[src/trunk]: src/sys/fs/sysvbfs In sysvbfs_lookup(), deny last component writ...

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

details:   https://anonhg.NetBSD.org/src/rev/94461a20c0f7
branches:  trunk
changeset: 761543:94461a20c0f7
user:      njoly <njoly%NetBSD.org@localhost>
date:      Mon Jan 31 18:48:50 2011 +0000

description:
In sysvbfs_lookup(), deny last component write operation on a
read-only mount.
Fix PR/44302: sysvbfs allows unlink on fs mounted MNT_RDONLY.

Reviewed by pooka.

diffstat:

 sys/fs/sysvbfs/sysvbfs_vnops.c |  10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diffs (35 lines):

diff -r 415dc2e98587 -r 94461a20c0f7 sys/fs/sysvbfs/sysvbfs_vnops.c
--- a/sys/fs/sysvbfs/sysvbfs_vnops.c    Mon Jan 31 18:28:05 2011 +0000
+++ b/sys/fs/sysvbfs/sysvbfs_vnops.c    Mon Jan 31 18:48:50 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sysvbfs_vnops.c,v 1.35 2010/11/30 10:43:04 dholland Exp $      */
+/*     $NetBSD: sysvbfs_vnops.c,v 1.36 2011/01/31 18:48:50 njoly Exp $ */
 
 /*-
  * Copyright (c) 2004 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sysvbfs_vnops.c,v 1.35 2010/11/30 10:43:04 dholland Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sysvbfs_vnops.c,v 1.36 2011/01/31 18:48:50 njoly Exp $");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
@@ -85,10 +85,16 @@
        *a->a_vpp = NULL;
 
        KASSERT((cnp->cn_flags & ISDOTDOT) == 0);
+
        if ((error = VOP_ACCESS(a->a_dvp, VEXEC, cnp->cn_cred)) != 0) {
                return error;   /* directory permission. */
        }
 
+       /* Deny last component write operation on a read-only mount */
+       if ((cnp->cn_flags & ISLASTCN) && (v->v_mount->mnt_flag & MNT_RDONLY) &&
+           (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
+               return EROFS;
+
        if (namelen == 1 && name[0] == '.') {   /* "." */
                vref(v);
                *a->a_vpp = v;