RFR(xs): 6991580: IPv6 Nameservers in resolv.conf throws NumberFormatException

[Severin Gehwolf]

On Mon, 2015-04-20 at 12:24 -0400, Andrew Hughes wrote:
> ----- Original Message -----
> > Adding in net-dev.
> > 
> > On Mon, 2015-04-20 at 14:02 +0200, Severin Gehwolf wrote:
> > > Hi,
> > > 
> > > Could I please get a review and a sponsor for the following patch?
> > > 
> > > The issue is that JDK's internal /etc/resolv.conf nameserver parsing
> > > does not properly account for IPv6 addresses on Linux/Unix. While the
> > > code in com.sun.jndi.dns.DnsClient seems to support IPv6 addresses
> > > passed in via the servers list in the constructor it expects IPv6
> > > addresses to be wrapped in '[' and ']' respectively. However,
> > > sun.net.dns.ResolverConfigurationImpl does no wrapping of IPv6 addresses
> > > when parsing "nameserver" keywords from /etc/resolv.conf, thus breaking
> > > DnsClient's contract.
> > > 
> > > The fix is to properly wrap IPv6 literal addresses in '[' and ']' if not
> > > already wrapped.
> > > 
> > > Bug: https://bugs.openjdk.java.net/browse/JDK-6991580
> > > Webrev:
> > > http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-6991580/webrev.01/
> > > 
> > > Testing done: Added regression test fails for unpatched 9 and passes for
> > > patched 9.
> > > 
> > > Thanks,
> > > Severin
> > > 
> > 
> > 
> > 
> > 
> 
> It'd be better to provide public nameservers in the test comment so everyone
> is able to run this test if they update /etc/resolv.conf appropriately.

OK fixed:
http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-6991580/webrev.02/

FWIW, I don't think the test needs IP addresses of DNS servers to be
functional, though. All it really does is passing it to
InetAddress.getByName(). Prior this patch DnsClient fails to parse the
IP literals.

> Google provides some: https://developers.google.com/speed/public-dns/docs/using
> 
> $ host redhat.com 2001:4860:4860::8888
> Using domain server:
> Name: 2001:4860:4860::8888
> Address: 2001:4860:4860::8888#53
> Aliases: 
> 
> redhat.com has address 209.132.183.105

On my F21 machine:
$ host redhat.com 2001:4860:4860::8888
;; connection timed out; no servers could be reached

But the test still works with a patched JDK:
[...]
DEBUG: 'nameserver = 127.0.0.1'
DEBUG: 'nameserver = [2001:4860:4860::8888]'
DEBUG: ==> Found IPv6 address in servers list: [2001:4860:4860::8888]
DEBUG: 'nameserver = [::1]:5353'
DEBUG: ==> Found IPv6 address in servers list: [::1]:5353
DEBUG: 'nameserver = 127.0.0.1:5353'
PASS: Found IPv6 address and DnsClient parsed it correctly.

Contrast this to unpatched:
[...]
DEBUG: 'nameserver = 127.0.0.1'
DEBUG: 'nameserver = 2001:4860:4860::8888'
DEBUG: ==> Found IPv6 address in servers list: 2001:4860:4860::8888
DEBUG: 'nameserver = [::1]:5353'
DEBUG: ==> Found IPv6 address in servers list: [::1]:5353
DEBUG: 'nameserver = 127.0.0.1:5353'
Exception in thread "main" java.lang.RuntimeException: FAIL: Tried to parse non-[]-encapsulated IPv6 address.
	at IPv6NameserverPlatformParsingTest.main(IPv6NameserverPlatformParsingTest.java:59)
Caused by: java.lang.NumberFormatException: For input string: "4860:4860::8888"
	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
	at java.lang.Integer.parseInt(Integer.java:580)
	at java.lang.Integer.parseInt(Integer.java:615)
	at com.sun.jndi.dns.DnsClient.<init>(DnsClient.java:127)
	at IPv6NameserverPlatformParsingTest.main(IPv6NameserverPlatformParsingTest.java:57)

Cheers,
Severin