Constellation: reuse cached verification state for RCS

play-services-constellation/core/src/main/kotlin/org/microg/gms/constellation/core/GetVerifiedPhoneNumbers.kt

@@ -73,6 +73,17 @@ internal suspend fun fetchVerifiedPhoneNumbers(
     response.phone_numbers
 }
 
+internal fun findMatchingVerifiedNumber(
+    numbers: List<VerifiedPhoneNumber>,
+    targetPhone: String?
+): VerifiedPhoneNumber? {
+    if (numbers.isEmpty()) return null
+    if (!targetPhone.isNullOrEmpty()) {
+        return numbers.firstOrNull { it.phone_number == targetPhone }
+    }
+    return numbers.firstOrNull()
+}
+
 internal fun VerifiedPhoneNumber.toPhoneNumberInfo(): PhoneNumberInfo {
     val extras = Bundle().apply {
         if (id_token.isNotEmpty()) {
@@ -89,7 +100,7 @@ internal fun VerifiedPhoneNumber.toPhoneNumberInfo(): PhoneNumberInfo {
     )
 }
 
-internal fun VerifiedPhoneNumber.toPhoneNumberVerification(): PhoneNumberVerification {
+internal fun VerifiedPhoneNumber.toPhoneNumberVerification(simSlot: Int = -1): PhoneNumberVerification {
     val extras = Bundle().apply {
         putInt("rcs_state", rcs_state.value)
     }
@@ -99,7 +110,7 @@ internal fun VerifiedPhoneNumber.toPhoneNumberVerification(): PhoneNumberVerific
         phone_number,
         verification_time?.toEpochMilli() ?: 0L,
         0,
-        -1,
+        simSlot,
         id_token.ifEmpty { null },
         extras,
         1,

play-services-constellation/core/src/main/kotlin/org/microg/gms/constellation/core/VerifyPhoneNumber.kt

@@ -285,6 +285,54 @@ private fun handleRpcError(error: GrpcException): Status {
     return Status(statusCode, error.message)
 }
 
+internal fun shouldTryCachedGpnvFastPath(
+    requiredConsumerConsent: String?,
+    verificationTokenCount: Int,
+    targetedSimCount: Int
+): Boolean {
+    return requiredConsumerConsent == "RCS" &&
+            verificationTokenCount > 0 &&
+            targetedSimCount <= 1
+}
+
+private suspend fun tryCachedGpnvVerification(
+    context: Context,
+    request: VerifyPhoneNumberRequest,
+    callingPackage: String,
+    imsiToInfoMap: Map<String, SubscriptionInfo>
+): Array<PhoneNumberVerification>? {
+    val verificationTokenCount = ConstellationStateStore.loadVerificationTokens(context).size
+    if (!shouldTryCachedGpnvFastPath(
+            request.extras.getString("required_consumer_consent"),
+            verificationTokenCount,
+            request.targetedSims.size
+        )
+    ) {
+        return null
+    }
+
+    val targetPhone = request.targetedSims.firstOrNull()
+        ?.phoneNumberHint
+        ?.takeIf { it.isNotEmpty() }
+    val gpnvBundle = Bundle().apply {
+        putString("certificate_hash", request.idTokenRequest.idToken ?: "")
+        putString("token_nonce", request.idTokenRequest.subscriberHash ?: "")
+        putString("calling_package", callingPackage)
+    }
+
+    Log.i(TAG, "Using cached verification state for RCS GetVerifiedPhoneNumbers")
+    val numbers = fetchVerifiedPhoneNumbers(context, gpnvBundle, callingPackage)
+    val matchingNumber = findMatchingVerifiedNumber(numbers, targetPhone)
+        ?: throw IllegalStateException("cached GPNV: no exact target-number match")
+    if (matchingNumber.id_token.isEmpty()) {
+        throw IllegalStateException("cached GPNV: empty JWT")
+    }
+
+    val targetImsi = request.targetedSims.firstOrNull()?.imsi?.takeIf { it.isNotEmpty() }
+    val simSlot = targetImsi?.let { imsiToInfoMap[it]?.simSlotIndex } ?: -1
+    return arrayOf(matchingNumber.toPhoneNumberVerification(simSlot))
+}
+
 internal fun hasRequiredVerificationConsent(
     response: GetConsentResponse,
     asterismClient: AsterismClient
@@ -328,6 +376,11 @@ private suspend fun runVerificationFlow(
         }
     }
 
+    // Keep the cached read path behind the fail-closed consent gate above.
+    tryCachedGpnvVerification(context, request, callingPackage, imsiToInfoMap)?.let {
+        return it
+    }
+
     val syncRequest = SyncRequest(
         context,
         sessionId,

play-services-constellation/core/src/test/kotlin/org/microg/gms/constellation/core/CachedGpnvFastPathTest.kt

@@ -0,0 +1,53 @@
+package org.microg.gms.constellation.core
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNull
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import org.microg.gms.constellation.core.proto.VerifiedPhoneNumber
+
+class CachedGpnvFastPathTest {
+    @Test
+    fun cachedFastPathRequiresRcsCachedStateAndAtMostOneTarget() {
+        assertTrue(shouldTryCachedGpnvFastPath("RCS", 1, 1))
+        assertTrue(shouldTryCachedGpnvFastPath("RCS", 1, 0))
+        assertTrue(!shouldTryCachedGpnvFastPath("RCS", 0, 1))
+        assertTrue(!shouldTryCachedGpnvFastPath(null, 1, 1))
+        assertTrue(!shouldTryCachedGpnvFastPath("OTHER", 1, 1))
+        assertTrue(!shouldTryCachedGpnvFastPath("RCS", 1, 2))
+    }
+
+    @Test
+    fun exactPhoneMatchWinsWhenTargetIsKnown() {
+        val first = VerifiedPhoneNumber(phone_number = "+441", id_token = "jwt-first")
+        val exact = VerifiedPhoneNumber(phone_number = "+442", id_token = "jwt-exact")
+        assertEquals(exact, findMatchingVerifiedNumber(listOf(first, exact), "+442"))
+    }
+
+    @Test
+    fun wrongPhoneIsRejectedWhenTargetIsKnown() {
+        val first = VerifiedPhoneNumber(phone_number = "+441", id_token = "jwt-first")
+        val second = VerifiedPhoneNumber(phone_number = "+442", id_token = "jwt-second")
+        assertNull(findMatchingVerifiedNumber(listOf(first, second), "+449"))
+    }
+
+    @Test
+    fun firstRecordIsRetainedWhenNoTargetIsKnown() {
+        val first = VerifiedPhoneNumber(phone_number = "+441", id_token = "jwt-first")
+        val second = VerifiedPhoneNumber(phone_number = "+442", id_token = "jwt-second")
+        assertEquals(first, findMatchingVerifiedNumber(listOf(first, second), null))
+    }
+
+    @Test
+    fun emptyResponseHasNoMatch() {
+        assertNull(findMatchingVerifiedNumber(emptyList(), "+441"))
+    }
+
+    @Test
+    fun cachedResultPreservesResolvedSimSlotAndJwt() {
+        val result = VerifiedPhoneNumber(phone_number = "+441", id_token = "jwt")
+            .toPhoneNumberVerification(simSlot = 2)
+        assertEquals(2, result.simSlot)
+        assertEquals("jwt", result.verificationToken)
+    }
+}