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Groups V2 protobufs and local conflict resolution.
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@alan-signal @greyson-signal
alan-signal authored and greyson-signal committed Mar 26, 2020
1 parent f449a45 commit 0269a3e
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13 changes: 13 additions & 0 deletions libsignal/service/src/main/java/org/whispersystems/signalservice/api/util/UuidUtil.java
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package org.whispersystems.signalservice.api.util;

import com.google.protobuf.ByteString;

import org.whispersystems.libsignal.util.guava.Optional;

import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.UUID;
import java.util.regex.Pattern;

Expand Down Expand Up @@ -43,4 +48,12 @@ public static byte[] toByteArray(UUID uuid) {

return buffer.array();
}

public static ByteString toByteString(UUID uuid) {
return ByteString.copyFrom(toByteArray(uuid));
}

public static UUID fromByteString(ByteString bytes) {
return parseOrThrow(bytes.toByteArray());
}
}
212 changes: 212 additions & 0 deletions ...ice/src/main/java/org/whispersystems/signalservice/internal/groupsv2/GroupChangeUtil.java
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package org.whispersystems.signalservice.internal.groupsv2;

import com.google.protobuf.ByteString;

import org.signal.storageservice.protos.groups.GroupChange;
import org.signal.storageservice.protos.groups.local.DecryptedGroup;
import org.signal.storageservice.protos.groups.local.DecryptedGroupChange;
import org.signal.storageservice.protos.groups.local.DecryptedMember;
import org.signal.storageservice.protos.groups.local.DecryptedModifyMemberRole;
import org.signal.storageservice.protos.groups.local.DecryptedPendingMember;
import org.signal.storageservice.protos.groups.local.DecryptedPendingMemberRemoval;

import java.util.HashMap;
import java.util.List;

public final class GroupChangeUtil {

private GroupChangeUtil() {
}

/**
* The maximum field we know about here.
*/
static final int CHANGE_ACTION_MAX_FIELD = 14;

/**
* True iff there are no change actions.
*/
public static boolean changeIsEmpty(GroupChange.Actions change) {
return change.getAddMembersCount() == 0 && // field 3
change.getDeleteMembersCount() == 0 && // field 4
change.getModifyMemberRolesCount() == 0 && // field 5
change.getModifyMemberProfileKeysCount() == 0 && // field 6
change.getAddPendingMembersCount() == 0 && // field 7
change.getDeletePendingMembersCount() == 0 && // field 8
change.getPromotePendingMembersCount() == 0 && // field 9
!change.hasModifyTitle() && // field 10
!change.hasModifyAvatar() && // field 11
!change.hasModifyDisappearingMessagesTimer() && // field 12
!change.hasModifyAttributesAccess() && // field 13
!change.hasModifyMemberAccess(); // field 14
}

/**
* Given the latest group state and a conflicting change, decides which changes to carry forward
* and returns a new group change which could be empty.
* <p>
* Titles, avatars, and other settings are carried forward if they are different. Last writer wins.
* <p>
* Membership additions and removals also respect last writer wins and are removed if they have
* already been applied. e.g. you add someone but they are already added.
* <p>
* Membership additions will be altered to {@link GroupChange.Actions.PromotePendingMemberAction}
* if someone has invited them since.
*
* @param groupState Latest group state in plaintext.
* @param conflictingChange The potentially conflicting change in plaintext.
* @param encryptedChange Encrypted version of the {@param conflictingChange}.
* @return A new change builder.
*/
public static GroupChange.Actions.Builder resolveConflict(DecryptedGroup groupState,
DecryptedGroupChange conflictingChange,
GroupChange.Actions encryptedChange)
{
GroupChange.Actions.Builder result = GroupChange.Actions.newBuilder(encryptedChange);
HashMap<ByteString, DecryptedMember> fullMembersByUuid = new HashMap<>(groupState.getMembersCount());
HashMap<ByteString, DecryptedPendingMember> pendingMembersByUuid = new HashMap<>(groupState.getPendingMembersCount());

for (DecryptedMember member : groupState.getMembersList()) {
fullMembersByUuid.put(member.getUuid(), member);
}

for (DecryptedPendingMember member : groupState.getPendingMembersList()) {
pendingMembersByUuid.put(member.getUuid(), member);
}

resolveField3AddMembers (conflictingChange, result, fullMembersByUuid, pendingMembersByUuid);
resolveField4DeleteMembers (conflictingChange, result, fullMembersByUuid);
resolveField5ModifyMemberRoles (conflictingChange, result, fullMembersByUuid);
resolveField6ModifyProfileKeys (conflictingChange, result, fullMembersByUuid);
resolveField7AddPendingMembers (conflictingChange, result, fullMembersByUuid, pendingMembersByUuid);
resolveField8DeletePendingMembers (conflictingChange, result, pendingMembersByUuid);
resolveField9PromotePendingMembers (conflictingChange, result, pendingMembersByUuid);
resolveField10ModifyTitle (groupState, conflictingChange, result);
resolveField11ModifyAvatar (groupState, conflictingChange, result);
resolveField12modifyDisappearingMessagesTimer(groupState, conflictingChange, result);
resolveField13modifyAttributesAccess (groupState, conflictingChange, result);
resolveField14modifyAttributesAccess (groupState, conflictingChange, result);

return result;
}

private static void resolveField3AddMembers(DecryptedGroupChange conflictingChange, GroupChange.Actions.Builder result, HashMap<ByteString, DecryptedMember> fullMembersByUuid, HashMap<ByteString, DecryptedPendingMember> pendingMembersByUuid) {
List<DecryptedMember> newMembersList = conflictingChange.getNewMembersList();

for (int i = newMembersList.size() - 1; i >= 0; i--) {
DecryptedMember member = newMembersList.get(i);

if (fullMembersByUuid.containsKey(member.getUuid())) {
result.removeAddMembers(i);
} else if (pendingMembersByUuid.containsKey(member.getUuid())) {
GroupChange.Actions.AddMemberAction addMemberAction = result.getAddMembersList().get(i);
result.removeAddMembers(i);
result.addPromotePendingMembers(GroupChange.Actions.PromotePendingMemberAction.newBuilder().setPresentation(addMemberAction.getAdded().getPresentation()));
}
}
}

private static void resolveField4DeleteMembers(DecryptedGroupChange conflictingChange, GroupChange.Actions.Builder result, HashMap<ByteString, DecryptedMember> fullMembersByUuid) {
List<ByteString> deletedMembersList = conflictingChange.getDeleteMembersList();

for (int i = deletedMembersList.size() - 1; i >= 0; i--) {
ByteString member = deletedMembersList.get(i);

if (!fullMembersByUuid.containsKey(member)) {
result.removeDeleteMembers(i);
}
}
}

private static void resolveField5ModifyMemberRoles(DecryptedGroupChange conflictingChange, GroupChange.Actions.Builder result, HashMap<ByteString, DecryptedMember> fullMembersByUuid) {
List<DecryptedModifyMemberRole> modifyRolesList = conflictingChange.getModifyMemberRolesList();

for (int i = modifyRolesList.size() - 1; i >= 0; i--) {
DecryptedModifyMemberRole modifyRoleAction = modifyRolesList.get(i);
DecryptedMember memberInGroup = fullMembersByUuid.get(modifyRoleAction.getUuid());

if (memberInGroup == null || memberInGroup.getRole() == modifyRoleAction.getRole()) {
result.removeModifyMemberRoles(i);
}
}
}

private static void resolveField6ModifyProfileKeys(DecryptedGroupChange conflictingChange, GroupChange.Actions.Builder result, HashMap<ByteString, DecryptedMember> fullMembersByUuid) {
List<DecryptedMember> modifyProfileKeysList = conflictingChange.getModifiedProfileKeysList();

for (int i = modifyProfileKeysList.size() - 1; i >= 0; i--) {
DecryptedMember member = modifyProfileKeysList.get(i);
DecryptedMember memberInGroup = fullMembersByUuid.get(member.getUuid());

if (memberInGroup == null || member.getProfileKey().equals(memberInGroup.getProfileKey())) {
result.removeModifyMemberProfileKeys(i);
}
}
}

private static void resolveField7AddPendingMembers(DecryptedGroupChange conflictingChange, GroupChange.Actions.Builder result, HashMap<ByteString, DecryptedMember> fullMembersByUuid, HashMap<ByteString, DecryptedPendingMember> pendingMembersByUuid) {
List<DecryptedPendingMember> newPendingMembersList = conflictingChange.getNewPendingMembersList();

for (int i = newPendingMembersList.size() - 1; i >= 0; i--) {
DecryptedPendingMember member = newPendingMembersList.get(i);

if (fullMembersByUuid.containsKey(member.getUuid()) || pendingMembersByUuid.containsKey(member.getUuid())) {
result.removeAddPendingMembers(i);
}
}
}

private static void resolveField8DeletePendingMembers(DecryptedGroupChange conflictingChange, GroupChange.Actions.Builder result, HashMap<ByteString, DecryptedPendingMember> pendingMembersByUuid) {
List<DecryptedPendingMemberRemoval> deletePendingMembersList = conflictingChange.getDeletePendingMembersList();

for (int i = deletePendingMembersList.size() - 1; i >= 0; i--) {
DecryptedPendingMemberRemoval member = deletePendingMembersList.get(i);

if (!pendingMembersByUuid.containsKey(member.getUuid())) {
result.removeDeletePendingMembers(i);
}
}
}

private static void resolveField9PromotePendingMembers(DecryptedGroupChange conflictingChange, GroupChange.Actions.Builder result, HashMap<ByteString, DecryptedPendingMember> pendingMembersByUuid) {
List<ByteString> promotePendingMembersList = conflictingChange.getPromotePendingMembersList();

for (int i = promotePendingMembersList.size() - 1; i >= 0; i--) {
ByteString member = promotePendingMembersList.get(i);

if (!pendingMembersByUuid.containsKey(member)) {
result.removePromotePendingMembers(i);
}
}
}

private static void resolveField10ModifyTitle(DecryptedGroup groupState, DecryptedGroupChange conflictingChange, GroupChange.Actions.Builder result) {
if (conflictingChange.hasNewTitle() && conflictingChange.getNewTitle().getValue().equals(groupState.getTitle())) {
result.clearModifyTitle();
}
}

private static void resolveField11ModifyAvatar(DecryptedGroup groupState, DecryptedGroupChange conflictingChange, GroupChange.Actions.Builder result) {
if (conflictingChange.hasNewAvatar() && conflictingChange.getNewAvatar().getValue().equals(groupState.getAvatar())) {
result.clearModifyAvatar();
}
}

private static void resolveField12modifyDisappearingMessagesTimer(DecryptedGroup groupState, DecryptedGroupChange conflictingChange, GroupChange.Actions.Builder result) {
if (conflictingChange.hasNewTimer() && conflictingChange.getNewTimer().getDuration() == groupState.getDisappearingMessagesTimer().getDuration()) {
result.clearModifyDisappearingMessagesTimer();
}
}

private static void resolveField13modifyAttributesAccess(DecryptedGroup groupState, DecryptedGroupChange conflictingChange, GroupChange.Actions.Builder result) {
if (conflictingChange.getNewAttributeAccess() == groupState.getAccessControl().getAttributes()) {
result.clearModifyAttributesAccess();
}
}

private static void resolveField14modifyAttributesAccess(DecryptedGroup groupState, DecryptedGroupChange conflictingChange, GroupChange.Actions.Builder result) {
if (conflictingChange.getNewMemberAccess() == groupState.getAccessControl().getMembers()) {
result.clearModifyMemberAccess();
}
}
}
73 changes: 73 additions & 0 deletions libsignal/service/src/main/proto/DecryptedGroups.proto
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/**
* Copyright (C) 2019 Open Whisper Systems
*
* Licensed according to the LICENSE file in this repository.
*/
syntax = "proto3";

option java_package = "org.signal.storageservice.protos.groups.local";
option java_multiple_files = true;

import "Groups.proto";

// Decrypted version of Member
// Keep field numbers in step
message DecryptedMember {
bytes uuid = 1;
Member.Role role = 2;
bytes profileKey = 3;
uint32 joinedAtVersion = 5;
}

message DecryptedPendingMember {
bytes uuid = 1;
Member.Role role = 2;
bytes addedByUuid = 3;
uint64 timestamp = 4;
bytes uuidCipherText = 5;
}

message DecryptedPendingMemberRemoval {
bytes uuid = 1;
bytes uuidCipherText = 2;
}

message DecryptedModifyMemberRole {
bytes uuid = 1;
Member.Role role = 2;
}

// Decrypted version of message Group
// Keep field numbers in step
message DecryptedGroup {
string title = 2;
string avatar = 3;
DisappearingMessagesTimer disappearingMessagesTimer = 4;
AccessControl accessControl = 5;
uint32 version = 6;
repeated DecryptedMember members = 7;
repeated DecryptedPendingMember pendingMembers = 8;
}

// Decrypted version of message GroupChange.Actions
// Keep field numbers in step
message DecryptedGroupChange {
bytes editor = 1;
uint32 version = 2;
repeated DecryptedMember newMembers = 3;
repeated bytes deleteMembers = 4;
repeated DecryptedModifyMemberRole modifyMemberRoles = 5;
repeated DecryptedMember modifiedProfileKeys = 6;
repeated DecryptedPendingMember newPendingMembers = 7;
repeated DecryptedPendingMemberRemoval deletePendingMembers = 8;
repeated bytes promotePendingMembers = 9;
DecryptedString newTitle = 10;
DecryptedString newAvatar = 11;
DisappearingMessagesTimer newTimer = 12;
AccessControl.AccessRequired newAttributeAccess = 13;
AccessControl.AccessRequired newMemberAccess = 14;
}

message DecryptedString {
string value = 1;
}

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