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
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
use crate::{
    mls::credential::ext::CredentialExt,
    prelude::{ConversationId, CryptoResult, MlsCentral, MlsConversation, MlsCredentialType},
    MlsError,
};

use mls_crypto_provider::MlsCryptoProvider;
use openmls_traits::OpenMlsCryptoProvider;
use wire_e2e_identity::prelude::WireIdentityReader;

use crate::context::CentralContext;
use crate::prelude::MlsCiphersuite;
use openmls::{
    messages::group_info::VerifiableGroupInfo,
    prelude::{Credential, Node},
    treesync::RatchetTree,
};

/// Indicates the state of a Conversation regarding end-to-end identity.
///
/// Note: this does not check pending state (pending commit, pending proposals) so it does not
/// consider members about to be added/removed
#[derive(Debug, Clone, Copy, Eq, PartialEq, serde::Serialize, serde::Deserialize)]
#[repr(u8)]
pub enum E2eiConversationState {
    /// All clients have a valid E2EI certificate
    Verified = 1,
    /// Some clients are either still Basic or their certificate is expired
    NotVerified,
    /// All clients are still Basic. If all client have expired certificates, [E2eiConversationState::NotVerified] is returned.
    NotEnabled,
}

impl CentralContext {
    /// Indicates when to mark a conversation as not verified i.e. when not all its members have a X509
    /// Credential generated by Wire's end-to-end identity enrollment
    pub async fn e2ei_conversation_state(&self, id: &ConversationId) -> CryptoResult<E2eiConversationState> {
        let conversation = self.get_conversation(id).await?;
        let conversation_guard = conversation.read().await;
        conversation_guard
            .e2ei_conversation_state(&self.mls_provider().await?)
            .await
    }

    /// See [MlsCentral::e2ei_verify_group_state].
    pub async fn e2ei_verify_group_state(
        &self,
        group_info: VerifiableGroupInfo,
    ) -> CryptoResult<E2eiConversationState> {
        let mls_provider = self.mls_provider().await?;
        let auth_service = mls_provider.authentication_service();
        auth_service.refresh_time_of_interest().await;
        let cs = group_info.ciphersuite().into();

        let is_sender = true; // verify the ratchet tree as sender to turn on hardened verification
        let Ok(rt) = group_info
            .take_ratchet_tree(&self.mls_provider().await?, is_sender)
            .await
        else {
            return Ok(E2eiConversationState::NotVerified);
        };

        let credentials = rt.iter().filter_map(|n| match n {
            Some(Node::LeafNode(ln)) => Some(ln.credential()),
            _ => None,
        });

        let auth_service = auth_service.borrow().await;
        Ok(compute_state(cs, credentials, MlsCredentialType::X509, auth_service.as_ref()).await)
    }

    /// See [MlsCentral::get_credential_in_use].
    pub async fn get_credential_in_use(
        &self,
        group_info: VerifiableGroupInfo,
        credential_type: MlsCredentialType,
    ) -> CryptoResult<E2eiConversationState> {
        let cs = group_info.ciphersuite().into();
        // Not verifying the supplied the GroupInfo here could let attackers lure the clients about
        // the e2ei state of a conversation and as a consequence degrade this conversation for all
        // participants once joining it.
        // This 👇 verifies the GroupInfo and the RatchetTree btw
        let rt = group_info
            .take_ratchet_tree(&self.mls_provider().await?, false)
            .await
            .map_err(MlsError::from)?;
        let mls_provider = self.mls_provider().await?;
        let auth_service = mls_provider.authentication_service().borrow().await;
        get_credential_in_use_in_ratchet_tree(cs, rt, credential_type, auth_service.as_ref()).await
    }
}

impl MlsCentral {
    /// Verifies a Group state before joining it
    pub async fn e2ei_verify_group_state(
        &self,
        group_info: VerifiableGroupInfo,
    ) -> CryptoResult<E2eiConversationState> {
        self.mls_backend
            .authentication_service()
            .refresh_time_of_interest()
            .await;

        let cs = group_info.ciphersuite().into();

        let is_sender = true; // verify the ratchet tree as sender to turn on hardened verification
        let Ok(rt) = group_info.take_ratchet_tree(&self.mls_backend, is_sender).await else {
            return Ok(E2eiConversationState::NotVerified);
        };

        let credentials = rt.iter().filter_map(|n| match n {
            Some(Node::LeafNode(ln)) => Some(ln.credential()),
            _ => None,
        });

        Ok(compute_state(
            cs,
            credentials,
            MlsCredentialType::X509,
            self.mls_backend.authentication_service().borrow().await.as_ref(),
        )
        .await)
    }

    /// Gets the e2ei conversation state from a `GroupInfo`. Useful to check if the group has e2ei
    /// turned on or not before joining it.
    pub async fn get_credential_in_use(
        &self,
        group_info: VerifiableGroupInfo,
        credential_type: MlsCredentialType,
    ) -> CryptoResult<E2eiConversationState> {
        let cs = group_info.ciphersuite().into();
        // Not verifying the supplied the GroupInfo here could let attackers lure the clients about
        // the e2ei state of a conversation and as a consequence degrade this conversation for all
        // participants once joining it.
        // This 👇 verifies the GroupInfo and the RatchetTree btw
        let rt = group_info
            .take_ratchet_tree(&self.mls_backend, false)
            .await
            .map_err(MlsError::from)?;
        get_credential_in_use_in_ratchet_tree(
            cs,
            rt,
            credential_type,
            self.mls_backend.authentication_service().borrow().await.as_ref(),
        )
        .await
    }
}

impl MlsConversation {
    async fn e2ei_conversation_state(&self, backend: &MlsCryptoProvider) -> CryptoResult<E2eiConversationState> {
        backend.authentication_service().refresh_time_of_interest().await;
        Ok(compute_state(
            self.ciphersuite(),
            self.group.members_credentials(),
            MlsCredentialType::X509,
            backend.authentication_service().borrow().await.as_ref(),
        )
        .await)
    }
}

async fn get_credential_in_use_in_ratchet_tree(
    ciphersuite: MlsCiphersuite,
    ratchet_tree: RatchetTree,
    credential_type: MlsCredentialType,
    env: Option<&wire_e2e_identity::prelude::x509::revocation::PkiEnvironment>,
) -> CryptoResult<E2eiConversationState> {
    let credentials = ratchet_tree.iter().filter_map(|n| match n {
        Some(Node::LeafNode(ln)) => Some(ln.credential()),
        _ => None,
    });
    Ok(compute_state(ciphersuite, credentials, credential_type, env).await)
}

/// _credential_type will be used in the future to get the usage of VC Credentials, even Basics one.
/// Right now though, we do not need anything other than X509 so let's keep things simple.
pub(crate) async fn compute_state<'a>(
    ciphersuite: MlsCiphersuite,
    credentials: impl Iterator<Item = &'a Credential>,
    _credential_type: MlsCredentialType,
    env: Option<&wire_e2e_identity::prelude::x509::revocation::PkiEnvironment>,
) -> E2eiConversationState {
    let mut is_e2ei = false;
    let mut state = E2eiConversationState::Verified;

    for credential in credentials {
        let Ok(Some(cert)) = credential.parse_leaf_cert() else {
            state = E2eiConversationState::NotVerified;
            if is_e2ei {
                break;
            }
            continue;
        };

        is_e2ei = true;

        let invalid_identity = cert.extract_identity(env, ciphersuite.e2ei_hash_alg()).is_err();

        use openmls_x509_credential::X509Ext as _;
        let is_time_valid = cert.is_time_valid().unwrap_or(false);
        let is_time_invalid = !is_time_valid;
        let is_revoked_or_invalid = env
            .map(|e| e.validate_cert_and_revocation(&cert).is_err())
            .unwrap_or(false);

        let is_invalid = invalid_identity || is_time_invalid || is_revoked_or_invalid;
        if is_invalid {
            state = E2eiConversationState::NotVerified;
            break;
        }
    }

    if is_e2ei {
        state
    } else {
        E2eiConversationState::NotEnabled
    }
}

#[cfg(test)]
mod tests {
    use crate::e2e_identity::rotate::tests::all::failsafe_ctx;
    use wasm_bindgen_test::*;

    use crate::{
        prelude::{CertificateBundle, Client, MlsCredentialType},
        test_utils::*,
    };

    use super::*;

    wasm_bindgen_test_configure!(run_in_browser);

    // testing the case where both Bob & Alice have the same Credential type
    #[apply(all_cred_cipher)]
    #[wasm_bindgen_test]
    async fn uniform_conversation_should_be_not_verified_when_basic(case: TestCase) {
        run_test_with_client_ids(case.clone(), ["alice", "bob"], move |[alice_central, bob_central]| {
            Box::pin(async move {
                let id = conversation_id();

                // That way the conversation creator (Alice) will have the same credential type as Bob
                let creator_ct = case.credential_type;
                alice_central
                    .context
                    .new_conversation(&id, creator_ct, case.cfg.clone())
                    .await
                    .unwrap();
                alice_central.invite_all(&case, &id, [&bob_central]).await.unwrap();

                match case.credential_type {
                    MlsCredentialType::Basic => {
                        let alice_state = alice_central.context.e2ei_conversation_state(&id).await.unwrap();
                        let bob_state = bob_central.context.e2ei_conversation_state(&id).await.unwrap();
                        assert_eq!(alice_state, E2eiConversationState::NotEnabled);
                        assert_eq!(bob_state, E2eiConversationState::NotEnabled);

                        let gi = alice_central.get_group_info(&id).await;
                        let state = alice_central
                            .context
                            .get_credential_in_use(gi, MlsCredentialType::X509)
                            .await
                            .unwrap();
                        assert_eq!(state, E2eiConversationState::NotEnabled);
                    }
                    MlsCredentialType::X509 => {
                        let alice_state = alice_central.context.e2ei_conversation_state(&id).await.unwrap();
                        let bob_state = bob_central.context.e2ei_conversation_state(&id).await.unwrap();
                        assert_eq!(alice_state, E2eiConversationState::Verified);
                        assert_eq!(bob_state, E2eiConversationState::Verified);

                        let gi = alice_central.get_group_info(&id).await;
                        let state = alice_central
                            .context
                            .get_credential_in_use(gi, MlsCredentialType::X509)
                            .await
                            .unwrap();
                        assert_eq!(state, E2eiConversationState::Verified);
                    }
                }
            })
        })
        .await
    }

    // testing the case where Bob & Alice have different Credential type
    #[apply(all_cred_cipher)]
    #[wasm_bindgen_test]
    async fn heterogeneous_conversation_should_be_not_verified(case: TestCase) {
        run_test_with_client_ids(
            case.clone(),
            ["alice", "bob"],
            move |[mut alice_central, mut bob_central]| {
                Box::pin(async move {
                    let id = conversation_id();
                    let x509_test_chain_arc =
                        failsafe_ctx(&mut [&mut alice_central, &mut bob_central], case.signature_scheme()).await;

                    let x509_test_chain = x509_test_chain_arc.as_ref().as_ref().unwrap();

                    // That way the conversation creator (Alice) will have a different credential type than Bob
                    let alice_client = alice_central.context.mls_client().await.unwrap();
                    let alice_provider = alice_central.context.mls_provider().await.unwrap();
                    let creator_ct = match case.credential_type {
                        MlsCredentialType::Basic => {
                            let intermediate_ca = x509_test_chain.find_local_intermediate_ca();
                            let cert_bundle =
                                CertificateBundle::rand(&alice_client.id().await.unwrap(), intermediate_ca);
                            alice_client
                                .init_x509_credential_bundle_if_missing(
                                    &alice_provider,
                                    case.signature_scheme(),
                                    cert_bundle,
                                )
                                .await
                                .unwrap();
                            MlsCredentialType::X509
                        }
                        MlsCredentialType::X509 => {
                            alice_client
                                .init_basic_credential_bundle_if_missing(&alice_provider, case.signature_scheme())
                                .await
                                .unwrap();
                            MlsCredentialType::Basic
                        }
                    };

                    alice_central
                        .context
                        .new_conversation(&id, creator_ct, case.cfg.clone())
                        .await
                        .unwrap();
                    alice_central.invite_all(&case, &id, [&bob_central]).await.unwrap();

                    // since in that case both have a different credential type the conversation is always not verified
                    let alice_state = alice_central.context.e2ei_conversation_state(&id).await.unwrap();
                    let bob_state = bob_central.context.e2ei_conversation_state(&id).await.unwrap();
                    assert_eq!(alice_state, E2eiConversationState::NotVerified);
                    assert_eq!(bob_state, E2eiConversationState::NotVerified);

                    let gi = alice_central.get_group_info(&id).await;
                    let state = alice_central
                        .context
                        .get_credential_in_use(gi, MlsCredentialType::X509)
                        .await
                        .unwrap();
                    assert_eq!(state, E2eiConversationState::NotVerified);
                })
            },
        )
        .await
    }

    #[apply(all_cred_cipher)]
    #[wasm_bindgen_test]
    async fn should_be_not_verified_when_one_expired(case: TestCase) {
        if !case.is_x509() {
            return;
        }
        run_test_with_client_ids(case.clone(), ["alice", "bob"], move |[alice_central, bob_central]| {
            Box::pin(async move {
                let id = conversation_id();

                alice_central
                    .context
                    .new_conversation(&id, case.credential_type, case.cfg.clone())
                    .await
                    .unwrap();
                alice_central.invite_all(&case, &id, [&bob_central]).await.unwrap();

                let expiration_time = core::time::Duration::from_secs(14);
                let start = fluvio_wasm_timer::Instant::now();

                let intermediate_ca = alice_central
                    .x509_test_chain
                    .as_ref()
                    .as_ref()
                    .expect("No x509 test chain")
                    .find_local_intermediate_ca();
                let cert = CertificateBundle::new_with_default_values(&intermediate_ca, Some(expiration_time));
                let cb = Client::new_x509_credential_bundle(cert.clone()).unwrap();
                let commit = alice_central.context.e2ei_rotate(&id, Some(&cb)).await.unwrap().commit;
                alice_central.context.commit_accepted(&id).await.unwrap();
                bob_central
                    .context
                    .decrypt_message(&id, commit.to_bytes().unwrap())
                    .await
                    .unwrap();

                let alice_client = alice_central.context.mls_client().await.unwrap();
                let alice_provider = alice_central.context.mls_provider().await.unwrap();
                // Needed because 'e2ei_rotate' does not do it directly and it's required for 'get_group_info'
                alice_client
                    .save_new_x509_credential_bundle(&alice_provider.keystore(), case.signature_scheme(), cert)
                    .await
                    .unwrap();

                // Need to fetch it before it becomes invalid & expires
                let gi = alice_central.get_group_info(&id).await;

                let elapsed = start.elapsed();
                // Give time to the certificate to expire
                if expiration_time > elapsed {
                    async_std::task::sleep(expiration_time - elapsed + core::time::Duration::from_secs(1)).await;
                }

                let alice_state = alice_central.context.e2ei_conversation_state(&id).await.unwrap();
                let bob_state = bob_central.context.e2ei_conversation_state(&id).await.unwrap();
                assert_eq!(alice_state, E2eiConversationState::NotVerified);
                assert_eq!(bob_state, E2eiConversationState::NotVerified);

                let state = alice_central
                    .context
                    .get_credential_in_use(gi, MlsCredentialType::X509)
                    .await
                    .unwrap();
                assert_eq!(state, E2eiConversationState::NotVerified);
            })
        })
        .await
    }

    #[apply(all_cred_cipher)]
    #[wasm_bindgen_test]
    async fn should_be_not_verified_when_all_expired(case: TestCase) {
        if case.is_x509() {
            run_test_with_client_ids(case.clone(), ["alice"], move |[alice_central]| {
                Box::pin(async move {
                    let id = conversation_id();

                    alice_central
                        .context
                        .new_conversation(&id, case.credential_type, case.cfg.clone())
                        .await
                        .unwrap();

                    let expiration_time = core::time::Duration::from_secs(14);
                    let start = fluvio_wasm_timer::Instant::now();
                    let alice_test_chain = alice_central.x509_test_chain.as_ref().as_ref().unwrap();

                    let alice_intermediate_ca = alice_test_chain.find_local_intermediate_ca();
                    let mut alice_cert = alice_test_chain
                        .actors
                        .iter()
                        .find(|actor| actor.name == "alice")
                        .unwrap()
                        .clone();
                    alice_intermediate_ca.update_end_identity(&mut alice_cert.certificate, Some(expiration_time));

                    let cert_bundle =
                        CertificateBundle::from_certificate_and_issuer(&alice_cert.certificate, &alice_intermediate_ca);
                    let cb = Client::new_x509_credential_bundle(cert_bundle.clone()).unwrap();
                    alice_central.context.e2ei_rotate(&id, Some(&cb)).await.unwrap();
                    alice_central.context.commit_accepted(&id).await.unwrap();

                    let alice_client = alice_central.client().await;
                    let alice_provider = alice_central.context.mls_provider().await.unwrap();

                    // Needed because 'e2ei_rotate' does not do it directly and it's required for 'get_group_info'
                    alice_client
                        .save_new_x509_credential_bundle(
                            &alice_provider.keystore(),
                            case.signature_scheme(),
                            cert_bundle,
                        )
                        .await
                        .unwrap();

                    let elapsed = start.elapsed();
                    // Give time to the certificate to expire
                    if expiration_time > elapsed {
                        async_std::task::sleep(expiration_time - elapsed + core::time::Duration::from_secs(1)).await;
                    }

                    let alice_state = alice_central.context.e2ei_conversation_state(&id).await.unwrap();
                    assert_eq!(alice_state, E2eiConversationState::NotVerified);

                    // Need to fetch it before it becomes invalid & expires
                    let gi = alice_central.get_group_info(&id).await;

                    let state = alice_central
                        .context
                        .get_credential_in_use(gi, MlsCredentialType::X509)
                        .await
                        .unwrap();
                    assert_eq!(state, E2eiConversationState::NotVerified);
                })
            })
            .await
        }
    }
}