Re: Illegal character in hostname

[David Fifield <david () bamsoftware com>]

On Sat, Jan 07, 2012 at 08:30:23PM +0100, Gisle Vanem wrote:
> I found that nmap doesn't like IP-addresses that simply resolves to
> a dot '.'. E.g. 77.247.181.164 -> '.'.
>
> nmap spews out a lot of these lines when encountering such a name:
>  Illegal character(s) in hostname -- replacing with '*'
>  Illegal character(s) in hostname -- replacing with '*'
>  Illegal character(s) in hostname -- replacing with '*'
>  Illegal character(s) in hostname -- replacing with '*'
>  Illegal character(s) in hostname -- replacing with '*
> ...
>
> I think the function encoded_name_to_normal() in nmap_dns.cc
> doesn't handle such "joke hostname"; it's stepping out-of-bounds.
> A patch that works for me:
>
> @@ -601,6 +602,13 @@
> // a normal decimal separated hostname.
> // ASSUMES NAME LENGTH/VALIDITY HAS ALREADY BEEN VERIFIED
> static int encoded_name_to_normal(unsigned char *buf, char *output, int outputsize){
> +
> +  if (!buf[0]) {
> +    *output++ = '.';
> +    *output++ = '\0';
> +    return 0;
> +  }
> +
>   while (buf[0]) {
>     if (buf[0] >= outputsize-1) return -1;
>     memcpy(output, buf+1, buf[0]);

Thanks, that's a good bug you found. I added some more error checking
and committed r27778.

David Fifield
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