From a2a10fb0c1ae4487f5a2b0dc1499ceacbca1afcf Mon Sep 17 00:00:00 2001
From: Greyson Parrelli <greyson@signal.org>
Date: Fri, 18 Apr 2025 10:52:02 -0400
Subject: [PATCH] Filter out bad E164s from GV1 groups.

---
 .../thoughtcrime/securesms/mms/MessageGroupContext.java   | 3 +++
 .../org/thoughtcrime/securesms/util/SignalE164Util.kt     | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/app/src/main/java/org/thoughtcrime/securesms/mms/MessageGroupContext.java b/app/src/main/java/org/thoughtcrime/securesms/mms/MessageGroupContext.java
index 2526ed762c..ec92f1b4e7 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/mms/MessageGroupContext.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/mms/MessageGroupContext.java
@@ -5,6 +5,7 @@ import androidx.annotation.Nullable;
 
 import com.annimon.stream.Stream;
 
+import org.signal.core.util.E164Util;
 import org.signal.libsignal.zkgroup.InvalidInputException;
 import org.signal.libsignal.zkgroup.groups.GroupMasterKey;
 import org.signal.storageservice.protos.groups.local.DecryptedGroup;
@@ -16,6 +17,7 @@ import org.thoughtcrime.securesms.messages.SignalServiceProtoUtil;
 import org.thoughtcrime.securesms.recipients.Recipient;
 import org.thoughtcrime.securesms.recipients.RecipientId;
 import org.signal.core.util.Base64;
+import org.thoughtcrime.securesms.util.SignalE164Util;
 import org.whispersystems.signalservice.api.groupsv2.DecryptedGroupUtil;
 import org.whispersystems.signalservice.api.push.ServiceId;
 import org.whispersystems.signalservice.api.push.ServiceId.ACI;
@@ -128,6 +130,7 @@ public final class MessageGroupContext {
       RecipientId selfId = Recipient.self().getId();
 
       return Stream.of(groupContext.members)
+                   .filter(m -> SignalE164Util.isPotentialE164(m.e164))
                    .map(m -> m.e164)
                    .withoutNulls()
                    .map(RecipientId::fromE164)
diff --git a/app/src/main/java/org/thoughtcrime/securesms/util/SignalE164Util.kt b/app/src/main/java/org/thoughtcrime/securesms/util/SignalE164Util.kt
index 72709e73a8..acfb828df1 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/util/SignalE164Util.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/util/SignalE164Util.kt
@@ -53,6 +53,14 @@ object SignalE164Util {
     return getFormatter().formatAsE164(input)
   }
 
+  /**
+   * Returns true if the input string can be considered an E164. Specifically, it returns true if we could figure out how to format it as an E164.
+   */
+  @JvmStatic
+  fun isPotentialE164(input: String): Boolean {
+    return formatAsE164(input) != null
+  }
+
   private fun getFormatter(): E164Util.Formatter {
     val localNumber = SignalStore.account.e164 ?: return defaultFormatter
     val formatter = cachedFormatters[localNumber]