Don't assert name during decryption (#13802)

go/chat/sender.go

@@ -150,8 +150,7 @@ func (s *BlockingSender) addPrevPointersAndCheckConvID(ctx context.Context, msg
 
 	for _, msg2 := range thread.Messages {
 		if msg2.IsValid() {
-			err = s.checkConvID(ctx, conv, msg, msg2)
-			if err != nil {
+			if err = s.checkConvID(ctx, conv, msg, msg2); err != nil {
 				return resMsg, err
 			}
 			break

go/chat/subteam_rename_test.go

@@ -79,6 +79,22 @@ func TestChatSubteamRename(t *testing.T) {
 				require.NoError(t, err)
 				convs = append(convs, ncres.Conv.Info)
 				versMap[ncres.Conv.GetConvID().String()] = ncres.Conv.Info.Version
+
+				// Write a message so we have something that uses the old team name in the chat history.
+				_, err = ctc.as(t, users[0]).chatLocalHandler().PostLocal(context.TODO(), chat1.PostLocalArg{
+					ConversationID: ncres.Conv.Info.Id,
+					Msg: chat1.MessagePlaintext{
+						ClientHeader: chat1.MessageClientHeader{
+							Conv:        ncres.Conv.Info.Triple,
+							MessageType: chat1.MessageType_TEXT,
+							TlfName:     ncres.Conv.Info.TlfName,
+						},
+						MessageBody: chat1.NewMessageBodyWithText(chat1.MessageText{
+							Body: "Hello",
+						}),
+					},
+				})
+				require.NoError(t, err)
 			}
 		}
 
@@ -157,6 +173,14 @@ func TestChatSubteamRename(t *testing.T) {
 				},
 			})
 			require.NoError(t, err)
+			// Make sure user1 (user0 did all the sends) can decrypt everything
+			// in conversation.
+			tv, err := tc.Context().ConvSource.Pull(context.TODO(), convID, users[1].GetUID().ToBytes(), chat1.GetThreadReason_GENERAL, nil,
+				nil)
+			require.NoError(t, err)
+			for _, msg := range tv.Messages {
+				require.True(t, msg.IsValid())
+			}
 		}
 	})
 }

go/chat/teams.go

@@ -60,9 +60,10 @@ func encryptionKeyViaFTL(m libkb.MetaContext, name string, tlfID chat1.TLFID) (r
 	return ftlRes.ApplicationKeys[0], ni, nil
 }
 
-func decryptionKeyViaFTL(m libkb.MetaContext, name string, tlfID chat1.TLFID, keyGeneration int) (res types.CryptKey, err error) {
+func decryptionKeyViaFTL(m libkb.MetaContext, tlfID chat1.TLFID, keyGeneration int) (res types.CryptKey, err error) {
 
-	ftlRes, err := getKeyViaFTL(m, name, tlfID, keyGeneration)
+	// We don't pass a `name` during decryption.
+	ftlRes, err := getKeyViaFTL(m, "" /*name*/, tlfID, keyGeneration)
 	if err != nil {
 		return nil, err
 	}
@@ -76,16 +77,21 @@ func getKeyViaFTL(m libkb.MetaContext, name string, tlfID chat1.TLFID, keyGenera
 	if err != nil {
 		return res, err
 	}
-
-	teamName, err := keybase1.TeamNameFromString(name)
-	if err != nil {
-		return res, err
+	// The `name` parameter is optional since subteams can be renamed and
+	// messages with the old name must be successfully decrypted.
+	var teamNamePtr *keybase1.TeamName
+	if name != "" {
+		teamName, err := keybase1.TeamNameFromString(name)
+		if err != nil {
+			return res, err
+		}
+		teamNamePtr = &teamName
 	}
 	arg := keybase1.FastTeamLoadArg{
 		ID:             teamID,
 		Public:         false,
 		Applications:   []keybase1.TeamApplication{keybase1.TeamApplication_CHAT},
-		AssertTeamName: &teamName,
+		AssertTeamName: teamNamePtr,
 	}
 
 	if keyGeneration > 0 {
@@ -357,7 +363,7 @@ func (t *TeamsNameInfoSource) DecryptionKey(ctx context.Context, name string, te
 
 	m := libkb.NewMetaContext(ctx, t.G().ExternalG())
 	if !kbfsEncrypted && !public && membersType == chat1.ConversationMembersType_TEAM && m.G().FeatureFlags.Enabled(m, libkb.FeatureFTL) {
-		res, err = decryptionKeyViaFTL(m, name, teamID, keyGeneration)
+		res, err = decryptionKeyViaFTL(m, teamID, keyGeneration)
 		if shouldFallbackToSlowLoadAfterFTLError(m, err) {
 			// See comment above in EncryptionKey()
 			err = nil