const_oid/
lib.rs

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
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
#![no_std]
#![cfg_attr(docsrs, feature(doc_cfg))]
#![doc = include_str!("../README.md")]
#![doc(
    html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg",
    html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/6ee8e381/logo.svg"
)]
#![forbid(unsafe_code)]
#![warn(
    clippy::integer_arithmetic,
    clippy::panic,
    clippy::panic_in_result_fn,
    clippy::unwrap_used,
    missing_docs,
    rust_2018_idioms,
    unused_lifetimes,
    unused_qualifications
)]

#[cfg(feature = "std")]
extern crate std;

#[macro_use]
mod checked;

mod arcs;
mod encoder;
mod error;
mod parser;

#[cfg(feature = "db")]
#[cfg_attr(docsrs, doc(cfg(feature = "db")))]
pub mod db;

pub use crate::{
    arcs::{Arc, Arcs},
    error::{Error, Result},
};

use crate::encoder::Encoder;
use core::{fmt, str::FromStr};

/// A trait which associates an OID with a type.
pub trait AssociatedOid {
    /// The OID associated with this type.
    const OID: ObjectIdentifier;
}

/// A trait which associates a dynamic, `&self`-dependent OID with a type,
/// which may change depending on the type's value.
///
/// This trait is object safe and auto-impl'd for any types which impl
/// [`AssociatedOid`].
pub trait DynAssociatedOid {
    /// Get the OID associated with this value.
    fn oid(&self) -> ObjectIdentifier;
}

impl<T: AssociatedOid> DynAssociatedOid for T {
    fn oid(&self) -> ObjectIdentifier {
        T::OID
    }
}

/// Object identifier (OID).
///
/// OIDs are hierarchical structures consisting of "arcs", i.e. integer
/// identifiers.
///
/// # Validity
///
/// In order for an OID to be considered valid by this library, it must meet
/// the following criteria:
///
/// - The OID MUST have at least 3 arcs
/// - The first arc MUST be within the range 0-2
/// - The second arc MUST be within the range 0-39
/// - The BER/DER encoding of the OID MUST be shorter than
///   [`ObjectIdentifier::MAX_SIZE`]
#[derive(Copy, Clone, Eq, Hash, PartialEq, PartialOrd, Ord)]
pub struct ObjectIdentifier {
    /// Length in bytes
    length: u8,

    /// Array containing BER/DER-serialized bytes (no header)
    bytes: [u8; Self::MAX_SIZE],
}

#[allow(clippy::len_without_is_empty)]
impl ObjectIdentifier {
    /// Maximum size of a BER/DER-encoded OID in bytes.
    pub const MAX_SIZE: usize = 39; // makes `ObjectIdentifier` 40-bytes total w\ 1-byte length

    /// Parse an [`ObjectIdentifier`] from the dot-delimited string form,
    /// panicking on parse errors.
    ///
    /// This function exists as a workaround for `unwrap` not yet being
    /// stable in `const fn` contexts, and is intended to allow the result to
    /// be bound to a constant value:
    ///
    /// ```
    /// use const_oid::ObjectIdentifier;
    ///
    /// pub const MY_OID: ObjectIdentifier = ObjectIdentifier::new_unwrap("1.2.840.113549.1.1.1");
    /// ```
    ///
    /// In future versions of Rust it should be possible to replace this with
    /// `ObjectIdentifier::new(...).unwrap()`.
    ///
    /// Use [`ObjectIdentifier::new`] for fallible parsing.
    // TODO(tarcieri): remove this when `Result::unwrap` is `const fn`
    pub const fn new_unwrap(s: &str) -> Self {
        match Self::new(s) {
            Ok(oid) => oid,
            Err(err) => err.panic(),
        }
    }

    /// Parse an [`ObjectIdentifier`] from the dot-delimited string form.
    pub const fn new(s: &str) -> Result<Self> {
        // TODO(tarcieri): use `?` when stable in `const fn`
        match parser::Parser::parse(s) {
            Ok(parser) => parser.finish(),
            Err(err) => Err(err),
        }
    }

    /// Parse an OID from a slice of [`Arc`] values (i.e. integers).
    pub fn from_arcs(arcs: impl IntoIterator<Item = Arc>) -> Result<Self> {
        let mut encoder = Encoder::new();

        for arc in arcs {
            encoder = encoder.arc(arc)?;
        }

        encoder.finish()
    }

    /// Parse an OID from from its BER/DER encoding.
    pub fn from_bytes(ber_bytes: &[u8]) -> Result<Self> {
        let len = ber_bytes.len();

        match len {
            0 => return Err(Error::Empty),
            3..=Self::MAX_SIZE => (),
            _ => return Err(Error::NotEnoughArcs),
        }
        let mut bytes = [0u8; Self::MAX_SIZE];
        bytes[..len].copy_from_slice(ber_bytes);

        let oid = Self {
            bytes,
            length: len as u8,
        };

        // Ensure arcs are well-formed
        let mut arcs = oid.arcs();
        while arcs.try_next()?.is_some() {}

        Ok(oid)
    }

    /// Get the BER/DER serialization of this OID as bytes.
    ///
    /// Note that this encoding omits the tag/length, and only contains the
    /// value portion of the encoded OID.
    pub fn as_bytes(&self) -> &[u8] {
        &self.bytes[..self.length as usize]
    }

    /// Return the arc with the given index, if it exists.
    pub fn arc(&self, index: usize) -> Option<Arc> {
        self.arcs().nth(index)
    }

    /// Iterate over the arcs (a.k.a. nodes) of an [`ObjectIdentifier`].
    ///
    /// Returns [`Arcs`], an iterator over [`Arc`] values.
    pub fn arcs(&self) -> Arcs<'_> {
        Arcs::new(self)
    }

    /// Get the length of this [`ObjectIdentifier`] in arcs.
    pub fn len(&self) -> usize {
        self.arcs().count()
    }

    /// Get the parent OID of this one (if applicable).
    pub fn parent(&self) -> Option<Self> {
        let num_arcs = self.len().checked_sub(1)?;
        Self::from_arcs(self.arcs().take(num_arcs)).ok()
    }

    /// Push an additional arc onto this OID, returning the child OID.
    pub const fn push_arc(self, arc: Arc) -> Result<Self> {
        // TODO(tarcieri): use `?` when stable in `const fn`
        match Encoder::extend(self).arc(arc) {
            Ok(encoder) => encoder.finish(),
            Err(err) => Err(err),
        }
    }
}

impl AsRef<[u8]> for ObjectIdentifier {
    fn as_ref(&self) -> &[u8] {
        self.as_bytes()
    }
}

impl FromStr for ObjectIdentifier {
    type Err = Error;

    fn from_str(string: &str) -> Result<Self> {
        Self::new(string)
    }
}

impl TryFrom<&[u8]> for ObjectIdentifier {
    type Error = Error;

    fn try_from(ber_bytes: &[u8]) -> Result<Self> {
        Self::from_bytes(ber_bytes)
    }
}

impl From<&ObjectIdentifier> for ObjectIdentifier {
    fn from(oid: &ObjectIdentifier) -> ObjectIdentifier {
        *oid
    }
}

impl fmt::Debug for ObjectIdentifier {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "ObjectIdentifier({})", self)
    }
}

impl fmt::Display for ObjectIdentifier {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let len = self.arcs().count();

        for (i, arc) in self.arcs().enumerate() {
            write!(f, "{}", arc)?;

            if let Some(j) = i.checked_add(1) {
                if j < len {
                    write!(f, ".")?;
                }
            }
        }

        Ok(())
    }
}

// Implement by hand because the derive would create invalid values.
// Use the constructor to create a valid oid with at least 3 arcs.
#[cfg(feature = "arbitrary")]
impl<'a> arbitrary::Arbitrary<'a> for ObjectIdentifier {
    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
        let first = u.int_in_range(0..=arcs::ARC_MAX_FIRST)?;
        let second = u.int_in_range(0..=arcs::ARC_MAX_SECOND)?;
        let third = u.arbitrary()?;

        let mut oid = Self::from_arcs([first, second, third])
            .map_err(|_| arbitrary::Error::IncorrectFormat)?;

        for arc in u.arbitrary_iter()? {
            oid = oid
                .push_arc(arc?)
                .map_err(|_| arbitrary::Error::IncorrectFormat)?;
        }

        Ok(oid)
    }

    fn size_hint(depth: usize) -> (usize, Option<usize>) {
        (Arc::size_hint(depth).0.saturating_mul(3), None)
    }
}