RFR JDK-8239595/JDK-8239594 : ssl context version is not respected/jdk.tls.client.protocols is not respected

Xuelei Fan xuelei.fan at oracle.com
Fri Mar 27 16:23:30 UTC 2020

On 3/27/2020 5:52 AM, Chris Hegarty wrote:
> Xuelei,
> Before commenting further on the interaction of the HTTP Client with various contorted configurations, I would like to get a better understanding of the `jdk.tls.client.protocols` property.
> Is there a specification or other documentation describing `jdk.tls.client.protocols` ?
See the jdk.tls.client.protocols line in table 'Table 8-3 System 
Properties and Customized Items" in JSSE Reference Guides:


For your quick reference, I copied the note here:

Customized Item:
Default handshaking protocols for TLS/DTLS clients.

To enable specific SunJSSE protocols on the client, specify them in a 
comma-separated list within quotation marks; all other supported 
protocols are not enabled on the client
For example,

     If jdk.tls.client.protocols="TLSv1,TLSv1.1", then the default 
protocol settings on the client for TLSv1 and TLSv1.1 are enabled, while 
SSLv3, TLSv1.2, TLSv1.3, and SSLv2Hello are not enabled

     If jdk.tls.client.protocols="DTLSv1.2" , then the protocol setting 
on the client for DTLS1.2 is enabled, while DTLS1.0 is not enabled

> It is my understanding that the property only affects the *default* protocol’s ( not the supported protocols ) of the *default* context. That is, the context returned by `SSLContext.getInstance("Default”)`,
It is correct that the property impact the default SSLContext only.  The 
default SSLContext instance could get from:

> and the protocol values returned by the following invocation on that context `getDefaultSSLParameters().getProtocols()`. Is this correct? If not, what does it do?


> -Chris.
>> On 26 Mar 2020, at 16:58, Xuelei Fan <xuelei.fan at oracle.com> wrote:
>> With this update, the logic looks like: if TLSv1.3 is not enabled in the SSLContext, use TLSv1.2 instead;  Otherwise, use TLSv1.3 and TLSv1.2.
>> There may be a couple of issues:
>> 1. TLSv1.2 may be not enabled, although TLSv1.3 is enabled.
>> For example:
>>    System.setProperty("jdk.tls.client.protocols", "TLSv1.3")
>>    System.setProperty("jdk.tls.client.protocols", "TLSv1.1, TLSv1.0")
>> 2. TLSv1.2 may be not supported in the SSLContext.
>> For example:
>>    SSLContext context = SSLContext.getInstance("DTLS");
>>    HttpClient.newBuilder().sslContext(context)...
>> 3. The application may not want to use TLS 1.2.
>> For example:
>>    System.setProperty("jdk.tls.client.protocols", "TLSv1.1, TLSv1.0")
>> The System property may be shared by code other than httpclient.  So the setting may not consider the impact on httpclient.
>> I may use enabled protocols only. If no TLSv1.2/TLSv1.3, I may use an empty protocol array, and test to see what happens in the httpclient implementation stack.
>> Xuelei
>> On 3/26/2020 9:28 AM, Sean Mullan wrote:
>>> Cross-posting to security-dev as this involves TLS/SSL configuration.
>>> --Sean
>>> On 3/26/20 10:02 AM, rahul.r.yadav at oracle.com wrote:
>>>> Hello,
>>>> Request to have my fix reviewed for issues:
>>>>       JDK-8239595 : ssl context version is not respected
>>>>       JDK-8239594 : jdk.tls.client.protocols is not respected
>>>> The fix updates jdk.internal.net.http.HttpClientImpl.getDefaultParams(SSLContext ctx)
>>>> to use ctx.getDefaultSSLParameters()instead of ctx.getSupportedSSLParameters(),
>>>> as the latter does not respect the context parameters set by the user.
>>>> Issue: https://bugs.openjdk.java.net/browse/JDK-8239595
>>>> Issue: https://bugs.openjdk.java.net/browse/JDK-8239594
>>>> Webrev: http://cr.openjdk.java.net/~jboes/rayayada/webrevs/8239595/webrev.00/
>>>> -- Rahul

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