[RFC PATCH 0/2] Add AF_VSOCK support to getnameinfo(3) and getaddrinfo(3)

[Florian Weimer]

On 09/30/2016 01:10 PM, Stefan Hajnoczi wrote:
> On Thu, Sep 29, 2016 at 03:25:55PM +0200, Florian Weimer wrote:
>> * Stefan Hajnoczi:
>>
>>> Many existing programs use getnameinfo(3) and getaddrinfo(3).
>>> Porting programs to support AF_VSOCK is easy if the library
>>> functions can handle this address family.  Without support in glibc
>>> each program needs to duplicate address parsing code and it becomes
>>> harder to port programs.
>>
>> What has changed since the previous discussion?
>>
>>   <https://sourceware.org/ml/libc-help/2015-08/msg00004.html>
>>
>> How do you expect that applications will know that they have to pass
>> AF_VSOCK to getaddrinfo instead of AF_UNSPEC?
>
> For example ncat(1) has --unixsock and --udp command-line options.  A
> --vsock option can be added.  At that point the program knows to use
> AF_VSOCK and the same getaddrinfo(3) code path can be used by TCP, UDP,
> UNIX, and vsock.

ncat doesn't use getaddrinfo AFAICS, so this isn't going to help it. 
The larger nmap codebase has a call to getaddrinfo, but the code leading 
to it assumes 16-bit port numbers, so it won't be able to use 
getaddrinfo either.

Do you have a better example?

Is there a test guest system which has NFS over AF_VSOCK running?  It 
looks to me that AF_VSOCK is fundamentally insecure, and I'm not sure if 
it can be fixed.

Florian