Create group link previews; don't open Signal links in browser first; allow ephemeral download of previously-error'd pack

js/modules/link_previews.d.ts

@@ -7,6 +7,8 @@ export function findLinks(text: string, caretLocation?: number): Array<string>;
 
 export function getDomain(href: string): string;
 
+export function isGroupLink(href: string): boolean;
+
 export function isLinkSneaky(link: string): boolean;
 
 export function isStickerPack(href: string): boolean;

js/modules/link_previews.js

@@ -12,6 +12,7 @@ const linkify = LinkifyIt();
 module.exports = {
   findLinks,
   getDomain,
+  isGroupLink,
   isLinkSafeToPreview,
   isLinkSneaky,
   isStickerPack,
@@ -34,6 +35,10 @@ function isStickerPack(link) {
   return (link || '').startsWith('https://signal.art/addstickers/');
 }
 
+function isGroupLink(link) {
+  return (link || '').startsWith('https://signal.group/');
+}
+
 function findLinks(text, caretLocation) {
   const haveCaretLocation = isNumber(caretLocation);
   const textLength = text ? text.length : 0;

js/modules/stickers.js

@@ -354,7 +354,12 @@ async function downloadEphemeralPack(packId, packKey) {
   } = getReduxStickerActions();
 
   const existingPack = getStickerPack(packId);
-  if (existingPack) {
+  if (
+    existingPack &&
+    (existingPack.status === 'downloaded' ||
+      existingPack.status === 'installed' ||
+      existingPack.status === 'pending')
+  ) {
     log.warn(
       `Ephemeral download for pack ${redactPackId(
         packId

main.js

@@ -99,7 +99,12 @@ const {
 const { installPermissionsHandler } = require('./app/permissions');
 const OS = require('./ts/OS');
 const { isBeta } = require('./ts/util/version');
-const { isSgnlHref, parseSgnlHref } = require('./ts/util/sgnlHref');
+const {
+  isSgnlHref,
+  isSignalHttpsLink,
+  parseSgnlHref,
+  parseSignalHttpsLink,
+} = require('./ts/util/sgnlHref');
 const {
   toggleMaximizedBrowserWindow,
 } = require('./ts/util/toggleMaximizedBrowserWindow');
@@ -227,6 +232,11 @@ async function handleUrl(event, target) {
   const { protocol, hostname } = url.parse(target);
   const isDevServer = config.enableHttp && hostname === 'localhost';
   // We only want to specially handle urls that aren't requesting the dev server
+  if (isSgnlHref(target) || isSignalHttpsLink(target)) {
+    handleSgnlHref(target);
+    return;
+  }
+
   if ((protocol === 'http:' || protocol === 'https:') && !isDevServer) {
     try {
       await shell.openExternal(target);
@@ -1476,7 +1486,16 @@ function getIncomingHref(argv) {
 }
 
 function handleSgnlHref(incomingHref) {
-  const { command, args, hash } = parseSgnlHref(incomingHref, logger);
+  let command;
+  let args;
+  let hash;
+
+  if (isSgnlHref(incomingHref)) {
+    ({ command, args, hash } = parseSgnlHref(incomingHref, logger));
+  } else if (isSignalHttpsLink(incomingHref)) {
+    ({ command, args, hash } = parseSignalHttpsLink(incomingHref, logger));
+  }
+
   if (command === 'addstickers' && mainWindow && mainWindow.webContents) {
     console.log('Opening sticker pack from sgnl protocol link');
     const packId = args.get('pack_id');

ts/groups.ts

@@ -3809,6 +3809,30 @@ async function applyGroupChange({
   };
 }
 
+export async function decryptGroupAvatar(
+  avatarKey: string,
+  secretParamsBase64: string
+): Promise<ArrayBuffer> {
+  const sender = window.textsecure.messaging;
+  if (!sender) {
+    throw new Error(
+      'decryptGroupAvatar: textsecure.messaging is not available!'
+    );
+  }
+
+  const ciphertext = await sender.getGroupAvatar(avatarKey);
+  const clientZkGroupCipher = getClientZkGroupCipher(secretParamsBase64);
+  const plaintext = decryptGroupBlob(clientZkGroupCipher, ciphertext);
+  const blob = window.textsecure.protobuf.GroupAttributeBlob.decode(plaintext);
+  if (blob.content !== 'avatar') {
+    throw new Error(
+      `decryptGroupAvatar: Returned blob had incorrect content: ${blob.content}`
+    );
+  }
+
+  return blob.avatar.toArrayBuffer();
+}
+
 // Ovewriting result.avatar as part of functionality
 /* eslint-disable no-param-reassign */
 export async function applyNewAvatar(
@@ -3825,30 +3849,11 @@ export async function applyNewAvatar(
 
     // Group has avatar; has it changed?
     if (newAvatar && (!result.avatar || result.avatar.url !== newAvatar)) {
-      const sender = window.textsecure.messaging;
-      if (!sender) {
-        throw new Error(
-          'applyNewAvatar: textsecure.messaging is not available!'
-        );
-      }
-
       if (!result.secretParams) {
         throw new Error('applyNewAvatar: group was missing secretParams!');
       }
 
-      const ciphertext = await sender.getGroupAvatar(newAvatar);
-      const clientZkGroupCipher = getClientZkGroupCipher(result.secretParams);
-      const plaintext = decryptGroupBlob(clientZkGroupCipher, ciphertext);
-      const blob = window.textsecure.protobuf.GroupAttributeBlob.decode(
-        plaintext
-      );
-      if (blob.content !== 'avatar') {
-        throw new Error(
-          `applyNewAvatar: Returned blob had incorrect content: ${blob.content}`
-        );
-      }
-
-      const data = blob.avatar.toArrayBuffer();
+      const data = await decryptGroupAvatar(newAvatar, result.secretParams);
       const hash = await computeHash(data);
 
       if (result.avatar && result.avatar.path && result.avatar.hash !== hash) {

ts/test-node/util/sgnlHref_test.ts

@@ -5,7 +5,12 @@ import { assert } from 'chai';
 import Sinon from 'sinon';
 import { LoggerType } from '../../types/Logging';
 
-import { isSgnlHref, parseSgnlHref } from '../../util/sgnlHref';
+import {
+  isSgnlHref,
+  isSignalHttpsLink,
+  parseSgnlHref,
+  parseSignalHttpsLink,
+} from '../../util/sgnlHref';
 
 function shouldNeverBeCalled() {
   assert.fail('This should never be called');
@@ -83,6 +88,67 @@ describe('sgnlHref', () => {
     });
   });
 
+  describe('isSignalHttpsLink', () => {
+    it('returns false for non-strings', () => {
+      const logger = {
+        ...explodingLogger,
+        warn: Sinon.spy(),
+      };
+
+      const castToString = (value: unknown): string => value as string;
+
+      assert.isFalse(isSignalHttpsLink(castToString(undefined), logger));
+      assert.isFalse(isSignalHttpsLink(castToString(null), logger));
+      assert.isFalse(isSignalHttpsLink(castToString(123), logger));
+
+      Sinon.assert.calledThrice(logger.warn);
+    });
+
+    it('returns false for invalid URLs', () => {
+      assert.isFalse(isSignalHttpsLink('', explodingLogger));
+      assert.isFalse(isSignalHttpsLink('https', explodingLogger));
+      assert.isFalse(isSignalHttpsLink('https://::', explodingLogger));
+    });
+
+    it('returns false if the protocol is not "https:"', () => {
+      assert.isFalse(isSignalHttpsLink('sgnl://signal.art', explodingLogger));
+      assert.isFalse(
+        isSignalHttpsLink(
+          'sgnl://signal.art/addstickers/?pack_id=abc',
+          explodingLogger
+        )
+      );
+      assert.isFalse(
+        isSignalHttpsLink('signal://signal.group', explodingLogger)
+      );
+    });
+
+    it('returns true if the protocol is "https:"', () => {
+      assert.isTrue(isSignalHttpsLink('https://signal.group', explodingLogger));
+      assert.isTrue(isSignalHttpsLink('https://signal.art', explodingLogger));
+      assert.isTrue(isSignalHttpsLink('HTTPS://signal.art', explodingLogger));
+    });
+
+    it('returns false if username or password are set', () => {
+      assert.isFalse(
+        isSignalHttpsLink('https://user:password@signal.group', explodingLogger)
+      );
+    });
+
+    it('returns false if port is set', () => {
+      assert.isFalse(
+        isSignalHttpsLink('https://signal.group:1234', explodingLogger)
+      );
+    });
+
+    it('accepts URL objects', () => {
+      const invalid = new URL('sgnl://example.com');
+      assert.isFalse(isSignalHttpsLink(invalid, explodingLogger));
+      const valid = new URL('https://signal.art');
+      assert.isTrue(isSignalHttpsLink(valid, explodingLogger));
+    });
+  });
+
   describe('parseSgnlHref', () => {
     it('returns a null command for invalid URLs', () => {
       ['', 'sgnl', 'https://example/?foo=bar'].forEach(href => {
@@ -188,4 +254,47 @@ describe('sgnlHref', () => {
       );
     });
   });
+
+  describe('parseSignalHttpsLink', () => {
+    it('returns a null command for invalid URLs', () => {
+      ['', 'https', 'https://example/?foo=bar'].forEach(href => {
+        assert.deepEqual(parseSignalHttpsLink(href, explodingLogger), {
+          command: null,
+          args: new Map<never, never>(),
+        });
+      });
+    });
+
+    it('handles signal.art links', () => {
+      assert.deepEqual(
+        parseSignalHttpsLink(
+          'https://signal.art/addstickers/#pack_id=baz&pack_key=Quux&num=123&empty=&encoded=hello%20world',
+          explodingLogger
+        ),
+        {
+          command: 'addstickers',
+          args: new Map([
+            ['pack_id', 'baz'],
+            ['pack_key', 'Quux'],
+            ['num', '123'],
+            ['empty', ''],
+            ['encoded', 'hello world'],
+          ]),
+          hash:
+            'pack_id=baz&pack_key=Quux&num=123&empty=&encoded=hello%20world',
+        }
+      );
+    });
+
+    it('handles signal.group links', () => {
+      assert.deepEqual(
+        parseSignalHttpsLink('https://signal.group/#data', explodingLogger),
+        {
+          command: 'signal.group',
+          args: new Map<never, never>(),
+          hash: 'data',
+        }
+      );
+    });
+  });
 });

ts/util/sgnlHref.ts

@@ -23,6 +23,21 @@ export function isSgnlHref(value: string | URL, logger: LoggerType): boolean {
   return url !== null && url.protocol === 'sgnl:';
 }
 
+export function isSignalHttpsLink(
+  value: string | URL,
+  logger: LoggerType
+): boolean {
+  const url = parseUrl(value, logger);
+  return Boolean(
+    url &&
+      !url.username &&
+      !url.password &&
+      !url.port &&
+      url.protocol === 'https:' &&
+      (url.host === 'signal.group' || url.host === 'signal.art')
+  );
+}
+
 type ParsedSgnlHref =
   | { command: null; args: Map<never, never> }
   | { command: string; args: Map<string, string>; hash: string | undefined };
@@ -48,3 +63,45 @@ export function parseSgnlHref(
     hash: url.hash ? url.hash.slice(1) : undefined,
   };
 }
+
+export function parseSignalHttpsLink(
+  href: string,
+  logger: LoggerType
+): ParsedSgnlHref {
+  const url = parseUrl(href, logger);
+  if (!url || !isSignalHttpsLink(url, logger)) {
+    return { command: null, args: new Map<never, never>() };
+  }
+
+  if (url.host === 'signal.art') {
+    const hash = url.hash.slice(1);
+    const hashParams = new URLSearchParams(hash);
+
+    const args = new Map<string, string>();
+    hashParams.forEach((value, key) => {
+      if (!args.has(key)) {
+        args.set(key, value);
+      }
+    });
+
+    if (!args.get('pack_id') || !args.get('pack_key')) {
+      return { command: null, args: new Map<never, never>() };
+    }
+
+    return {
+      command: url.pathname.replace(/\//g, ''),
+      args,
+      hash: url.hash ? url.hash.slice(1) : undefined,
+    };
+  }
+
+  if (url.host === 'signal.group') {
+    return {
+      command: url.host,
+      args: new Map<string, string>(),
+      hash: url.hash ? url.hash.slice(1) : undefined,
+    };
+  }
+
+  return { command: null, args: new Map<never, never>() };
+}

ts/views/conversation_view.ts

@@ -12,16 +12,18 @@ type GroupV2PendingMemberType = import('../model-types.d').GroupV2PendingMemberT
 type MediaItemType = import('../components/LightboxGallery').MediaItemType;
 type MessageType = import('../state/ducks/conversations').MessageType;
 
+type GetLinkPreviewImageResult = {
+  data: ArrayBuffer;
+  size: number;
+  contentType: string;
+  width?: number;
+  height?: number;
+};
+
 type GetLinkPreviewResult = {
   title: string;
   url: string;
-  image: {
-    data: ArrayBuffer;
-    size: number;
-    contentType: string;
-    width: number;
-    height: number;
-  };
+  image?: GetLinkPreviewImageResult;
   description: string | null;
   date: number | null;
 };
@@ -3580,7 +3582,10 @@ Whisper.ConversationView = Whisper.View.extend({
     this.renderLinkPreview();
   },
 
-  async getStickerPackPreview(url: any) {
+  async getStickerPackPreview(
+    url: string,
+    abortSignal: any
+  ): Promise<null | GetLinkPreviewResult> {
     const isPackDownloaded = (pack: any) =>
       pack && (pack.status === 'downloaded' || pack.status === 'installed');
     const isPackValid = (pack: any) =>
@@ -3604,7 +3609,12 @@ Whisper.ConversationView = Whisper.View.extend({
         await window.Signal.Stickers.downloadEphemeralPack(id, keyBase64);
       }
 
+      if (abortSignal.aborted) {
+        return null;
+      }
+
       const pack = window.Signal.Stickers.getStickerPack(id);
+
       if (!isPackValid(pack)) {
         return null;
       }
@@ -3619,6 +3629,10 @@ Whisper.ConversationView = Whisper.View.extend({
           ? await window.Signal.Migrations.readTempData(sticker.path)
           : await window.Signal.Migrations.readStickerData(sticker.path);
 
+      if (abortSignal.aborted) {
+        return null;
+      }
+
       return {
         title,
         url,
@@ -3628,6 +3642,8 @@ Whisper.ConversationView = Whisper.View.extend({
           size: data.byteLength,
           contentType: 'image/webp',
         },
+        description: null,
+        date: null,
       };
     } catch (error) {
       window.log.error(
@@ -3642,12 +3658,99 @@ Whisper.ConversationView = Whisper.View.extend({
     }
   },
 
+  async getGroupPreview(
+    url: string,
+    abortSignal: any
+  ): Promise<null | GetLinkPreviewResult> {
+    let urlObject;
+    try {
+      urlObject = new URL(url);
+    } catch (err) {
+      return null;
+    }
+
+    const { hash } = urlObject;
+    if (!hash) {
+      return null;
+    }
+    const groupData = hash.slice(1);
+
+    const {
+      inviteLinkPassword,
+      masterKey,
+    } = window.Signal.Groups.parseGroupLink(groupData);
+
+    const fields = window.Signal.Groups.deriveGroupFields(
+      window.Signal.Crypto.base64ToArrayBuffer(masterKey)
+    );
+    const id = window.Signal.Crypto.arrayBufferToBase64(fields.id);
+    const logId = `groupv2(${id})`;
+    const secretParams = window.Signal.Crypto.arrayBufferToBase64(
+      fields.secretParams
+    );
+
+    window.log.info(`getGroupPreview/${logId}: Fetching pre-join state`);
+    const result = await window.Signal.Groups.getPreJoinGroupInfo(
+      inviteLinkPassword,
+      masterKey
+    );
+
+    if (abortSignal.aborted) {
+      return null;
+    }
+
+    const title =
+      window.Signal.Groups.decryptGroupTitle(result.title, secretParams) ||
+      window.i18n('unknownGroup');
+    const description =
+      result.memberCount === 1 || result.memberCount === undefined
+        ? window.i18n('GroupV2--join--member-count--single')
+        : window.i18n('GroupV2--join--member-count--multiple', {
+            count: result.memberCount.toString(),
+          });
+    let image: undefined | GetLinkPreviewImageResult;
+
+    if (result.avatar) {
+      try {
+        const data = await window.Signal.Groups.decryptGroupAvatar(
+          result.avatar,
+          secretParams
+        );
+        image = {
+          data,
+          size: data.byteLength,
+          contentType: 'image/jpeg',
+        };
+      } catch (error) {
+        const errorString = error && error.stack ? error.stack : error;
+        window.log.error(
+          `getGroupPreview/${logId}: Failed to fetch avatar ${errorString}`
+        );
+      }
+    }
+
+    if (abortSignal.aborted) {
+      return null;
+    }
+
+    return {
+      title,
+      description,
+      url,
+      image,
+      date: null,
+    };
+  },
+
   async getPreview(
     url: string,
     abortSignal: any
   ): Promise<null | GetLinkPreviewResult> {
     if (window.Signal.LinkPreviews.isStickerPack(url)) {
-      return this.getStickerPackPreview(url);
+      return this.getStickerPackPreview(url, abortSignal);
+    }
+    if (window.Signal.LinkPreviews.isGroupLink(url)) {
+      return this.getGroupPreview(url, abortSignal);
     }
 
     // This is already checked elsewhere, but we want to be extra-careful.