Use shared net lock for DIOCGETIFACES

snmpd(8) and 'pfctl -s Interfaces' dump pf's internal list of interfaces.

pf's internal interface list is completely protected by the pf lock,
pf lock assertions since pf_if.c r1.110 from over a week ago support this.

pfi_*() iterate over net lock protected if_groups lists, but only to read,
so downgrade from exclusive write net lock to a shared read-only one.

Feedback mvs
OK sashan

diff --git a/sys/net/pf_ioctl.c b/sys/net/pf_ioctl.c
index 499330b..26e1fa0 100644 (file)
--- a/sys/net/pf_ioctl.c
+++ b/sys/net/pf_ioctl.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: pf_ioctl.c,v 1.407 2023/06/27 17:29:38 kn Exp $ */
+/*     $OpenBSD: pf_ioctl.c,v 1.408 2023/06/27 17:36:56 kn Exp $ */
 
 /*
  * Copyright (c) 2001 Daniel Hartmeier
@@ -2944,11 +2944,11 @@ pfioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct proc *p)
                        goto fail;
                }
 
-               NET_LOCK();
+               NET_LOCK_SHARED();
                PF_LOCK();
                pfi_get_ifaces(io->pfiio_name, kif_buf, &io->pfiio_size);
                PF_UNLOCK();
-               NET_UNLOCK();
+               NET_UNLOCK_SHARED();
                if (copyout(kif_buf, io->pfiio_buffer, sizeof(*kif_buf) *
                    io->pfiio_size))
                        error = EFAULT;