cannot handle an IPv6 address correctly

[Hajimu UMEMOTO]

sshguard cannot handle an IPv6 address correctly. It ends up with following syslog message:

Unable to interpret resolution result as IPv6 address: No space left on device.
Giving up entry.

The attached patch should fix the problem.

[Kevin Zheng]

Your patch is correct, but IPv6 addresses should not trigger a name resolution. What was the attack (or perhaps just the address) that's triggering this issue?

[Hajimu UMEMOTO]

Just doing FTP with wrong password. At that time, following messages are loggied with my patch applied.

Mar 21 11:44:32 saku ftpd[23077]: FTP LOGIN FAILED FROM <REVERSE DNS NAME>, <USER>
Mar 21 11:44:32 saku sshguard[8478]: Successfully resolved '<REVERSE DNS NAME>' --> 6:'<IPv6 ADDRESS>'.

I think thre is no reason to exclude an IPv6 address from trigering a name resolution.

[Kevin Zheng]

Ahh, sorry, I assumed it was an IPv6 address that showed up in the logs, and the address was triggering the name resolution. As you indicated it's a hostname that shows up in the logs.

[Kevin Zheng]

Fixed in 960d68a, thanks!