Fix circular ringbuffer used in socket implementation

dart/sdk/lib/io/secure_socket.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.io;
 
 /**
  * A high-level class for communicating securely over a TCP socket, using
  * TLS and SSL. The [SecureSocket] exposes both a [Stream] and an
  * [IOSink] interface, making it ideal for using together with
@@ skipping 1117 matching lines @@
     if (bytes == null) {
       bytes = length;
     } else {
       bytes = min(bytes, length);
     }
     if (bytes == 0) return null;
     List<int> result = new Uint8List(bytes);
     int bytesRead = 0;
     // Loop over zero, one, or two linear data ranges.
     while (bytesRead < bytes) {
-      int toRead = min(bytes, linearLength);
+      int toRead = min(bytes - bytesRead, linearLength);
       result.setRange(bytesRead,
                       bytesRead + toRead,
                       data,
                       start);
       advanceStart(toRead);
       bytesRead += toRead;
     }
     return result;
   }
 
@@ skipping 118 matching lines @@
 /**
  * An exception that happens in the handshake phase of establishing
  * a secure network connection, when looking up or verifying a
  * certificate.
  */
 class CertificateException extends TlsException {
   const CertificateException([String message = "",
                             OSError osError = null])
      : super._("CertificateException", message, osError);
 }