Read support for 12-byte IVs in addition to 16-byte IVs

5 files changed, 17 insertions, 4 deletions

diff --git a/src/main/java/de/pixart/messenger/entities/DownloadableFile.java b/src/main/java/de/pixart/messenger/entities/DownloadableFile.java
index 94fae97a4..6993b6b38 100644
--- a/src/main/java/de/pixart/messenger/entities/DownloadableFile.java
+++ b/src/main/java/de/pixart/messenger/entities/DownloadableFile.java
@@ -50,11 +50,18 @@ public class DownloadableFile extends File {
     }
 
     public void setKeyAndIv(byte[] keyIvCombo) {
+        // originally, we used a 16 byte IV, then found for aes-gcm a 12 byte IV is ideal
+        // this code supports reading either length, with sending 12 byte IV to be done in future
         if (keyIvCombo.length == 48) {
             this.aeskey = new byte[32];
             this.iv = new byte[16];
             System.arraycopy(keyIvCombo, 0, this.iv, 0, 16);
             System.arraycopy(keyIvCombo, 16, this.aeskey, 0, 32);
+        } else if (keyIvCombo.length == 44) {
+            this.aeskey = new byte[32];
+            this.iv = new byte[12];
+            System.arraycopy(keyIvCombo, 0, this.iv, 0, 12);
+            System.arraycopy(keyIvCombo, 12, this.aeskey, 0, 32);
         } else if (keyIvCombo.length >= 32) {
             this.aeskey = new byte[32];
             System.arraycopy(keyIvCombo, 0, aeskey, 0, 32);
diff --git a/src/main/java/de/pixart/messenger/entities/Message.java b/src/main/java/de/pixart/messenger/entities/Message.java
index 317605167..06bfcf4b6 100644
--- a/src/main/java/de/pixart/messenger/entities/Message.java
+++ b/src/main/java/de/pixart/messenger/entities/Message.java
@@ -675,7 +675,7 @@ public class Message extends AbstractEntity {
                 final URL url = new URL(body);
                 final String ref = url.getRef();
                 final String protocol = url.getProtocol();
-                final boolean encrypted = ref != null && ref.matches("([A-Fa-f0-9]{2}){48}");
+                final boolean encrypted = ref != null && AesGcmURLStreamHandler.IV_KEY.matcher(ref).matches();
                 treatAsDownloadable = (AesGcmURLStreamHandler.PROTOCOL_NAME.equalsIgnoreCase(protocol) && encrypted)
                         || (("http".equalsIgnoreCase(protocol) || "https".equalsIgnoreCase(protocol)) && (oob || encrypted));
             } catch (MalformedURLException e) {
diff --git a/src/main/java/de/pixart/messenger/http/AesGcmURLStreamHandler.java b/src/main/java/de/pixart/messenger/http/AesGcmURLStreamHandler.java
index 64188c5db..4ec164344 100644
--- a/src/main/java/de/pixart/messenger/http/AesGcmURLStreamHandler.java
+++ b/src/main/java/de/pixart/messenger/http/AesGcmURLStreamHandler.java
@@ -4,10 +4,16 @@ import java.io.IOException;
 import java.net.URL;
 import java.net.URLConnection;
 import java.net.URLStreamHandler;
+import java.util.regex.Pattern;
 
 
 public class AesGcmURLStreamHandler extends URLStreamHandler {
 
+    /**
+     * This matches a 48 or 44 byte IV + KEY hex combo, like used in http/aesgcm upload anchors
+     */
+    public static final Pattern IV_KEY = Pattern.compile("([A-Fa-f0-9]{2}){48}|([A-Fa-f0-9]{2}){44}");
+
     public static final String PROTOCOL_NAME = "aesgcm";
 
     @Override
diff --git a/src/main/java/de/pixart/messenger/http/HttpDownloadConnection.java b/src/main/java/de/pixart/messenger/http/HttpDownloadConnection.java
index 7326cbf4b..9f49ac218 100644
--- a/src/main/java/de/pixart/messenger/http/HttpDownloadConnection.java
+++ b/src/main/java/de/pixart/messenger/http/HttpDownloadConnection.java
@@ -98,7 +98,7 @@ public class HttpDownloadConnection implements Transferable {
             message.setRelativeFilePath(filename + "." + extension);
             this.file = mXmppConnectionService.getFileBackend().getFile(message, false);
             final String reference = mUrl.getRef();
-            if (reference != null && reference.matches("([A-Fa-f0-9]{2}){48}")) {
+            if (reference != null && AesGcmURLStreamHandler.IV_KEY.matcher(reference).matches()) {
                 this.file.setKeyAndIv(CryptoHelper.hexToBytes(reference));
             }
 
@@ -383,7 +383,7 @@ public class HttpDownloadConnection implements Transferable {
             message.setType(Message.TYPE_FILE);
             final URL url;
             final String ref = mUrl.getRef();
-            if (ref != null && ref.matches("([A-Fa-f0-9]{2}){48}")) {
+            if (ref != null && AesGcmURLStreamHandler.IV_KEY.matcher(ref).matches()) {
                 url = CryptoHelper.toAesGcmUrl(mUrl);
             } else {
                 url = mUrl;
diff --git a/src/main/java/de/pixart/messenger/http/HttpUploadConnection.java b/src/main/java/de/pixart/messenger/http/HttpUploadConnection.java
index 22fec6888..3d3ad5e73 100644
--- a/src/main/java/de/pixart/messenger/http/HttpUploadConnection.java
+++ b/src/main/java/de/pixart/messenger/http/HttpUploadConnection.java
@@ -105,7 +105,7 @@ public class HttpUploadConnection implements Transferable {
         if (Config.ENCRYPT_ON_HTTP_UPLOADED
                 || message.getEncryption() == Message.ENCRYPTION_AXOLOTL
                 || message.getEncryption() == Message.ENCRYPTION_OTR) {
-            this.key = new byte[48];
+            this.key = new byte[48]; // todo: change this to 44 for 12-byte IV instead of 16-byte at some point in future
             mXmppConnectionService.getRNG().nextBytes(this.key);
             this.file.setKeyAndIv(this.key);
         }