Reject attachments with unrecognized CDN numbers instead of crashing.

app/src/main/java/org/thoughtcrime/securesms/attachments/Cdn.kt

@@ -41,12 +41,16 @@ enum class Cdn(private val value: Int) {
     }
 
     fun fromCdnNumber(cdnNumber: Int): Cdn {
+      return fromCdnNumberOrNull(cdnNumber) ?: throw UnsupportedOperationException("Invalid CDN number: $cdnNumber")
+    }
+
+    fun fromCdnNumberOrNull(cdnNumber: Int): Cdn? {
       return when (cdnNumber) {
         -1 -> S3
         0 -> CDN_0
         2 -> CDN_2
         3 -> CDN_3
-        else -> throw UnsupportedOperationException("Invalid CDN number: $cdnNumber")
+        else -> null
       }
     }
   }

app/src/main/java/org/thoughtcrime/securesms/attachments/PointerAttachment.kt

@@ -5,6 +5,7 @@ import android.os.Parcel
 import androidx.annotation.VisibleForTesting
 import org.signal.blurhash.BlurHash
 import org.signal.core.util.Base64
+import org.signal.core.util.logging.Log
 import org.thoughtcrime.securesms.database.AttachmentTable
 import org.thoughtcrime.securesms.stickers.StickerLocator
 import org.whispersystems.signalservice.api.InvalidMessageStructureException
@@ -76,6 +77,8 @@ class PointerAttachment : Attachment {
   override val thumbnailUri: Uri? = null
 
   companion object {
+    private val TAG = Log.tag(PointerAttachment::class)
+
     @JvmStatic
     fun forPointers(pointers: Optional<List<SignalServiceAttachment>>): List<Attachment> {
       if (!pointers.isPresent) {
@@ -102,6 +105,13 @@ class PointerAttachment : Attachment {
         return Optional.empty()
       }
 
+      val cdnNumber = pointer.get().asPointer().cdnNumber
+      val cdn = Cdn.fromCdnNumberOrNull(cdnNumber)
+      if (cdn == null) {
+        Log.w(TAG, "Encountered an attachment pointer with an unsupported CDN number ($cdnNumber). Skipping attachment.")
+        return Optional.empty()
+      }
+
       val encodedKey: String? = pointer.get().asPointer().key?.let { Base64.encodeWithPadding(it) }
 
       return Optional.of(
@@ -110,7 +120,7 @@ class PointerAttachment : Attachment {
           transferState = transferState,
           size = pointer.get().asPointer().size.orElse(0).toLong(),
           fileName = pointer.get().asPointer().fileName.orElse(null),
-          cdn = Cdn.fromCdnNumber(pointer.get().asPointer().cdnNumber),
+          cdn = cdn,
           location = pointer.get().asPointer().remoteId.toString(),
           key = encodedKey,
           iv = null,
@@ -145,7 +155,13 @@ class PointerAttachment : Attachment {
         return Optional.empty()
       }
 
-      val cdn = Cdn.fromCdnNumber(thumbnail?.asPointer()?.cdnNumber ?: 0)
+      val cdnNumber = thumbnail?.asPointer()?.cdnNumber ?: 0
+      val cdn = Cdn.fromCdnNumberOrNull(cdnNumber)
+      if (cdn == null) {
+        Log.w(TAG, "Encountered a quote thumbnail with an unsupported CDN number ($cdnNumber). Skipping attachment.")
+        return Optional.empty()
+      }
+
       if (cdn == Cdn.S3) {
         return Optional.empty()
       }

app/src/main/java/org/thoughtcrime/securesms/backup/v2/util/ArchiveConverterExtensions.kt

@@ -11,6 +11,7 @@ import org.signal.archive.proto.FilePointer
 import org.signal.core.util.Base64
 import org.signal.core.util.UuidUtil
 import org.signal.core.util.isNotNullOrBlank
+import org.signal.core.util.logging.Log
 import org.signal.core.util.nullIfBlank
 import org.signal.core.util.orNull
 import org.signal.libsignal.usernames.BaseUsernameException
@@ -32,6 +33,8 @@ import org.whispersystems.signalservice.api.messages.SignalServiceAttachmentRemo
 import java.util.Optional
 import org.signal.archive.proto.AvatarColor as RemoteAvatarColor
 
+private const val TAG = "ArchiveConverter"
+
 /**
  * Converts a [FilePointer] to a local [Attachment] object for inserting into the database.
  */
@@ -58,10 +61,16 @@ fun FilePointer?.toLocalAttachment(
 
   return when (attachmentType) {
     AttachmentType.ARCHIVE -> {
+      val cdnNumber = locatorInfo.transitCdnNumber ?: Cdn.CDN_0.cdnNumber
+      if (Cdn.fromCdnNumberOrNull(cdnNumber) == null) {
+        Log.w(TAG, "Encountered an archived attachment with an unsupported CDN number ($cdnNumber). Skipping attachment.")
+        return null
+      }
+
       ArchivedAttachment(
         contentType = contentType,
         size = locatorInfo.size.toLong(),
-        cdn = locatorInfo.transitCdnNumber ?: Cdn.CDN_0.cdnNumber,
+        cdn = cdnNumber,
         uploadTimestamp = locatorInfo.transitTierUploadTimestamp ?: 0,
         key = locatorInfo.key.toByteArray(),
         cdnKey = locatorInfo.transitCdnKey?.nullIfBlank(),

app/src/main/java/org/thoughtcrime/securesms/contactshare/ContactModelMapper.java

@@ -119,13 +119,15 @@ public class ContactModelMapper {
     if (contact.avatar != null && contact.avatar.avatar != null) {
       try {
         SignalServiceAttachmentPointer attachmentPointer = AttachmentPointerUtil.createSignalAttachmentPointer(contact.avatar.avatar);
-        Attachment                     attachment        = PointerAttachment.forPointer(Optional.of(attachmentPointer.asPointer())).get();
+        Optional<Attachment>           attachment        = PointerAttachment.forPointer(Optional.of(attachmentPointer.asPointer()));
 
-        if (attachment.cdn == Cdn.S3) {
+        if (!attachment.isPresent()) {
+          Log.w(TAG, "Unable to create avatar attachment for contact. Ignoring avatar.");
+        } else if (attachment.get().cdn == Cdn.S3) {
           Log.w(TAG, "Ignoring contact avatar that resolves to the internal release-channel CDN.");
         } else {
           boolean isProfile = Boolean.TRUE.equals(contact.avatar.isProfile);
-          avatar = new Avatar(null, attachment, isProfile);
+          avatar = new Avatar(null, attachment.get(), isProfile);
         }
       } catch (InvalidMessageStructureException e) {
         Log.w(TAG, "Unable to create avatar for contact", e);