fix(security): make allowFrom id-only by default with dangerous name opt-in (#24907)

* fix(channels): default allowFrom to id-only; add dangerous name opt-in

* docs(security): align channel allowFrom docs with id-only default

src/slack/monitor/allow-list.test.ts

@@ -15,7 +15,7 @@ describe("slack/allow-list", () => {
     expect(normalizeSlackSlug(" #Ops.Room ")).toBe("#ops.room");
   });
 
-  it("matches wildcard, id, and prefixed name candidates", () => {
+  it("matches wildcard and id candidates by default", () => {
     expect(resolveSlackAllowListMatch({ allowList: ["*"], id: "u1", name: "alice" })).toEqual({
       allowed: true,
       matchKey: "*",
@@ -40,6 +40,15 @@ describe("slack/allow-list", () => {
         id: "u2",
         name: "alice",
       }),
+    ).toEqual({ allowed: false });
+
+    expect(
+      resolveSlackAllowListMatch({
+        allowList: ["slack:alice"],
+        id: "u2",
+        name: "alice",
+        allowNameMatching: true,
+      }),
     ).toEqual({
       allowed: true,
       matchKey: "slack:alice",

src/slack/monitor/allow-list.ts

@@ -25,6 +25,7 @@ export function resolveSlackAllowListMatch(params: {
   allowList: string[];
   id?: string;
   name?: string;
+  allowNameMatching?: boolean;
 }): SlackAllowListMatch {
   const allowList = params.allowList;
   if (allowList.length === 0) {
@@ -40,9 +41,13 @@ export function resolveSlackAllowListMatch(params: {
     { value: id, source: "id" },
     { value: id ? `slack:${id}` : undefined, source: "prefixed-id" },
     { value: id ? `user:${id}` : undefined, source: "prefixed-user" },
-    { value: name, source: "name" },
-    { value: name ? `slack:${name}` : undefined, source: "prefixed-name" },
-    { value: slug, source: "slug" },
+    ...(params.allowNameMatching === true
+      ? ([
+          { value: name, source: "name" as const },
+          { value: name ? `slack:${name}` : undefined, source: "prefixed-name" as const },
+          { value: slug, source: "slug" as const },
+        ] satisfies Array<{ value?: string; source: SlackAllowListMatch["matchSource"] }>)
+      : []),
   ];
   for (const candidate of candidates) {
     if (!candidate.value) {
@@ -59,7 +64,12 @@ export function resolveSlackAllowListMatch(params: {
   return { allowed: false };
 }
 
-export function allowListMatches(params: { allowList: string[]; id?: string; name?: string }) {
+export function allowListMatches(params: {
+  allowList: string[];
+  id?: string;
+  name?: string;
+  allowNameMatching?: boolean;
+}) {
   return resolveSlackAllowListMatch(params).allowed;
 }
 
@@ -67,6 +77,7 @@ export function resolveSlackUserAllowed(params: {
   allowList?: Array<string | number>;
   userId?: string;
   userName?: string;
+  allowNameMatching?: boolean;
 }) {
   const allowList = normalizeAllowListLower(params.allowList);
   if (allowList.length === 0) {
@@ -76,5 +87,6 @@ export function resolveSlackUserAllowed(params: {
     allowList,
     id: params.userId,
     name: params.userName,
+    allowNameMatching: params.allowNameMatching,
   });
 }

src/slack/monitor/auth.ts

@@ -14,14 +14,16 @@ export function isSlackSenderAllowListed(params: {
   allowListLower: string[];
   senderId: string;
   senderName?: string;
+  allowNameMatching?: boolean;
 }) {
-  const { allowListLower, senderId, senderName } = params;
+  const { allowListLower, senderId, senderName, allowNameMatching } = params;
   return (
     allowListLower.length === 0 ||
     allowListMatches({
       allowList: allowListLower,
       id: senderId,
       name: senderName,
+      allowNameMatching,
     })
   );
 }

src/slack/monitor/channel-config.ts

@@ -47,6 +47,7 @@ export function shouldEmitSlackReactionNotification(params: {
   userId: string;
   userName?: string | null;
   allowlist?: Array<string | number> | null;
+  allowNameMatching?: boolean;
 }) {
   const { mode, botId, messageAuthorId, userId, userName, allowlist } = params;
   const effectiveMode = mode ?? "own";
@@ -68,6 +69,7 @@ export function shouldEmitSlackReactionNotification(params: {
       allowList: users,
       id: userId,
       name: userName ?? undefined,
+      allowNameMatching: params.allowNameMatching,
     });
   }
   return true;

src/slack/monitor/context.ts

@@ -68,6 +68,7 @@ export type SlackMonitorContext = {
   dmEnabled: boolean;
   dmPolicy: DmPolicy;
   allowFrom: string[];
+  allowNameMatching: boolean;
   groupDmEnabled: boolean;
   groupDmChannels: string[];
   defaultRequireMention: boolean;
@@ -129,6 +130,7 @@ export function createSlackMonitorContext(params: {
   dmEnabled: boolean;
   dmPolicy: DmPolicy;
   allowFrom: Array<string | number> | undefined;
+  allowNameMatching: boolean;
   groupDmEnabled: boolean;
   groupDmChannels: Array<string | number> | undefined;
   defaultRequireMention?: boolean;
@@ -391,6 +393,7 @@ export function createSlackMonitorContext(params: {
     dmEnabled: params.dmEnabled,
     dmPolicy: params.dmPolicy,
     allowFrom,
+    allowNameMatching: params.allowNameMatching,
     groupDmEnabled: params.groupDmEnabled,
     groupDmChannels,
     defaultRequireMention,

src/slack/monitor/message-handler/prepare.test.ts

@@ -60,6 +60,7 @@ describe("slack prepareSlackMessage inbound contract", () => {
       dmEnabled: true,
       dmPolicy: "open",
       allowFrom: [],
+      allowNameMatching: false,
       groupDmEnabled: true,
       groupDmChannels: [],
       defaultRequireMention: params.defaultRequireMention ?? true,

src/slack/monitor/message-handler/prepare.ts

@@ -142,6 +142,7 @@ export async function prepareSlackMessage(params: {
       const allowMatch = resolveSlackAllowListMatch({
         allowList: allowFromLower,
         id: directUserId,
+        allowNameMatching: ctx.allowNameMatching,
       });
       const allowMatchMeta = formatAllowlistMatchMeta(allowMatch);
       if (!allowMatch.allowed) {
@@ -244,6 +245,7 @@ export async function prepareSlackMessage(params: {
         allowList: channelConfig?.users,
         userId: senderId,
         userName: senderName,
+        allowNameMatching: ctx.allowNameMatching,
       })
     : true;
   if (isRoom && !channelUserAuthorized) {
@@ -263,6 +265,7 @@ export async function prepareSlackMessage(params: {
     allowList: allowFromLower,
     id: senderId,
     name: senderName,
+    allowNameMatching: ctx.allowNameMatching,
   }).allowed;
   const channelUsersAllowlistConfigured =
     isRoom && Array.isArray(channelConfig?.users) && channelConfig.users.length > 0;
@@ -272,6 +275,7 @@ export async function prepareSlackMessage(params: {
           allowList: channelConfig?.users,
           userId: senderId,
           userName: senderName,
+          allowNameMatching: ctx.allowNameMatching,
         })
       : false;
   const commandGate = resolveControlCommandGate({

src/slack/monitor/monitor.test.ts

@@ -77,6 +77,7 @@ const baseParams = () => ({
   dmEnabled: true,
   dmPolicy: "open" as const,
   allowFrom: [],
+  allowNameMatching: false,
   groupDmEnabled: true,
   groupDmChannels: [],
   defaultRequireMention: true,

src/slack/monitor/provider.ts

@@ -210,6 +210,7 @@ export async function monitorSlackProvider(opts: MonitorSlackOpts = {}) {
     dmEnabled,
     dmPolicy,
     allowFrom,
+    allowNameMatching: slackCfg.dangerouslyAllowNameMatching === true,
     groupDmEnabled,
     groupDmChannels,
     defaultRequireMention: slackCfg.requireMention,

src/slack/monitor/slash.ts

@@ -361,6 +361,7 @@ export async function registerSlackMonitorSlashCommands(params: {
             allowList: effectiveAllowFromLower,
             id: command.user_id,
             name: senderName,
+            allowNameMatching: ctx.allowNameMatching,
           });
           const allowMatchMeta = formatAllowlistMatchMeta(allowMatch);
           if (!allowMatch.allowed) {
@@ -446,6 +447,7 @@ export async function registerSlackMonitorSlashCommands(params: {
             allowList: channelConfig?.users,
             userId: command.user_id,
             userName: senderName,
+            allowNameMatching: ctx.allowNameMatching,
           })
         : false;
       if (channelUsersAllowlistConfigured && !channelUserAllowed) {
@@ -460,6 +462,7 @@ export async function registerSlackMonitorSlashCommands(params: {
         allowList: effectiveAllowFromLower,
         id: command.user_id,
         name: senderName,
+        allowNameMatching: ctx.allowNameMatching,
       }).allowed;
       // DMs: allow chatting in dmPolicy=open, but keep privileged command gating intact by setting
       // CommandAuthorized based on allowlists/access-groups (downstream decides which commands need it).