xmpp_parsers/
caps.rs

1// Copyright (c) 2017 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
2//
3// This Source Code Form is subject to the terms of the Mozilla Public
4// License, v. 2.0. If a copy of the MPL was not distributed with this
5// file, You can obtain one at http://mozilla.org/MPL/2.0/.
6
7use xso::{AsXml, FromXml};
8
9use crate::data_forms::DataForm;
10use crate::disco::{DiscoInfoQuery, DiscoInfoResult, Feature, Identity};
11use crate::hashes::{Algo, Hash};
12use crate::ns;
13use crate::presence::PresencePayload;
14use base64::{engine::general_purpose::STANDARD as Base64, Engine};
15use blake2::Blake2bVar;
16use digest::{Digest, Update, VariableOutput};
17use sha1::Sha1;
18use sha2::{Sha256, Sha512};
19use sha3::{Sha3_256, Sha3_512};
20
21/// Represents a capability hash for a given client.
22///
23/// Warning: This protocol is insecure, you may want to switch to
24/// [ecaps2](../ecaps2/index.html) instead, see [this
25/// email](https://mail.jabber.org/pipermail/security/2009-July/000812.html).
26#[derive(FromXml, AsXml, Debug, Clone)]
27#[xml(namespace = ns::CAPS, name = "c")]
28pub struct Caps {
29    /// Deprecated list of additional feature bundles.
30    #[xml(attribute(default))]
31    pub ext: Option<String>,
32
33    /// A URI identifying an XMPP application.
34    #[xml(attribute)]
35    pub node: String,
36
37    /// The algorithm of the hash of these caps.
38    #[xml(attribute)]
39    pub hash: Algo,
40
41    /// The hash of that application’s
42    /// [disco#info](../disco/struct.DiscoInfoResult.html).
43    #[xml(attribute(codec = Base64))]
44    pub ver: Vec<u8>,
45}
46
47impl PresencePayload for Caps {}
48
49impl Caps {
50    /// Create a Caps element from its node and hash.
51    pub fn new<N: Into<String>>(node: N, hash: Hash) -> Caps {
52        Caps {
53            ext: None,
54            node: node.into(),
55            hash: hash.algo,
56            ver: hash.hash,
57        }
58    }
59}
60
61fn compute_item(field: &str) -> Vec<u8> {
62    let mut bytes = field.as_bytes().to_vec();
63    bytes.push(b'<');
64    bytes
65}
66
67fn compute_items<T, F: Fn(&T) -> Vec<u8>>(things: &[T], encode: F) -> Vec<u8> {
68    let mut string: Vec<u8> = vec![];
69    let mut accumulator: Vec<Vec<u8>> = vec![];
70    for thing in things {
71        let bytes = encode(thing);
72        accumulator.push(bytes);
73    }
74    // This works using the expected i;octet collation.
75    accumulator.sort();
76    for mut bytes in accumulator {
77        string.append(&mut bytes);
78    }
79    string
80}
81
82fn compute_features(features: &[Feature]) -> Vec<u8> {
83    compute_items(features, |feature| compute_item(&feature.var))
84}
85
86fn compute_identities(identities: &[Identity]) -> Vec<u8> {
87    compute_items(identities, |identity| {
88        let lang = identity.lang.clone().unwrap_or_default();
89        let name = identity.name.clone().unwrap_or_default();
90        let string = format!("{}/{}/{}/{}", identity.category, identity.type_, lang, name);
91        let mut vec = string.as_bytes().to_vec();
92        vec.push(b'<');
93        vec
94    })
95}
96
97fn compute_extensions(extensions: &[DataForm]) -> Vec<u8> {
98    compute_items(extensions, |extension| {
99        // TODO: maybe handle the error case?
100        let mut bytes = if let Some(ref form_type) = extension.form_type {
101            form_type.as_bytes().to_vec()
102        } else {
103            vec![]
104        };
105        bytes.push(b'<');
106        for field in extension.fields.clone() {
107            if field.var.as_deref() == Some("FORM_TYPE") {
108                continue;
109            }
110            if let Some(var) = &field.var {
111                bytes.append(&mut compute_item(var));
112            }
113            bytes.append(&mut compute_items(&field.values, |value| {
114                compute_item(value)
115            }));
116        }
117        bytes
118    })
119}
120
121/// Applies the caps algorithm on the provided disco#info result, to generate
122/// the hash input.
123///
124/// Warning: This protocol is insecure, you may want to switch to
125/// [ecaps2](../ecaps2/index.html) instead, see [this
126/// email](https://mail.jabber.org/pipermail/security/2009-July/000812.html).
127pub fn compute_disco(disco: &DiscoInfoResult) -> Vec<u8> {
128    let identities_string = compute_identities(&disco.identities);
129    let features_string = compute_features(&disco.features);
130    let extensions_string = compute_extensions(&disco.extensions);
131
132    let mut final_string = vec![];
133    final_string.extend(identities_string);
134    final_string.extend(features_string);
135    final_string.extend(extensions_string);
136    final_string
137}
138
139/// Hashes the result of [compute_disco()] with one of the supported [hash
140/// algorithms](../hashes/enum.Algo.html).
141pub fn hash_caps(data: &[u8], algo: Algo) -> Result<Hash, String> {
142    Ok(Hash {
143        hash: match algo {
144            Algo::Sha_1 => {
145                let hash = Sha1::digest(data);
146                hash.to_vec()
147            }
148            Algo::Sha_256 => {
149                let hash = Sha256::digest(data);
150                hash.to_vec()
151            }
152            Algo::Sha_512 => {
153                let hash = Sha512::digest(data);
154                hash.to_vec()
155            }
156            Algo::Sha3_256 => {
157                let hash = Sha3_256::digest(data);
158                hash.to_vec()
159            }
160            Algo::Sha3_512 => {
161                let hash = Sha3_512::digest(data);
162                hash.to_vec()
163            }
164            Algo::Blake2b_256 => {
165                let mut hasher = Blake2bVar::new(32).unwrap();
166                hasher.update(data);
167                let mut vec = vec![0u8; 32];
168                hasher.finalize_variable(&mut vec).unwrap();
169                vec
170            }
171            Algo::Blake2b_512 => {
172                let mut hasher = Blake2bVar::new(64).unwrap();
173                hasher.update(data);
174                let mut vec = vec![0u8; 64];
175                hasher.finalize_variable(&mut vec).unwrap();
176                vec
177            }
178            Algo::Unknown(algo) => return Err(format!("Unknown algorithm: {}.", algo)),
179        },
180        algo,
181    })
182}
183
184/// Helper function to create the query for the disco#info corresponding to a
185/// caps hash.
186pub fn query_caps(caps: Caps) -> DiscoInfoQuery {
187    DiscoInfoQuery {
188        node: Some(format!("{}#{}", caps.node, Base64.encode(&caps.ver))),
189    }
190}
191
192#[cfg(test)]
193mod tests {
194    use super::*;
195    use crate::caps;
196    use minidom::Element;
197    use xso::error::{Error, FromElementError};
198
199    #[cfg(target_pointer_width = "32")]
200    #[test]
201    fn test_size() {
202        assert_size!(Caps, 48);
203    }
204
205    #[cfg(target_pointer_width = "64")]
206    #[test]
207    fn test_size() {
208        assert_size!(Caps, 96);
209    }
210
211    #[test]
212    fn test_parse() {
213        let elem: Element = "<c xmlns='http://jabber.org/protocol/caps' hash='sha-256' node='coucou' ver='K1Njy3HZBThlo4moOD5gBGhn0U0oK7/CbfLlIUDi6o4='/>".parse().unwrap();
214        let caps = Caps::try_from(elem).unwrap();
215        assert_eq!(caps.node, String::from("coucou"));
216        assert_eq!(caps.hash, Algo::Sha_256);
217        assert_eq!(
218            caps.ver,
219            Base64
220                .decode("K1Njy3HZBThlo4moOD5gBGhn0U0oK7/CbfLlIUDi6o4=")
221                .unwrap()
222        );
223    }
224
225    #[cfg(not(feature = "disable-validation"))]
226    #[test]
227    fn test_invalid_child() {
228        let elem: Element = "<c xmlns='http://jabber.org/protocol/caps' node='coucou' hash='sha-256' ver='K1Njy3HZBThlo4moOD5gBGhn0U0oK7/CbfLlIUDi6o4='><hash xmlns='urn:xmpp:hashes:2' algo='sha-256'>K1Njy3HZBThlo4moOD5gBGhn0U0oK7/CbfLlIUDi6o4=</hash></c>".parse().unwrap();
229        let error = Caps::try_from(elem).unwrap_err();
230        let message = match error {
231            FromElementError::Invalid(Error::Other(string)) => string,
232            _ => panic!(),
233        };
234        assert_eq!(message, "Unknown child in Caps element.");
235    }
236
237    #[test]
238    fn test_simple() {
239        let elem: Element = "<query xmlns='http://jabber.org/protocol/disco#info'><identity category='client' type='pc'/><feature var='http://jabber.org/protocol/disco#info'/></query>".parse().unwrap();
240        let disco = DiscoInfoResult::try_from(elem).unwrap();
241        let caps = caps::compute_disco(&disco);
242        assert_eq!(caps.len(), 50);
243    }
244
245    #[test]
246    fn test_xep_5_2() {
247        let elem: Element = r#"<query xmlns='http://jabber.org/protocol/disco#info'
248       node='http://psi-im.org#q07IKJEyjvHSyhy//CH0CxmKi8w='>
249  <identity category='client' name='Exodus 0.9.1' type='pc'/>
250  <feature var='http://jabber.org/protocol/caps'/>
251  <feature var='http://jabber.org/protocol/disco#info'/>
252  <feature var='http://jabber.org/protocol/disco#items'/>
253  <feature var='http://jabber.org/protocol/muc'/>
254</query>
255"#
256        .parse()
257        .unwrap();
258
259        let expected = b"client/pc//Exodus 0.9.1<http://jabber.org/protocol/caps<http://jabber.org/protocol/disco#info<http://jabber.org/protocol/disco#items<http://jabber.org/protocol/muc<".to_vec();
260        let disco = DiscoInfoResult::try_from(elem).unwrap();
261        let caps = caps::compute_disco(&disco);
262        assert_eq!(caps, expected);
263
264        let sha_1 = caps::hash_caps(&caps, Algo::Sha_1).unwrap();
265        assert_eq!(
266            sha_1.hash,
267            Base64.decode("QgayPKawpkPSDYmwT/WM94uAlu0=").unwrap()
268        );
269    }
270
271    #[test]
272    fn test_xep_5_3() {
273        let elem: Element = r#"<query xmlns='http://jabber.org/protocol/disco#info'
274       node='http://psi-im.org#q07IKJEyjvHSyhy//CH0CxmKi8w='>
275  <identity xml:lang='en' category='client' name='Psi 0.11' type='pc'/>
276  <identity xml:lang='el' category='client' name='Ψ 0.11' type='pc'/>
277  <feature var='http://jabber.org/protocol/caps'/>
278  <feature var='http://jabber.org/protocol/disco#info'/>
279  <feature var='http://jabber.org/protocol/disco#items'/>
280  <feature var='http://jabber.org/protocol/muc'/>
281  <x xmlns='jabber:x:data' type='result'>
282    <field var='FORM_TYPE' type='hidden'>
283      <value>urn:xmpp:dataforms:softwareinfo</value>
284    </field>
285    <field var='ip_version'>
286      <value>ipv4</value>
287      <value>ipv6</value>
288    </field>
289    <field var='os'>
290      <value>Mac</value>
291    </field>
292    <field var='os_version'>
293      <value>10.5.1</value>
294    </field>
295    <field var='software'>
296      <value>Psi</value>
297    </field>
298    <field var='software_version'>
299      <value>0.11</value>
300    </field>
301  </x>
302</query>
303"#
304        .parse()
305        .unwrap();
306        let expected = b"client/pc/el/\xce\xa8 0.11<client/pc/en/Psi 0.11<http://jabber.org/protocol/caps<http://jabber.org/protocol/disco#info<http://jabber.org/protocol/disco#items<http://jabber.org/protocol/muc<urn:xmpp:dataforms:softwareinfo<ip_version<ipv4<ipv6<os<Mac<os_version<10.5.1<software<Psi<software_version<0.11<".to_vec();
307        let disco = DiscoInfoResult::try_from(elem).unwrap();
308        let caps = caps::compute_disco(&disco);
309        assert_eq!(caps, expected);
310
311        let sha_1 = caps::hash_caps(&caps, Algo::Sha_1).unwrap();
312        assert_eq!(
313            sha_1.hash,
314            Base64.decode("q07IKJEyjvHSyhy//CH0CxmKi8w=").unwrap()
315        );
316    }
317}
xmpp_parsers/caps.rs

xmpp_parsers/
caps.rs
