From 2ac0179d65462b9947b145e568a2230aec4c706d Mon Sep 17 00:00:00 2001
From: Moxie Marlinspike <moxie@thoughtcrime.org>
Date: Wed, 18 Apr 2018 21:20:06 -0700
Subject: [PATCH] Handle odd sized buffers on backup import decrypt

Fixes #7701
---
 .../securesms/backup/FullBackupImporter.java        | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/org/thoughtcrime/securesms/backup/FullBackupImporter.java b/src/org/thoughtcrime/securesms/backup/FullBackupImporter.java
index 138707b3ca..8f760467e3 100644
--- a/src/org/thoughtcrime/securesms/backup/FullBackupImporter.java
+++ b/src/org/thoughtcrime/securesms/backup/FullBackupImporter.java
@@ -204,11 +204,20 @@ public class FullBackupImporter extends FullBackupBase {
           mac.update(buffer, 0, read);
 
           byte[] plaintext = cipher.update(buffer, 0, read);
-          out.write(plaintext, 0, plaintext.length);
+
+          if (plaintext != null) {
+            out.write(plaintext, 0, plaintext.length);
+          }
 
           length -= read;
         }
 
+        byte[] plaintext = cipher.doFinal();
+
+        if (plaintext != null) {
+          out.write(plaintext, 0, plaintext.length);
+        }
+
         out.close();
 
         byte[] ourMac   = mac.doFinal();
@@ -225,7 +234,7 @@ public class FullBackupImporter extends FullBackupBase {
           //destination.delete();
           throw new IOException("Bad MAC");
         }
-      } catch (InvalidKeyException | InvalidAlgorithmParameterException e) {
+      } catch (InvalidKeyException | InvalidAlgorithmParameterException | IllegalBlockSizeException | BadPaddingException e) {
         throw new AssertionError(e);
       }
     }