From 06eb890761598c3de842efea102f481fb4167767 Mon Sep 17 00:00:00 2001
From: Chris Eager <chris@signal.org>
Date: Wed, 10 Aug 2022 12:24:01 -0500
Subject: [PATCH] Improve e164 normalization check by re-parsing without
 country code

---
 .../textsecuregcm/util/Util.java              | 27 ++++++++++++++++---
 .../tests/util/ValidNumberTest.java           |  6 ++++-
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/util/Util.java b/service/src/main/java/org/whispersystems/textsecuregcm/util/Util.java
index 482e6352a..413327330 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/util/Util.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/util/Util.java
@@ -42,11 +42,30 @@ public class Util {
     }
 
     try {
-      final PhoneNumber phoneNumber = PHONE_NUMBER_UTIL.parse(number, null);
-      final String normalizedNumber = PHONE_NUMBER_UTIL.format(phoneNumber, PhoneNumberFormat.E164);
+      final PhoneNumber inputNumber = PHONE_NUMBER_UTIL.parse(number, null);
 
-      if (!number.equals(normalizedNumber)) {
-        throw new NonNormalizedPhoneNumberException(number, normalizedNumber);
+      // For normalization, we want to format from a version parsed with the country code removed.
+      // This handles some cases of "possible", but non-normalized input numbers with a doubled country code, that is
+      // with the format "+{country code} {country code} {national number}"
+      final int countryCode = inputNumber.getCountryCode();
+      final String region = PHONE_NUMBER_UTIL.getRegionCodeForCountryCode(countryCode);
+
+      final PhoneNumber normalizedNumber = switch (region) {
+        // the country code has no associated region. Be lenient (and simple) and accept the input number
+        case "ZZ", "001" -> inputNumber;
+        default -> {
+          final String maybeLeadingZero =
+              inputNumber.hasItalianLeadingZero() && inputNumber.isItalianLeadingZero() ? "0" : "";
+          yield PHONE_NUMBER_UTIL.parse(
+              maybeLeadingZero + inputNumber.getNationalNumber(), region);
+        }
+      };
+
+      final String normalizedE164 = PHONE_NUMBER_UTIL.format(normalizedNumber,
+          PhoneNumberFormat.E164);
+
+      if (!number.equals(normalizedE164)) {
+        throw new NonNormalizedPhoneNumberException(number, normalizedE164);
       }
     } catch (final NumberParseException e) {
       throw new ImpossiblePhoneNumberException(e);
diff --git a/service/src/test/java/org/whispersystems/textsecuregcm/tests/util/ValidNumberTest.java b/service/src/test/java/org/whispersystems/textsecuregcm/tests/util/ValidNumberTest.java
index 669794aad..1780c8688 100644
--- a/service/src/test/java/org/whispersystems/textsecuregcm/tests/util/ValidNumberTest.java
+++ b/service/src/test/java/org/whispersystems/textsecuregcm/tests/util/ValidNumberTest.java
@@ -24,11 +24,13 @@ class ValidNumberTest {
       "+71234567890",
       "+447535742222",
       "+4915174108888",
+      "+2250707312345",
       "+298123456",
       "+299123456",
       "+376123456",
       "+68512345",
-      "+689123456"})
+      "+689123456",
+      "+80011111111"})
   void requireNormalizedNumber(final String number) {
     assertDoesNotThrow(() -> Util.requireNormalizedNumber(number));
   }
@@ -56,6 +58,8 @@ class ValidNumberTest {
   @ParameterizedTest
   @ValueSource(strings = {
       "+4407700900111",
+      "+49493023125000", // double country code - this e164 is "possible"
+      "+494915110000000", // double country code - this e164 is "possible" and "valid"
       "+1 415 123 1234",
       "+1 (415) 123-1234",
       "+1 415)123-1234",