From f46df2ddd9c800ac806be9a31291a9f97d706e93 Mon Sep 17 00:00:00 2001
From: Travis Ralston <travpc@gmail.com>
Date: Thu, 14 Feb 2019 11:09:37 -0700
Subject: [PATCH] Add a bit of safety around reading events for room settings

Fixes https://github.com/vector-im/riot-web/issues/8530 and maybe https://github.com/vector-im/riot-web/issues/8641
---
 .../settings/tabs/RolesRoomSettingsTab.js     |  6 +++--
 .../settings/tabs/SecurityRoomSettingsTab.js  | 24 ++++++++++++++++---
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/src/components/views/settings/tabs/RolesRoomSettingsTab.js b/src/components/views/settings/tabs/RolesRoomSettingsTab.js
index 2195017782..d223e8f2e9 100644
--- a/src/components/views/settings/tabs/RolesRoomSettingsTab.js
+++ b/src/components/views/settings/tabs/RolesRoomSettingsTab.js
@@ -116,7 +116,8 @@ export default class RolesRoomSettingsTab extends React.Component {
     _onPowerLevelsChanged = (value, powerLevelKey) => {
         const client = MatrixClientPeg.get();
         const room = client.getRoom(this.props.roomId);
-        let plContent = room.currentState.getStateEvents('m.room.power_levels', '').getContent() || {};
+        const plEvent = room.currentState.getStateEvents('m.room.power_levels', '');
+        let plContent = plEvent ? (plEvent.getContent() || {}) : {};
 
         // Clone the power levels just in case
         plContent = Object.assign({}, plContent);
@@ -151,7 +152,8 @@ export default class RolesRoomSettingsTab extends React.Component {
 
         const client = MatrixClientPeg.get();
         const room = client.getRoom(this.props.roomId);
-        const plContent = room.currentState.getStateEvents('m.room.power_levels', '').getContent() || {};
+        const plEvent = room.currentState.getStateEvents('m.room.power_levels', '');
+        const plContent = plEvent ? (plEvent.getContent() || {}) : {};
         const canChangeLevels = room.currentState.mayClientSendStateEvent('m.room.power_levels', client);
 
         const powerLevelDescriptors = {
diff --git a/src/components/views/settings/tabs/SecurityRoomSettingsTab.js b/src/components/views/settings/tabs/SecurityRoomSettingsTab.js
index 593e8151d2..698f67dd18 100644
--- a/src/components/views/settings/tabs/SecurityRoomSettingsTab.js
+++ b/src/components/views/settings/tabs/SecurityRoomSettingsTab.js
@@ -43,13 +43,31 @@ export default class SecurityRoomSettingsTab extends React.Component {
 
         const room = MatrixClientPeg.get().getRoom(this.props.roomId);
         const state = room.currentState;
-        const joinRule = state.getStateEvents("m.room.join_rules", "").getContent()['join_rule'];
-        const guestAccess = state.getStateEvents("m.room.guest_access", "").getContent()['guest_access'];
-        const history = state.getStateEvents("m.room.history_visibility", "").getContent()['history_visibility'];
+
+        const joinRule = this._pullContentPropertyFromEvent(
+            state.getStateEvents("m.room.join_rules", ""),
+            'join_rule',
+            'invite',
+        );
+        const guestAccess = this._pullContentPropertyFromEvent(
+            state.getStateEvents("m.room.guest_access", ""),
+            'guest_access',
+            'forbidden',
+        );
+        const history = this._pullContentPropertyFromEvent(
+            state.getStateEvents("m.room.history_visibility", ""),
+            'history_visibility',
+            'shared',
+        );
         const encrypted = MatrixClientPeg.get().isRoomEncrypted(this.props.roomId);
         this.setState({joinRule, guestAccess, history, encrypted});
     }
 
+    _pullContentPropertyFromEvent(event, key, defaultValue) {
+        if (!event || !event.getContent()) return defaultValue;
+        return event.getContent()[key] || defaultValue;
+    }
+
     componentWillUnmount(): void {
         MatrixClientPeg.get().removeListener("RoomState.events", this._onStateEvent);
     }