RFR 8067105: Socket returned by ServerSocket.accept() is inherited by child process on Windows

[Dmitry Samersoff]

Chris,

> OK, but there can be no expectation that something like this can work
> with java.net.Socket, or SocketChannel. I am only proposing to change
> these two specific implementations.

OK. Thank you for clarification.

The fix looks good for me.

-Dmitry


On 2014-12-18 15:52, Chris Hegarty wrote:
> On 18 Dec 2014, at 12:22, Dmitry Samersoff <dmitry.samersoff at oracle.com> wrote:
> 
>> Chris,
>>
>> In a windows world it's rather common to rely on socket inheritance
>> e.g. set socket to stdin(stdout) of child process and do CreateProcess.
> 
> OK, but there can be no expectation that something like this can work with java.net.Socket, or SocketChannel. I am only proposing to change these two specific implementations.
> 
>> So please make sure your changes don't have side effects,
> 
> The changes will have an effect, accepted sockets/channels will no longer be inherited. No other potential side-effect is possible.
> 
>> also it might
>> be better to control handler inheritance in one place only (at
>> CreateProcess call) and don't manage it explicitly in other places.
> 
> There is some handling of a small set of “special” handles in the native process implementation. I don’t think we want to prevent all handles from being inherited. Are you suggesting something different ?
> 
> -Chris.
> 
>> -Dmitry
>>
>>
>> On 2014-12-17 18:47, Chris Hegarty wrote:
>>> A socket connection which is returned by ServerSocket.accept() is
>>> inherited by a child process. The expected behavior is that the socket
>>> connection is not inherited by the child process. This is an oversight
>>> in the original implementation, that only sets HANDLE_FLAG_INHERIT for
>>> newly created sockets.
>>>
>>> The native socket returned by ServerSocket.accept() should be configured
>>> so it will not be inherited by a child process,
>>> SetHandleInformation(<HANDLE>, HANDLE_FLAG_INHERIT, FALSE) .
>>>
>>> The change is in Java_java_net_DualStackPlainSocketImpl_accept0
>>>
>>> diff --git
>>> a/src/java.base/windows/native/libnet/DualStackPlainSocketImpl.c
>>> b/src/java.base/windows/native/libnet/DualStackPlainSocketImpl.c
>>> --- a/src/java.base/windows/native/libnet/DualStackPlainSocketImpl.c
>>> +++ b/src/java.base/windows/native/libnet/DualStackPlainSocketImpl.c
>>> @@ -294,6 +294,8 @@
>>>         return -1;
>>>     }
>>>
>>> +    SetHandleInformation((HANDLE)(UINT_PTR)newfd, HANDLE_FLAG_INHERIT,
>>> FALSE);
>>> +
>>>     ia = NET_SockaddrToInetAddress(env, (struct sockaddr *)&sa, &port);
>>>     isa = (*env)->NewObject(env, isa_class, isa_ctorID, ia, port);
>>>     (*env)->SetObjectArrayElement(env, isaa, 0, isa);
>>>
>>> -Chris.
>>
>>
>> -- 
>> Dmitry Samersoff
>> Oracle Java development team, Saint Petersburg, Russia
>> * I would love to change the world, but they won't give me the sources.
> 


-- 
Dmitry Samersoff
Oracle Java development team, Saint Petersburg, Russia
* I would love to change the world, but they won't give me the sources.