apply same fix used on DecryptingPartInputStream to AttachmentCipherInputStream // FREEBIE

library/src/org/whispersystems/textsecure/crypto/AttachmentCipherInputStream.java

@@ -52,6 +52,7 @@ public class AttachmentCipherInputStream extends FileInputStream {
   private boolean done;
   private long    totalDataSize;
   private long    totalRead;
+  private byte[] overflowBuffer;
 
   public AttachmentCipherInputStream(File file, byte[] combinedKeyMaterial)
       throws IOException, InvalidMessageException
@@ -125,6 +126,25 @@ public class AttachmentCipherInputStream extends FileInputStream {
   }
 
   private int readIncremental(byte[] buffer, int offset, int length) throws IOException {
+    int readLength = 0;
+    if (null != overflowBuffer) {
+      if (overflowBuffer.length > length) {
+        System.arraycopy(overflowBuffer, 0, buffer, offset, length);
+        overflowBuffer = Arrays.copyOfRange(overflowBuffer, length, overflowBuffer.length);
+        return length;
+      } else if (overflowBuffer.length == length) {
+        System.arraycopy(overflowBuffer, 0, buffer, offset, length);
+        overflowBuffer = null;
+        return length;
+      } else {
+        System.arraycopy(overflowBuffer, 0, buffer, offset, overflowBuffer.length);
+        readLength += overflowBuffer.length;
+        offset += readLength;
+        length -= readLength;
+        overflowBuffer = null;
+      }
+    }
+
     if (length + totalRead > totalDataSize)
       length = (int)(totalDataSize - totalRead);
 
@@ -133,7 +153,24 @@ public class AttachmentCipherInputStream extends FileInputStream {
     totalRead            += read;
 
     try {
-      return cipher.update(internalBuffer, 0, read, buffer, offset);
+      int outputLen = cipher.getOutputSize(read);
+
+      if (outputLen <= length) {
+        readLength += cipher.update(internalBuffer, 0, read, buffer, offset);
+        return readLength;
+      }
+
+      byte[] transientBuffer = new byte[outputLen];
+      outputLen = cipher.update(internalBuffer, 0, read, transientBuffer, 0);
+      if (outputLen <= length) {
+        System.arraycopy(transientBuffer, 0, buffer, offset, outputLen);
+        readLength += outputLen;
+      } else {
+        System.arraycopy(transientBuffer, 0, buffer, offset, length);
+        overflowBuffer = Arrays.copyOfRange(transientBuffer, length, outputLen);
+        readLength += length;
+      }
+      return readLength;
     } catch (ShortBufferException e) {
       throw new AssertionError(e);
     }