Panic (in firewall while doing lots of ifconfigs)

Dmitry Pryanishnikov dmitry at
Tue Aug 29 09:00:12 UTC 2006


On Tue, 29 Aug 2006, Ian FREISLICH wrote:
> 2589                            case O_IP_SRC_ME:
> 2590                                    if (is_ipv4) {
> 2591                                            struct ifnet *tif;
> 2592
> 2593                                            INADDR_TO_IFP(src_ip, tif);
> 2594                                            match = (tif != NULL);
> 2595                                    }

    Looks like a lack of the proper locking against IP address 
addition/removal. These (O_IP_SRC_ME/O_IP_DST_ME), 
as well as matching of interface by IP address in the iface_match():

                 /* XXX lock? */
                 TAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) {
                         if (ia->ifa_addr == NULL)

are worrying for these races exist since version 1.1 of the ip_fw2.c
for more than 4 years! Alas I'm not an expert in kernel locking, that's why
I don't know how to correctly lock these places.

Sincerely, Dmitry
Atlantis ISP, System Administrator
e-mail:  dmitry at
nic-hdl: LYNX-RIPE

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