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
281
282
283
284
285
286
287
288
289
290
use std::fmt;
use std::cmp::Ordering;
use std::hash::{Hash, Hasher};

use quickcheck::{Arbitrary, Gen};

use crate::packet::Packet;

/// The OpenPGP packet tags as defined in [Section 4.3 of RFC 4880].
///
///   [Section 4.3 of RFC 4880]: https://tools.ietf.org/html/rfc4880#section-4.3
///
/// The values correspond to the serialized format.
#[derive(Clone, Copy, Debug)]
pub enum Tag {
    /// Reserved Packet tag.
    Reserved,
    /// Public-Key Encrypted Session Key Packet.
    PKESK,
    /// Signature Packet.
    Signature,
    /// Symmetric-Key Encrypted Session Key Packet.
    SKESK,
    /// One-Pass Signature Packet.
    OnePassSig,
    /// Secret-Key Packet.
    SecretKey,
    /// Public-Key Packet.
    PublicKey,
    /// Secret-Subkey Packet.
    SecretSubkey,
    /// Compressed Data Packet.
    CompressedData,
    /// Symmetrically Encrypted Data Packet.
    SED,
    /// Marker Packet (Obsolete Literal Packet).
    Marker,
    /// Literal Data Packet.
    Literal,
    /// Trust Packet.
    Trust,
    /// User ID Packet.
    UserID,
    /// Public-Subkey Packet.
    PublicSubkey,
    /// User Attribute Packet.
    UserAttribute,
    /// Sym. Encrypted and Integrity Protected Data Packet.
    SEIP,
    /// Modification Detection Code Packet.
    MDC,
    /// AEAD Encrypted Data Packet.
    ///
    /// This feature is [experimental](../index.html#experimental-features).
    AED,
    /// Unassigned packets (as of RFC4880).
    Unknown(u8),
    /// Experimental packets.
    Private(u8),
}

impl Eq for Tag {}

impl PartialEq for Tag {
    fn eq(&self, other: &Tag) -> bool {
        self.cmp(other) == Ordering::Equal
    }
}

impl PartialOrd for Tag
{
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

impl Ord for Tag
{
    fn cmp(&self, other: &Self) -> Ordering {
        let a : u8 = (*self).into();
        let b : u8 = (*other).into();
        a.cmp(&b)
    }
}

impl Hash for Tag {
    fn hash<H: Hasher>(&self, state: &mut H) {
        let t: u8 = (*self).into();
        t.hash(state);
    }
}

impl From<u8> for Tag {
    fn from(u: u8) -> Self {
        use crate::packet::Tag::*;

        match u {
            0 => Reserved,
            1 => PKESK,
            2 => Signature,
            3 => SKESK,
            4 => OnePassSig,
            5 => SecretKey,
            6 => PublicKey,
            7 => SecretSubkey,
            8 => CompressedData,
            9 => SED,
            10 => Marker,
            11 => Literal,
            12 => Trust,
            13 => UserID,
            14 => PublicSubkey,
            17 => UserAttribute,
            18 => SEIP,
            19 => MDC,
            20 => AED,
            60..=63 => Private(u),
            _ => Unknown(u),
        }
    }
}

impl From<Tag> for u8 {
    fn from(t: Tag) -> u8 {
        (&t).into()
    }
}

impl From<&Tag> for u8 {
    fn from(t: &Tag) -> u8 {
        match t {
            &Tag::Reserved => 0,
            &Tag::PKESK => 1,
            &Tag::Signature => 2,
            &Tag::SKESK => 3,
            &Tag::OnePassSig => 4,
            &Tag::SecretKey => 5,
            &Tag::PublicKey => 6,
            &Tag::SecretSubkey => 7,
            &Tag::CompressedData => 8,
            &Tag::SED => 9,
            &Tag::Marker => 10,
            &Tag::Literal => 11,
            &Tag::Trust => 12,
            &Tag::UserID => 13,
            &Tag::PublicSubkey => 14,
            &Tag::UserAttribute => 17,
            &Tag::SEIP => 18,
            &Tag::MDC => 19,
            &Tag::AED => 20,
            &Tag::Private(x) => x,
            &Tag::Unknown(x) => x,
        }
    }
}

impl From<&Packet> for Tag {
    fn from(p: &Packet) -> Tag {
        p.tag()
    }
}

impl From<Packet> for Tag {
    fn from(p: Packet) -> Tag {
        p.tag()
    }
}

impl fmt::Display for Tag {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            Tag::Reserved =>
                f.write_str("Reserved - a packet tag MUST NOT have this value"),
            Tag::PKESK =>
                f.write_str("Public-Key Encrypted Session Key Packet"),
            Tag::Signature =>
                f.write_str("Signature Packet"),
            Tag::SKESK =>
                f.write_str("Symmetric-Key Encrypted Session Key Packet"),
            Tag::OnePassSig =>
                f.write_str("One-Pass Signature Packet"),
            Tag::SecretKey =>
                f.write_str("Secret-Key Packet"),
            Tag::PublicKey =>
                f.write_str("Public-Key Packet"),
            Tag::SecretSubkey =>
                f.write_str("Secret-Subkey Packet"),
            Tag::CompressedData =>
                f.write_str("Compressed Data Packet"),
            Tag::SED =>
                f.write_str("Symmetrically Encrypted Data Packet"),
            Tag::Marker =>
                f.write_str("Marker Packet"),
            Tag::Literal =>
                f.write_str("Literal Data Packet"),
            Tag::Trust =>
                f.write_str("Trust Packet"),
            Tag::UserID =>
                f.write_str("User ID Packet"),
            Tag::PublicSubkey =>
                f.write_str("Public-Subkey Packet"),
            Tag::UserAttribute =>
                f.write_str("User Attribute Packet"),
            Tag::SEIP =>
                f.write_str("Sym. Encrypted and Integrity Protected Data Packet"),
            Tag::MDC =>
                f.write_str("Modification Detection Code Packet"),
            Tag::AED =>
                f.write_str("AEAD Encrypted Data Packet"),
            Tag::Private(u) =>
                f.write_fmt(format_args!("Private/Experimental Packet {}", u)),
            Tag::Unknown(u) =>
                f.write_fmt(format_args!("Unknown Packet {}", u)),
        }
    }
}

impl Arbitrary for Tag {
    fn arbitrary<G: Gen>(g: &mut G) -> Self {
        u8::arbitrary(g).into()
    }
}

impl Tag {
    /// Returns whether the `Tag` can be at the start of a valid
    /// message.
    ///
    /// [Certs] can start with `PublicKey`, [TSKs] with a `SecretKey`.
    ///
    ///   [Certs]: https://tools.ietf.org/html/rfc4880#section-11.1
    ///   [TSKs]: https://tools.ietf.org/html/rfc4880#section-11.2
    ///
    /// [Messages] start with a `OnePassSig`, `Signature` (old style
    /// non-one pass signatures), `PKESK`, `SKESK`, `CompressedData`,
    /// or `Literal`.
    ///
    ///   [Messages]: https://tools.ietf.org/html/rfc4880#section-11.3
    ///
    /// Signatures can standalone either as a [detached signature], a
    /// third-party certification, or a revocation certificate.
    ///
    ///   [detached signature]: https://tools.ietf.org/html/rfc4880#section-11.3
    pub fn valid_start_of_message(&self) -> bool {
        // Cert
        *self == Tag::PublicKey || *self == Tag::SecretKey
            // Message.
            || *self == Tag::PKESK || *self == Tag::SKESK
            || *self == Tag::Literal || *self == Tag::CompressedData
            // Signed message.
            || *self == Tag::OnePassSig
            // Standalone signature, old-style signature.
            || *self == Tag::Signature
    }
}

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

    quickcheck! {
        fn roundtrip(tag: Tag) -> bool {
            let val: u8 = tag.into();
            tag == Tag::from(val)
        }
    }

    quickcheck! {
        fn display(tag: Tag) -> bool {
            let s = format!("{}", tag);
            !s.is_empty()
        }
    }

    quickcheck! {
        fn unknown_private(tag: Tag) -> bool {
            match tag {
                Tag::Unknown(u) => u > 19 || u == 15 || u == 16,
                Tag::Private(u) => u >= 60 && u <= 63,
                _ => true
            }
        }
    }

    #[test]
    fn parse() {
        for i in 0..0x100usize {
            Tag::from(i as u8);
        }
    }
}