Module Name: src
Committed By: chs
Date: Wed Dec 21 02:28:06 UTC 2022
Modified Files:
src/sys/uvm: uvm_swap.c
Log Message:
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.
Reported-by: syzbot+90a23d2f19e5a0a30...@syzkaller.appspotmail.com
To generate a diff of this commit:
cvs rdiff -u -r1.206 -r1.207 src/sys/uvm/uvm_swap.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/uvm/uvm_swap.c
diff -u src/sys/uvm/uvm_swap.c:1.206 src/sys/uvm/uvm_swap.c:1.207
--- src/sys/uvm/uvm_swap.c:1.206 Mon Aug 23 13:08:18 2021
+++ src/sys/uvm/uvm_swap.c Wed Dec 21 02:28:06 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_swap.c,v 1.206 2021/08/23 13:08:18 hannken Exp $ */
+/* $NetBSD: uvm_swap.c,v 1.207 2022/12/21 02:28:06 chs 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 1.207 2022/12/21 02:28:06 chs Exp $");
#include "opt_uvmhist.h"
#include "opt_compat_netbsd.h"
@@ -1190,6 +1190,22 @@ again:
*/
/*
+ * 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 @@ swwrite(dev_t dev, struct uio *uio, int
}
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,
