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, 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: &[String]) -> Vec<u8> {
83    compute_items(features, |feature| compute_item(&feature))
84}
85
86fn compute_identities(identities: &[Identity]) -> Vec<u8> {
87    compute_items(identities, |identity| {
88        let lang = identity.lang.as_deref().unwrap_or_default();
89        let name = identity.name.as_deref().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(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 {
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    // TODO: Figure out a way to remove the clones here.
129    let features: Vec<_> = disco.features.iter().cloned().collect();
130
131    let identities_string = compute_identities(&disco.identities);
132    let features_string = compute_features(&features);
133    let extensions_string = compute_extensions(&disco.extensions);
134
135    let mut final_string = vec![];
136    final_string.extend(identities_string);
137    final_string.extend(features_string);
138    final_string.extend(extensions_string);
139    final_string
140}
141
142/// Hashes the result of [compute_disco()] with one of the supported [hash
143/// algorithms](../hashes/enum.Algo.html).
144pub fn hash_caps(data: &[u8], algo: Algo) -> Result<Hash, String> {
145    Ok(Hash {
146        hash: match algo {
147            Algo::Sha_1 => {
148                let hash = Sha1::digest(data);
149                hash.to_vec()
150            }
151            Algo::Sha_256 => {
152                let hash = Sha256::digest(data);
153                hash.to_vec()
154            }
155            Algo::Sha_512 => {
156                let hash = Sha512::digest(data);
157                hash.to_vec()
158            }
159            Algo::Sha3_256 => {
160                let hash = Sha3_256::digest(data);
161                hash.to_vec()
162            }
163            Algo::Sha3_512 => {
164                let hash = Sha3_512::digest(data);
165                hash.to_vec()
166            }
167            Algo::Blake2b_256 => {
168                let mut hasher = Blake2bVar::new(32).unwrap();
169                hasher.update(data);
170                let mut vec = vec![0u8; 32];
171                hasher.finalize_variable(&mut vec).unwrap();
172                vec
173            }
174            Algo::Blake2b_512 => {
175                let mut hasher = Blake2bVar::new(64).unwrap();
176                hasher.update(data);
177                let mut vec = vec![0u8; 64];
178                hasher.finalize_variable(&mut vec).unwrap();
179                vec
180            }
181            Algo::Unknown(algo) => return Err(format!("Unknown algorithm: {}.", algo)),
182        },
183        algo,
184    })
185}
186
187/// Helper function to create the query for the disco#info corresponding to a
188/// caps hash.
189pub fn query_caps(caps: Caps) -> DiscoInfoQuery {
190    DiscoInfoQuery {
191        node: Some(format!("{}#{}", caps.node, Base64.encode(&caps.ver))),
192    }
193}
194
195#[cfg(test)]
196mod tests {
197    use super::*;
198    use crate::caps;
199    use minidom::Element;
200    #[cfg(not(feature = "disable-validation"))]
201    use xso::error::{Error, FromElementError};
202
203    #[cfg(target_pointer_width = "32")]
204    #[test]
205    fn test_size() {
206        assert_size!(Caps, 48);
207    }
208
209    #[cfg(target_pointer_width = "64")]
210    #[test]
211    fn test_size() {
212        assert_size!(Caps, 96);
213    }
214
215    #[test]
216    fn test_parse() {
217        let elem: Element = "<c xmlns='http://jabber.org/protocol/caps' hash='sha-256' node='coucou' ver='K1Njy3HZBThlo4moOD5gBGhn0U0oK7/CbfLlIUDi6o4='/>".parse().unwrap();
218        let caps = Caps::try_from(elem).unwrap();
219        assert_eq!(caps.node, String::from("coucou"));
220        assert_eq!(caps.hash, Algo::Sha_256);
221        assert_eq!(
222            caps.ver,
223            Base64
224                .decode("K1Njy3HZBThlo4moOD5gBGhn0U0oK7/CbfLlIUDi6o4=")
225                .unwrap()
226        );
227    }
228
229    #[cfg(not(feature = "disable-validation"))]
230    #[test]
231    fn test_invalid_child() {
232        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();
233        let error = Caps::try_from(elem).unwrap_err();
234        let message = match error {
235            FromElementError::Invalid(Error::Other(string)) => string,
236            _ => panic!(),
237        };
238        assert_eq!(message, "Unknown child in Caps element.");
239    }
240
241    #[test]
242    fn test_simple() {
243        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();
244        let disco = DiscoInfoResult::try_from(elem).unwrap();
245        let caps = caps::compute_disco(&disco);
246        assert_eq!(caps.len(), 50);
247    }
248
249    #[test]
250    fn test_xep_5_2() {
251        let elem: Element = r#"<query xmlns='http://jabber.org/protocol/disco#info'
252       node='http://psi-im.org#q07IKJEyjvHSyhy//CH0CxmKi8w='>
253  <identity category='client' name='Exodus 0.9.1' type='pc'/>
254  <feature var='http://jabber.org/protocol/caps'/>
255  <feature var='http://jabber.org/protocol/disco#info'/>
256  <feature var='http://jabber.org/protocol/disco#items'/>
257  <feature var='http://jabber.org/protocol/muc'/>
258</query>
259"#
260        .parse()
261        .unwrap();
262
263        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();
264        let disco = DiscoInfoResult::try_from(elem).unwrap();
265        let caps = caps::compute_disco(&disco);
266        assert_eq!(caps, expected);
267
268        let sha_1 = caps::hash_caps(&caps, Algo::Sha_1).unwrap();
269        assert_eq!(
270            sha_1.hash,
271            Base64.decode("QgayPKawpkPSDYmwT/WM94uAlu0=").unwrap()
272        );
273    }
274
275    #[test]
276    fn test_xep_5_3() {
277        let elem: Element = r#"<query xmlns='http://jabber.org/protocol/disco#info'
278       node='http://psi-im.org#q07IKJEyjvHSyhy//CH0CxmKi8w='>
279  <identity xml:lang='en' category='client' name='Psi 0.11' type='pc'/>
280  <identity xml:lang='el' category='client' name='Ψ 0.11' type='pc'/>
281  <feature var='http://jabber.org/protocol/caps'/>
282  <feature var='http://jabber.org/protocol/disco#info'/>
283  <feature var='http://jabber.org/protocol/disco#items'/>
284  <feature var='http://jabber.org/protocol/muc'/>
285  <x xmlns='jabber:x:data' type='result'>
286    <field var='FORM_TYPE' type='hidden'>
287      <value>urn:xmpp:dataforms:softwareinfo</value>
288    </field>
289    <field var='ip_version'>
290      <value>ipv4</value>
291      <value>ipv6</value>
292    </field>
293    <field var='os'>
294      <value>Mac</value>
295    </field>
296    <field var='os_version'>
297      <value>10.5.1</value>
298    </field>
299    <field var='software'>
300      <value>Psi</value>
301    </field>
302    <field var='software_version'>
303      <value>0.11</value>
304    </field>
305  </x>
306</query>
307"#
308        .parse()
309        .unwrap();
310        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();
311        let disco = DiscoInfoResult::try_from(elem).unwrap();
312        let caps = caps::compute_disco(&disco);
313        assert_eq!(caps, expected);
314
315        let sha_1 = caps::hash_caps(&caps, Algo::Sha_1).unwrap();
316        assert_eq!(
317            sha_1.hash,
318            Base64.decode("q07IKJEyjvHSyhy//CH0CxmKi8w=").unwrap()
319        );
320    }
321}
xmpp_parsers/caps.rs

xmpp_parsers/
caps.rs
