Bug in blitiri.com.ar/go/spf

[Behrang Sabeghi]

Hello,

I think I've found a bug in the SPF library and I wanted to report it.

The bug is related to this section: https://github.com/albertito/spf/blob/master/spf.go#L301-L306

As mentioned in the comment there NXDOMAIN should result in a 'none' result, however, in testing I realized that I get a 'permerror' and when I turned on trace logs, this is what I saw:

ERRO[0004] check "abcdefghijklmnopqrstuvwxyzabc.com" 0 0
ERRO[0004] dns perm error: lookup abcdefghijklmnopqrstuvwxyzabc.com on 127.0.0.53:53: cannot marshal DNS message

 Thank you for your time.

Best,

Behrang Sabeghi

[Alberto Bertogli]

That's because the DNS lookup of abcdefghijklmnopqrstuvwxyzabc.com is,
in your environment, not returning "does not exist" (which would get
mapped to 'none'), it is returning a message that cannot be parsed by
the Go library, which is considered a permanent error.

So this is something between your DNS server and the Go DNS client, and
not an issue in the SPF library.

If I try that domain here on my machine, I correctly get a 'none'
result.

I suggest you look at your DNS server because it is strange it's sending
an invalid reply (as shown by the "cannot marshal DNS message").

Thanks!
Alberto

[Behrang Sabeghi]

Thank you very much for your swift response, I really appreciate it.

Just wanted to let you know that I tested it once more on an AWS EC2 instance and I got a 'none' result as you said. I had already taken a tcpdump in my local environment on port 53 before emailing you and I could see that the response to the query is NXDOMAIN but there must be something else wrong with my local DNS.

Thanks again,

Behrang