Files
web-terminal/control-plane/src/boot/ca-wiring.ts
Yaojia Wang af630143de feat(control-plane): production native-CA wiring for on-disk P-256 CAs (A2-prep)
Wire the prod boot to issue frp-client + device leaves from the existing on-disk
P-256 CAs: NATIVE_* env vars, a file-backed KmsResolver (loads the PEM key,
validates prime256v1, never logs key material), buildFileBackedNativeCas threaded
into buildControlPlane via a nativeCas override. Fail-closed on partial NATIVE_*.
281 tests pass.
2026-07-18 15:04:04 +02:00

155 lines
6.9 KiB
TypeScript

/**
* T15 — CA-key / secret-manager bootstrap + KMS-signer factory (§3.1). The intermediate
* leaf-signing key is a non-exportable KMS/HSM key: signing is a `sign()` CALL, the raw private
* key is NEVER loaded into control-plane memory. `buildCaSigner` FAILS FAST at startup (INV9) if
* the key ref is unresolvable OR its policy does not restrict `sign` to the control-plane
* service principal. Both T8 `signHostLeaf` and T15 `renewHostLeaf` call this shared primitive —
* neither loads a raw key.
*
* Two in-process dev/test signers implement the SAME `CaSigner` surface (never a KMS — production
* mandates a real non-exportable key): `inProcessCaSigner` (Ed25519, the relay agent-CA path) and
* `inProcessP256CaSigner` (ECDSA-with-SHA256, the native-tunnel `frp-client-CA` / `device-CA` P-256
* path). The P-256 signer returns a raw P1363 `r||s` signature — the shape hardware emits — which
* `x509-assembler` normalizes to DER; both expose the same `sign()` so callers stay KMS-shaped.
*/
import { createPublicKey, generateKeyPairSync, sign as nodeSign } from 'node:crypto'
import { readFileSync } from 'node:fs'
import type { ControlPlaneEnv } from '../env.js'
import { createPrivateKey, ed25519Sign, generateEd25519, type KeyObject } from '../util/crypto.js'
/** Wraps KMS `sign()`; no raw key ever crosses this boundary. */
export interface CaSigner {
sign(tbsCert: Uint8Array): Promise<Uint8Array>
/** Public verifying key of the CA (for tests / chain assembly). */
readonly publicKeyRaw: Uint8Array
}
/**
* KMS resolver seam. Production resolves a real KMS/HSM key handle + policy; tests inject a fake.
* A resolver returns `{ canSign, policyRestrictedToServicePrincipal }` for the given ref, or throws
* if the ref cannot be resolved at all.
*/
export interface KmsResolver {
resolve(keyRef: string): Promise<{
readonly signer: CaSigner
readonly policyRestrictedToServicePrincipal: boolean
}>
}
/**
* Build the CA signer for the configured intermediate KMS key. Fail-fast (INV9, §3.1):
* - throws if the resolver cannot resolve the ref;
* - throws if the KMS key policy is broader than the control-plane service principal.
*/
export async function buildCaSigner(env: ControlPlaneEnv, resolver: KmsResolver): Promise<CaSigner> {
let resolved
try {
resolved = await resolver.resolve(env.caIntermediateKmsKeyRef)
} catch (err: unknown) {
// Never log the ref VALUE — only that resolution failed (INV9).
throw new Error(
`CA intermediate KMS key could not be resolved: ${err instanceof Error ? err.message : 'unknown'}`,
)
}
if (!resolved.policyRestrictedToServicePrincipal) {
throw new Error(
'CA intermediate KMS key policy is broader than the control-plane service principal (§3.1) — refusing to boot',
)
}
return resolved.signer
}
/**
* In-process Ed25519 CA signer — TEST/DEV ONLY (clearly NOT a KMS; the plan mandates a real
* non-exportable KMS key in production, §3.1). Exposes the same `sign()` surface so callers are
* KMS-shaped and never touch a raw key path themselves.
*/
export function inProcessCaSigner(privateKey?: KeyObject): CaSigner {
const key = privateKey ?? generateEd25519().privateKey
const pub = derivePublicRaw(key)
return {
publicKeyRaw: pub,
async sign(tbsCert) {
return ed25519Sign(key, tbsCert)
},
}
}
function derivePublicRaw(privateKey: KeyObject): Uint8Array {
// Recover the raw 32-byte Ed25519 public key from the private KeyObject.
const spki = createPublicKey(privateKey).export({ format: 'der', type: 'spki' }) as Buffer
return new Uint8Array(spki.subarray(spki.length - 32))
}
/**
* In-process P-256 (ECDSA-with-SHA256) CA signer — TEST/DEV ONLY, same disclaimer as the Ed25519
* variant. This is the dev stand-in for the native-tunnel `frp-client-CA` / `device-CA` (both P-256).
* `sign()` returns a RAW P1363 `r||s` (64-byte) signature over the TBS — the same shape hardware
* (Secure Enclave / StrongBox / WebCrypto) emits — which `x509-assembler` normalizes to DER.
* `publicKeyRaw` carries the CA's SubjectPublicKeyInfo DER (not a bare point) so tests can import it
* directly as a verifying key.
*/
export function inProcessP256CaSigner(privateKey?: KeyObject): CaSigner {
const key = privateKey ?? generateKeyPairSync('ec', { namedCurve: 'P-256' }).privateKey
const spkiDer = createPublicKey(key).export({ format: 'der', type: 'spki' }) as Buffer
return {
publicKeyRaw: new Uint8Array(spkiDer),
async sign(tbsCert) {
return new Uint8Array(nodeSign('sha256', Buffer.from(tbsCert), { key, dsaEncoding: 'ieee-p1363' }))
},
}
}
/** Prefix marking a KMS key ref that is actually an on-disk PEM key path (`file:<path>`). */
const FILE_KEY_REF_PREFIX = 'file:'
/** OpenSSL's name for the P-256 (secp256r1) curve — the ONLY curve the native-tunnel CAs use. */
const P256_CURVE = 'prime256v1'
/** Build a `file:<path>` KMS key ref from an on-disk native-CA private key path. */
export function fileKeyRef(path: string): string {
return `${FILE_KEY_REF_PREFIX}${path}`
}
/**
* Load a PKCS#8 PEM P-256 private key from disk and wrap it in the SAME `CaSigner` surface as
* `inProcessP256CaSigner` (raw P1363 `r||s` over the DER TBS). FAIL-FAST on an unreadable file,
* malformed PEM, or a non-P-256 key. The raw key stays in-process — NEVER logged/serialised (INV9).
*/
function loadP256FileSigner(path: string): CaSigner {
let pem: string
try {
pem = readFileSync(path, 'utf8')
} catch {
// Never echo the path contents — only that the file was unreadable (INV9).
throw new Error('native-CA private key file is unreadable')
}
let key: KeyObject
try {
key = createPrivateKey(pem)
} catch {
throw new Error('native-CA private key is not a valid PEM private key')
}
if (key.asymmetricKeyType !== 'ec' || key.asymmetricKeyDetails?.namedCurve !== P256_CURVE) {
throw new Error('native-CA private key must be a P-256 (prime256v1) EC key')
}
return inProcessP256CaSigner(key)
}
/**
* FILE-BACKED KmsResolver — the production native-tunnel key custody for the single-owner VPS deploy.
* Resolves a key ref of the form `file:<path>` (or a bare path) by loading the on-disk PEM P-256 key
* into an in-process `CaSigner`. `policyRestrictedToServicePrincipal` is TRUE because the on-disk key
* IS the control-plane's sole custody (documented file-custody reality; a real non-exportable KMS —
* `KmsResolver` in front of KMS/HSM — is the future upgrade). Throws if the ref cannot be resolved so
* `buildCaSigner` fails fast at boot. NEVER logs key material (INV9).
*/
export function fileKmsResolver(): KmsResolver {
return {
async resolve(keyRef: string) {
const path = keyRef.startsWith(FILE_KEY_REF_PREFIX) ? keyRef.slice(FILE_KEY_REF_PREFIX.length) : keyRef
if (path.length === 0) throw new Error('file KMS key ref has an empty path')
return { signer: loadP256FileSigner(path), policyRestrictedToServicePrincipal: true }
},
}
}