#26488: Validate that DirAuthority address is IPv4

[rl1987]

https://trac.torproject.org/projects/tor/ticket/26488

[dgoulet-tor]

I think we could avoid the dup() entirely here and simply passing addrport_sep - addrport to this function. This avoid us an allocation and free.

[rl1987]

That doesn't work, as it tries feeding the address to tor_inet_pton and sees if parsing succeeded. It doesn't like the separating colon.

[dgoulet-tor]

Isn't addrportsep - addrport is only the address without the semicolon?

[rl1987]

Umm no? It's number of bytes from the start of addrport to colon (pointer value in const char *addrport_sep) - a length of address alone (without colon and port). string_is_valid_ipv4_address() only takes the string and does not have a second parameter that says "check this much of the input". That's why I'm using tor_strndup() to copy only the part I can check with string_is_valid_ipv4_address().

Maybe there's some code clarity improvement to be made?

[dgoulet-tor]

Ahhhh! yes ok I get it. That is fine then. Lets merge this!

[coveralls]

Coverage decreased (-0.02%) to 59.875% when pulling f628d58 on rl1987:bug26488 into b556894 on torproject:master.