conf: Correct length checking of interface names in conf_ports()

When interface names are specified in forwarding specs, we need to check
the length of the given interface name against the limit of IFNAMSIZ - 1
(15) characters.  However, we managed to have 3 separate off-by-one errors
here meaning we only accepted interface names up to 12 characters.

1. At the point of the check 'ifname' was still on the '%' character, not
   the first character of the name, meaning we overestimated the length by
   one
2. At the point of the check 'spec' had been advanced one character past
   the '/' which terminates the interface name, meaning we overestimated
   the length by another one
3. We checked if the (miscalculated) length was >= IFNAMSIZ - 1, that is
   >= 15, whereas lengths equal to 15 should be accepted.

Correct all 3 errors.

Link: https://bugs.passt.top/show_bug.cgi?id=61
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

0 files changed, 0 insertions, 0 deletions