From: kn <kn@openbsd.org>
Date: Tue, 27 Jun 2023 17:36:56 +0000 (+0000)
Subject: Use shared net lock for DIOCGETIFACES
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=dfc1a6aabefdbfd088581d3bfa33633abf17eb90;p=openbsd

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 499330b84b0..26e1fa07faf 100644
--- 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;