pfctl segmentation fault in pfctl_optimize.c

Kristof Provost kp at
Fri Mar 12 13:06:25 UTC 2021

On 12 Mar 2021, at 14:00, Patrick Lamaiziere wrote:
> I've read the code of pfctl a bit. If pfctl crashes in 
> pfctl_optimize_ruleset, is there a risk to leave pf in a bad state ?
> Looks like the rules are sent to pf via ioctl after the optimization 
> so a crash before should be harmless (?).
That should be the case, yes.

I’ve not checked the pfctl code to see if it actually starts the 
operation to change the rules or not, but either way, pf rule changes 
are atomic.
They either succeed completely or not at all.

Pf accomplishes this by keeping an active and inactive ruleset, and when 
you load new rules pfctl will start a transaction (DIOCXBEGIN), add the 
complete new ruleset (DIOCADDRULE) and only then commit to swapping the 
active and inactive rulesets (DIOCXCOMMIT).

Best regards,

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