1package com.peachpasswords.sync23import kotlinx.serialization.builtins.serializer4import kotlinx.serialization.json.Json5import org.bouncycastle.crypto.params.Ed25519PrivateKeyParameters67const val DEVICE_MANIFEST_VERSION = 0x018private const val DEVICE_MANIFEST_FRESHNESS_MS = 5 * 60_000L910interface PairedDeviceRegistry {11 fun getAll(): List<PairedDevice>12 fun get(id: String): PairedDevice?13 fun upsert(device: PairedDevice)14}1516fun buildSignedDeviceManifest(17 issuerDeviceId: String,18 devices: List<ManifestDeviceEntry>,19 signingPrivateKey: Ed25519PrivateKeyParameters,20 nowMs: Long = System.currentTimeMillis(),21): SignedDeviceManifest {22 require(issuerDeviceId.isNotBlank()) { "issuerDeviceId is required" }23 val body = DeviceManifestBody(24 manifestVersion = DEVICE_MANIFEST_VERSION,25 issuerDeviceId = issuerDeviceId,26 issuedAt = nowMs,27 devices = devices.mapNotNull(::normaliseManifestEntry),28 )29 val signature = signEd25519(signingPrivateKey, canonicalDeviceManifestBody(body).toByteArray(Charsets.UTF_8))30 return SignedDeviceManifest(body, pubkeyToHex(signature))31}3233fun verifyDeviceManifest(34 manifest: SignedDeviceManifest,35 issuerSigningPublicKey: ByteArray,36 nowMs: Long = System.currentTimeMillis(),37 freshnessMs: Long = DEVICE_MANIFEST_FRESHNESS_MS,38): DeviceManifestBody? {39 val body = manifest.body40 if (body.manifestVersion != DEVICE_MANIFEST_VERSION) return null41 if (kotlin.math.abs(nowMs - body.issuedAt) > freshnessMs) return null42 if (!isHex(manifest.signatureHex, 128)) return null43 if (!body.devices.all { normaliseManifestEntry(it) != null }) return null44 val signature = runCatching { hexToPubkey(manifest.signatureHex) }.getOrNull() ?: return null45 val canonical = canonicalDeviceManifestBody(body).toByteArray(Charsets.UTF_8)46 if (!verifyEd25519(issuerSigningPublicKey, canonical, signature)) return null47 return body48}4950fun canonicalDeviceManifestBody(body: DeviceManifestBody): String =51 canonicalise(52 mapOf(53 "devices" to body.devices.map { manifestEntryMap(it) },54 "issuedAt" to body.issuedAt,55 "issuerDeviceId" to body.issuerDeviceId,56 "manifestVersion" to body.manifestVersion,57 ),58 )5960fun PairedDevice.toManifestEntry(): ManifestDeviceEntry? {61 val id = deviceId.takeIf { it.isNotBlank() } ?: return null62 val name = deviceName?.takeIf { it.isNotBlank() } ?: return null63 val type = deviceType?.takeIf { it in setOf("extension", "android", "ios", "desktop") } ?: return null64 val longTerm = longTermPublicKeyHex?.lowercase()?.takeIf { isHex(it, 64) } ?: return null65 val signing = signingPublicKeyHex?.lowercase()?.takeIf { isHex(it, 64) } ?: return null66 return ManifestDeviceEntry(67 deviceId = id,68 deviceName = name,69 deviceType = type,70 longTermPublicKeyHex = longTerm,71 signingPublicKeyHex = signing,72 wsPort = wsPort,73 pairedAt = pairedAt,74 )75}7677private fun normaliseManifestEntry(entry: ManifestDeviceEntry): ManifestDeviceEntry? {78 if (entry.deviceId.isBlank() || entry.deviceName.isBlank()) return null79 if (entry.deviceType !in setOf("extension", "android", "ios", "desktop")) return null80 if (!isHex(entry.longTermPublicKeyHex, 64) || !isHex(entry.signingPublicKeyHex, 64)) return null81 if (entry.wsPort != null && entry.wsPort !in 1..65_535) return null82 return entry.copy(83 longTermPublicKeyHex = entry.longTermPublicKeyHex.lowercase(),84 signingPublicKeyHex = entry.signingPublicKeyHex.lowercase(),85 )86}8788private fun manifestEntryMap(entry: ManifestDeviceEntry): Map<String, Any> {89 val normalised = normaliseManifestEntry(entry) ?: entry90 val map = linkedMapOf<String, Any>(91 "deviceId" to normalised.deviceId,92 "deviceName" to normalised.deviceName,93 "deviceType" to normalised.deviceType,94 "longTermPublicKeyHex" to normalised.longTermPublicKeyHex.lowercase(),95 "pairedAt" to normalised.pairedAt,96 "signingPublicKeyHex" to normalised.signingPublicKeyHex.lowercase(),97 )98 normalised.wsPort?.let { map["wsPort"] = it }99 return map100}101102private fun canonicalise(value: Any?): String = when (value) {103 null -> "null"104 is Number -> {105 val d = value.toDouble()106 require(d.isFinite()) { "non-finite number" }107 if (d % 1.0 == 0.0) value.toLong().toString() else value.toString()108 }109 is String -> Json.encodeToString(String.serializer(), value)110 is Boolean -> if (value) "true" else "false"111 is List<*> -> value.joinToString(prefix = "[", postfix = "]", separator = ",") { canonicalise(it) }112 is Map<*, *> -> value.entries113 .map { (k, v) -> k.toString() to v }114 .sortedBy { it.first }115 .joinToString(prefix = "{", postfix = "}", separator = ",") { (k, v) ->116 Json.encodeToString(String.serializer(), k) + ":" + canonicalise(v)117 }118 else -> error("cannot canonicalise ${value::class.simpleName}")119}120121private fun isHex(value: String, length: Int): Boolean =122 value.length == length && value.all { it in '0'..'9' || it in 'a'..'f' }