feat(interception): add AUTO mode TEE race for G10 attestation consistency

AUTO mode now races TEE hardware against software generation via
CompletableFuture. If TEE succeeds, the cert chain is patched and
cached in teeResponses before returning, making attestation
stress-resilient. If TEE fails, software fallback is used.

ConfigurationManager no longer resolves AUTO at config time; it
passes Mode.AUTO through to KeyMintSecurityLevelInterceptor for
runtime dispatch. shouldPatch() returns true for both PATCH and
AUTO modes. TEE status file persistence removed entirely.

Aligns handleGenerateKey with upstream PR #157 three-way dispatch:
forceGenerate, raceTeePatch, or hardware forwarding with post-patch.

Hardware keygen rate limiting removed (replaced by raceTeePatch for
AUTO, plain Continue for PATCH). Attest key override in
Keystore2Interceptor now patches authorizations and uses null-safe
nspace assignment.
This commit is contained in:
Enginex0
2026-03-20 04:44:52 +01:00
parent b6f9d7b486
commit 8fdc59a142
3 changed files with 108 additions and 104 deletions
@@ -7,7 +7,6 @@ import android.os.IBinder
import android.os.ServiceManager import android.os.ServiceManager
import java.io.File import java.io.File
import java.util.concurrent.ConcurrentHashMap import java.util.concurrent.ConcurrentHashMap
import org.matrix.TEESimulator.attestation.DeviceAttestationService
import org.matrix.TEESimulator.logging.SystemLogger import org.matrix.TEESimulator.logging.SystemLogger
import org.matrix.TEESimulator.pki.KeyBoxManager import org.matrix.TEESimulator.pki.KeyBoxManager
@@ -31,7 +30,6 @@ object ConfigurationManager {
// --- Configuration Paths --- // --- Configuration Paths ---
const val CONFIG_PATH = "/data/adb/tricky_store" const val CONFIG_PATH = "/data/adb/tricky_store"
private const val TARGET_PACKAGES_FILE = "target.txt" private const val TARGET_PACKAGES_FILE = "target.txt"
private const val TEE_STATUS_FILE = "tee_status.txt"
private const val PATCH_LEVEL_FILE = "security_patch.txt" private const val PATCH_LEVEL_FILE = "security_patch.txt"
private const val DEFAULT_KEYBOX_FILE = "keybox.xml" private const val DEFAULT_KEYBOX_FILE = "keybox.xml"
private val configRoot = File(CONFIG_PATH) private val configRoot = File(CONFIG_PATH)
@@ -39,7 +37,6 @@ object ConfigurationManager {
// --- In-Memory Configuration State --- // --- In-Memory Configuration State ---
@Volatile private var packageModes = mapOf<String, Mode>() @Volatile private var packageModes = mapOf<String, Mode>()
@Volatile private var packageKeyboxes = mapOf<String, String>() @Volatile private var packageKeyboxes = mapOf<String, String>()
@Volatile private var isTeeBroken: Boolean? = null
@Volatile private var globalCustomPatchLevel: CustomPatchLevel? = null @Volatile private var globalCustomPatchLevel: CustomPatchLevel? = null
@Volatile private var packagePatchLevels = mapOf<String, CustomPatchLevel>() @Volatile private var packagePatchLevels = mapOf<String, CustomPatchLevel>()
@@ -68,8 +65,6 @@ object ConfigurationManager {
// Initial load of all configuration files. // Initial load of all configuration files.
loadTargetPackages(File(configRoot, TARGET_PACKAGES_FILE)) loadTargetPackages(File(configRoot, TARGET_PACKAGES_FILE))
loadPatchLevelConfig(File(configRoot, PATCH_LEVEL_FILE)) loadPatchLevelConfig(File(configRoot, PATCH_LEVEL_FILE))
storeTeeStatus() // Check and store the current TEE status.
// Start watching for any subsequent file changes. // Start watching for any subsequent file changes.
ConfigObserver.startWatching() ConfigObserver.startWatching()
SystemLogger.info("Configuration initialized and file observer started.") SystemLogger.info("Configuration initialized and file observer started.")
@@ -87,33 +82,31 @@ object ConfigurationManager {
return packages.firstNotNullOfOrNull { pkg -> packageKeyboxes[pkg] } ?: DEFAULT_KEYBOX_FILE return packages.firstNotNullOfOrNull { pkg -> packageKeyboxes[pkg] } ?: DEFAULT_KEYBOX_FILE
} }
/** Determines if the certificate for a given UID needs to be patched. */ fun shouldPatch(uid: Int): Boolean {
fun shouldPatch(uid: Int): Boolean = getPackageModeForUid(uid) == Mode.PATCH val mode = getPackageModeForUid(uid)
return mode == Mode.PATCH || mode == Mode.AUTO
}
/** Determines if a new certificate needs to be generated for a given UID. */ /** Determines if a new certificate needs to be generated for a given UID. */
fun shouldGenerate(uid: Int): Boolean = getPackageModeForUid(uid) == Mode.GENERATE fun shouldGenerate(uid: Int): Boolean = getPackageModeForUid(uid) == Mode.GENERATE
/** Determines if no operation is needed for a given UID. */
fun shouldSkipUid(uid: Int): Boolean = getPackageModeForUid(uid) == null fun shouldSkipUid(uid: Int): Boolean = getPackageModeForUid(uid) == null
/** Resolves the operating mode for a given UID based on its packages and the TEE status. */ fun isAutoMode(uid: Int): Boolean = getPackageModeForUid(uid) == Mode.AUTO
private fun getPackageModeForUid(uid: Int): Mode? { private fun getPackageModeForUid(uid: Int): Mode? {
val packages = getPackagesForUid(uid) val packages = getPackagesForUid(uid)
if (packages.isEmpty()) return null if (packages.isEmpty()) return null
// Lazily load TEE status if it hasn't been checked yet.
if (isTeeBroken == null) loadTeeStatus()
// Find the first configured mode for any of the UID's packages.
for (pkg in packages) { for (pkg in packages) {
when (packageModes[pkg]) { when (packageModes[pkg]) {
Mode.GENERATE -> return Mode.GENERATE Mode.GENERATE -> return Mode.GENERATE
Mode.PATCH -> return Mode.PATCH Mode.PATCH -> return Mode.PATCH
Mode.AUTO -> return if (isTeeBroken == true) Mode.GENERATE else Mode.PATCH Mode.AUTO -> return Mode.AUTO
null -> continue // No config for this package, check the next one. null -> continue
} }
} }
return null // No configuration found for this UID. return null
} }
/** /**
@@ -280,29 +273,6 @@ object ConfigurationManager {
} }
} }
/** Checks the device's TEE status and writes the result to a file for persistence. */
private fun storeTeeStatus() {
val statusFile = File(configRoot, TEE_STATUS_FILE)
isTeeBroken = !DeviceAttestationService.isTeeFunctional
try {
statusFile.writeText("tee_broken=$isTeeBroken")
SystemLogger.info("TEE status stored: isTeeBroken=$isTeeBroken")
} catch (e: Exception) {
SystemLogger.error("Failed to write TEE status to file.", e)
}
}
/** Loads the TEE status from the file. */
private fun loadTeeStatus() {
val statusFile = File(configRoot, TEE_STATUS_FILE)
isTeeBroken =
if (statusFile.exists()) {
statusFile.readText().trim() == "tee_broken=true"
} else {
null // Status is unknown.
}
}
/** /**
* A FileObserver that monitors the configuration directory for changes and triggers reloads of * A FileObserver that monitors the configuration directory for changes and triggers reloads of
* the relevant settings. * the relevant settings.
@@ -358,14 +358,19 @@ object Keystore2Interceptor : AbstractKeystoreInterceptor() {
keyData.second.toTypedArray(), keyData.second.toTypedArray(),
) )
.getOrThrow() .getOrThrow()
response.metadata.authorizations =
InterceptorUtils.patchAuthorizations(
response.metadata.authorizations,
callingUid,
)
keyDescriptor.nspace = SecureRandom().nextLong() val newNspace = SecureRandom().nextLong()
response.metadata.key.nspace = keyDescriptor.nspace response.metadata.key?.let { it.nspace = newNspace }
KeyMintSecurityLevelInterceptor.generatedKeys[keyId] = KeyMintSecurityLevelInterceptor.generatedKeys[keyId] =
KeyMintSecurityLevelInterceptor.GeneratedKeyInfo( KeyMintSecurityLevelInterceptor.GeneratedKeyInfo(
keyData.first, keyData.first,
null, null,
keyDescriptor.nspace, newNspace,
response, response,
parsedParameters, parsedParameters,
) )
@@ -374,7 +379,7 @@ object Keystore2Interceptor : AbstractKeystoreInterceptor() {
GeneratedKeyPersistence.save( GeneratedKeyPersistence.save(
keyId = keyId, keyId = keyId,
keyPair = keyData.first, keyPair = keyData.first,
nspace = keyDescriptor.nspace, nspace = newNspace,
securityLevel = response.metadata.keySecurityLevel, securityLevel = response.metadata.keySecurityLevel,
certChain = keyData.second, certChain = keyData.second,
algorithm = parsedParameters.algorithm, algorithm = parsedParameters.algorithm,
@@ -20,6 +20,7 @@ import java.security.SecureRandom
import java.security.cert.Certificate import java.security.cert.Certificate
import java.security.cert.CertificateFactory import java.security.cert.CertificateFactory
import java.security.spec.PKCS8EncodedKeySpec import java.security.spec.PKCS8EncodedKeySpec
import java.util.concurrent.CompletableFuture
import java.util.concurrent.ConcurrentHashMap import java.util.concurrent.ConcurrentHashMap
import java.util.concurrent.ConcurrentLinkedDeque import java.util.concurrent.ConcurrentLinkedDeque
import java.util.concurrent.Executors import java.util.concurrent.Executors
@@ -116,12 +117,6 @@ class KeyMintSecurityLevelInterceptor(
reply: Parcel?, reply: Parcel?,
resultCode: Int, resultCode: Int,
): TransactionResult { ): TransactionResult {
if (code == GENERATE_KEY_TRANSACTION && hardwareKeygenTxIds.remove(txId)) {
val remaining = hardwareKeygenCount(callingUid).decrementAndGet()
SystemLogger.info("[TX_ID: $txId] PERMIT_RELEASED uid=$callingUid concurrent_remaining=$remaining result=${if (resultCode == 0) "OK" else "ERROR($resultCode)"}")
}
// We only care about successful transactions.
if (resultCode != 0 || reply == null || InterceptorUtils.hasException(reply)) if (resultCode != 0 || reply == null || InterceptorUtils.hasException(reply))
return TransactionResult.SkipTransaction return TransactionResult.SkipTransaction
@@ -468,38 +463,23 @@ class KeyMintSecurityLevelInterceptor(
val keyId = KeyIdentifier(callingUid, keyDescriptor.alias) val keyId = KeyIdentifier(callingUid, keyDescriptor.alias)
val isAttestKeyRequest = parsedParams.isAttestKey() val isAttestKeyRequest = parsedParams.isAttestKey()
val needsSoftwareGeneration = val forceGenerate =
ConfigurationManager.shouldGenerate(callingUid) || ConfigurationManager.shouldGenerate(callingUid) ||
(ConfigurationManager.shouldPatch(callingUid) && isAttestKeyRequest) || (ConfigurationManager.shouldPatch(callingUid) && isAttestKeyRequest) ||
(attestationKey != null && (attestationKey != null &&
isAttestationKey(KeyIdentifier(callingUid, attestationKey.alias))) isAttestationKey(KeyIdentifier(callingUid, attestationKey.alias)))
if (needsSoftwareGeneration) { val isAuto = ConfigurationManager.isAutoMode(callingUid)
return doSoftwareKeyGen(callingUid, keyDescriptor, attestationKey, parsedParams, keyId, isAttestKeyRequest)
} else if (parsedParams.attestationChallenge != null) {
val windowUsed = hardwareKeygenWindowCount(callingUid)
val concurrentUsed = hardwareKeygenCount(callingUid).get()
// Sliding window rate limit when {
if (windowUsed >= MAX_HW_KEYGEN_PER_WINDOW) { forceGenerate -> doSoftwareKeyGen(callingUid, keyDescriptor, attestationKey, parsedParams, keyId, isAttestKeyRequest)
SystemLogger.info("[TX_ID: $txId] RATE_LIMITED uid=$callingUid window=$windowUsed/$MAX_HW_KEYGEN_PER_WINDOW concurrent=$concurrentUsed → software fallback") isAuto && !teeFunctional -> raceTeePatch(callingUid, keyDescriptor, attestationKey, params, parsedParams, keyId, isAttestKeyRequest)
return doSoftwareKeyGen(callingUid, keyDescriptor, attestationKey, parsedParams, keyId, isAttestKeyRequest) parsedParams.attestationChallenge != null -> TransactionResult.Continue
else -> {
cleanupKeyData(keyId)
TransactionResult.ContinueAndSkipPost
} }
// Concurrent cap
if (hardwareKeygenCount(callingUid).incrementAndGet() > MAX_CONCURRENT_HW_KEYGEN_PER_UID) {
hardwareKeygenCount(callingUid).decrementAndGet()
SystemLogger.info("[TX_ID: $txId] CONCURRENT_LIMITED uid=$callingUid window=$windowUsed/$MAX_HW_KEYGEN_PER_WINDOW concurrent=${concurrentUsed + 1}/$MAX_CONCURRENT_HW_KEYGEN_PER_UID → software fallback")
return doSoftwareKeyGen(callingUid, keyDescriptor, attestationKey, parsedParams, keyId, isAttestKeyRequest)
}
// Both checks passed — commit the window permit and forward to hardware TEE
recordHardwareKeygen(callingUid)
hardwareKeygenTxIds.add(txId)
SystemLogger.info("[TX_ID: $txId] HARDWARE_KEYGEN uid=$callingUid window=${windowUsed + 1}/$MAX_HW_KEYGEN_PER_WINDOW concurrent=${concurrentUsed + 1}/$MAX_CONCURRENT_HW_KEYGEN_PER_UID → forwarding to TEE")
return TransactionResult.Continue
} }
cleanupKeyData(keyId)
TransactionResult.ContinueAndSkipPost
} }
.getOrElse { .getOrElse {
SystemLogger.error("Error during generateKey handling for UID $callingUid.", it) SystemLogger.error("Error during generateKey handling for UID $callingUid.", it)
@@ -608,6 +588,85 @@ class KeyMintSecurityLevelInterceptor(
return InterceptorUtils.createTypedObjectReply(response.metadata) return InterceptorUtils.createTypedObjectReply(response.metadata)
} }
private fun raceTeePatch(
callingUid: Int,
keyDescriptor: KeyDescriptor,
attestationKey: KeyDescriptor?,
rawParams: Array<KeyParameter>,
parsedParams: KeyMintAttestation,
keyId: KeyIdentifier,
isAttestKeyRequest: Boolean,
): TransactionResult {
SystemLogger.info("AUTO: racing TEE vs software for ${keyDescriptor.alias}")
val teeDescriptor = KeyDescriptor().apply {
domain = keyDescriptor.domain
nspace = keyDescriptor.nspace
alias = keyDescriptor.alias
blob = keyDescriptor.blob
}
val teeAttestKey = attestationKey?.let {
KeyDescriptor().apply {
domain = it.domain
nspace = it.nspace
alias = it.alias
blob = it.blob
}
}
val threadA = CompletableFuture.supplyAsync {
original.generateKey(teeDescriptor, teeAttestKey, rawParams, 0, byteArrayOf())
}
val swDescriptor = KeyDescriptor().apply {
domain = keyDescriptor.domain
nspace = secureRandom.nextLong()
alias = keyDescriptor.alias
blob = keyDescriptor.blob
}
val swKeyId = KeyIdentifier(callingUid, keyDescriptor.alias)
val threadB = CompletableFuture.supplyAsync {
doSoftwareKeyGen(callingUid, swDescriptor, attestationKey, parsedParams, swKeyId, isAttestKeyRequest)
}
return try {
val teeMetadata = threadA.join()
threadB.cancel(true)
teeFunctional = true
SystemLogger.info("AUTO: TEE succeeded for ${keyDescriptor.alias}, marked functional.")
val originalChain = CertificateHelper.getCertificateChain(teeMetadata)
if (originalChain != null && originalChain.size > 1) {
val newChain = AttestationPatcher.patchCertificateChain(originalChain, callingUid)
CertificateHelper.updateCertificateChain(teeMetadata, newChain).getOrThrow()
teeMetadata.authorizations =
InterceptorUtils.patchAuthorizations(teeMetadata.authorizations, callingUid)
cleanupKeyData(keyId)
patchedChains[keyId] = newChain
}
teeResponses[keyId] = KeyEntryResponse().apply {
this.metadata = teeMetadata
iSecurityLevel = original
}
InterceptorUtils.createTypedObjectReply(teeMetadata)
} catch (_: Exception) {
SystemLogger.info("AUTO: TEE failed for ${keyDescriptor.alias}, using software result.")
try {
threadB.join()
} catch (e: Exception) {
SystemLogger.error("AUTO: both paths failed for ${keyDescriptor.alias}.", e)
val code =
if (e.cause is android.os.ServiceSpecificException)
(e.cause as android.os.ServiceSpecificException).errorCode
else SECURE_HW_COMMUNICATION_FAILED
InterceptorUtils.createServiceSpecificErrorReply(code)
}
}
}
private fun generateAttestedKeyPairNative( private fun generateAttestedKeyPairNative(
callingUid: Int, callingUid: Int,
params: KeyMintAttestation, params: KeyMintAttestation,
@@ -811,6 +870,7 @@ class KeyMintSecurityLevelInterceptor(
companion object { companion object {
private val secureRandom = SecureRandom() private val secureRandom = SecureRandom()
@Volatile var teeFunctional = false
// Maximum alias length to prevent binder buffer exhaustion (Issue #109) // Maximum alias length to prevent binder buffer exhaustion (Issue #109)
// Binder buffer is ~1MB; 256KB provides 4x safety margin for transaction overhead // Binder buffer is ~1MB; 256KB provides 4x safety margin for transaction overhead
@@ -830,43 +890,12 @@ class KeyMintSecurityLevelInterceptor(
private const val MAX_CONCURRENT_OPS_PER_UID = 15 private const val MAX_CONCURRENT_OPS_PER_UID = 15
private const val STRONGBOX_MAX_CONCURRENT_OPS = 4 private const val STRONGBOX_MAX_CONCURRENT_OPS = 4
private const val STRONGBOX_OP_WINDOW_NS = 10_000_000_000L // 10s private const val STRONGBOX_OP_WINDOW_NS = 10_000_000_000L // 10s
private const val MAX_CONCURRENT_HW_KEYGEN_PER_UID = 2
// Sliding window: max hardware keygen permits per UID within the burst window
private const val MAX_HW_KEYGEN_PER_WINDOW = 2
private const val BURST_WINDOW_MS = 30_000L
private val uidHardwareKeygenCount = ConcurrentHashMap<Int, AtomicInteger>()
private val hardwareKeygenTxIds = ConcurrentHashMap.newKeySet<Long>()
private val uidKeygenTimestamps = ConcurrentHashMap<Int, MutableList<Long>>()
private fun isStrongBoxCapable(params: KeyMintAttestation): Boolean = when (params.algorithm) { private fun isStrongBoxCapable(params: KeyMintAttestation): Boolean = when (params.algorithm) {
Algorithm.RSA -> params.keySize <= 2048 Algorithm.RSA -> params.keySize <= 2048
Algorithm.EC -> params.ecCurve == null || params.ecCurve == EcCurve.P_256 Algorithm.EC -> params.ecCurve == null || params.ecCurve == EcCurve.P_256
else -> true else -> true
} }
private fun hardwareKeygenCount(uid: Int): AtomicInteger =
uidHardwareKeygenCount.computeIfAbsent(uid) { AtomicInteger(0) }
private fun hardwareKeygenWindowCount(uid: Int): Int {
val now = System.currentTimeMillis()
val timestamps = uidKeygenTimestamps.computeIfAbsent(uid) { mutableListOf() }
synchronized(timestamps) {
timestamps.removeAll { now - it > BURST_WINDOW_MS }
if (timestamps.isEmpty()) {
uidKeygenTimestamps.remove(uid, timestamps)
uidHardwareKeygenCount.remove(uid)
}
return timestamps.size
}
}
private fun recordHardwareKeygen(uid: Int) {
val timestamps = uidKeygenTimestamps.computeIfAbsent(uid) { mutableListOf() }
synchronized(timestamps) {
timestamps.add(System.currentTimeMillis())
}
}
private val GENERATE_KEY_TRANSACTION = private val GENERATE_KEY_TRANSACTION =
InterceptorUtils.getTransactCode(IKeystoreSecurityLevel.Stub::class.java, "generateKey") InterceptorUtils.getTransactCode(IKeystoreSecurityLevel.Stub::class.java, "generateKey")
private val IMPORT_KEY_TRANSACTION = private val IMPORT_KEY_TRANSACTION =