RELENG_6 weird '..' permission troubles

[Dmitry Morozovsky]

On Sun, 19 Feb 2006, Yar Tikhiy wrote:

YT> On Thu, Feb 16, 2006 at 04:57:57PM +0300, Dmitry Morozovsky wrote:
YT> > On Thu, 16 Feb 2006, James Wyatt wrote:
YT> > 
YT> > JW> I've seen something very similar when the permissions of the mount point's
YT> > JW> underlieing subdirectory wasn't 777. Really strange to see, but it was a
YT> > JW> fallout from a company-wide change to make umask and directory permissions
YT> > JW> that wasn't quite implemented correctly.  Hope this helps - Jy@
YT> > 
YT> > Exactly, see my other followup.
YT> > 
YT> > I suppose 0777 is bad choice because if for some reason file system would not 
YT> > mount, anyone can fill up this directory. 0111 or 0555 or standard 0755 would 
YT> > be safe though.
YT> 
YT> This looks like a file-a-PR case if you are sure you didn't overlook
YT> anything.  To the best of my knowledge, the underlying mount point
YT> permissions should affect nothing since the FS was mounted.  But
YT> you didn't show us output from "ls -la /" so please judge by yourself.

I can't show you exact output of ls -la / before other FS mount because of 
headlessness (nor serial console) of machine in question. However, there was 
one file system which I could unmount without dropping to single user, and I 
*did* see underlying directory mode of 0750.

What should I file? Test case? It's rather simple (attached).

Sincerely,
D.Marck                                     [DM5020, MCK-RIPE, DM3-RIPN]
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*** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck at rinet.ru ***
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Script started on Sun Feb 19 15:59:12 2006
root at woozle:/var/tmp# unalias ls
root at woozle:/var/tmp# cd /var/tmp
root at woozle:/var/tmp# dd if=/dev/zero of=image1.img bs=1m count=4
4+0 records in
4+0 records out
4194304 bytes transferred in 0.057493 secs (72953335 bytes/sec)
root at woozle:/var/tmp# mdconfig -a -t vnode -f image1.img
md1
root at woozle:/var/tmp# newfs /dev/md1
/dev/md1: 4.0MB (8192 sectors) block size 16384, fragment size 2048
	using 4 cylinder groups of 1.02MB, 65 blks, 192 inodes.
super-block backups (for fsck -b #) at:
 160, 2240, 4320, 6400
root at woozle:/var/tmp# mkdir -m 700 mnt
root at woozle:/var/tmp# ls -la mnt
total 4
drwx------  2 root  wheel  512 Feb 19 16:00 .
drwxrwxrwt  8 root  wheel  512 Feb 19 16:00 ..
root at woozle:/var/tmp#  mount /dev/md1 mnt
root at woozle:/var/tmp# ls -la mnt
total 6
drwxr-xr-x  3 root  wheel     512 Feb 19 16:00 .
drwxrwxrwt  8 root  wheel     512 Feb 19 16:00 ..
drwxrwxr-x  2 root  operator  512 Feb 19 16:00 .snap
root at woozle:/var/tmp# echo '/bin/sh -c "ls -la /var/tmp"' | su -m nobody
total 54560
drwxrwxrwt   8 root   wheel       512 Feb 19 16:00 .
drwxr-xr-x  26 root   wheel       512 Feb 16 12:59 ..
drwxrwxr-x   2 marck  wheel       512 Feb  7 16:21 cd
drwx------   3 marck  wheel       512 Feb 14 16:20 gconfd-marck
-rw-r--r--   1 root   wheel   4194304 Feb 19 16:00 image1.img
-rw-r--r--   1 root   wheel  51579766 Jan 31 18:50 jdk-1.5.0p2_3.tbz
drwxr-xr-x   3 root   wheel       512 Feb 19 16:00 mnt
drwx------   2 marck  wheel       512 Feb 14 22:17 orbit-marck
drwxrwxrwt   5 root   wheel       512 Jan 26 14:17 texfonts
drwxrwxrwt   2 root   wheel       512 Jan 31 16:17 vi.recover
root at woozle:/var/tmp# echo '/bin/sh -c "ls -la /var/tmp/mnt/"' |  su -m nobody
ls: ..: Permission denied
total 4
drwxr-xr-x  3 root  wheel     512 Feb 19 16:00 .
drwxrwxr-x  2 root  operator  512 Feb 19 16:00 .snap
root at woozle:/var/tmp# exit
exit

Script done on Sun Feb 19 16:00:47 2006