fix(connectors): allow self-hosted private DB hosts via opt-in flag (#5322)

* fix(connectors): allow self-hosted private DB hosts via opt-in flag

Database/connector tools rejected any host resolving to a private/reserved/
loopback IP, blocking the common self-hosted topology where the DB is reached
by a Docker/K8s/Swarm service name. Add an opt-in ALLOW_PRIVATE_DATABASE_HOSTS
flag that bypasses the private-host block in validateDatabaseHost while still
resolving and pinning DNS. Blocked on the hosted platform regardless of the env
var, mirroring DISABLE_AUTH.

Fixes #4319

* fix(connectors): pin postgres IP in all ssl modes; strip IPv6 brackets

Address review on #5322:
- validateDatabaseHost now strips surrounding IPv6 brackets before the
  localhost/private-IP checks and DNS lookup, so a bracketed loopback like
  [::1] is classified correctly instead of failing as unresolvable.
- PostgreSQL connector always connects to the validated, pinned IP (removed
  the ssl='preferred' carve-out that passed the original hostname and let the
  driver re-resolve during connection). Matches the MySQL/MongoDB pin pattern.
- Add postgres connector pinning tests and bracketed-IPv6 host tests.

* fix(connectors): rename flag to isPrivateDatabaseHostsAllowed; trim comment

- Rename env-flag const to satisfy the env-flags 'is' prefix CI check
  (env var ALLOW_PRIVATE_DATABASE_HOSTS is unchanged).
- Tighten the postgres pinning comment to a single line.

apps/sim/.env.example

@@ -12,6 +12,9 @@ BETTER_AUTH_URL=http://localhost:3000
 # Authentication Bypass (Optional - for self-hosted deployments behind private networks)
 # DISABLE_AUTH=true  # Uncomment to bypass authentication entirely. Creates an anonymous session for all requests.
 
+# Private Database Hosts (Optional - for self-hosted deployments only)
+# ALLOW_PRIVATE_DATABASE_HOSTS=true  # Uncomment to let database/connector tools reach private/reserved/loopback hosts (e.g. Docker/K8s service names, localhost). Loosens the SSRF boundary; only enable on a trusted private network.
+
 # NextJS (Required)
 NEXT_PUBLIC_APP_URL=http://localhost:3000
 # INTERNAL_API_BASE_URL=http://sim-app.default.svc.cluster.local:3000  # Optional: internal URL for server-side /api self-calls; defaults to NEXT_PUBLIC_APP_URL

apps/sim/app/api/tools/postgresql/utils.test.ts

@@ -0,0 +1,73 @@
+/**
+ * @vitest-environment node
+ */
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import type { PostgresConnectionConfig } from '@/tools/postgresql/types'
+
+const { mockValidateDatabaseHost, mockPostgres } = vi.hoisted(() => ({
+  mockValidateDatabaseHost: vi.fn(),
+  mockPostgres: vi.fn(() => ({})),
+}))
+
+vi.mock('postgres', () => ({ default: mockPostgres }))
+
+vi.mock('@/lib/core/security/input-validation.server', () => ({
+  validateDatabaseHost: mockValidateDatabaseHost,
+}))
+
+import { createPostgresConnection } from '@/app/api/tools/postgresql/utils'
+
+function makeConfig(overrides: Partial<PostgresConnectionConfig> = {}): PostgresConnectionConfig {
+  return {
+    host: 'db.example.com',
+    port: 5432,
+    database: 'app',
+    username: 'app',
+    password: 'secret',
+    ssl: 'required',
+    ...overrides,
+  }
+}
+
+describe('createPostgresConnection DNS pinning', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    mockValidateDatabaseHost.mockResolvedValue({
+      isValid: true,
+      resolvedIP: '93.184.216.34',
+      originalHostname: 'db.example.com',
+    })
+  })
+
+  it('never opens a connection when host validation fails (no SSRF window)', async () => {
+    mockValidateDatabaseHost.mockResolvedValue({
+      isValid: false,
+      error: 'host resolves to a blocked IP address',
+    })
+
+    await expect(
+      createPostgresConnection(makeConfig({ host: 'rebind.attacker.example' }))
+    ).rejects.toThrow('host resolves to a blocked IP address')
+    expect(mockPostgres).not.toHaveBeenCalled()
+  })
+
+  it.each(['disabled', 'required', 'preferred'] as const)(
+    'connects to the validated IP for ssl=%s (hostname never re-resolved)',
+    async (ssl) => {
+      await createPostgresConnection(makeConfig({ host: 'rebind.attacker.example', ssl }))
+
+      expect(mockValidateDatabaseHost).toHaveBeenCalledWith('rebind.attacker.example', 'host')
+      const options = mockPostgres.mock.calls[0][0]
+      // The TCP target is always the validated IP — re-resolution can never happen.
+      expect(options.host).toBe('93.184.216.34')
+    }
+  )
+
+  it('preserves the hostname as the TLS servername for verifying ssl modes', async () => {
+    await createPostgresConnection(makeConfig({ host: 'db.example.com', ssl: 'required' }))
+
+    const options = mockPostgres.mock.calls[0][0]
+    expect(options.host).toBe('93.184.216.34')
+    expect(options.ssl).toMatchObject({ servername: 'db.example.com' })
+  })
+})

apps/sim/app/api/tools/postgresql/utils.ts

@@ -9,7 +9,6 @@ export async function createPostgresConnection(config: PostgresConnectionConfig)
   }
 
   const resolvedHost = hostValidation.resolvedIP ?? config.host
-  const pinIP = config.ssl !== 'preferred'
 
   const sslConfig: boolean | 'prefer' | { rejectUnauthorized: boolean; servername?: string } =
     config.ssl === 'disabled'
@@ -19,7 +18,8 @@ export async function createPostgresConnection(config: PostgresConnectionConfig)
         : { rejectUnauthorized: false, servername: config.host }
 
   const sql = postgres({
-    host: pinIP ? resolvedHost : config.host,
+    // Pin the validated IP (never the hostname) to prevent DNS rebinding; SNI stays the hostname above.
+    host: resolvedHost,
     port: config.port,
     database: config.database,
     username: config.username,

apps/sim/lib/core/config/env-flags.ts

@@ -74,6 +74,35 @@ if (isTruthy(env.DISABLE_AUTH)) {
     })
 }
 
+/**
+ * Whether database/connector tools may connect to private, reserved, or loopback
+ * hosts (e.g. Docker/K8s service names, localhost). Off by default: the SSRF guard
+ * in {@link validateDatabaseHost} blocks these so an untrusted user cannot pivot
+ * into the deployment's internal network. Self-hosted operators can opt in when
+ * their database lives on the same private network. Blocked on the hosted platform
+ * regardless of the env var, mirroring {@link isAuthDisabled}.
+ */
+export const isPrivateDatabaseHostsAllowed = isTruthy(env.ALLOW_PRIVATE_DATABASE_HOSTS) && !isHosted
+
+if (isTruthy(env.ALLOW_PRIVATE_DATABASE_HOSTS)) {
+  import('@sim/logger')
+    .then(({ createLogger }) => {
+      const logger = createLogger('EnvFlags')
+      if (isHosted) {
+        logger.error(
+          'ALLOW_PRIVATE_DATABASE_HOSTS is set but ignored on hosted environment. Private/reserved database hosts remain blocked for security.'
+        )
+      } else {
+        logger.warn(
+          'ALLOW_PRIVATE_DATABASE_HOSTS is enabled. Database/connector tools may reach private, reserved, and loopback hosts. Only use this in trusted private networks.'
+        )
+      }
+    })
+    .catch(() => {
+      // Fallback during config compilation when logger is unavailable
+    })
+}
+
 /**
  * Is user registration disabled
  */

apps/sim/lib/core/config/env.ts

@@ -33,6 +33,7 @@ export const env = createEnv({
     DISABLE_REGISTRATION:                  z.boolean().optional(),                 // Flag to disable new user registration
     EMAIL_PASSWORD_SIGNUP_ENABLED:         z.boolean().optional().default(true),   // Enable email/password authentication (server-side enforcement)
     DISABLE_AUTH:                          z.boolean().optional(),                 // Bypass authentication entirely (self-hosted only, creates anonymous session)
+    ALLOW_PRIVATE_DATABASE_HOSTS:          z.boolean().optional(),                 // Opt-in (self-hosted only): let database/connector tools reach private/reserved/loopback hosts (e.g. Docker/K8s service names). Loosens the SSRF boundary; ignored on the hosted platform.
     ALLOWED_LOGIN_EMAILS:                  z.string().optional(),                  // Comma-separated list of allowed email addresses for login
     ALLOWED_LOGIN_DOMAINS:                 z.string().optional(),                  // Comma-separated list of allowed email domains for login
     BLOCKED_SIGNUP_DOMAINS:                z.string().optional(),                  // Comma-separated list of email domains blocked from signing up (e.g., "gmail.com,yahoo.com")

apps/sim/lib/core/security/input-validation.server.ts

@@ -6,7 +6,7 @@ import { createLogger } from '@sim/logger'
 import { toError } from '@sim/utils/errors'
 import * as ipaddr from 'ipaddr.js'
 import { Agent, type RequestInit as UndiciRequestInit, fetch as undiciFetch } from 'undici'
-import { isHosted } from '@/lib/core/config/env-flags'
+import { isHosted, isPrivateDatabaseHostsAllowed } from '@/lib/core/config/env-flags'
 import { type ValidationResult, validateExternalUrl } from '@/lib/core/security/input-validation'
 import { PayloadSizeLimitError } from '@/lib/core/utils/stream-limits'
 
@@ -152,6 +152,12 @@ export async function validateUrlWithDNS(
  * database hostnames (e.g. underscores in Docker/K8s service names). It only
  * blocks localhost and private/reserved IPs.
  *
+ * Self-hosted operators can set `ALLOW_PRIVATE_DATABASE_HOSTS` to reach databases
+ * on their private network (e.g. a Docker/Swarm service name that resolves to an
+ * internal IP). The opt-in only bypasses the private/reserved/loopback block; DNS
+ * is still resolved so the caller can pin the connection to the resolved IP. The
+ * bypass is never honored on the hosted platform (see {@link isPrivateDatabaseHostsAllowed}).
+ *
  * @param host - The database hostname to validate
  * @param paramName - Name of the parameter for error messages
  * @returns AsyncValidationResult with resolved IP
@@ -165,19 +171,25 @@ export async function validateDatabaseHost(
   }
 
   const lowerHost = host.toLowerCase()
+  const cleanHost =
+    lowerHost.startsWith('[') && lowerHost.endsWith(']') ? lowerHost.slice(1, -1) : lowerHost
 
-  if (lowerHost === 'localhost') {
+  if (cleanHost === 'localhost' && !isPrivateDatabaseHostsAllowed) {
     return { isValid: false, error: `${paramName} cannot be localhost` }
   }
 
-  if (ipaddr.isValid(lowerHost) && isPrivateOrReservedIP(lowerHost)) {
+  if (
+    ipaddr.isValid(cleanHost) &&
+    isPrivateOrReservedIP(cleanHost) &&
+    !isPrivateDatabaseHostsAllowed
+  ) {
     return { isValid: false, error: `${paramName} cannot be a private IP address` }
   }
 
   try {
-    const { address } = await dns.lookup(host, { verbatim: true })
+    const { address } = await dns.lookup(cleanHost, { verbatim: true })
 
-    if (isPrivateOrReservedIP(address)) {
+    if (isPrivateOrReservedIP(address) && !isPrivateDatabaseHostsAllowed) {
       logger.warn('Database host resolves to blocked IP address', {
         paramName,
         hostname: host,

apps/sim/lib/core/security/input-validation.test.ts

@@ -28,6 +28,7 @@ import {
 } from '@/lib/core/security/input-validation'
 import {
   isPrivateOrReservedIP,
+  validateDatabaseHost,
   validateUrlWithDNS,
 } from '@/lib/core/security/input-validation.server'
 import { sanitizeForLogging } from '@/lib/core/security/redaction'
@@ -762,6 +763,86 @@ describe('validateUrlWithDNS', () => {
   })
 })
 
+describe('validateDatabaseHost', () => {
+  afterEach(() => {
+    envFlagsMock.isPrivateDatabaseHostsAllowed = false
+  })
+
+  describe('default (SSRF guard on)', () => {
+    it('rejects a missing host', async () => {
+      const result = await validateDatabaseHost(undefined)
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('required')
+    })
+
+    it('rejects localhost', async () => {
+      const result = await validateDatabaseHost('localhost')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('localhost')
+    })
+
+    it('rejects a literal private IP', async () => {
+      const result = await validateDatabaseHost('10.0.0.5')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('private IP')
+    })
+
+    it('rejects a literal loopback IP', async () => {
+      const result = await validateDatabaseHost('127.0.0.1')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('private IP')
+    })
+
+    it('rejects a bracketed IPv6 loopback as a private IP (not unresolvable)', async () => {
+      const result = await validateDatabaseHost('[::1]')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('private IP')
+    })
+
+    it('accepts a public IP and pins the resolved address', async () => {
+      const result = await validateDatabaseHost('1.1.1.1')
+      expect(result.isValid).toBe(true)
+      expect(result.resolvedIP).toBe('1.1.1.1')
+    })
+  })
+
+  describe('self-host opt-in (ALLOW_PRIVATE_DATABASE_HOSTS)', () => {
+    beforeEach(() => {
+      envFlagsMock.isPrivateDatabaseHostsAllowed = true
+    })
+
+    it('allows localhost and still resolves an IP to pin', async () => {
+      const result = await validateDatabaseHost('localhost')
+      expect(result.isValid).toBe(true)
+      expect(result.resolvedIP).toBeDefined()
+    })
+
+    it('allows a literal private IP and pins it', async () => {
+      const result = await validateDatabaseHost('10.0.0.5')
+      expect(result.isValid).toBe(true)
+      expect(result.resolvedIP).toBe('10.0.0.5')
+    })
+
+    it('allows a literal loopback IP and pins it', async () => {
+      const result = await validateDatabaseHost('127.0.0.1')
+      expect(result.isValid).toBe(true)
+      expect(result.resolvedIP).toBe('127.0.0.1')
+    })
+
+    it('allows a bracketed IPv6 loopback and pins the unbracketed address', async () => {
+      const result = await validateDatabaseHost('[::1]')
+      expect(result.isValid).toBe(true)
+      expect(result.resolvedIP).toBe('::1')
+    })
+
+    it('still surfaces unresolvable hostnames', async () => {
+      const result = await validateDatabaseHost('this-host-does-not-exist.invalid')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('could not be resolved')
+    })
+  })
+})
+
 describe('validateInteger', () => {
   describe('valid integers', () => {
     it.concurrent('should accept positive integers', () => {

packages/testing/src/mocks/env-flags.mock.ts

@@ -17,6 +17,7 @@ export const envFlagsMock = {
   isBillingEnabled: false,
   isEmailVerificationEnabled: false,
   isAuthDisabled: false,
+  isPrivateDatabaseHostsAllowed: false,
   isRegistrationDisabled: false,
   isEmailPasswordEnabled: false,
   isTriggerDevEnabled: false,