fix(keystore): forge device-property attestation

The canAttestDeviceIds gate (3575c74) probed the live TEE to decide
whether to honor device-property/ID attestation. That probe is gated on
isTeeFunctional, which is false on every dead-TEE device the module
serves, so GENERATE mode rejected all such requests with
CANNOT_ATTEST_IDS, including GMS Play Integrity's hardware path, which
broke BHIM and any UPI/Play-Integrity-gated app.

Remove the gate. Device-property attestation (BRAND/MODEL/...) now forges
unconditionally, as genuine devices universally attest it. Device-ID
attestation stays governed by the pre-existing caller-permission check,
the real KeyMint rule: privileged callers get it, ordinary apps do not.
Drop the now-unused DeviceAttestationService.canAttestDeviceIds probe.

app/src/main/java/org/matrix/TEESimulator/attestation/DeviceAttestationService.kt

@@ -1,7 +1,6 @@
 package org.matrix.TEESimulator.attestation
 
 import android.annotation.SuppressLint
-import android.os.Build
 import android.security.keystore.KeyGenParameterSpec
 import android.security.keystore.KeyProperties
 import java.security.KeyPairGenerator
@@ -61,23 +60,12 @@ object DeviceAttestationService {
     // A unique alias for the key used to perform the TEE functionality check.
     private const val TEE_CHECK_KEY_ALIAS = "TEESimulator_AttestationCheck"
 
-    // Alias for the device-ID attestation capability probe.
-    private const val DEVICE_ID_CHECK_KEY_ALIAS = "TEESimulator_DeviceIdCheck"
-
     /**
      * Lazily determines if the device's TEE is functional by attempting to generate an
      * attestation-backed key pair. The result is cached.
      */
     val isTeeFunctional: Boolean by lazy { checkTeeFunctionality() }
 
-    /**
-     * Lazily mirrors whether the real TEE can attest device identifiers/properties (the tags added
-     * by `setDevicePropertiesAttestationIncluded`). Hardware that never provisioned device IDs
-     * returns CANNOT_ATTEST_IDS; the synthesizer consults this so it never forges a capability the
-     * real silicon lacks. Cached.
-     */
-    val canAttestDeviceIds: Boolean by lazy { checkDeviceIdAttestation() }
-
     /**
      * Lazily fetches and parses attestation data from a genuinely generated certificate. The result
      * is cached. Returns null if the TEE is not functional or parsing fails.
@@ -118,37 +106,6 @@ object DeviceAttestationService {
         }
     }
 
-    /**
-     * Probes whether the real TEE can satisfy device-ID/property attestation, mirroring its actual
-     * capability. Gated behind [isTeeFunctional] so a dead TEE never triggers a second doomed
-     * probe — it simply reports `false` (cannot attest), the faithful result for such hardware.
-     */
-    private fun checkDeviceIdAttestation(): Boolean {
-        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.S) return false
-        if (!isTeeFunctional) return false
-        return try {
-            val keyStore = KeyStore.getInstance("AndroidKeyStore").apply { load(null) }
-            val keyPairGenerator =
-                KeyPairGenerator.getInstance(KeyProperties.KEY_ALGORITHM_EC, "AndroidKeyStore")
-            val challenge = ByteArray(16).apply { SecureRandom().nextBytes(this) }
-            val spec =
-                KeyGenParameterSpec.Builder(DEVICE_ID_CHECK_KEY_ALIAS, KeyProperties.PURPOSE_SIGN)
-                    .setAlgorithmParameterSpec(ECGenParameterSpec("secp256r1"))
-                    .setDigests(KeyProperties.DIGEST_SHA256)
-                    .setAttestationChallenge(challenge)
-                    .setDevicePropertiesAttestationIncluded(true)
-                    .build()
-            keyPairGenerator.initialize(spec)
-            keyPairGenerator.generateKeyPair()
-            runCatching { keyStore.deleteEntry(DEVICE_ID_CHECK_KEY_ALIAS) }
-            SystemLogger.info("Device-ID attestation supported by TEE.")
-            true
-        } catch (_: Exception) {
-            SystemLogger.info("Device-ID attestation not supported by TEE; mirroring as cannot-attest.")
-            false
-        }
-    }
-
     /**
      * Retrieves the attestation certificate generated during the TEE check. The key entry is
      * deleted after retrieval to clean up.
@@ -192,7 +149,8 @@ object DeviceAttestationService {
             // The extension's value is an ASN.1 sequence.
             val keyDescriptionSeq = ASN1Sequence.getInstance(extension.extnValue.octets)
             SystemLogger.verbose {
-                val formattedString = keyDescriptionSeq.joinToString(separator = ", ") {
+                val formattedString =
+                    keyDescriptionSeq.joinToString(separator = ", ") {
                         AttestationPatcher.formatAsn1Primitive(it)
                     }
                 "Cached attestation data: $formattedString"

app/src/main/java/org/matrix/TEESimulator/interception/keystore/shim/KeyMintSecurityLevelInterceptor.kt

@@ -29,7 +29,6 @@ import java.util.concurrent.locks.LockSupport
 import org.matrix.TEESimulator.attestation.AttestationBuilder
 import org.matrix.TEESimulator.attestation.AttestationConstants
 import org.matrix.TEESimulator.attestation.AttestationPatcher
-import org.matrix.TEESimulator.attestation.DeviceAttestationService
 import org.matrix.TEESimulator.attestation.KeyMintAttestation
 import org.matrix.TEESimulator.config.ConfigurationManager
 import org.matrix.TEESimulator.interception.core.BinderInterceptor
@@ -478,22 +477,11 @@ class KeyMintSecurityLevelInterceptor(
                     it.tag == Tag.ATTESTATION_ID_SECOND_IMEI 
                 }
 
-                val hasDevicePropertyAttestation = parsedParams.brand != null ||
+                // Device-ID attestation mirrors a real KeyMint: privileged callers (GMS/system)
-                    parsedParams.device != null ||
+                // get it, ordinary apps get CANNOT_ATTEST_IDS. The permission check below is that
-                    parsedParams.product != null ||
+                // rule. Device-property attestation (BRAND/MODEL/...) is honored unconditionally —
-                    parsedParams.manufacturer != null ||
+                // genuine devices universally attest it, and it is what Play Integrity's hardware
-                    parsedParams.model != null
+                // path needs. Capability is keyed to the device we present, not the real (dead) TEE.
-
-                // Mirror the real TEE's capability: hardware that never provisioned device IDs
-                // returns CANNOT_ATTEST_IDS. Synthesizing device-ID/property attestation a chip of
-                // this class cannot produce is an over-capability tell — a genuine device fails the
-                // same request. Forge health, mirror capability.
-                if ((hasDeviceIdAttestation || hasDevicePropertyAttestation) &&
-                    !DeviceAttestationService.canAttestDeviceIds) {
-                    SystemLogger.info("[TX_ID: $txId] Real TEE cannot attest device IDs; returning CANNOT_ATTEST_IDS for uid=$callingUid (mirroring hardware)")
-                    return InterceptorUtils.createErrorReply(KEYMINT_CANNOT_ATTEST_IDS)
-                }
-
                 if(hasDeviceIdAttestation && !AndroidPermissionUtils.hasDeviceAttestationPermission(callingUid)) {
                     SystemLogger.warning("[TX_ID: $txId] Rejecting DEVICE_ID_ATTESTATION for uid=$callingUid")
                     return InterceptorUtils.createErrorReply(KEYMINT_CANNOT_ATTEST_IDS)