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
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
#[cfg(feature = "logging")]
use crate::log::{debug, trace};
use crate::x509;
use crate::{key, DistinguishedName};
use crate::{CertificateError, Error};
/// A trust anchor, commonly known as a "Root Certificate."
#[derive(Debug, Clone)]
pub struct OwnedTrustAnchor {
subject_dn_header_len: usize,
subject_dn: DistinguishedName,
spki: Vec<u8>,
name_constraints: Option<Vec<u8>>,
}
impl OwnedTrustAnchor {
/// Get a `webpki::TrustAnchor` by borrowing the owned elements.
pub(crate) fn to_trust_anchor(&self) -> webpki::TrustAnchor {
webpki::TrustAnchor {
subject: &self.subject_dn.as_ref()[self.subject_dn_header_len..],
spki: &self.spki,
name_constraints: self.name_constraints.as_deref(),
}
}
/// Constructs an `OwnedTrustAnchor` from its components.
///
/// All inputs are DER-encoded.
///
/// `subject` is the [Subject] field of the trust anchor *without* the outer SEQUENCE
/// encoding.
///
/// `spki` is the [SubjectPublicKeyInfo] field of the trust anchor.
///
/// `name_constraints` is the [Name Constraints] to
/// apply for this trust anchor, if any.
///
/// [Subject]: https://datatracker.ietf.org/doc/html/rfc5280#section-4.1.2.6
/// [SubjectPublicKeyInfo]: https://datatracker.ietf.org/doc/html/rfc5280#section-4.1.2.7
/// [Name Constraints]: https://datatracker.ietf.org/doc/html/rfc5280#section-4.2.1.10
pub fn from_subject_spki_name_constraints(
subject: impl Into<Vec<u8>>,
spki: impl Into<Vec<u8>>,
name_constraints: Option<impl Into<Vec<u8>>>,
) -> Self {
let (subject_dn, subject_dn_header_len) = {
let mut subject = subject.into();
let before_len = subject.len();
x509::wrap_in_sequence(&mut subject);
let header_len = subject.len().saturating_sub(before_len);
(DistinguishedName::from(subject), header_len)
};
Self {
subject_dn_header_len,
subject_dn,
spki: spki.into(),
name_constraints: name_constraints.map(|x| x.into()),
}
}
/// Return the subject field including its outer SEQUENCE encoding.
///
/// This can be decoded using [x509-parser's FromDer trait](https://docs.rs/x509-parser/latest/x509_parser/prelude/trait.FromDer.html).
///
/// ```ignore
/// use x509_parser::prelude::FromDer;
/// println!("{}", x509_parser::x509::X509Name::from_der(anchor.subject())?.1);
/// ```
pub fn subject(&self) -> &DistinguishedName {
&self.subject_dn
}
}
/// A container for root certificates able to provide a root-of-trust
/// for connection authentication.
#[derive(Debug, Clone)]
pub struct RootCertStore {
/// The list of roots.
pub roots: Vec<OwnedTrustAnchor>,
}
impl RootCertStore {
/// Make a new, empty `RootCertStore`.
pub fn empty() -> Self {
Self { roots: Vec::new() }
}
/// Return true if there are no certificates.
pub fn is_empty(&self) -> bool {
self.len() == 0
}
/// Say how many certificates are in the container.
pub fn len(&self) -> usize {
self.roots.len()
}
/// Add a single DER-encoded certificate to the store.
///
/// This is suitable for a small set of root certificates that are expected to parse
/// successfully. For large collections of roots (for example from a system store) it
/// is expected that some of them might not be valid according to the rules rustls
/// implements. As long as a relatively limited number of certificates are affected,
/// this should not be a cause for concern. Use [`RootCertStore::add_parsable_certificates`]
/// in order to add as many valid roots as possible and to understand how many certificates
/// have been diagnosed as malformed.
pub fn add(&mut self, der: &key::Certificate) -> Result<(), Error> {
let ta = webpki::TrustAnchor::try_from_cert_der(&der.0)
.map_err(|_| Error::InvalidCertificate(CertificateError::BadEncoding))?;
let ota = OwnedTrustAnchor::from_subject_spki_name_constraints(
ta.subject,
ta.spki,
ta.name_constraints,
);
self.roots.push(ota);
Ok(())
}
/// Adds all the given TrustAnchors `anchors`. This does not
/// fail.
pub fn add_server_trust_anchors(
&mut self,
trust_anchors: impl Iterator<Item = OwnedTrustAnchor>,
) {
self.roots.extend(trust_anchors);
}
/// Parse the given DER-encoded certificates and add all that can be parsed
/// in a best-effort fashion.
///
/// This is because large collections of root certificates often
/// include ancient or syntactically invalid certificates.
///
/// Returns the number of certificates added, and the number that were ignored.
pub fn add_parsable_certificates(&mut self, der_certs: &[Vec<u8>]) -> (usize, usize) {
let mut valid_count = 0;
let mut invalid_count = 0;
for der_cert in der_certs {
#[cfg_attr(not(feature = "logging"), allow(unused_variables))]
match self.add(&key::Certificate(der_cert.clone())) {
Ok(_) => valid_count += 1,
Err(err) => {
trace!("invalid cert der {:?}", der_cert);
debug!("certificate parsing failed: {:?}", err);
invalid_count += 1;
}
}
}
debug!(
"add_parsable_certificates processed {} valid and {} invalid certs",
valid_count, invalid_count
);
(valid_count, invalid_count)
}
}
mod tests {
#[test]
fn ownedtrustanchor_subject_is_correctly_encoding_dn() {
let subject = b"subject".to_owned();
let ota = super::OwnedTrustAnchor::from_subject_spki_name_constraints(
subject,
b"".to_owned(),
None::<Vec<u8>>,
);
let expected_prefix = vec![ring::io::der::Tag::Sequence as u8, subject.len() as u8];
assert_eq!(
ota.subject().as_ref(),
[expected_prefix, subject.to_vec()].concat()
);
}
}