external mount utilities and utab

external mount utilities and utab

[Phillip Susi]

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When mount runs mount.cifs, /run/mount/utab is not updated, so the
user mount flag is lost and thus, I can't umount as the user.  Running
mount -i works correctly.  Is this a bug in mount.cifs, or should
mount be recording these options whether it runs the external helper
or not?
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Re: external mount utilities and utab

[Karel Zak]

On Fri, Nov 01, 2013 at 03:21:13PM -0400, Phillip Susi wrote:
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> 
> When mount runs mount.cifs, /run/mount/utab is not updated, so the
> user mount flag is lost and thus, I can't umount as the user.  Running
> mount -i works correctly.  Is this a bug in mount.cifs, or should
> mount be recording these options whether it runs the external helper
> or not?

 This problem is fixed in mount.nfs where we use libmount. The question 
 is if really need to link all the helpers with libmount. I'll try to
 play with that and prepare a solution.

    Karel


-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: external mount utilities and utab

[Karel Zak]

On Fri, Nov 01, 2013 at 03:21:13PM -0400, Phillip Susi wrote:
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> Hash: SHA1
> 
> When mount runs mount.cifs, /run/mount/utab is not updated, so the
> user mount flag is lost and thus, I can't umount as the user.  Running
> mount -i works correctly.  Is this a bug in mount.cifs, or should
> mount be recording these options whether it runs the external helper
> or not?

 Fixed, so if you have suid mount.cifs then you can use "user" mount
 option and libmount will (after successful external helper) update
 /run/mount/utab.

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: external mount utilities and utab

[Karel Zak]

On Fri, Nov 01, 2013 at 03:21:13PM -0400, Phillip Susi wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> When mount runs mount.cifs, /run/mount/utab is not updated, so the
> user mount flag is lost and thus, I can't umount as the user.  Running
> mount -i works correctly.  Is this a bug in mount.cifs, or should
> mount be recording these options whether it runs the external helper
> or not?

 ah.. note, that mount.cifs is not suid on Fedora, only suid mount
 helper is mount.nfs on my machine.

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: external mount utilities and utab

[Phillip Susi]

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Are you saying then that all of the helpers should now be using
libmount, and taking care of the utab updates themselves rather than
just having mount do it?

On 11/4/2013 8:37 AM, Karel Zak wrote:
> On Fri, Nov 01, 2013 at 03:21:13PM -0400, Phillip Susi wrote:
>> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
>> 
>> When mount runs mount.cifs, /run/mount/utab is not updated, so
>> the user mount flag is lost and thus, I can't umount as the user.
>> Running mount -i works correctly.  Is this a bug in mount.cifs,
>> or should mount be recording these options whether it runs the
>> external helper or not?
> 
> ah.. note, that mount.cifs is not suid on Fedora, only suid mount 
> helper is mount.nfs on my machine.
> 
> Karel
> 

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Re: external mount utilities and utab

[Karel Zak]

On Mon, Nov 04, 2013 at 09:07:08AM -0500, Phillip Susi wrote:
> Are you saying then that all of the helpers should now be using
> libmount, and taking care of the utab updates themselves rather than
> just having mount do it?

 That would be the best solution (and not only for utab, but also for
 options parsing, userspace options, command line options used for
 helpers, etc.). It's better to have all the things in one library.

 Anyway, the change I did today allows to use "user" fstab mount
 option also for non-libmount external helper.

 It's already in my TODO list to write libmount patch for mount.cifs.


    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: external mount utilities and utab

[Phillip Susi]

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On 11/4/2013 9:07 AM, Phillip Susi wrote:
> Are you saying then that all of the helpers should now be using 
> libmount, and taking care of the utab updates themselves rather
> than just having mount do it?

ping... still wondering if the proper fix for this is to link
mount.cifs with libmount and make it suid, or if mount needs fixed to
do the utab update?

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Re: external mount utilities and utab

[Karel Zak]

On Wed, Nov 13, 2013 at 01:28:28PM -0500, Phillip Susi wrote:
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> 
> On 11/4/2013 9:07 AM, Phillip Susi wrote:
> > Are you saying then that all of the helpers should now be using 
> > libmount, and taking care of the utab updates themselves rather
> > than just having mount do it?
> 
> ping... still wondering if the proper fix for this is to link
> mount.cifs with libmount and make it suid, or if mount needs fixed to
> do the utab update?

I have improved libmount (in git tree) and now it updates utab for the
helpers. 

Anyway if your mount.cifs is not suid then user= does not make sense
and you also don't have to care about utab at all. For example on
Fedora we don't have suid mount.cifs for years.

IMHO it's better to minimize number of suid binaries. I guess that 
the user= functionality has been introduced to mount regular
filesystems (ext2, ...) from removable devices.

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com

Re: external mount utilities and utab

[Phillip Susi]

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On 11/14/2013 3:39 AM, Karel Zak wrote:
> I have improved libmount (in git tree) and now it updates utab for
> the helpers.

But does that mean that the helper has to use libmount?


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Re: external mount utilities and utab

[Karel Zak]

On Thu, Nov 14, 2013 at 11:17:49AM -0500, Phillip Susi wrote:
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> 
> On 11/14/2013 3:39 AM, Karel Zak wrote:
> > I have improved libmount (in git tree) and now it updates utab for
> > the helpers.
> 
> But does that mean that the helper has to use libmount?

No, after successful helper execution (helper has to return 0) the
library checks utab and update the file if there is user= mount option
and the mountpoint is not in the file.

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com