Updated to handle handle optional CertificateVerify message:
http://cr.openjdk.java.net/~xuelei/8167680/webrev.02/
Thanks,
Xuelei
On 10/21/2016 11:31 AM, Xuelei Fan wrote:
Updated webrev per Jamil's comments:
http://cr.openjdk.java.net/~xuelei/8167680/webrev.01/
Xuelei
On 10/13/2016 10:36 PM, Xuelei Fan wrote:
Hi,
Please review the fix for JDK-8167680:
http://cr.openjdk.java.net/~xuelei/8167680/webrev.00/
There are a few implementation bugs in JDK.
1. The sequence number is increased by 2 for GCM cipher suites.
Both GCM crypto operation and DTLS record use the sequence number. The
current implementation may increase the sequence number for each of the
two operations. It is not the expected behavior.
2. The implementation does not response to handshake retransmissions.
In the current implementation, receiving of retransmitted handshake
messages does not kick off a retransmission of the previous delivered
flight. Retransmission happens on timeout. Timeout is expensive.
Supporting response to peer retransmitted handshake messages would speed
up the handshaking.
3. the final CCC and finished message cannot be retransmitted.
It is an implementation bug. Every handshake message should be able to
get retransmitted.
4. the first application data may be discarded if the last flight get
lost.
Applications may send application data immediately after the handshake
completed. However, the peer may have not receive the handshake
complete message, and therefor discard the application data. As may
impact application logic.
For example
Client Server
....
-- ClientKeyExchange -->
-- ChangeCipherSpec -->
-- Finished -->
X <-- ChangeCipherSpec --
X <-- Finished --
<-- Application Data --
----- ... --->
-- ClientKeyExchange -->
-- ChangeCipherSpec -->
-- Finished -->
<-- ChangeCipherSpec --
<-- Finished --
1. (omit the previous handshake messages) server sends ChangeCipherSpec
and Finished messages.
2. server handshake complete
3. server send application
4. client does not receive the ChangeCipherSpec or Finished messages.
5. client receives the application data. Client cannot handle the
encrypted message, and may discard it. Client re-transmit the previous
flight.
6. server retransmit the last flight.
7. client receives the last flight.
In this update, the last flight will be transmit twice. As may mitigate
the impact of the issue.
5. resuming handshaking need no cookie exchange.
It is an implementation bug. Cookie exchange is performed for
handshaking resuming now. It is not the expected behavior.
6. need more debug log for DTLS handshake message fragmentation and
reassembly.
Thanks,
Xuelei
