From 8140fbad22814b99ad56e1161a43ec203da669d8 Mon Sep 17 00:00:00 2001
From: Kenneth Lien <kenneth@anthropic.com>
Date: Fri, 20 Mar 2026 10:37:13 -0700
Subject: [PATCH] Lock telegram/discord .env files to owner (chmod 600)

The bot token is a credential. Tighten perms on load so hand-written
or pre-existing .env files get locked down, and update the configure
skill to chmod after writing. No-op on Windows.
---
 external_plugins/discord/server.ts                  | 4 +++-
 external_plugins/discord/skills/configure/SKILL.md  | 3 ++-
 external_plugins/telegram/server.ts                 | 4 +++-
 external_plugins/telegram/skills/configure/SKILL.md | 3 ++-
 4 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/external_plugins/discord/server.ts b/external_plugins/discord/server.ts
index f34006a..078c29a 100644
--- a/external_plugins/discord/server.ts
+++ b/external_plugins/discord/server.ts
@@ -25,7 +25,7 @@ import {
   type Attachment,
 } from 'discord.js'
 import { randomBytes } from 'crypto'
-import { readFileSync, writeFileSync, mkdirSync, readdirSync, rmSync, statSync, renameSync, realpathSync } from 'fs'
+import { readFileSync, writeFileSync, mkdirSync, readdirSync, rmSync, statSync, renameSync, realpathSync, chmodSync } from 'fs'
 import { homedir } from 'os'
 import { join, sep } from 'path'
 
@@ -37,6 +37,8 @@ const ENV_FILE = join(STATE_DIR, '.env')
 // Load ~/.claude/channels/discord/.env into process.env. Real env wins.
 // Plugin-spawned servers don't get an env block — this is where the token lives.
 try {
+  // Token is a credential — lock to owner. No-op on Windows (would need ACLs).
+  chmodSync(ENV_FILE, 0o600)
   for (const line of readFileSync(ENV_FILE, 'utf8').split('\n')) {
     const m = line.match(/^(\w+)=(.*)$/)
     if (m && process.env[m[1]] === undefined) process.env[m[1]] = m[2]
diff --git a/external_plugins/discord/skills/configure/SKILL.md b/external_plugins/discord/skills/configure/SKILL.md
index b6d8df0..a1e15f8 100644
--- a/external_plugins/discord/skills/configure/SKILL.md
+++ b/external_plugins/discord/skills/configure/SKILL.md
@@ -80,7 +80,8 @@ as the correct long-term choice. Don't skip the lockdown offer.
 2. `mkdir -p ~/.claude/channels/discord`
 3. Read existing `.env` if present; update/add the `DISCORD_BOT_TOKEN=` line,
    preserve other keys. Write back, no quotes around the value.
-4. Confirm, then show the no-args status so the user sees where they stand.
+4. `chmod 600 ~/.claude/channels/discord/.env` — the token is a credential.
+5. Confirm, then show the no-args status so the user sees where they stand.
 
 ### `clear` — remove the token
 
diff --git a/external_plugins/telegram/server.ts b/external_plugins/telegram/server.ts
index e2265b8..8acd52a 100644
--- a/external_plugins/telegram/server.ts
+++ b/external_plugins/telegram/server.ts
@@ -18,7 +18,7 @@ import {
 import { Bot, InputFile, type Context } from 'grammy'
 import type { ReactionTypeEmoji } from 'grammy/types'
 import { randomBytes } from 'crypto'
-import { readFileSync, writeFileSync, mkdirSync, readdirSync, rmSync, statSync, renameSync, realpathSync } from 'fs'
+import { readFileSync, writeFileSync, mkdirSync, readdirSync, rmSync, statSync, renameSync, realpathSync, chmodSync } from 'fs'
 import { homedir } from 'os'
 import { join, extname, sep } from 'path'
 
@@ -30,6 +30,8 @@ const ENV_FILE = join(STATE_DIR, '.env')
 // Load ~/.claude/channels/telegram/.env into process.env. Real env wins.
 // Plugin-spawned servers don't get an env block — this is where the token lives.
 try {
+  // Token is a credential — lock to owner. No-op on Windows (would need ACLs).
+  chmodSync(ENV_FILE, 0o600)
   for (const line of readFileSync(ENV_FILE, 'utf8').split('\n')) {
     const m = line.match(/^(\w+)=(.*)$/)
     if (m && process.env[m[1]] === undefined) process.env[m[1]] = m[2]
diff --git a/external_plugins/telegram/skills/configure/SKILL.md b/external_plugins/telegram/skills/configure/SKILL.md
index 3d846cf..31ad2f3 100644
--- a/external_plugins/telegram/skills/configure/SKILL.md
+++ b/external_plugins/telegram/skills/configure/SKILL.md
@@ -77,7 +77,8 @@ offer.
 2. `mkdir -p ~/.claude/channels/telegram`
 3. Read existing `.env` if present; update/add the `TELEGRAM_BOT_TOKEN=` line,
    preserve other keys. Write back, no quotes around the value.
-4. Confirm, then show the no-args status so the user sees where they stand.
+4. `chmod 600 ~/.claude/channels/telegram/.env` — the token is a credential.
+5. Confirm, then show the no-args status so the user sees where they stand.
 
 ### `clear` — remove the token