1// Copyright 2015 Brian Smith.
2//
3// Permission to use, copy, modify, and/or distribute this software for any
4// purpose with or without fee is hereby granted, provided that the above
5// copyright notice and this permission notice appear in all copies.
6//
7// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
8// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
10// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
12// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
13// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
14
15use crate::der::{self, CONSTRUCTED, CONTEXT_SPECIFIC, DerIterator, FromDer};
16use crate::error::{DerTypeId, Error};
17use crate::subject_name::GeneralName;
18
19pub(crate) struct Extension<'a> {
20 pub(crate) critical: bool,
21 pub(crate) id: untrusted::Input<'a>,
22 pub(crate) value: untrusted::Input<'a>,
23}
24
25impl Extension<'_> {
26 pub(crate) fn unsupported(&self) -> Result<(), Error> {
27 match self.critical {
28 true => Err(Error::UnsupportedCriticalExtension),
29 false => Ok(()),
30 }
31 }
32}
33
34impl<'a> FromDer<'a> for Extension<'a> {
35 fn from_der(reader: &mut untrusted::Reader<'a>) -> Result<Self, Error> {
36 let id: Input<'_> = der::expect_tag(input:reader, der::Tag::OID)?;
37 let critical: bool = bool::from_der(reader)?;
38 let value: Input<'_> = der::expect_tag(input:reader, der::Tag::OctetString)?;
39 Ok(Extension {
40 id,
41 critical,
42 value,
43 })
44 }
45
46 const TYPE_ID: DerTypeId = DerTypeId::Extension;
47}
48
49pub(crate) fn set_extension_once<T>(
50 destination: &mut Option<T>,
51 parser: impl Fn() -> Result<T, Error>,
52) -> Result<(), Error> {
53 match destination {
54 // The extension value has already been set, indicating that we encountered it
55 // more than once in our serialized data. That's invalid!
56 Some(..) => Err(Error::ExtensionValueInvalid),
57 None => {
58 *destination = Some(parser()?);
59 Ok(())
60 }
61 }
62}
63
64pub(crate) fn remember_extension(
65 extension: &Extension<'_>,
66 mut handler: impl FnMut(u8) -> Result<(), Error>,
67) -> Result<(), Error> {
68 // ISO arc for standard certificate and CRL extensions.
69 // https://www.rfc-editor.org/rfc/rfc5280#appendix-A.2
70 static ID_CE: [u8; 2] = oid![2, 5, 29];
71
72 if extension.id.len() != ID_CE.len() + 1
73 || !extension.id.as_slice_less_safe().starts_with(&ID_CE)
74 {
75 return extension.unsupported();
76 }
77
78 // safety: we verify len is non-zero and has the correct prefix above.
79 let last_octet: u8 = *extension.id.as_slice_less_safe().last().unwrap();
80 handler(last_octet)
81}
82
83/// A certificate revocation list (CRL) distribution point name, describing a source of
84/// CRL information for a given certificate as described in RFC 5280 section 4.2.3.13[^1].
85///
86/// [^1]: <https://datatracker.ietf.org/doc/html/rfc5280#section-4.2.1.13>
87pub(crate) enum DistributionPointName<'a> {
88 /// The distribution point name is a relative distinguished name, relative to the CRL issuer.
89 NameRelativeToCrlIssuer,
90 /// The distribution point name is a sequence of [GeneralName] items.
91 FullName(DerIterator<'a, GeneralName<'a>>),
92}
93
94impl<'a> FromDer<'a> for DistributionPointName<'a> {
95 fn from_der(reader: &mut untrusted::Reader<'a>) -> Result<Self, Error> {
96 // RFC 5280 section ยง4.2.1.13:
97 // When the distributionPoint field is present, it contains either a
98 // SEQUENCE of general names or a single value, nameRelativeToCRLIssuer
99 const FULL_NAME_TAG: u8 = CONTEXT_SPECIFIC | CONSTRUCTED;
100 const NAME_RELATIVE_TO_CRL_ISSUER_TAG: u8 = CONTEXT_SPECIFIC | CONSTRUCTED | 1;
101
102 let (tag: u8, value: Input<'_>) = der::read_tag_and_get_value(input:reader)?;
103 match tag {
104 FULL_NAME_TAG => Ok(DistributionPointName::FullName(DerIterator::new(input:value))),
105 NAME_RELATIVE_TO_CRL_ISSUER_TAG => Ok(DistributionPointName::NameRelativeToCrlIssuer),
106 _ => Err(Error::BadDer),
107 }
108 }
109
110 const TYPE_ID: DerTypeId = DerTypeId::DistributionPointName;
111}
112