[src/netbsd-10]: src/sys/uvm Pull up following revision(s) (requested by chs ...

[martin <martin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f50344a176cf
branches:  netbsd-10
changeset: 372703:f50344a176cf
user:      martin <martin%NetBSD.org@localhost>
date:      Wed Dec 21 09:33:17 2022 +0000

description:
Pull up following revision(s) (requested by chs in ticket #13):

        sys/uvm/uvm_swap.c: revision 1.207

swap: disallow user opens of swap block device

the swap/drum block device was never intended to allow user opens,
but when the internal VOP_OPEN() in uvm_swap_init() was added
back in rev 1.135, the d_open method was changed from always-fail
to always-succeed in order to allow the new initial internal open.
this had the side effect of incorrectly allowing user opens too.
fix this by replacing the swap_bdevsw d_open with one that succeeds
for the first call but fails for all subsequent calls.

diffstat:

 sys/uvm/uvm_swap.c |  24 ++++++++++++++++++++----
 1 files changed, 20 insertions(+), 4 deletions(-)

diffs (52 lines):

diff -r 025bbadc9035 -r f50344a176cf sys/uvm/uvm_swap.c
--- a/sys/uvm/uvm_swap.c        Tue Dec 20 09:55:19 2022 +0000
+++ b/sys/uvm/uvm_swap.c        Wed Dec 21 09:33:17 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_swap.c,v 1.206 2021/08/23 13:08:18 hannken Exp $   */
+/*     $NetBSD: uvm_swap.c,v 1.206.4.1 2022/12/21 09:33:17 martin Exp $        */
 
 /*
  * Copyright (c) 1995, 1996, 1997, 2009 Matthew R. Green
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_swap.c,v 1.206 2021/08/23 13:08:18 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_swap.c,v 1.206.4.1 2022/12/21 09:33:17 martin Exp $");
 
 #include "opt_uvmhist.h"
 #include "opt_compat_netbsd.h"
@@ -1190,6 +1190,22 @@
  */
 
 /*
+ * swopen: allow the initial open from uvm_swap_init() and reject all others.
+ */
+
+static int
+swopen(dev_t dev, int flag, int mode, struct lwp *l)
+{
+       static bool inited = false;
+
+       if (!inited) {
+               inited = true;
+               return 0;
+       }
+       return ENODEV;
+}
+
+/*
  * swstrategy: perform I/O on the drum
  *
  * => we must map the i/o request from the drum to the correct swapdev.
@@ -1308,8 +1324,8 @@
 }
 
 const struct bdevsw swap_bdevsw = {
-       .d_open = nullopen,
-       .d_close = nullclose,
+       .d_open = swopen,
+       .d_close = noclose,
        .d_strategy = swstrategy,
        .d_ioctl = noioctl,
        .d_dump = nodump,