session-android/app/src/main/java/org/thoughtcrime/securesms/notifications/PushReceiver.kt

124 lines
5.2 KiB
Kotlin

package org.thoughtcrime.securesms.notifications
import android.content.Context
import androidx.core.app.NotificationCompat
import androidx.core.app.NotificationManagerCompat
import com.goterl.lazysodium.LazySodiumAndroid
import com.goterl.lazysodium.SodiumAndroid
import com.goterl.lazysodium.interfaces.AEAD
import com.goterl.lazysodium.utils.Key
import dagger.hilt.android.qualifiers.ApplicationContext
import kotlinx.serialization.decodeFromString
import kotlinx.serialization.json.Json
import org.session.libsession.messaging.jobs.BatchMessageReceiveJob
import org.session.libsession.messaging.jobs.JobQueue
import org.session.libsession.messaging.jobs.MessageReceiveParameters
import org.session.libsession.messaging.sending_receiving.notifications.PushNotificationMetadata
import org.session.libsession.messaging.utilities.MessageWrapper
import org.session.libsession.messaging.utilities.SodiumUtilities
import org.session.libsession.utilities.bencode.Bencode
import org.session.libsession.utilities.bencode.BencodeList
import org.session.libsession.utilities.bencode.BencodeString
import org.session.libsignal.utilities.Base64
import org.session.libsignal.utilities.Log
import org.thoughtcrime.securesms.crypto.IdentityKeyUtil
import javax.inject.Inject
private const val TAG = "PushHandler"
class PushReceiver @Inject constructor(@ApplicationContext val context: Context) {
private val sodium = LazySodiumAndroid(SodiumAndroid())
fun onPush(dataMap: Map<String, String>?) {
onPush(dataMap?.asByteArray())
}
fun onPush(data: ByteArray?) {
if (data == null) {
onPush()
return
}
try {
val envelopeAsData = MessageWrapper.unwrap(data).toByteArray()
val job = BatchMessageReceiveJob(listOf(MessageReceiveParameters(envelopeAsData)), null)
JobQueue.shared.add(job)
} catch (e: Exception) {
Log.d(TAG, "Failed to unwrap data for message due to error: $e.")
}
}
private fun onPush() {
Log.d(TAG, "Failed to decode data for message.")
val builder = NotificationCompat.Builder(context, NotificationChannels.OTHER)
.setSmallIcon(network.loki.messenger.R.drawable.ic_notification)
.setColor(context.getColor(network.loki.messenger.R.color.textsecure_primary))
.setContentTitle("Session")
.setContentText("You've got a new message.")
.setPriority(NotificationCompat.PRIORITY_DEFAULT)
.setAutoCancel(true)
NotificationManagerCompat.from(context).notify(11111, builder.build())
}
private fun Map<String, String>.asByteArray() =
when {
// this is a v2 push notification
containsKey("spns") -> {
try {
decrypt(Base64.decode(this["enc_payload"]))
} catch (e: Exception) {
Log.e(TAG, "Invalid push notification: ${e.message}")
null
}
}
// old v1 push notification; we still need this for receiving legacy closed group notifications
else -> this["ENCRYPTED_DATA"]?.let(Base64::decode)
}
fun decrypt(encPayload: ByteArray): ByteArray? {
Log.d(TAG, "decrypt() called")
val encKey = getOrCreateNotificationKey()
val nonce = encPayload.take(AEAD.XCHACHA20POLY1305_IETF_NPUBBYTES).toByteArray()
val payload = encPayload.drop(AEAD.XCHACHA20POLY1305_IETF_NPUBBYTES).toByteArray()
val padded = SodiumUtilities.decrypt(payload, encKey.asBytes, nonce)
?: error("Failed to decrypt push notification")
val decrypted = padded.dropLastWhile { it.toInt() == 0 }.toByteArray()
val bencoded = Bencode.Decoder(decrypted)
val expectedList = (bencoded.decode() as? BencodeList)?.values
?: error("Failed to decode bencoded list from payload")
val metadataJson = (expectedList[0] as? BencodeString)?.value ?: error("no metadata")
val metadata: PushNotificationMetadata = Json.decodeFromString(String(metadataJson))
val content: ByteArray? =
if (expectedList.size >= 2) (expectedList[1] as? BencodeString)?.value else null
// null content is valid only if we got a "data_too_long" flag
if (content == null)
check(metadata.data_too_long) { "missing message data, but no too-long flag" }
else
check(metadata.data_len == content.size) { "wrong message data size" }
Log.d(
TAG,
"Received push for ${metadata.account}/${metadata.namespace}, msg ${metadata.msg_hash}, ${metadata.data_len}B"
)
return content
}
fun getOrCreateNotificationKey(): Key {
if (IdentityKeyUtil.retrieve(context, IdentityKeyUtil.NOTIFICATION_KEY) == null) {
// generate the key and store it
val key = sodium.keygen(AEAD.Method.XCHACHA20_POLY1305_IETF)
IdentityKeyUtil.save(context, IdentityKeyUtil.NOTIFICATION_KEY, key.asHexString)
}
return Key.fromHexString(
IdentityKeyUtil.retrieve(
context,
IdentityKeyUtil.NOTIFICATION_KEY
)
)
}
}