json: reject too long interface names

json: reject too long interface names

Blamed commit added a length check on ifnames to the bison parser.
Unfortunately that wasn't enough, json parser has the same issue.

Bogon results in:
BUG: Interface length 44 exceeds limit
nft: src/mnl.c:742: nft_dev_add: Assertion `0' failed.

After patch, included bogon results in:
Error: Invalid device at index 0. name d2345678999999999999999999999999999999012345 too long

I intentionally did not extend evaluate.c to catch this, past sentiment
was that frontends should not send garbage.

I'll send a followup patch to also catch this from eval stage in case there
are further reports for frontends passing in such long names.

Fixes: fa52bc225806 ("parser: reject zero-length interface names")
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Pablo Neira Ayuso <pablo@netfilter.org>