Bug#962218: gnutls28: build fails on IPv6-only buildds

[Julien Cristau]

On Thu, Jun  4, 2020 at 22:18:10 +0300, Adrian Bunk wrote:

> On Thu, Jun 04, 2020 at 07:55:32PM +0200, Julien Cristau wrote:
> > Control: tag -1 moreinfo
> > 
> > On Thu, Jun 04, 2020 at 07:59:22PM +0300, Adrian Bunk wrote:
> > > FAIL: dtls_hello_random_value
> > > =============================
> > > 
> > > testing: default
> > > client:156: client: Handshake failed: Resource temporarily unavailable, try again.
> > > server:271: server: Handshake has failed: The TLS connection was non-properly terminated.
> > > 
> > > FAIL dtls_hello_random_value (exit status: 1)
> > > 
> > This particular test seems to use a AF_UNIX socketpair, I'm not sure
> > how it would fail due to network setup?
> 
> I copied the log from the 3.6.13-4 arm64 failure.
> This specific test passes in the other logs.
> 
> The binary-all log (non-conova) of 3.6.13-4 has no test failures,
> but the build fails due to timeout after 150 minutes without output.
> 
> My gut feeling is that there might be an (unrelated) problem with 
> the #961889 fix, but this is just a guess.
> 
The arch:all failure is at grnet and that buildd has both v4 and v6
addresses, so presumably unrelated.

Which leaves us with the armel failure (on arm-conova-03) which does
look related to the lack of public v4 address, e.g.:

> FAIL: sni-hostname.sh
> =====================
> 
> Checking SNI hostname in gnutls-cli
> Echo Server listening on IPv6 :: port 26448...done
> Could not connect to 127.0.0.1:26448: Connection refused
> Failure: 1. handshake should have succeeded!
> Exiting via signal 15
> FAIL sni-hostname.sh (exit status: 1)

If we listen on :: and then try to connect to 127.0.0.1, that won't work.

And indeed gnutls-serv seems to call getaddrinfo with node == NULL and
hints.ai_flags == AI_PASSIVE|AI_ADDRCONFIG, to figure out what address
to listen on.  If the host has no non-local ipv4 address, that
getaddrinfo call returns :: but not 0.0.0.0; and then the test hardcodes
127.0.0.1 as the address for gnutls-cli to connect to, and sadness
ensues.

Cheers,
Julien