Date: Sun, 26 Oct 1997 11:41:56 +0100 (MET) From: Wolfram Schneider <wosch@cs.tu-berlin.de> To: freebsd-fs@freebsd.org Subject: disabled symlinks Message-ID: <199710261041.LAA00556@panke.panke.de>
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I want mount a file system without symlinks, e.g.
mount -t mfs -o nodev,nosuid,nosymlink /dev/sd0b /tmp
The nosymlink flag do not allow the creation of a symlink
on the mounted file system.
Here is a patch for the kernel and mount(8).
# This is a shell archive. Save it in a file, remove anything before
# this line, and then unpack it by entering "sh file". Note, it may
# create directories; files and directories will be owned by you and
# have default permissions.
#
# This archive contains:
#
# nosymlink-kernel.diff
# nosymlink-user.diff
#
echo x - nosymlink-kernel.diff
sed 's/^X//' >nosymlink-kernel.diff << 'END-of-nosymlink-kernel.diff'
XIndex: kern/vfs_syscalls.c
X===================================================================
XRCS file: /usr/cvs/src/sys/kern/vfs_syscalls.c,v
Xretrieving revision 1.51.2.6
Xdiff -u -r1.51.2.6 vfs_syscalls.c
X--- vfs_syscalls.c 1997/10/23 18:04:55 1.51.2.6
X+++ vfs_syscalls.c 1997/10/25 18:18:44
X@@ -183,9 +183,11 @@
X else if (mp->mnt_flag & MNT_RDONLY)
X mp->mnt_flag |= MNT_WANTRDWR;
X mp->mnt_flag &=~ (MNT_NOSUID | MNT_NOEXEC | MNT_NODEV |
X- MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_NOATIME);
X+ MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_NOATIME |
X+ MNT_NOSYMLINK);
X mp->mnt_flag |= uap->flags & (MNT_NOSUID | MNT_NOEXEC | MNT_NODEV |
X- MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_FORCE | MNT_NOATIME);
X+ MNT_SYNCHRONOUS | MNT_UNION | MNT_ASYNC | MNT_FORCE | MNT_NOATIME |
X+ MNT_NOSYMLINK);
X /*
X * Mount the filesystem.
X */
XIndex: sys/mount.h
X===================================================================
XRCS file: /usr/cvs/src/sys/sys/mount.h,v
Xretrieving revision 1.34.2.1
Xdiff -u -r1.34.2.1 mount.h
X--- mount.h 1997/08/17 13:33:43 1.34.2.1
X+++ mount.h 1997/10/25 17:23:00
X@@ -161,6 +161,7 @@
X #define MNT_UNION 0x00000020 /* union with underlying filesystem */
X #define MNT_ASYNC 0x00000040 /* file system written asynchronously */
X #define MNT_NOATIME 0x10000000 /* Disable update of file access times */
X+#define MNT_NOSYMLINK 0x20000000 /* Disable symlinks */
X
X /*
X * exported mount flags.
X@@ -185,7 +186,8 @@
X #define MNT_VISFLAGMASK (MNT_RDONLY|MNT_SYNCHRONOUS|MNT_NOEXEC|MNT_NOSUID| \
X MNT_NODEV|MNT_UNION|MNT_ASYNC|MNT_EXRDONLY|MNT_EXPORTED| \
X MNT_DEFEXPORTED|MNT_EXPORTANON|MNT_EXKERB|MNT_LOCAL| \
X- MNT_QUOTA|MNT_ROOTFS|MNT_USER|MNT_NOATIME)
X+ MNT_QUOTA|MNT_ROOTFS|MNT_USER|MNT_NOATIME|\
X+ MNT_NOSYMLINK)
X
X /*
X * filesystem control flags.
XIndex: ufs/ufs/ufs_vnops.c
X===================================================================
XRCS file: /usr/cvs/src/sys/ufs/ufs/ufs_vnops.c,v
Xretrieving revision 1.41.2.3
Xdiff -u -r1.41.2.3 ufs_vnops.c
X--- ufs_vnops.c 1997/06/29 08:48:50 1.41.2.3
X+++ ufs_vnops.c 1997/10/25 22:27:27
X@@ -1515,6 +1515,12 @@
X register struct inode *ip;
X int len, error;
X
X+ /* do not create symlinks on this file system */
X+ if (ap->a_dvp->v_mount->mnt_flag & MNT_NOSYMLINK) {
X+ vput(ap->a_dvp);
X+ return ENOSYS;
X+ }
X+
X error = ufs_makeinode(IFLNK | ap->a_vap->va_mode, ap->a_dvp,
X vpp, ap->a_cnp);
X if (error)
END-of-nosymlink-kernel.diff
echo x - nosymlink-user.diff
sed 's/^X//' >nosymlink-user.diff << 'END-of-nosymlink-user.diff'
XIndex: mount/mntopts.h
X===================================================================
XRCS file: /usr/cvs/src/sbin/mount/mntopts.h,v
Xretrieving revision 1.7
Xdiff -u -r1.7 mntopts.h
X--- mntopts.h 1996/09/03 07:13:55 1.7
X+++ mntopts.h 1997/10/20 15:55:25
X@@ -47,6 +47,7 @@
X #define MOPT_NODEV { "dev", 1, MNT_NODEV, 0 }
X #define MOPT_NOEXEC { "exec", 1, MNT_NOEXEC, 0 }
X #define MOPT_NOSUID { "suid", 1, MNT_NOSUID, 0 }
X+#define MOPT_NOSYMLINK { "symlink", 1, MNT_NOSYMLINK, 0 }
X #define MOPT_RDONLY { "rdonly", 0, MNT_RDONLY, 0 }
X #define MOPT_SYNC { "sync", 0, MNT_SYNCHRONOUS, 0 }
X #define MOPT_UNION { "union", 0, MNT_UNION, 0 }
X@@ -75,6 +76,7 @@
X MOPT_NODEV, \
X MOPT_NOEXEC, \
X MOPT_NOSUID, \
X+ MOPT_NOSYMLINK, \
X MOPT_RDONLY, \
X MOPT_UNION
X
XIndex: mount/mount.8
X===================================================================
XRCS file: /usr/cvs/src/sbin/mount/mount.8,v
Xretrieving revision 1.11.2.2
Xdiff -u -r1.11.2.2 mount.8
X--- mount.8 1997/08/24 17:52:01 1.11.2.2
X+++ mount.8 1997/10/25 22:41:36
X@@ -134,6 +134,10 @@
X wrapper like
X .Xr suidperl
X is installed on your system.
X+.It nosymlink
X+Do not allow the creation of a
X+.Xr symlink 2
X+on the mounted file system.
X .It rdonly
X The same as
X .Fl r ;
XIndex: mount/mount.c
X===================================================================
XRCS file: /usr/cvs/src/sbin/mount/mount.c,v
Xretrieving revision 1.15
Xdiff -u -r1.15 mount.c
X--- mount.c 1996/09/03 07:13:56 1.15
X+++ mount.c 1997/10/25 17:25:58
X@@ -92,6 +92,7 @@
X { MNT_NODEV, "nodev" },
X { MNT_NOEXEC, "noexec" },
X { MNT_NOSUID, "nosuid" },
X+ { MNT_NOSYMLINK, "nosymlink" },
X { MNT_QUOTA, "with quotas" },
X { MNT_RDONLY, "read-only" },
X { MNT_SYNCHRONOUS, "synchronous" },
X@@ -588,6 +589,9 @@
X
X if (ent->f_flags & MNT_ASYNC)
X printf (",async");
X+
X+ if (ent->f_flags & MNT_NOSYMLINK)
X+ printf (",nosymlink");
X
X if (fst = getfsspec (ent->f_mntfromname))
X printf ("\t%u %u\n", fst->fs_freq, fst->fs_passno);
END-of-nosymlink-user.diff
exit
--
Wolfram Schneider <wosch@apfel.de> http://www.apfel.de/~wosch/
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