(b)?;
151	375×	let m = map(&v, "policy")?;
152	375×	check_version(m)?;
153	375×	let roots = map(field(m, 3, "roots")?, "roots")?;
154	375×	let mut rules = Vec::new();
155	377×	for r in array(field(m, 4, "rules")?, "rules")? {
156	377×	let rm = map(r, "rule")?;
157	377×	rules.push(Rule {
158	377×	pattern: text(field(rm, 0, "pattern")?, "pattern")?.to_owned(),
159	377×	keys: Self::keys_from(field(rm, 1, "rule keys")?, "rule keys")?,
160	377×	threshold: uint(field(rm, 2, "threshold")?, "threshold")? as u32,
161	377×	require: Require::from_tag(uint(field(rm, 3, "require")?, "require")?)?,
162	377×	allow_conflicts: field(rm, 4, "allow_conflicts")?
163	377×	.as_bool()
164	377×	.ok_or_else(\|\| ObjectError::Schema("allow_conflicts: expected bool".into()))?,
165		});
166		}
167	375×	let identities = array(field(m, 5, "identities")?, "identities")?
168	375×	.iter()
169	846×	.map(\|i\| Identity::decode(bytes(i, "identity")?))
170	375×	.collect::<Result<Vec<_>, _>>()?;
171	375×	let p = Policy {
172	375×	repo: bytes(field(m, 1, "repo")?, "repo")?
173	375×	.try_into()
174	375×	.map_err(\|_\| ObjectError::Schema("repo: expected 16 bytes".into()))?,
175	375×	serial: uint(field(m, 2, "serial")?, "serial")?,
176	375×	roots: Self::keys_from(field(roots, 0, "root keys")?, "root keys")?,
177	375×	root_threshold: uint(field(roots, 1, "root threshold")?, "root threshold")? as u32,
178	375×	rules,
179	375×	identities,
180	375×	revoked: Self::keys_from(field(m, 6, "revoked")?, "revoked")?,
181	375×	expires: uint(field(m, 7, "expires")?, "expires")?,
182		};
183	375×	if p.root_threshold == 0 \|\| p.root_threshold as usize > p.roots.len() {
184	1×	return Err(ObjectError::Schema(
185	1×	"root threshold must be between 1 and the number of root keys".into(),
186	1×	));
187	374×	}
188	375×	for r in &p.rules {
189	375×	if r.threshold == 0 \|\| r.threshold as usize > r.keys.len() {
190	0×	return Err(ObjectError::Schema(format!(
191	0×	"rule {:?}: threshold must be between 1 and the number of keys",
192	0×	r.pattern
193	0×	)));
194	375×	}
195		}
196	374×	Ok(p)
197	375×	}
198
199	97×	pub fn identity(&self, key: &KeyId) -> Option<&Identity> {
200	198×	self.identities.iter().find(\|i\| i.hash() == *key)
201	97×	}
202
203	206×	pub fn is_revoked(&self, key: &KeyId) -> bool {
204	206×	self.revoked.contains(key)
205	206×	}
206
207	3×	pub fn is_expired(&self, now_ms: u64) -> bool {
208	3×	now_ms > self.expires
209	3×	}
210
211		/// The first rule whose pattern matches `reference`.
212	78×	pub fn rule_for(&self, reference: &str) -> Option<&Rule> {
213	78×	self.rules
214	78×	.iter()
215	79×	.find(\|r\| glob_matches(&r.pattern, reference))
216	78×	}
217
218		/// Whether `key` may update `reference`: listed in the matching rule and not revoked.
219	39×	pub fn authorizes(&self, key: &KeyId, reference: &str) -> bool {
220	39×	!self.is_revoked(key)
221	38×	&& self
222	38×	.rule_for(reference)
223	38×	.is_some_and(\|r\| r.keys.contains(key))
224	39×	}
225
226		/// Verify that `sigs` over this policy's hash meet `trusted`'s root
227		/// threshold (`trusted` is the previous policy, or this one when
228		/// bootstrapping). Returns the signing root keys.
229	49×	pub fn verify_signatures(
230	49×	&self,
231	49×	sigs: &[Signature],
232	49×	trusted: &Policy,
233	49×	) -> Result<Vec<KeyId>, String> {
234	49×	let target = self.hash();
235	49×	let mut signers = Vec::new();
236	72×	for sig in sigs {
237	72×	if !trusted.roots.contains(&sig.key) \|\| trusted.is_revoked(&sig.key) {
238	17×	continue;
239	55×	}
240	55×	let Some(id) = trusted
241	55×	.identity(&sig.key)
242	55×	.or_else(\|\| self.identity(&sig.key))
243		else {
244	0×	continue;
245		};
246	55×	if identity::verify(id, sig, Domain::Policy, &target).is_ok()
247	55×	&& !signers.contains(&sig.key)
248	54×	{
249	54×	signers.push(sig.key);
250	54×	}
251		}
252	49×	if (signers.len() as u32) < trusted.root_threshold {
253	6×	return Err(format!(
254	6×	"policy needs {} root signature(s), has {}",
255	6×	trusted.root_threshold,
256	6×	signers.len()
257	6×	));
258	43×	}
259	43×	Ok(signers)
260	49×	}
261
262		/// Bootstrap check for the first policy a repository sees (trust on
263		/// first use): at least one valid signature by one of its own roots.
264		/// The full threshold applies only to updates from a trusted policy,
265		/// whose signers are the previous roots and need not be the new ones.
266	10×	pub fn verify_bootstrap(&self, sigs: &[Signature]) -> Result<KeyId, String> {
267	10×	let target = self.hash();
268	10×	for sig in sigs {
269	10×	if !self.roots.contains(&sig.key) \|\| self.is_revoked(&sig.key) {
270	0×	continue;
271	10×	}
272	10×	if let Some(id) = self.identity(&sig.key) {
273	10×	if identity::verify(id, sig, Domain::Policy, &target).is_ok() {
274	10×	return Ok(sig.key);
275	0×	}
276	0×	}
277		}
278	0×	Err("policy carries no valid signature by one of its own root keys".into())
279	10×	}
280
281		/// A single-root policy letting `root` do everything on every reference.
282	11×	pub fn single_root(repo: [u8; 16], root: Identity, expires: u64) -> Policy {
283	11×	let key = root.hash();
284	11×	Policy {
285	11×	repo,
286	11×	serial: 1,
287	11×	roots: vec![key],
288	11×	root_threshold: 1,
289	11×	rules: vec![Rule {
290	11×	pattern: "*".into(),
291	11×	keys: vec![key],
292	11×	threshold: 1,
293	11×	require: Require::Any,
294	11×	allow_conflicts: true,
295	11×	}],
296	11×	identities: vec![root],
297	11×	revoked: vec![],
298	11×	expires,
299	11×	}
300	11×	}
301
302		/// Whether `key` appears anywhere in the policy (roots, rules, identities).
303	7×	pub fn mentions(&self, key: &KeyId) -> bool {
304	7×	self.roots.contains(key)
305	1×	\|\| self.rules.iter().any(\|r\| r.keys.contains(key))
306	0×	\|\| self.identity(key).is_some()
307	7×	}
308
309		/// Whether `key` is `rule_key` or one of its predecessors in the
310		/// rotation chain (`previous` links, spec §14.2), so that changes signed
311		/// before a rotation remain authorized. Revoked keys never qualify.
312	21×	pub fn succeeds(&self, rule_key: &KeyId, key: &KeyId) -> bool {
313	21×	if self.is_revoked(key) {
314	0×	return false;
315	21×	}
316	21×	let mut cur = Some(*rule_key);
317	21×	for _ in 0..32 {
318	30×	match cur {
319	30×	Some(k) if k == *key => return true,
320	14×	Some(k) => cur = self.identity(&k).and_then(\|i\| i.previous),
321	5×	None => return false,
322		}
323		}
324	0×	false
325	21×	}
326
327		/// Replace `old` by `new` in the roots and every rule and embed `new`'s
328		/// identity (a rotation, spec §14.2). The old identity stays embedded so
329		/// signatures made before the rotation still verify; it is superseded,
330		/// not revoked.
331	6×	pub fn substitute_key(&mut self, old: &KeyId, new: Identity) {
332	6×	let nk = new.hash();
333	12×	for k in self
334	6×	.roots
335	6×	.iter_mut()
336	6×	.chain(self.rules.iter_mut().flat_map(\|r\| r.keys.iter_mut()))
337		{
338	12×	if k == old {
339	12×	*k = nk;
340	12×	}
341		}
342	6×	for r in &mut self.rules {
343	6×	r.keys.sort();
344	6×	r.keys.dedup();
345	6×	}
346	6×	self.roots.sort();
347	6×	self.roots.dedup();
348	6×	if self.identity(&nk).is_none() {
349	6×	self.identities.push(new);
350	6×	}
351	6×	}
352
353		/// Identities keyed by KeyId.
354	0×	pub fn identity_map(&self) -> BTreeMap<KeyId, &Identity> {
355	0×	self.identities.iter().map(\|i\| (i.hash(), i)).collect()
356	0×	}
357		}
358
359		#[cfg(test)]
360		mod tests {
361		use super::*;
362		use crate::identity::SecretKey;
363
364	5×	fn sk(n: u8) -> SecretKey {
365	5×	SecretKey {
366	5×	ed_seed: [n; 32],
367	5×	ml_seed: [n + 100; 32],
368	5×	}
369	5×	}
370
371		#[test]
372	1×	fn globs() {
373	1×	assert!(glob_matches("*", "main"));
374	1×	assert!(glob_matches("release/*", "release/1.0"));
375	1×	assert!(!glob_matches("release/*", "main"));
376	1×	assert!(glob_matches("main", "main"));
377	1×	assert!(!glob_matches("main", "main2"));
378	1×	assert!(glob_matches("-rc", "1.0-rc2"));
379	1×	assert!(glob_matches("", ""));
380	1×	}
381
382		#[test]
383	1×	fn round_trip_and_rules() {
384	1×	let root = sk(1).identity("Root", "r@x", 0);
385	1×	let dev = sk(2).identity("Dev", "d@x", 0);
386	1×	let mut p = Policy::single_root([9; 16], root.clone(), 10);
387	1×	p.rules.insert(
388		0,
389	1×	Rule {
390	1×	pattern: "release/*".into(),
391	1×	keys: vec![root.hash()],
392	1×	threshold: 1,
393	1×	require: Require::Signed,
394	1×	allow_conflicts: false,
395	1×	},
396		);
397	1×	p.rules[1].keys.push(dev.hash());
398	1×	p.identities.push(dev.clone());
399	1×	p.revoked.push(ObjectRef([7; 32]));
400	1×	let d = Policy::decode(&p.encode()).unwrap();
401	1×	assert_eq!(d.rules.len(), 2);
402	1×	assert_eq!(d.rules[0].require, Require::Signed);
403	1×	assert_eq!(d.identity(&dev.hash()), Some(&dev));
404	1×	assert!(d.authorizes(&dev.hash(), "main"));
405	1×	assert!(!d.authorizes(&dev.hash(), "release/1"));
406	1×	assert!(d.authorizes(&root.hash(), "release/1"));
407	1×	assert!(d.is_expired(11) && !d.is_expired(10));
408	1×	assert_eq!(d.hash(), p.hash());
409
410	1×	let mut bad = p.clone();
411	1×	bad.root_threshold = 5;
412	1×	assert!(Policy::decode(&bad.encode()).is_err());
413	1×	}
414
415		#[test]
416	1×	fn signatures_need_root_threshold() {
417	1×	let r1 = sk(1);
418	1×	let r2 = sk(2);
419	1×	let i1 = r1.identity("a", "a", 0);
420	1×	let i2 = r2.identity("b", "b", 0);
421	1×	let mut p = Policy::single_root([1; 16], i1.clone(), 100);
422	1×	p.roots.push(i2.hash());
423	1×	p.roots.sort();
424	1×	p.root_threshold = 2;
425	1×	p.identities.push(i2.clone());
426	1×	let h = p.hash();
427	1×	let s1 = r1.sign(Domain::Policy, &i1.hash(), &h);
428	1×	let s2 = r2.sign(Domain::Policy, &i2.hash(), &h);
429	1×	assert!(p.verify_signatures(std::slice::from_ref(&s1), &p).is_err());
430	1×	assert_eq!(
431	1×	p.verify_signatures(&[s1.clone(), s2.clone()], &p)
432	1×	.unwrap()
433	1×	.len(),
434		2
435		);
436		// Duplicates do not count twice; a non-root signer does not count.
437	1×	assert!(p.verify_signatures(&[s1.clone(), s1.clone()], &p).is_err());
438	1×	let stranger = sk(3);
439	1×	let si = stranger.identity("s", "s", 0);
440	1×	let s3 = stranger.sign(Domain::Policy, &si.hash(), &h);
441	1×	assert!(p.verify_signatures(&[s1.clone(), s3], &p).is_err());
442		// A successor policy is verified against the previous roots.
443	1×	let mut next = p.clone();
444	1×	next.serial = 2;
445	1×	next.revoked.push(i2.hash());
446	1×	let nh = next.hash();
447	1×	let n1 = r1.sign(Domain::Policy, &i1.hash(), &nh);
448	1×	let n2 = r2.sign(Domain::Policy, &i2.hash(), &nh);
449	1×	assert_eq!(next.verify_signatures(&[n1, n2], &p).unwrap().len(), 2);
450	1×	}
451		}

Coverage / crates/oxy-core/src/policy.rs 92.7%

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