Re: netsec 682578f 4/6: Add option to bypass NSM TLS checks on local networks

[Robert Pluim <rpluim@gmail.com>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Robert Pluim <rpluim@gmail.com>
>> Date: Mon, 16 Jul 2018 15:34:35 +0200
>> Cc: emacs-devel@gnu.org
>> 
>> Eli, I see thereʼs a sys_getaddrinfo in w32.c, is something needed
>> to get emacs to use that on MS-Windows?
>
> No, you don't need anything special.  nt/inc/socket.h redirects
> getaddrinfo into sys_getaddrinfo, and all our C sources see the
> redirection.

Thanks. I always forget how the nt stuff works.

>> +DEFUN ("get-address-info", Fget_address_info, Sget_address_info, 1, 2, 0,
>> +       doc: /* Look up ip address info of NAME.
>> +Optional parameter FAMILY controls whether to look up IPv4 or IPv6
>> +addresses.  The default of nil means look up both, symbol `ipv4' means
>> +IPv4 only, symbol `ipv6' mean IPv6 only.  Returns a list of addresses,
>> +or nil if none were found.  */)
>
> This doc string doesn't tell that each address is a vector or a
> string.

Yes. Iʼm waiting for Jimmy to tell me if the format works for him,
then Iʼll document whatever we end up with (and it can currently only
return a vector, and includes a port, which is probably not needed).

>> +  if (EQ (family, Qipv4))
>> +    hints.ai_family = AF_INET;
>> +#ifdef AF_INET6
>> +  if (EQ (family, Qipv6))
>> +    hints.ai_family = AF_INET6;
>> +#endif
>
> Should we signal an error if 'ipv6' is requested on a system that
> doesn't support that?

Iʼd be more inclined to return nil in that case. The effect is the
same, and the caller doesnʼt need to do redundant error handling.

>> +  ret = getaddrinfo (SSDATA (name), NULL, &hints, &res);
>
> You should encode NAME (using ENCODE_SYSTEM), because it could include
> non-ASCII characters.  In general, any Lisp string should be encoded
> before you can pass its data to a C library function.
>

My understanding is that this API only supports ASCII anyway. For
internationalized domain names you'd need to use puny-code (and we
donʼt currently use ENCODE_SYSTEM when calling getaddrinfo elsewhere).

> Thanks.
>
> P.S. This needs a NEWS entry, at the very least, and perhaps also an
> update for the ELisp manual.

Both, for sure.

Robert