Group Description: Edit/Receive

ts/groups.ts

@@ -178,6 +178,10 @@ export type GroupV2AdminApprovalRemoveOneChangeType = {
   conversationId: string;
   inviter?: string;
 };
+export type GroupV2DescriptionChangeType = {
+  type: 'description';
+  removed?: boolean;
+};
 
 export type GroupV2ChangeDetailType =
   | GroupV2AccessAttributesChangeType
@@ -187,9 +191,10 @@ export type GroupV2ChangeDetailType =
   | GroupV2AdminApprovalAddOneChangeType
   | GroupV2AdminApprovalRemoveOneChangeType
   | GroupV2AvatarChangeType
+  | GroupV2DescriptionChangeType
   | GroupV2GroupLinkAddChangeType
-  | GroupV2GroupLinkResetChangeType
   | GroupV2GroupLinkRemoveChangeType
+  | GroupV2GroupLinkResetChangeType
   | GroupV2MemberAddChangeType
   | GroupV2MemberAddFromAdminApprovalChangeType
   | GroupV2MemberAddFromInviteChangeType
@@ -251,12 +256,13 @@ type UploadedAvatarType = {
 
 export const MASTER_KEY_LENGTH = 32;
 const GROUP_TITLE_MAX_ENCRYPTED_BYTES = 1024;
+const GROUP_DESC_MAX_ENCRYPTED_BYTES = 8192;
 export const ID_V1_LENGTH = 16;
 export const ID_LENGTH = 32;
 const TEMPORAL_AUTH_REJECTED_CODE = 401;
 const GROUP_ACCESS_DENIED_CODE = 403;
 const GROUP_NONEXISTENT_CODE = 404;
-const SUPPORTED_CHANGE_EPOCH = 1;
+const SUPPORTED_CHANGE_EPOCH = 2;
 export const LINK_VERSION_ERROR = 'LINK_VERSION_ERROR';
 const GROUP_INVITE_LINK_PASSWORD_LENGTH = 16;
 
@@ -415,6 +421,25 @@ function buildGroupTitleBuffer(
   return result;
 }
 
+function buildGroupDescriptionBuffer(
+  clientZkGroupCipher: ClientZkGroupCipher,
+  description: string
+): ArrayBuffer {
+  const attrsBlob = new window.textsecure.protobuf.GroupAttributeBlob();
+  attrsBlob.descriptionText = description;
+  const attrsBlobPlaintext = attrsBlob.toArrayBuffer();
+
+  const result = encryptGroupBlob(clientZkGroupCipher, attrsBlobPlaintext);
+
+  if (result.byteLength > GROUP_DESC_MAX_ENCRYPTED_BYTES) {
+    throw new Error(
+      'buildGroupDescriptionBuffer: encrypted group title is too long'
+    );
+  }
+
+  return result;
+}
+
 function buildGroupProto(
   attributes: Pick<
     ConversationAttributesType,
@@ -716,6 +741,7 @@ export async function buildUpdateAttributesChange(
   >,
   attributes: Readonly<{
     avatar?: undefined | ArrayBuffer;
+    description?: string;
     title?: string;
   }>
 ): Promise<undefined | GroupChangeClass.Actions> {
@@ -774,6 +800,17 @@ export async function buildUpdateAttributesChange(
     );
   }
 
+  const { description } = attributes;
+  if (typeof description === 'string') {
+    hasChangedSomething = true;
+
+    actions.modifyDescription = new window.textsecure.protobuf.GroupChange.Actions.ModifyDescriptionAction();
+    actions.modifyDescription.descriptionBytes = buildGroupDescriptionBuffer(
+      clientZkGroupCipher,
+      description
+    );
+  }
+
   if (!hasChangedSomething) {
     // This shouldn't happen. When these actions are passed to `modifyGroupV2`, a warning
     //   will be logged.
@@ -3612,6 +3649,14 @@ function extractDiffs({
     });
   }
 
+  // description
+  if (old.description !== current.description) {
+    details.push({
+      type: 'description',
+      removed: !current.description,
+    });
+  }
+
   // No disappearing message timer check here - see below
 
   // membersV2
@@ -4396,6 +4441,19 @@ async function applyGroupChange({
     }
   }
 
+  // modifyDescription?: GroupChangeClass.Actions.ModifyDescriptionAction;
+  if (actions.modifyDescription) {
+    const { descriptionBytes } = actions.modifyDescription;
+    if (descriptionBytes && descriptionBytes.content === 'descriptionText') {
+      result.description = descriptionBytes.descriptionText;
+    } else {
+      window.log.warn(
+        `applyGroupChange/${logId}: Clearing group description due to missing data.`
+      );
+      result.description = undefined;
+    }
+  }
+
   if (ourConversationId) {
     result.left = !members[ourConversationId];
   }
@@ -4669,6 +4727,14 @@ async function applyGroupState({
     result.groupInviteLinkPassword = undefined;
   }
 
+  // descriptionBytes
+  const { descriptionBytes } = groupState;
+  if (descriptionBytes && descriptionBytes.content === 'descriptionText') {
+    result.description = descriptionBytes.descriptionText;
+  } else {
+    result.description = undefined;
+  }
+
   return {
     newAttributes: result,
     newProfileKeys,
@@ -5219,6 +5285,29 @@ function decryptGroupChange(
     actions.modifyInviteLinkPassword = undefined;
   }
 
+  // modifyDescription?: GroupChangeClass.Actions.ModifyDescriptionAction;
+  if (
+    actions.modifyDescription &&
+    !isByteBufferEmpty(actions.modifyDescription.descriptionBytes)
+  ) {
+    try {
+      actions.modifyDescription.descriptionBytes = window.textsecure.protobuf.GroupAttributeBlob.decode(
+        decryptGroupBlob(
+          clientZkGroupCipher,
+          actions.modifyDescription.descriptionBytes.toArrayBuffer()
+        )
+      );
+    } catch (error) {
+      window.log.warn(
+        `decryptGroupChange/${logId}: Unable to decrypt modifyDescription.descriptionBytes`,
+        error && error.stack ? error.stack : error
+      );
+      actions.modifyDescription.descriptionBytes = undefined;
+    }
+  } else if (actions.modifyDescription) {
+    actions.modifyDescription.descriptionBytes = undefined;
+  }
+
   return actions;
 }
 
@@ -5240,6 +5329,26 @@ export function decryptGroupTitle(
   return undefined;
 }
 
+export function decryptGroupDescription(
+  description: ProtoBinaryType,
+  secretParams: string
+): string | undefined {
+  const clientZkGroupCipher = getClientZkGroupCipher(secretParams);
+  if (isByteBufferEmpty(description)) {
+    return undefined;
+  }
+
+  const blob = window.textsecure.protobuf.GroupAttributeBlob.decode(
+    decryptGroupBlob(clientZkGroupCipher, description.toArrayBuffer())
+  );
+
+  if (blob && blob.content === 'descriptionText') {
+    return blob.descriptionText;
+  }
+
+  return undefined;
+}
+
 function decryptGroupState(
   groupState: GroupClass,
   groupSecretParams: string,
@@ -5349,6 +5458,26 @@ function decryptGroupState(
     groupState.inviteLinkPassword = undefined;
   }
 
+  // descriptionBytes
+  if (!isByteBufferEmpty(groupState.descriptionBytes)) {
+    try {
+      groupState.descriptionBytes = window.textsecure.protobuf.GroupAttributeBlob.decode(
+        decryptGroupBlob(
+          clientZkGroupCipher,
+          groupState.descriptionBytes.toArrayBuffer()
+        )
+      );
+    } catch (error) {
+      window.log.warn(
+        `decryptGroupState/${logId}: Unable to decrypt descriptionBytes. Clearing it.`,
+        error && error.stack ? error.stack : error
+      );
+      groupState.descriptionBytes = undefined;
+    }
+  } else {
+    groupState.descriptionBytes = undefined;
+  }
+
   return groupState;
 }