nmode's Git Repositories - signal-cli/blob - lib/src/main/java/org/asamk/signal/manager/helper/GroupV2Helper.java

   1 package org.asamk.signal.manager.helper;
   2
   3 import com.google.protobuf.InvalidProtocolBufferException;
   4
   5 import org.asamk.signal.manager.SignalDependencies;
   6 import org.asamk.signal.manager.api.Pair;
   7 import org.asamk.signal.manager.groups.GroupLinkPassword;
   8 import org.asamk.signal.manager.groups.GroupLinkState;
   9 import org.asamk.signal.manager.groups.GroupPermission;
  10 import org.asamk.signal.manager.groups.GroupUtils;
  11 import org.asamk.signal.manager.groups.NotAGroupMemberException;
  12 import org.asamk.signal.manager.storage.groups.GroupInfoV2;
  13 import org.asamk.signal.manager.storage.recipients.RecipientId;
  14 import org.asamk.signal.manager.util.IOUtils;
  15 import org.asamk.signal.manager.util.Utils;
  16 import org.signal.libsignal.zkgroup.InvalidInputException;
  17 import org.signal.libsignal.zkgroup.VerificationFailedException;
  18 import org.signal.libsignal.zkgroup.auth.AuthCredentialResponse;
  19 import org.signal.libsignal.zkgroup.groups.GroupMasterKey;
  20 import org.signal.libsignal.zkgroup.groups.GroupSecretParams;
  21 import org.signal.libsignal.zkgroup.groups.UuidCiphertext;
  22 import org.signal.storageservice.protos.groups.AccessControl;
  23 import org.signal.storageservice.protos.groups.GroupChange;
  24 import org.signal.storageservice.protos.groups.Member;
  25 import org.signal.storageservice.protos.groups.local.DecryptedGroup;
  26 import org.signal.storageservice.protos.groups.local.DecryptedGroupChange;
  27 import org.signal.storageservice.protos.groups.local.DecryptedGroupJoinInfo;
  28 import org.signal.storageservice.protos.groups.local.DecryptedPendingMember;
  29 import org.slf4j.Logger;
  30 import org.slf4j.LoggerFactory;
  31 import org.whispersystems.signalservice.api.groupsv2.DecryptedGroupUtil;
  32 import org.whispersystems.signalservice.api.groupsv2.GroupCandidate;
  33 import org.whispersystems.signalservice.api.groupsv2.GroupLinkNotActiveException;
  34 import org.whispersystems.signalservice.api.groupsv2.GroupsV2AuthorizationString;
  35 import org.whispersystems.signalservice.api.groupsv2.GroupsV2Operations;
  36 import org.whispersystems.signalservice.api.groupsv2.InvalidGroupStateException;
  37 import org.whispersystems.signalservice.api.groupsv2.NotAbleToApplyGroupV2ChangeException;
  38 import org.whispersystems.signalservice.api.push.ACI;
  39 import org.whispersystems.signalservice.api.push.ServiceId;
  40 import org.whispersystems.signalservice.api.push.SignalServiceAddress;
  41 import org.whispersystems.signalservice.api.push.exceptions.NonSuccessfulResponseCodeException;
  42
  43 import java.io.File;
  44 import java.io.FileInputStream;
  45 import java.io.IOException;
  46 import java.io.InputStream;
  47 import java.util.ArrayList;
  48 import java.util.HashMap;
  49 import java.util.List;
  50 import java.util.Optional;
  51 import java.util.Set;
  52 import java.util.UUID;
  53 import java.util.concurrent.TimeUnit;
  54 import java.util.stream.Collectors;
  55
  56 class GroupV2Helper {
  57
  58     private final static Logger logger = LoggerFactory.getLogger(GroupV2Helper.class);
  59
  60     private final SignalDependencies dependencies;
  61     private final Context context;
  62
  63     private HashMap<Integer, AuthCredentialResponse> groupApiCredentials;
  64
  65     GroupV2Helper(final Context context) {
  66         this.dependencies = context.getDependencies();
  67         this.context = context;
  68     }
  69
  70     DecryptedGroup getDecryptedGroup(final GroupSecretParams groupSecretParams) throws NotAGroupMemberException {
  71         try {
  72             final var groupsV2AuthorizationString = getGroupAuthForToday(groupSecretParams);
  73             return dependencies.getGroupsV2Api().getGroup(groupSecretParams, groupsV2AuthorizationString);
  74         } catch (NonSuccessfulResponseCodeException e) {
  75             if (e.getCode() == 403) {
  76                 throw new NotAGroupMemberException(GroupUtils.getGroupIdV2(groupSecretParams), null);
  77             }
  78             logger.warn("Failed to retrieve Group V2 info, ignoring: {}", e.getMessage());
  79             return null;
  80         } catch (IOException | VerificationFailedException | InvalidGroupStateException e) {
  81             logger.warn("Failed to retrieve Group V2 info, ignoring: {}", e.getMessage());
  82             return null;
  83         }
  84     }
  85
  86     DecryptedGroupJoinInfo getDecryptedGroupJoinInfo(
  87             GroupMasterKey groupMasterKey, GroupLinkPassword password
  88     ) throws IOException, GroupLinkNotActiveException {
  89         var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupMasterKey);
  90
  91         return dependencies.getGroupsV2Api()
  92                 .getGroupJoinInfo(groupSecretParams,
  93                         Optional.ofNullable(password).map(GroupLinkPassword::serialize),
  94                         getGroupAuthForToday(groupSecretParams));
  95     }
  96
  97     Pair<GroupInfoV2, DecryptedGroup> createGroup(
  98             String name, Set<RecipientId> members, File avatarFile
  99     ) throws IOException {
 100         final var avatarBytes = readAvatarBytes(avatarFile);
 101         final var newGroup = buildNewGroup(name, members, avatarBytes);
 102         if (newGroup == null) {
 103             return null;
 104         }
 105
 106         final var groupSecretParams = newGroup.getGroupSecretParams();
 107
 108         final GroupsV2AuthorizationString groupAuthForToday;
 109         final DecryptedGroup decryptedGroup;
 110         try {
 111             groupAuthForToday = getGroupAuthForToday(groupSecretParams);
 112             dependencies.getGroupsV2Api().putNewGroup(newGroup, groupAuthForToday);
 113             decryptedGroup = dependencies.getGroupsV2Api().getGroup(groupSecretParams, groupAuthForToday);
 114         } catch (IOException | VerificationFailedException | InvalidGroupStateException e) {
 115             logger.warn("Failed to create V2 group: {}", e.getMessage());
 116             return null;
 117         }
 118         if (decryptedGroup == null) {
 119             logger.warn("Failed to create V2 group, unknown error!");
 120             return null;
 121         }
 122
 123         final var groupId = GroupUtils.getGroupIdV2(groupSecretParams);
 124         final var masterKey = groupSecretParams.getMasterKey();
 125         var g = new GroupInfoV2(groupId, masterKey);
 126
 127         return new Pair<>(g, decryptedGroup);
 128     }
 129
 130     private byte[] readAvatarBytes(final File avatarFile) throws IOException {
 131         final byte[] avatarBytes;
 132         try (InputStream avatar = avatarFile == null ? null : new FileInputStream(avatarFile)) {
 133             avatarBytes = avatar == null ? null : IOUtils.readFully(avatar);
 134         }
 135         return avatarBytes;
 136     }
 137
 138     private GroupsV2Operations.NewGroup buildNewGroup(
 139             String name, Set<RecipientId> members, byte[] avatar
 140     ) {
 141         final var profileKeyCredential = context.getProfileHelper()
 142                 .getRecipientProfileKeyCredential(context.getAccount().getSelfRecipientId());
 143         if (profileKeyCredential == null) {
 144             logger.warn("Cannot create a V2 group as self does not have a versioned profile");
 145             return null;
 146         }
 147
 148         final var self = new GroupCandidate(getSelfAci().uuid(), Optional.of(profileKeyCredential));
 149         final var memberList = new ArrayList<>(members);
 150         final var credentials = context.getProfileHelper().getRecipientProfileKeyCredential(memberList).stream();
 151         final var uuids = memberList.stream()
 152                 .map(member -> context.getRecipientHelper().resolveSignalServiceAddress(member).getServiceId().uuid());
 153         var candidates = Utils.zip(uuids,
 154                         credentials,
 155                         (uuid, credential) -> new GroupCandidate(uuid, Optional.ofNullable(credential)))
 156                 .collect(Collectors.toSet());
 157
 158         final var groupSecretParams = GroupSecretParams.generate();
 159         return dependencies.getGroupsV2Operations()
 160                 .createNewGroup(groupSecretParams,
 161                         name,
 162                         Optional.ofNullable(avatar),
 163                         self,
 164                         candidates,
 165                         Member.Role.DEFAULT,
 166                         0);
 167     }
 168
 169     Pair<DecryptedGroup, GroupChange> updateGroup(
 170             GroupInfoV2 groupInfoV2, String name, String description, File avatarFile
 171     ) throws IOException {
 172         final var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupInfoV2.getMasterKey());
 173         var groupOperations = dependencies.getGroupsV2Operations().forGroup(groupSecretParams);
 174
 175         var change = name != null ? groupOperations.createModifyGroupTitle(name) : GroupChange.Actions.newBuilder();
 176
 177         if (description != null) {
 178             change.setModifyDescription(groupOperations.createModifyGroupDescriptionAction(description));
 179         }
 180
 181         if (avatarFile != null) {
 182             final var avatarBytes = readAvatarBytes(avatarFile);
 183             var avatarCdnKey = dependencies.getGroupsV2Api()
 184                     .uploadAvatar(avatarBytes, groupSecretParams, getGroupAuthForToday(groupSecretParams));
 185             change.setModifyAvatar(GroupChange.Actions.ModifyAvatarAction.newBuilder().setAvatar(avatarCdnKey));
 186         }
 187
 188         change.setSourceUuid(getSelfAci().toByteString());
 189
 190         return commitChange(groupInfoV2, change);
 191     }
 192
 193     Pair<DecryptedGroup, GroupChange> addMembers(
 194             GroupInfoV2 groupInfoV2, Set<RecipientId> newMembers
 195     ) throws IOException {
 196         GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 197
 198         final var memberList = new ArrayList<>(newMembers);
 199         final var credentials = context.getProfileHelper().getRecipientProfileKeyCredential(memberList).stream();
 200         final var uuids = memberList.stream()
 201                 .map(member -> context.getRecipientHelper().resolveSignalServiceAddress(member).getServiceId().uuid());
 202         var candidates = Utils.zip(uuids,
 203                         credentials,
 204                         (uuid, credential) -> new GroupCandidate(uuid, Optional.ofNullable(credential)))
 205                 .collect(Collectors.toSet());
 206         final var bannedUuids = groupInfoV2.getBannedMembers()
 207                 .stream()
 208                 .map(member -> context.getRecipientHelper().resolveSignalServiceAddress(member).getServiceId().uuid())
 209                 .collect(Collectors.toSet());
 210
 211         final var aci = getSelfAci();
 212         final var change = groupOperations.createModifyGroupMembershipChange(candidates, bannedUuids, aci.uuid());
 213
 214         change.setSourceUuid(getSelfAci().toByteString());
 215
 216         return commitChange(groupInfoV2, change);
 217     }
 218
 219     Pair<DecryptedGroup, GroupChange> leaveGroup(
 220             GroupInfoV2 groupInfoV2, Set<RecipientId> membersToMakeAdmin
 221     ) throws IOException {
 222         var pendingMembersList = groupInfoV2.getGroup().getPendingMembersList();
 223         final var selfAci = getSelfAci();
 224         var selfPendingMember = DecryptedGroupUtil.findPendingByUuid(pendingMembersList, selfAci.uuid());
 225
 226         if (selfPendingMember.isPresent()) {
 227             return revokeInvites(groupInfoV2, Set.of(selfPendingMember.get()));
 228         }
 229
 230         final var adminUuids = membersToMakeAdmin.stream()
 231                 .map(context.getRecipientHelper()::resolveSignalServiceAddress)
 232                 .map(SignalServiceAddress::getServiceId)
 233                 .map(ServiceId::uuid)
 234                 .toList();
 235         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 236         return commitChange(groupInfoV2,
 237                 groupOperations.createLeaveAndPromoteMembersToAdmin(selfAci.uuid(), adminUuids));
 238     }
 239
 240     Pair<DecryptedGroup, GroupChange> removeMembers(
 241             GroupInfoV2 groupInfoV2, Set<RecipientId> members
 242     ) throws IOException {
 243         final var memberUuids = members.stream()
 244                 .map(context.getRecipientHelper()::resolveSignalServiceAddress)
 245                 .map(SignalServiceAddress::getServiceId)
 246                 .map(ServiceId::uuid)
 247                 .collect(Collectors.toSet());
 248         return ejectMembers(groupInfoV2, memberUuids);
 249     }
 250
 251     Pair<DecryptedGroup, GroupChange> revokeInvitedMembers(
 252             GroupInfoV2 groupInfoV2, Set<RecipientId> members
 253     ) throws IOException {
 254         var pendingMembersList = groupInfoV2.getGroup().getPendingMembersList();
 255         final var memberUuids = members.stream()
 256                 .map(context.getRecipientHelper()::resolveSignalServiceAddress)
 257                 .map(SignalServiceAddress::getServiceId)
 258                 .map(ServiceId::uuid)
 259                 .map(uuid -> DecryptedGroupUtil.findPendingByUuid(pendingMembersList, uuid))
 260                 .filter(Optional::isPresent)
 261                 .map(Optional::get)
 262                 .collect(Collectors.toSet());
 263         return revokeInvites(groupInfoV2, memberUuids);
 264     }
 265
 266     Pair<DecryptedGroup, GroupChange> banMembers(
 267             GroupInfoV2 groupInfoV2, Set<RecipientId> block
 268     ) throws IOException {
 269         GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 270
 271         final var uuids = block.stream()
 272                 .map(member -> context.getRecipientHelper().resolveSignalServiceAddress(member).getServiceId().uuid())
 273                 .collect(Collectors.toSet());
 274
 275         final var change = groupOperations.createBanUuidsChange(uuids,
 276                 false,
 277                 groupInfoV2.getGroup().getBannedMembersList());
 278
 279         change.setSourceUuid(getSelfAci().toByteString());
 280
 281         return commitChange(groupInfoV2, change);
 282     }
 283
 284     Pair<DecryptedGroup, GroupChange> unbanMembers(
 285             GroupInfoV2 groupInfoV2, Set<RecipientId> block
 286     ) throws IOException {
 287         GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 288
 289         final var uuids = block.stream()
 290                 .map(member -> context.getRecipientHelper().resolveSignalServiceAddress(member).getServiceId().uuid())
 291                 .collect(Collectors.toSet());
 292
 293         final var change = groupOperations.createUnbanUuidsChange(uuids);
 294
 295         change.setSourceUuid(getSelfAci().toByteString());
 296
 297         return commitChange(groupInfoV2, change);
 298     }
 299
 300     Pair<DecryptedGroup, GroupChange> resetGroupLinkPassword(GroupInfoV2 groupInfoV2) throws IOException {
 301         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 302         final var newGroupLinkPassword = GroupLinkPassword.createNew().serialize();
 303         final var change = groupOperations.createModifyGroupLinkPasswordChange(newGroupLinkPassword);
 304         return commitChange(groupInfoV2, change);
 305     }
 306
 307     Pair<DecryptedGroup, GroupChange> setGroupLinkState(
 308             GroupInfoV2 groupInfoV2, GroupLinkState state
 309     ) throws IOException {
 310         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 311
 312         final var accessRequired = toAccessControl(state);
 313         final var requiresNewPassword = state != GroupLinkState.DISABLED && groupInfoV2.getGroup()
 314                 .getInviteLinkPassword()
 315                 .isEmpty();
 316
 317         final var change = requiresNewPassword ? groupOperations.createModifyGroupLinkPasswordAndRightsChange(
 318                 GroupLinkPassword.createNew().serialize(),
 319                 accessRequired) : groupOperations.createChangeJoinByLinkRights(accessRequired);
 320         return commitChange(groupInfoV2, change);
 321     }
 322
 323     Pair<DecryptedGroup, GroupChange> setEditDetailsPermission(
 324             GroupInfoV2 groupInfoV2, GroupPermission permission
 325     ) throws IOException {
 326         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 327
 328         final var accessRequired = toAccessControl(permission);
 329         final var change = groupOperations.createChangeAttributesRights(accessRequired);
 330         return commitChange(groupInfoV2, change);
 331     }
 332
 333     Pair<DecryptedGroup, GroupChange> setAddMemberPermission(
 334             GroupInfoV2 groupInfoV2, GroupPermission permission
 335     ) throws IOException {
 336         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 337
 338         final var accessRequired = toAccessControl(permission);
 339         final var change = groupOperations.createChangeMembershipRights(accessRequired);
 340         return commitChange(groupInfoV2, change);
 341     }
 342
 343     GroupChange joinGroup(
 344             GroupMasterKey groupMasterKey,
 345             GroupLinkPassword groupLinkPassword,
 346             DecryptedGroupJoinInfo decryptedGroupJoinInfo
 347     ) throws IOException {
 348         final var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupMasterKey);
 349         final var groupOperations = dependencies.getGroupsV2Operations().forGroup(groupSecretParams);
 350
 351         final var selfRecipientId = context.getAccount().getSelfRecipientId();
 352         final var profileKeyCredential = context.getProfileHelper().getRecipientProfileKeyCredential(selfRecipientId);
 353         if (profileKeyCredential == null) {
 354             throw new IOException("Cannot join a V2 group as self does not have a versioned profile");
 355         }
 356
 357         var requestToJoin = decryptedGroupJoinInfo.getAddFromInviteLink() == AccessControl.AccessRequired.ADMINISTRATOR;
 358         var change = requestToJoin
 359                 ? groupOperations.createGroupJoinRequest(profileKeyCredential)
 360                 : groupOperations.createGroupJoinDirect(profileKeyCredential);
 361
 362         change.setSourceUuid(context.getRecipientHelper()
 363                 .resolveSignalServiceAddress(selfRecipientId)
 364                 .getServiceId()
 365                 .toByteString());
 366
 367         return commitChange(groupSecretParams, decryptedGroupJoinInfo.getRevision(), change, groupLinkPassword);
 368     }
 369
 370     Pair<DecryptedGroup, GroupChange> acceptInvite(GroupInfoV2 groupInfoV2) throws IOException {
 371         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 372
 373         final var selfRecipientId = context.getAccount().getSelfRecipientId();
 374         final var profileKeyCredential = context.getProfileHelper().getRecipientProfileKeyCredential(selfRecipientId);
 375         if (profileKeyCredential == null) {
 376             throw new IOException("Cannot join a V2 group as self does not have a versioned profile");
 377         }
 378
 379         final var change = groupOperations.createAcceptInviteChange(profileKeyCredential);
 380
 381         final var aci = context.getRecipientHelper().resolveSignalServiceAddress(selfRecipientId).getServiceId();
 382         change.setSourceUuid(aci.toByteString());
 383
 384         return commitChange(groupInfoV2, change);
 385     }
 386
 387     Pair<DecryptedGroup, GroupChange> setMemberAdmin(
 388             GroupInfoV2 groupInfoV2, RecipientId recipientId, boolean admin
 389     ) throws IOException {
 390         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 391         final var address = context.getRecipientHelper().resolveSignalServiceAddress(recipientId);
 392         final var newRole = admin ? Member.Role.ADMINISTRATOR : Member.Role.DEFAULT;
 393         final var change = groupOperations.createChangeMemberRole(address.getServiceId().uuid(), newRole);
 394         return commitChange(groupInfoV2, change);
 395     }
 396
 397     Pair<DecryptedGroup, GroupChange> setMessageExpirationTimer(
 398             GroupInfoV2 groupInfoV2, int messageExpirationTimer
 399     ) throws IOException {
 400         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 401         final var change = groupOperations.createModifyGroupTimerChange(messageExpirationTimer);
 402         return commitChange(groupInfoV2, change);
 403     }
 404
 405     Pair<DecryptedGroup, GroupChange> setIsAnnouncementGroup(
 406             GroupInfoV2 groupInfoV2, boolean isAnnouncementGroup
 407     ) throws IOException {
 408         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 409         final var change = groupOperations.createAnnouncementGroupChange(isAnnouncementGroup);
 410         return commitChange(groupInfoV2, change);
 411     }
 412
 413     private AccessControl.AccessRequired toAccessControl(final GroupLinkState state) {
 414         return switch (state) {
 415             case DISABLED -> AccessControl.AccessRequired.UNSATISFIABLE;
 416             case ENABLED -> AccessControl.AccessRequired.ANY;
 417             case ENABLED_WITH_APPROVAL -> AccessControl.AccessRequired.ADMINISTRATOR;
 418         };
 419     }
 420
 421     private AccessControl.AccessRequired toAccessControl(final GroupPermission permission) {
 422         return switch (permission) {
 423             case EVERY_MEMBER -> AccessControl.AccessRequired.MEMBER;
 424             case ONLY_ADMINS -> AccessControl.AccessRequired.ADMINISTRATOR;
 425         };
 426     }
 427
 428     private GroupsV2Operations.GroupOperations getGroupOperations(final GroupInfoV2 groupInfoV2) {
 429         final var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupInfoV2.getMasterKey());
 430         return dependencies.getGroupsV2Operations().forGroup(groupSecretParams);
 431     }
 432
 433     private Pair<DecryptedGroup, GroupChange> revokeInvites(
 434             GroupInfoV2 groupInfoV2, Set<DecryptedPendingMember> pendingMembers
 435     ) throws IOException {
 436         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 437         final var uuidCipherTexts = pendingMembers.stream().map(member -> {
 438             try {
 439                 return new UuidCiphertext(member.getUuidCipherText().toByteArray());
 440             } catch (InvalidInputException e) {
 441                 throw new AssertionError(e);
 442             }
 443         }).collect(Collectors.toSet());
 444         return commitChange(groupInfoV2, groupOperations.createRemoveInvitationChange(uuidCipherTexts));
 445     }
 446
 447     private Pair<DecryptedGroup, GroupChange> ejectMembers(
 448             GroupInfoV2 groupInfoV2, Set<UUID> uuids
 449     ) throws IOException {
 450         final GroupsV2Operations.GroupOperations groupOperations = getGroupOperations(groupInfoV2);
 451         return commitChange(groupInfoV2, groupOperations.createRemoveMembersChange(uuids, false, List.of()));
 452     }
 453
 454     private Pair<DecryptedGroup, GroupChange> commitChange(
 455             GroupInfoV2 groupInfoV2, GroupChange.Actions.Builder change
 456     ) throws IOException {
 457         final var groupSecretParams = GroupSecretParams.deriveFromMasterKey(groupInfoV2.getMasterKey());
 458         final var groupOperations = dependencies.getGroupsV2Operations().forGroup(groupSecretParams);
 459         final var previousGroupState = groupInfoV2.getGroup();
 460         final var nextRevision = previousGroupState.getRevision() + 1;
 461         final var changeActions = change.setRevision(nextRevision).build();
 462         final DecryptedGroupChange decryptedChange;
 463         final DecryptedGroup decryptedGroupState;
 464
 465         try {
 466             decryptedChange = groupOperations.decryptChange(changeActions, getSelfAci().uuid());
 467             decryptedGroupState = DecryptedGroupUtil.apply(previousGroupState, decryptedChange);
 468         } catch (VerificationFailedException | InvalidGroupStateException | NotAbleToApplyGroupV2ChangeException e) {
 469             throw new IOException(e);
 470         }
 471
 472         var signedGroupChange = dependencies.getGroupsV2Api()
 473                 .patchGroup(changeActions, getGroupAuthForToday(groupSecretParams), Optional.empty());
 474
 475         return new Pair<>(decryptedGroupState, signedGroupChange);
 476     }
 477
 478     private GroupChange commitChange(
 479             GroupSecretParams groupSecretParams,
 480             int currentRevision,
 481             GroupChange.Actions.Builder change,
 482             GroupLinkPassword password
 483     ) throws IOException {
 484         final var nextRevision = currentRevision + 1;
 485         final var changeActions = change.setRevision(nextRevision).build();
 486
 487         return dependencies.getGroupsV2Api()
 488                 .patchGroup(changeActions,
 489                         getGroupAuthForToday(groupSecretParams),
 490                         Optional.ofNullable(password).map(GroupLinkPassword::serialize));
 491     }
 492
 493     DecryptedGroup getUpdatedDecryptedGroup(
 494             DecryptedGroup group, byte[] signedGroupChange, GroupMasterKey groupMasterKey
 495     ) {
 496         try {
 497             final var decryptedGroupChange = getDecryptedGroupChange(signedGroupChange, groupMasterKey);
 498             if (decryptedGroupChange == null) {
 499                 return null;
 500             }
 501             return DecryptedGroupUtil.apply(group, decryptedGroupChange);
 502         } catch (NotAbleToApplyGroupV2ChangeException e) {
 503             return null;
 504         }
 505     }
 506
 507     private DecryptedGroupChange getDecryptedGroupChange(byte[] signedGroupChange, GroupMasterKey groupMasterKey) {
 508         if (signedGroupChange != null) {
 509             var groupOperations = dependencies.getGroupsV2Operations()
 510                     .forGroup(GroupSecretParams.deriveFromMasterKey(groupMasterKey));
 511
 512             try {
 513                 return groupOperations.decryptChange(GroupChange.parseFrom(signedGroupChange), true).orElse(null);
 514             } catch (VerificationFailedException | InvalidGroupStateException | InvalidProtocolBufferException e) {
 515                 return null;
 516             }
 517         }
 518
 519         return null;
 520     }
 521
 522     private static int currentTimeDays() {
 523         return (int) TimeUnit.MILLISECONDS.toDays(System.currentTimeMillis());
 524     }
 525
 526     private GroupsV2AuthorizationString getGroupAuthForToday(
 527             final GroupSecretParams groupSecretParams
 528     ) throws IOException {
 529         final var today = currentTimeDays();
 530         if (groupApiCredentials == null || !groupApiCredentials.containsKey(today)) {
 531             // Returns credentials for the next 7 days
 532             groupApiCredentials = dependencies.getGroupsV2Api().getCredentials(today);
 533             // TODO cache credentials on disk until they expire
 534         }
 535         var authCredentialResponse = groupApiCredentials.get(today);
 536         final var aci = getSelfAci();
 537         try {
 538             return dependencies.getGroupsV2Api()
 539                     .getGroupsV2AuthorizationString(aci, today, groupSecretParams, authCredentialResponse);
 540         } catch (VerificationFailedException e) {
 541             throw new IOException(e);
 542         }
 543     }
 544
 545     private ACI getSelfAci() {
 546         return context.getAccount().getAci();
 547     }
 548 }