> Date: Thu, 5 May 2022 22:41:01 +0200
> From: Alexander Bluhm <alexander.bl...@gmx.net>
>
> Hi,
>
> The easiest way to make divert_packet() MP safe for now, is to
> protect sbappendaddr() with kernel lock.
All other invocations of sbappendaddr() run with the kernel lock held?
If so, maybe that should be asserted inside sbappendaddr()?
If not, I don't understand how this would help...
> ok?
>
> bluhm
>
> Index: netinet/ip_divert.c
> ===================================================================
> RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/ip_divert.c,v
> retrieving revision 1.67
> diff -u -p -r1.67 ip_divert.c
> --- netinet/ip_divert.c 5 May 2022 16:44:22 -0000 1.67
> +++ netinet/ip_divert.c 5 May 2022 20:36:23 -0000
> @@ -222,11 +222,18 @@ divert_packet(struct mbuf *m, int dir, u
> }
>
> so = inp->inp_socket;
> + /*
> + * XXXSMP sbappendaddr() is not MP safe and this function is called
> + * from pf with shared netlock. To run only one sbappendaddr()
> + * protect it with kernel lock. Socket buffer access from system
> + * call is protected with exclusive net lock.
> + */
> + KERNEL_LOCK();
> if (sbappendaddr(so, &so->so_rcv, sintosa(&sin), m, NULL) == 0) {
> + KERNEL_UNLOCK();
> divstat_inc(divs_fullsock);
> goto bad;
> }
> - KERNEL_LOCK();
> sorwakeup(inp->inp_socket);
> KERNEL_UNLOCK();
>
> Index: netinet6/ip6_divert.c
> ===================================================================
> RCS file: /data/mirror/openbsd/cvs/src/sys/netinet6/ip6_divert.c,v
> retrieving revision 1.66
> diff -u -p -r1.66 ip6_divert.c
> --- netinet6/ip6_divert.c 5 May 2022 16:44:22 -0000 1.66
> +++ netinet6/ip6_divert.c 5 May 2022 20:36:23 -0000
> @@ -228,11 +228,18 @@ divert6_packet(struct mbuf *m, int dir,
> }
>
> so = inp->inp_socket;
> + /*
> + * XXXSMP sbappendaddr() is not MP safe and this function is called
> + * from pf with shared netlock. To run only one sbappendaddr()
> + * protect it with kernel lock. Socket buffer access from system
> + * call is protected with exclusive net lock.
> + */
> + KERNEL_LOCK();
> if (sbappendaddr(so, &so->so_rcv, sin6tosa(&sin6), m, NULL) == 0) {
> + KERNEL_UNLOCK();
> div6stat_inc(div6s_fullsock);
> goto bad;
> }
> - KERNEL_LOCK();
> sorwakeup(inp->inp_socket);
> KERNEL_UNLOCK();
>
>
>
