kern/165939: [ipw] security bug: incomplete firewall rules loaded if tables are used in ipfw.conf

[Ian Smith]

On Sat, 14 Jul 2012, crees at freebsd.org wrote:
 > http://www.freebsd.org/cgi/query-pr.cgi?pr=165939

 > Description
 > If user has tables used in /etc/ipfw.conf for example:
 >
 > table 1 add 64.6.108.239
 >
 > then firewall restart:
 >
 > /etc/rc.d/ipfw start
 >
 > fails with:
 > Line 8: setsockopt(IP_FW_TABLE_ADD): File exists
 > Firewall rules loaded.
 >
 > and incomplete ruleset is loaded. This is serious security problem.
 >
 > How-To-Repeat
 > Fix
 > in /etc/rc.firewall
 >
 > after ${fwcmd} -f flush
 > you need to flush tables too with command
 >
 > ipfw table all flush

Yes, to such a ruleset you'd need to add 'table all flush' too.

ipfw flush specifically does not flush tables.  I've long relied upon 
that, using mostly static tables only reloaded from a file saved hourly 
by cron, when $firewall_script finds tables are not loaded - ie at boot.

cheers, Ian