Use URL for S3.

Thanks to Oscar Mira <valldrac@molly.im> for bringing this to our attention.

app/src/main/java/org/thoughtcrime/securesms/messages/SignalServiceProtoUtil.kt

@@ -8,6 +8,7 @@ import org.signal.libsignal.protocol.message.DecryptionErrorMessage
 import org.signal.libsignal.zkgroup.groups.GroupMasterKey
 import org.signal.storageservice.protos.groups.local.DecryptedGroupChange
 import org.thoughtcrime.securesms.attachments.Attachment
+import org.thoughtcrime.securesms.attachments.Cdn
 import org.thoughtcrime.securesms.attachments.PointerAttachment
 import org.thoughtcrime.securesms.database.model.StoryType
 import org.thoughtcrime.securesms.groups.GroupId
@@ -172,7 +173,12 @@ object SignalServiceProtoUtil {
 
   fun AttachmentPointer.toPointer(stickerLocator: StickerLocator? = null): Attachment? {
     return try {
-      PointerAttachment.forPointer(Optional.of(toSignalServiceAttachmentPointer()), stickerLocator).orNull()
+      val pointer = PointerAttachment.forPointer(Optional.of(toSignalServiceAttachmentPointer()), stickerLocator).orNull()
+      if (pointer?.cdn != Cdn.S3) {
+        pointer
+      } else {
+        null
+      }
     } catch (e: InvalidMessageStructureException) {
       null
     }

app/src/main/java/org/thoughtcrime/securesms/s3/S3.kt

@@ -1,6 +1,7 @@
 package org.thoughtcrime.securesms.s3
 
 import android.content.Context
+import androidx.annotation.VisibleForTesting
 import androidx.annotation.WorkerThread
 import okhttp3.Request
 import okhttp3.Response
@@ -20,6 +21,9 @@ import java.io.File
 import java.io.FileOutputStream
 import java.io.IOException
 import java.io.OutputStream
+import java.net.URI
+import java.net.URISyntaxException
+import java.net.URL
 import java.nio.charset.Charset
 import java.security.MessageDigest
 import java.util.regex.Matcher
@@ -33,7 +37,6 @@ object S3 {
 
   private val okHttpClient = ApplicationDependencies.getSignalOkHttpClient()
 
-  private const val S3_BASE = "https://updates2.signal.org"
   const val DYNAMIC_PATH = "/dynamic"
   const val STATIC_PATH = "/static"
 
@@ -78,6 +81,8 @@ object S3 {
 
   /**
    * Retrieves an S3 object from the given endpoint.
+   *
+   * @param endpoint Must be an absolute path to the resource
    */
   @WorkerThread
   @JvmStatic
@@ -85,7 +90,7 @@ object S3 {
   fun getObject(endpoint: String): Response {
     val request = Request.Builder()
       .get()
-      .url("$S3_BASE$endpoint")
+      .url(s3Url(endpoint))
       .build()
 
     return okHttpClient.newCall(request).execute()
@@ -191,12 +196,14 @@ object S3 {
 
   /**
    * Downloads and parses the ETAG from an S3 object, utilizing a HEAD request.
+   *
+   * @param endpoint Must be an absolute path to the resource
    */
   @WorkerThread
   fun getObjectMD5(endpoint: String): ByteArray? {
     val request = Request.Builder()
       .head()
-      .url("$S3_BASE$endpoint")
+      .url(s3Url(endpoint))
       .build()
 
     try {
@@ -229,5 +236,15 @@ object S3 {
     }
   }
 
+  @Throws(IOException::class)
+  @VisibleForTesting
+  fun s3Url(path: String): URL {
+    try {
+      return URI("https", "updates2.signal.org", path, null).toURL()
+    } catch (e: URISyntaxException) {
+      throw IOException(e)
+    }
+  }
+
   class Md5FailureException : IOException("Failed to getting or comparing MD5")
 }

app/src/test/java/org/thoughtcrime/securesms/s3/S3Test_getS3Url.kt

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2024 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.thoughtcrime.securesms.s3
+
+import okio.IOException
+import org.junit.Test
+import org.thoughtcrime.securesms.assertIs
+
+@Suppress("ClassName")
+class S3Test_getS3Url {
+
+  @Test
+  fun validS3Urls() {
+    S3.s3Url("/static/heart.png").toString() assertIs "https://updates2.signal.org/static/heart.png"
+    S3.s3Url("/static/heart.png?weee=1").toString() assertIs "https://updates2.signal.org/static/heart.png%3Fweee=1"
+    S3.s3Url("/@signal.org").toString() assertIs "https://updates2.signal.org/@signal.org"
+  }
+
+  @Test(expected = IOException::class)
+  fun invalid() {
+    S3.s3Url("@signal.org")
+  }
+
+  @Test(expected = IOException::class)
+  fun invalidRelative() {
+    S3.s3Url("static/heart.png")
+  }
+}