Debian Bug report logs - #211614
autofs: mount options are reordered, which could change their meaning

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Teddy Hogeborn <teddy@fukt.bth.se>

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: autofs: mount options are reordered, which could change their meaning

Date: Fri, 19 Sep 2003 02:24:43 +0200

Package: autofs
Version: 3.9.99-4.0.0pre10-1
Severity: normal
Tags: patch

The order of mount options specified in a NIS auto.master map (maybe
also an /etc/auto.master file, I haven't checked) are reordered by
autofs, so that when mount(8) is called, the options are passed in a
different order than written in auto.master.

Proof:

$ ypcat -k auto.master
/home auto.home defaults,nosuid,nodev,timeo=14,rsize=8192,wsize=8192,soft
$ invoke-rc.d autofs getmounts
/usr/sbin/automount  /home yp auto.home  nosuid,timeo=14,wsize=8192,defaults,soft,rsize=8192,nodev

See how the "nodev" moved from being the second option to being last,
and how the "defaults" option moved from the first to the fourth
postion?  What you would expect is the options to retain the same
order as given.

Reordering the options is bad, because this could alter the options'
meaning.  Excerpt from the mount(8) man page:

----
[...]
              user   Allow  an  ordinary  user  to mount the file
                     system.  The name of the  mounting  user  is
                     written  to  mtab so that he can unmount the
                     file system again.  This option implies  the
                     options  noexec,  nosuid,  and nodev (unless
                     overridden by subsequent options, as in  the
                     option line user,exec,dev,suid).
[...]
----

Here is a patch to /etc/init.d/autofs to make it preserve the order of
the options as given:

----
--- /etc/init.d/autofs.~4~	Fri Jul 21 16:15:54 2000
+++ /etc/init.d/autofs	Sat Jul 22 07:49:07 2000
@@ -180,6 +180,7 @@
 	FS="="
 	daemon_opts[ "timeout" ] = "timeout"
 	daemon_opts[ "t" ] = "timeout"
+	numoptions = 0
 }
 {
 	if ( $0 ~ /^$/ )
@@ -187,7 +188,8 @@
 	if ( $1 in daemon_opts ) {
 		daemon[ daemon_opts[ $1 ] ] = $2
 	} else {
-		mount[$0] = 1
+		numoptions++
+		option[numoptions] = $0
 	}
 }
 END {
@@ -196,11 +198,11 @@
 			printf "--timeout=%s\n", daemon["timeout"]
 		}
 	} else {
-		for ( a in mount ) {
+		for ( a=1; a <= numoptions ; a++ ) {
 			if ( length( out ) )
-				out=out "," a
+				out=out "," option[a]
 			else
-				out=a
+				out=option[a]
 		}
 		printf "%s\n", out
 	}
----

(Tested with both mawk and gawk.)

This bug and patch was previously mentioned in the thread about
another bug (#67294), where the maintainer said he would fix it soon.
Since I was not affected by the bug, I did not file another bug
report.  But the bug is still not fixed, so I am reporting it now.

/Teddy

-- System Information
Debian Release: 3.0
Architecture: i386
Kernel: Linux tower 2.4.20 #1 SMP Tue Aug 12 15:26:49 CEST 2003 i686
Locale: LANG=C, LC_CTYPE=en_US.UTF-8

Versions of packages autofs depends on:
ii  libc6                   2.2.5-11.5       GNU C Library: Shared libraries an
ii  procps                  1:2.0.7-8.woody1 The /proc file system utilities.

Message #8 received at 211614-submitter@bugs.debian.org (full text, mbox, reply):

From: Petter Reinholdtsen <pere@hungry.com>

To: 211614-submitter@bugs.debian.org

Subject: Re: autofs: mount options are reordered, which could change their meaning

Date: Sun, 21 Sep 2003 14:28:24 +0200

I believe this problem is fixed in version 3.9.99-4.0.0pre10-14.  At
least the code is rewritten so the patch do not apply cleanly, and as
far as I can read the code it is rewritten to keep the order of the
options.

Message #13 received at 211614-done@bugs.debian.org (full text, mbox, reply):

From: "Arthur Korn" <arthur@korn.ch>

To: 211614-done@bugs.debian.org

Subject: fixed with Bug#147774

Date: Tue, 31 Aug 2004 00:52:24 +0200

fixed with Bug#147774

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