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LocalContainer not adhering to specifications #48

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189 changes: 115 additions & 74 deletions wrapper/src/main/java/io/yubicolabs/wwwwallet/credentials/LocalContainer.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -70,45 +70,38 @@ class LocalContainer(
options: JSONObject,
successCallback: (JSONObject) -> Unit,
failureCallback: (Throwable) -> Unit,
) = create(options, null, successCallback, failureCallback)

fun create(
options: JSONObject,
clientDataJsonHash: ByteArray?,
successCallback: (JSONObject) -> Unit,
failureCallback: (Throwable) -> Unit,
) = try {
val credential = createCredential(options)
val credential = createCredential(options, clientDataJsonHash)
successCallback(credential)
} catch (th: Throwable) {
YOLOLogger.e(tagForLog, "Cannot create credential.", th)
failureCallback(th)
}

private fun createCredential(options: JSONObject): JSONObject {
private fun createCredential(
options: JSONObject,
clientDataHash: ByteArray?,
): JSONObject {
val selectedAlgorithm = selectAlgorithm(options)
val (algorithmSpec, keyAlgorithm) = getAlgorithmParams(selectedAlgorithm)

val credentialId = ByteArray(32)
SecureRandom().nextBytes(credentialId)

val challenge =
(options.getNested("publicKey.challenge") as? String)?.decodeBase64()?.toByteArray()
?: byteArrayOf()

val spec = buildKeyGenParameterSpec(credentialId, challenge, algorithmSpec)
val spec = buildKeyGenParameterSpec(credentialId, algorithmSpec)
val keyPair = generateKeyPair(keyAlgorithm, spec)

val rpId =
options.getNested("publicKey.rp.id") as? String
?: throw IllegalStateException("'publicKey.rp.id' on credential create options not set.")

val clientDataJson =
getClientOptions(
type = "webauthn.create",
challenge = challenge,
origin = rpId,
)

val clientDataJsonB64 =
encodeToString(
clientDataJson,
NO_PADDING or NO_WRAP or URL_SAFE,
)

val (attestationObject, authenticatorData) =
createAttestationObject(
rpId = rpId,
Expand All @@ -120,10 +113,14 @@ class LocalContainer(
signatureCount = 0,
)

val challenge =
(options.getNested("publicKey.challenge") as? String)?.decodeBase64()?.toByteArray()
?: throw (IllegalStateException("Challenge not present."))

val credential =
createPublicKeyCredential(
credentialId,
clientDataJsonB64,
clientDataHash ?: getClientOptions(type = "webauthn.create", challenge = challenge, origin = rpId),
attestationObject,
authenticatorData,
selectedAlgorithm,
Expand All @@ -137,6 +134,35 @@ class LocalContainer(
return credential
}

fun delete(
credentialId: String,
successCallback: () -> Unit,
failureCallback: (Throwable) -> Unit,
) = try {
val byteId = credentialId.decodeBase64()?.toByteArray() ?: byteArrayOf()
val alias = "$origin+${byteId.toHexString()}"
val filename = byteId.credIdToFilename()

if (secureStore.containsAlias(alias)) {
secureStore.deleteEntry(alias)
} else {
failureCallback(IllegalStateException("Credential alias nor found."))
}
Comment on lines +146 to +150
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@jessevanmuijden jessevanmuijden Dec 4, 2025

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Suggested change
if (secureStore.containsAlias(alias)) {
secureStore.deleteEntry(alias)
} else {
failureCallback(IllegalStateException("Credential alias nor found."))
}
if (!secureStore.containsAlias(alias)) {
failureCallback(IllegalStateException("Credential alias nor found."))
}
secureStore.deleteEntry(alias)

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@mariobodemann mariobodemann Dec 4, 2025

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I am not sure about this one: It looks like you'd always delete an entry, if it exists or not.

(Also just noticed a typo in the original code: nor should probably be not.)


if (filename !in context.fileList()) {
// no delete necessary
failureCallback(IllegalStateException("File $filename not found."))
} else {
if (context.deleteFile(filename)) {
successCallback()
} else {
failureCallback(RuntimeException("Failed to delete $filename file."))
}
}
Comment on lines +152 to +161
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@jessevanmuijden jessevanmuijden Dec 4, 2025

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Suggested change
if (filename !in context.fileList()) {
// no delete necessary
failureCallback(IllegalStateException("File $filename not found."))
} else {
if (context.deleteFile(filename)) {
successCallback()
} else {
failureCallback(RuntimeException("Failed to delete $filename file."))
}
}
if (filename !in context.fileList()) {
// no delete necessary
failureCallback(IllegalStateException("File $filename not found."))
}
if (!context.deleteFile(filename)) {
failureCallback(RuntimeException("Failed to delete $filename file."))
}
successCallback()

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@mariobodemann mariobodemann Dec 4, 2025

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🤔

Wouldn't that open the possibility to call the failureCallback() and then the successCallback() when the file doesn't exist.

Also the failure callback would get invoked twice if the file doesn't exist: First on check, and then when the non existant file is tried to get deleted...

The idea for me is that there shouldn't be an option where both callbacks can get called (or one callback gets called multiple times).

} catch (th: Throwable) {
failureCallback(th)
}

private fun selectAlgorithm(options: JSONObject): Int {
val pubKeyCredParams: List<*> =
options.getNested("publicKey.pubKeyCredParams") as? List<*> ?: listOf<Any>()
Expand All @@ -157,23 +183,19 @@ class LocalContainer(

private fun buildKeyGenParameterSpec(
credentialId: ByteArray,
challenge: ByteArray,
algorithmSpec: AlgorithmParameterSpec,
): KeyGenParameterSpec =
KeyGenParameterSpec
.Builder(
"$origin+${credentialId.toHexString()}",
PURPOSE_SIGN or PURPOSE_VERIFY,
)
.setAlgorithmParameterSpec(algorithmSpec)
).setAlgorithmParameterSpec(algorithmSpec)
.setIsStrongBoxBacked(
isStrongBoxed,
).setDigests(
DIGEST_SHA256,
DIGEST_SHA384,
DIGEST_SHA512,
).setAttestationChallenge(
challenge,
).build()

private fun generateKeyPair(
Expand All @@ -191,7 +213,7 @@ class LocalContainer(

private fun createPublicKeyCredential(
credentialId: ByteArray,
clientDataJsonB64: String,
clientDataHash: ByteArray,
attestationObject: String,
authenticatorData: ByteArray,
publicKeyAlgorithm: Int,
Expand All @@ -200,7 +222,11 @@ class LocalContainer(
val response =
JSONObject(
mapOf(
"clientDataJSON" to clientDataJsonB64,
"clientDataJSON" to
encodeToString(
clientDataHash,
NO_PADDING or NO_WRAP or URL_SAFE,
),
"attestationObject" to attestationObject,
"authenticatorData" to
encodeToString(
Expand Down Expand Up @@ -241,9 +267,13 @@ class LocalContainer(
type: String,
challenge: ByteArray,
origin: String,
): ByteArray {
return """{"type":"$type","challenge":"${encodeToString(challenge, NO_PADDING or NO_WRAP or URL_SAFE)}","origin":"${origin.fullyQualified()}","crossOrigin":false}""".toByteArray()
}
): ByteArray =
"""{"type":"$type","challenge":"${
encodeToString(
challenge,
NO_PADDING or NO_WRAP or URL_SAFE,
)
}","origin":"${origin.fullyQualified()}","crossOrigin":false}""".toByteArray()

private fun createAttestationObject(
rpId: String,
Expand All @@ -266,7 +296,8 @@ class LocalContainer(

val attestationObject =
encodeToString(
CBORObject.NewMap()
CBORObject
.NewMap()
.Add("fmt", "none")
.Add("attStmt", CBORObject.NewMap())
.Add("authData", authenticatorData)
Expand All @@ -281,7 +312,8 @@ class LocalContainer(
cosePublicKey: ByteArray,
): ByteArray {
val attestedCredentialDataLength = 16 + 2 + credentialId.size + cosePublicKey.size
return ByteBuffer.allocate(attestedCredentialDataLength)
return ByteBuffer
.allocate(attestedCredentialDataLength)
.order(ByteOrder.BIG_ENDIAN)
.put(aaguid.toByteArray(), 0, 16)
.putShort(credentialId.size.toShort())
Expand Down Expand Up @@ -309,7 +341,8 @@ class LocalContainer(
?: 0
) + (extensions?.size ?: 0)
val authenticatorData =
ByteBuffer.allocate(authenticatorDataLength)
ByteBuffer
.allocate(authenticatorDataLength)
.order(ByteOrder.BIG_ENDIAN)
.put(rpIdHash, 0, 32)
.put(flags)
Expand Down Expand Up @@ -345,53 +378,57 @@ class LocalContainer(
return flags.toByte()
}

private fun isAlgorithmSupported(alg: Int): Boolean {
return alg in listOf(-7, -257, -35, -36)
}
private fun isAlgorithmSupported(alg: Int): Boolean = alg in listOf(-7, -257, -35, -36)

private fun getAlgorithmParams(alg: Int): Pair<AlgorithmParameterSpec, String> {
return when (alg) {
private fun getAlgorithmParams(alg: Int): Pair<AlgorithmParameterSpec, String> =
when (alg) {
-7 -> ECGenParameterSpec("secp256r1") to KEY_ALGORITHM_EC
-35 -> ECGenParameterSpec("secp384r1") to KEY_ALGORITHM_EC
-36 -> ECGenParameterSpec("secp521r1") to KEY_ALGORITHM_EC
else -> throw IllegalArgumentException("Unsupported algorithm: $alg")
}
}

fun getAll(
options: JSONObject,
maybeClientDataJsonHash: ByteArray? = null,
successCallback: (JSONArray) -> Unit,
failureCallback: (Throwable) -> Unit,
) = try {
YOLOLogger.i("found credentials", "get options: ${options.toString(2)}")

val allowedCredentials: List<Map<*, *>> =
(options.getNested("publicKey.allowCredentials") as? List<Map<*, *>>) ?: listOf<Map<*, *>>()

val rpId = options.getNested("publicKey.rpId") as? String ?: ""

val challenge =
(options.getNested("publicKey.challenge") as? String)?.decodeBase64()?.toByteArray()
?: byteArrayOf()

val rpId = options.getNested("publicKey.rpId") as? String ?: ""
val clientDataJsonHash =
maybeClientDataJsonHash ?: getClientOptions(type = "webauthn.get", challenge = challenge, origin = rpId)

// retrieve allowed or all credentials
val selectedCredentials =
if (allowedCredentials.isNotEmpty()) {
allowedCredentials.mapNotNull { allowed ->
val type = allowed.getOrDefault("type", null) as? String ?: ""
if (type != "public-key") {
YOLOLogger.e(tagForLog, "Found non 'public-key' credential id in allow list.")
}

val allowedIdB64 = allowed.getOrDefault("id", null) as? String ?: ""
val allowedIdRaw = allowedIdB64.decodeBase64()
val allowedId = allowedIdRaw?.hex() ?: ""
val alias = "$origin+$allowedId"

if (secureStore.containsAlias(alias)) {
alias to secureStore.getEntry(alias, null)
} else {
null
}
}.associate { it }
allowedCredentials
.mapNotNull { allowed ->
val type = allowed.getOrDefault("type", null) as? String ?: ""
if (type != "public-key") {
YOLOLogger.e(tagForLog, "Found non 'public-key' credential id in allow list.")
}

val allowedIdB64 = allowed.getOrDefault("id", null) as? String ?: ""
val allowedIdRaw = allowedIdB64.decodeBase64()
val allowedId = allowedIdRaw?.hex() ?: ""
val alias = "$origin+$allowedId"

if (secureStore.containsAlias(alias)) {
alias to secureStore.getEntry(alias, null)
} else {
null
}
}.associate { it }
} else {
secureStore.aliases().toList().associate { key ->
key to secureStore.getEntry(key, null)
Expand All @@ -408,11 +445,18 @@ class LocalContainer(
finalSelection.mapNotNull { selectionEntry ->
val (key, keyEntry) = selectionEntry
(keyEntry as? KeyStore.PrivateKeyEntry)
?.toResponse(key, challenge, rpId)
?.toResponse(
id = key,
clientDataJson = clientDataJsonHash,
rpId = rpId,
)
}

val credentialsJson = JSONArray(credentials)
val msg = credentialsJson.toString(2)
YOLOLogger.i("Found credentials", "get response: $msg")
successCallback(
JSONArray(credentials),
credentialsJson,
)
} catch (th: Throwable) {
YOLOLogger.e(tagForLog, "Couldn't return all credentials.", th)
Expand All @@ -423,9 +467,17 @@ class LocalContainer(
options: JSONObject,
successCallback: (JSONObject) -> Unit,
failureCallback: (Throwable) -> Unit,
) = get(options, null, successCallback, failureCallback)

fun get(
options: JSONObject,
clientDataJsonHash: ByteArray?,
successCallback: (JSONObject) -> Unit,
failureCallback: (Throwable) -> Unit,
) = try {
getAll(
options = options,
maybeClientDataJsonHash = clientDataJsonHash,
successCallback = { jsonArray ->
if (jsonArray.length() > 0) {
successCallback(jsonArray.getJSONObject(0))
Expand All @@ -442,18 +494,12 @@ class LocalContainer(

private fun KeyStore.PrivateKeyEntry.toResponse(
id: String,
challenge: ByteArray,
clientDataJson: ByteArray,
rpId: String,
): JSONObject {
val credentialId =
id.replace("$origin+", "").hexToByteArray()

val clientDataJson =
getClientOptions(
type = "webauthn.get",
challenge = challenge,
origin = rpId,
)
val clientDataJsonB64 =
encodeToString(
clientDataJson,
Expand Down Expand Up @@ -500,11 +546,7 @@ class LocalContainer(
signature,
NO_PADDING or NO_WRAP or URL_SAFE,
),
"userHandle" to
encodeToString(
userId.toByteArray(),
NO_PADDING or NO_WRAP or URL_SAFE,
),
"userHandle" to userId,
"userName" to userName,
"userDisplayName" to userDisplayName,
),
Expand Down Expand Up @@ -589,8 +631,7 @@ class LocalContainer(
.digest(
"AES+${toHexString()}"
.toByteArray(),
)
.toHexString()
).toHexString()
}

private fun PrivateKey.deriveKeyFromKeyPair(): SecretKeySpec {
Expand Down
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