Re: [Moosefs-users] Question about mounting suid,dev

[Michał B. <mic...@co...>]

Hi Ricardo!

As we can see the problem lies between fuse (mount.fuse) and plain mount
command:

# strace -f -s512 -e trace=execve mount -t fuse mfsmount /mnt/mfs -o #
mfsmaster=mfsmaster,ro,suid,nodev,[...]
execve("/bin/mount", ["mount", "-t", "fuse", "mfsmount", "/mnt/mfs", "-o",
"mfsmaster=mfsmaster,ro,suid,nodev,[...]"], [/* 12 vars */]) = 0 [pid  2218]
execve("/sbin/mount.fuse", ["/sbin/mount.fuse", "mfsmount", "/mnt/mfs",
"-o", "ro,nodev,mfsmaster=mfsmaster,[...]"], [/* 8 vars */]) = 0 [pid  2218]
execve("/bin/sh", ["/bin/sh", "-c", "'mfsmount' '/mnt/mfs' '-o'
'ro,nodev,mfsmaster=mfsmaster,[...]'"], [/* 9 vars */]) = 0 [pid  2218]
execve("/usr/bin/mfsmount", ["mfsmount", "/mnt/mfs", "-o",
"ro,nodev,mfsmaster=mfsmaster,[...]"], [/* 8 vars */]) = 0


As you can see mount strips "suid" option from flag before calling
mount.fuse (assuming that it's the default).
But it's not the default for mount.fuse.

I think it should be reported both to fuse and util-linux projects (the
latter maintains the mount utility) and let them cooperate.
Probably the best solution would be to always pass user-specified "suid" and
"dev" flags to mount.XXX (on mount side).


Kind regards
Michal


-----Original Message-----
From: Ricardo J. Barberis [mailto:ric...@da...] 
Sent: Friday, April 13, 2012 10:36 PM
To: moo...@li...
Subject: [Moosefs-users] Question about mounting suid,dev

Hello, list.

I need to mount a filesystem with suid enabled and found I can't do it from
fstab: mo matter what options I set there, the mount always uses
nosuid,nodev which are fuse's default.

This is in my /etc/fstab:

mfsmount  /opt  fuse
defaults,noatime,suid,nodev,_netdev,mfsmaster=master,mfssubfolder=/  0 0

And this is in /proc/mounts:

mfs#master:9421 /opt fuse
rw,nosuid,nodev,noatime,user_id=0,group_id=0,default_permissions,allow_other
0 0

However, if I mount it with:

mfsmount -o noatime,suid,nodev /opt -H master -S /

I got this in /proc/mounts:

mfs#master:9421 /opt fuse
rw,nodev,noatime,user_id=0,group_id=0,default_permissions,allow_other 0 0

I have tried putting "suid" in /etc/mfs/mfsmount.cfg on the client but it
makes no difference when using fstab.

All this is with CentOS 5.8 64 bits servers and a CentOS 5.8 32 bits client
but it also happens in a CentOS 5.8 64 bits client, all of them running
mfs-1.6.24 installed from RepoForge RPMs and fuse 2.7.4 from standard CentOS
repositories.


According to fuse's README:

"Filesystems are mounted with '-onodev,nosuid' by default, which can only be
overridden by a privileged user."

But I'm mounting MFS as root from command line.

Is this a bug in MFS? fuse? me?

Thank you,
--
Ricardo J. Barberis
Senior SysAdmin / ITI
Dattatec.com :: Soluciones de Web Hosting Tu Hosting hecho Simple!

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