fix(previews): a page can no longer pose as a YouTube (etc.) player via its og:url (#326)

The embed fallback used the preview's og:url whatever site was posted.
og:url is set by the page, so evil.example could render as a playable
YouTube card (attacker's video) whose links go to evil.example. Only use
an og:url on the same provider as the posted link, including the
provider's own short-link domains (youtu.be, spotify.link, redd.it, …).

Fixes #326

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/app/components/AccountDataEditor.tsx

@@ -297,7 +297,7 @@ export function AccountDataEditor({
             </Chip>
           </Box>
           <Box shrink="No">
-            <IconButton onClick={requestClose} variant="Surface" aria-label="Close">
+            <IconButton type="button" onClick={requestClose} variant="Surface" aria-label="Close">
               <Icon src={Icons.Cross} />
             </IconButton>
           </Box>

src/app/components/DeviceVerificationSetup.tsx

@@ -315,7 +315,7 @@ export const DeviceVerificationSetup = forwardRef<HTMLDivElement, DeviceVerifica
               Setup Device Verification
             </Text>
           </Box>
-          <IconButton size="300" radii="300" onClick={onCancel} aria-label="Cancel">
+          <IconButton type="button" size="300" radii="300" onClick={onCancel} aria-label="Cancel">
             <Icon src={Icons.Cross} />
           </IconButton>
         </Header>
@@ -361,7 +361,7 @@ export const DeviceVerificationReset = forwardRef<HTMLDivElement, DeviceVerifica
               Reset Device Verification
             </Text>
           </Box>
-          <IconButton size="300" radii="300" onClick={onCancel} aria-label="Cancel">
+          <IconButton type="button" size="300" radii="300" onClick={onCancel} aria-label="Cancel">
             <Icon src={Icons.Cross} />
           </IconButton>
         </Header>

src/app/components/create-room/utils.ts

@@ -139,8 +139,11 @@ export const createRoom = async (mx: MatrixClient, data: CreateRoomData): Promis
       data.allowFederation,
       data.additionalCreators,
     ),
-    power_level_content_override:
-      data.type === RoomType.Call ? createVoiceRoomPowerLevelsOverride() : undefined,
+    // [Gitea #328] Every non-space room gets call.member at user level, not just
+    // voice rooms: the call button is shown in private group rooms too, and with
+    // Synapse's state_default (50) only admins could start or join a call there
+    // ("You don't have permission to join!").
+    power_level_content_override: createVoiceRoomPowerLevelsOverride(),
     initial_state: initialState,
   };
 

src/app/components/url-preview/UrlPreviewCard.tsx

@@ -54,6 +54,7 @@ import {
   GIF_PREVIEW_MAX_WIDTH,
   gifPreviewBox,
 } from '../../utils/gifPreviewSize';
+import { sameProvider } from './embedProvider';
 
 const linkStyles = { color: color.Success.Main };
 
@@ -2497,7 +2498,10 @@ export const UrlPreviewCard = as<'div', { url: string; ts: number }>(
     const resolveEmbed = (prev: IPreviewUrlResponse): MediaEmbed | null => {
       if (embed) return embed;
       const ogUrl = prev['og:url'];
-      return typeof ogUrl === 'string' && ogUrl !== url
+      // [Gitea #326] …but only from an og:url on the posted link's own
+      // provider: the page sets og:url, so any site could otherwise show up
+      // as a playable YouTube (etc.) card that links to itself.
+      return typeof ogUrl === 'string' && ogUrl !== url && sameProvider(url, ogUrl)
         ? parseMediaEmbed(ogUrl, window.location.hostname)
         : null;
     };

src/app/components/url-preview/embedProvider.test.ts

@@ -0,0 +1,22 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { sameProvider } from './embedProvider';
+
+test("sameProvider: a page cannot borrow another provider's embed via og:url (#326)", () => {
+  const yt = 'https://www.youtube.com/watch?v=dQw4w9WgXcQ';
+  assert.equal(sameProvider('https://evil.example/free-gift', yt), false);
+  assert.equal(sameProvider('https://youtube.com.evil.example/x', yt), false);
+  assert.equal(sameProvider('https://youtu.be/abc', yt), true);
+  assert.equal(sameProvider('https://m.youtube.com/shorts/abc', yt), true);
+  assert.equal(
+    sameProvider('https://vm.tiktok.com/ZM123/', 'https://www.tiktok.com/@a/video/1'),
+    true,
+  );
+  assert.equal(sameProvider('https://spotify.link/abc', 'https://open.spotify.com/track/1'), true);
+  assert.equal(sameProvider('https://on.soundcloud.com/x', 'https://soundcloud.com/a/b'), true);
+  assert.equal(
+    sameProvider('https://redd.it/abc', 'https://www.reddit.com/r/x/comments/abc/'),
+    true,
+  );
+  assert.equal(sameProvider('not a url', yt), false);
+});

src/app/components/url-preview/embedProvider.ts

@@ -0,0 +1,36 @@
+/**
+ * [Gitea #326] A page's og:url is chosen by the page itself, so a phishing
+ * link could serve `og:url = youtube.com/watch?v=…` and render as a playable
+ * YouTube card linking to the attacker. Only trust an og:url on the same
+ * provider as the link actually posted (including the provider's own
+ * short-link domains).
+ */
+const PROVIDER_ALIASES: Record<string, string> = {
+  'youtu.be': 'youtube.com',
+  'youtube-nocookie.com': 'youtube.com',
+  'spotify.link': 'spotify.com',
+  'redd.it': 'reddit.com',
+  'x.com': 'twitter.com',
+  'twitch.tv': 'twitch.tv',
+  'apple.co': 'apple.com',
+};
+
+/**
+ * Pure: the provider a host belongs to (last two labels, aliases folded). Hosts
+ * under two-part public suffixes (`*.co.uk`) share a value, which is harmless
+ * here: no embeddable provider lives under one.
+ */
+export const providerOf = (host: string): string => {
+  const parts = host.toLowerCase().replace(/\.$/, '').split('.');
+  const base = parts.slice(-2).join('.');
+  return PROVIDER_ALIASES[base] ?? base;
+};
+
+/** Pure: whether `ogUrl` is on the same provider as the posted `url`. */
+export function sameProvider(url: string, ogUrl: string): boolean {
+  try {
+    return providerOf(new URL(url).hostname) === providerOf(new URL(ogUrl).hostname);
+  } catch {
+    return false;
+  }
+}

src/app/features/common-settings/developer-tools/StateEventEditor.tsx

@@ -275,7 +275,7 @@ export function StateEventEditor({ type, stateKey, requestClose }: StateEventEdi
             </Chip>
           </Box>
           <Box shrink="No">
-            <IconButton onClick={requestClose} variant="Surface" aria-label="Close">
+            <IconButton type="button" onClick={requestClose} variant="Surface" aria-label="Close">
               <Icon src={Icons.Cross} />
             </IconButton>
           </Box>

src/app/features/room/PollCreator.tsx

@@ -143,7 +143,7 @@ export function PollCreator({ roomId, threadRootId, onClose }: PollCreatorProps)
                   Create Poll
                 </Text>
               </Box>
-              <IconButton size="300" radii="300" onClick={onClose} aria-label="Close">
+              <IconButton type="button" size="300" radii="300" onClick={onClose} aria-label="Close">
                 <Icon src={Icons.Cross} />
               </IconButton>
             </Header>

src/app/features/room/ReportRoomModal.tsx

@@ -118,7 +118,7 @@ export function ReportRoomModal({ roomId, onClose }: ReportRoomModalProps) {
                   Report Room
                 </Text>
               </Box>
-              <IconButton size="300" onClick={onClose} radii="300" aria-label="Close">
+              <IconButton type="button" size="300" onClick={onClose} radii="300" aria-label="Close">
                 <Icon src={Icons.Cross} />
               </IconButton>
             </Header>

src/app/features/room/ReportUserModal.tsx

@@ -124,7 +124,7 @@ export function ReportUserModal({ userId, onClose }: ReportUserModalProps) {
                   Report User
                 </Text>
               </Box>
-              <IconButton size="300" onClick={onClose} radii="300" aria-label="Close">
+              <IconButton type="button" size="300" onClick={onClose} radii="300" aria-label="Close">
                 <Icon src={Icons.Cross} />
               </IconButton>
             </Header>

src/app/features/room/ScheduleMessageModal.tsx

@@ -202,7 +202,7 @@ export function ScheduleMessageModal({
                   {title}
                 </Text>
               </Box>
-              <IconButton size="300" radii="300" onClick={onClose} aria-label="Close">
+              <IconButton type="button" size="300" radii="300" onClick={onClose} aria-label="Close">
                 <Icon src={Icons.Cross} />
               </IconButton>
             </Header>

src/app/features/room/message/Message.tsx

@@ -725,7 +725,13 @@ export const MessageDeleteItem = as<
                     Delete Message
                   </Text>
                 </Box>
-                <IconButton size="300" onClick={handleClose} radii="300" aria-label="Close">
+                <IconButton
+                  type="button"
+                  size="300"
+                  onClick={handleClose}
+                  radii="300"
+                  aria-label="Close"
+                >
                   <Icon src={Icons.Cross} />
                 </IconButton>
               </Header>
@@ -865,7 +871,13 @@ export const MessageReportItem = as<
                     Report Message
                   </Text>
                 </Box>
-                <IconButton size="300" onClick={handleClose} radii="300" aria-label="Close">
+                <IconButton
+                  type="button"
+                  size="300"
+                  onClick={handleClose}
+                  radii="300"
+                  aria-label="Close"
+                >
                   <Icon src={Icons.Cross} />
                 </IconButton>
               </Header>

src/app/features/room/message/Reactions.tsx

@@ -69,8 +69,15 @@ export const Reactions = as<'div', ReactionsProps>(
     const measure = useCallback(() => {
       const container = containerRef.current;
       if (!container) return;
-      const rowWidth = container.getBoundingClientRect().width;
-      const gap = parseFloat(getComputedStyle(container).columnGap) || 8;
+      // [Gitea #305] The width the chips actually get (content box). The border
+      // box grows by 4 px while collapsed (margin -2 / padding 2), and measuring
+      // it made a row within 4 px of fitting flip collapsed↔expanded every frame.
+      const cs = getComputedStyle(container);
+      const rowWidth =
+        container.clientWidth -
+        (parseFloat(cs.paddingLeft) || 0) -
+        (parseFloat(cs.paddingRight) || 0);
+      const gap = parseFloat(cs.columnGap) || 8;
       const chips = keys ? keys.split('\u0000').map((k) => chipRefs.current.get(k)) : [];
       const widths = chips.map((el) => el?.getBoundingClientRect().width ?? 0);
       const moreWidth = moreRef.current?.getBoundingClientRect().width ?? 48;
@@ -110,8 +117,21 @@ export const Reactions = as<'div', ReactionsProps>(
         style={{
           ...props.style,
           ...(collapsed && rowHeight
-            ? // 2px breathing room so row-1 focus outlines are not clipped.
-              { maxHeight: rowHeight + 4, overflow: 'hidden', padding: 2, margin: -2 }
+            ? // 2px breathing room so row-1 focus outlines are not clipped. Longhand
+              // margins so the timeline's marginTop survives (Gitea #305: the
+              // `margin` shorthand overrode it and, once removed, cleared it).
+              {
+                maxHeight: rowHeight + 4,
+                overflow: 'hidden',
+                padding: 2,
+                marginLeft: -2,
+                marginRight: -2,
+                marginBottom: -2,
+                marginTop:
+                  props.style?.marginTop !== undefined
+                    ? `calc(${typeof props.style.marginTop === 'number' ? `${props.style.marginTop}px` : props.style.marginTop} - 2px)`
+                    : -2,
+              }
             : {}),
         }}
         ref={(el) => {