Forbid to have len(alias) == len(id) to avoid service hijacking

[krhubert]

No description provided.

[NicolasMahe]

@krhubert can you provide more details and explanation please

[krhubert]

Suppose there is a service with ID = a and someone created another service with ALIAS = a. Then as long as service with ID = aexists it will receive the traffic, but when it will be shut down then ALIAS = a will receive all traffic, which probably wasn't intentional.

By forbidding len(alias) == len(id) we avoid this security leak and probably many others that might cause trouble due to having id same as alias.

[krhubert]

Also, 63 char is the maximum length of "labels"; see https://tools.ietf.org/html/rfc1035#section-2.3.4.

[NicolasMahe]

@krhubert This is done by #583, right?

[krhubert]

Yes