Sloppy workaround for unreported bug: floppy mounts with root owner

[John Hupp]

On 4/18/2015 8:24 PM, Israel wrote:
> On 04/18/2015 06:10 PM, John Hupp wrote:
>> I installed Lubuntu 14.04 for someone who had an XP-era PC.  He also 
>> has a really, really old offline PC that he uses for a few familiar 
>> programs, and wants to ferry some files back and forth between the 
>> two PC's using floppies.
>>
>> This should be no problem, except that the floppy mounts in Lubuntu 
>> with root ownership, and only root can change content, so ordinary 
>> users cannot copy files to or edit files on a floppy.
>>
>> Someone somewhere (!) reported that the behavior could be duplicated 
>> in a virtual machine with no actual floppy drive.
>>
>> Design behavior should be that the floppy mounts with the logged-in 
>> user as owner, which is what happens with USB flash drives.
>>
>> As far as I can tell, this is a new instance of a regression in the 
>> kernel and/or udisks2 that has previously been reported and fixed.
>>
>> See for instance:
>> udisks2 mounts floppy disk as root 
>> <http://bugs.freedesktop.org/show_bug.cgi?id=63849>
>> Bug fix released <http://lkml.org/lkml/2014/5/28/297>
>> udisks2: mounts floppy always for root:root (not writable for normal 
>> users) <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=740190>
>>
>> I couldn't figure out how to get floppies to mount with the logged-in 
>> user as owner, but I do have a sloppy workaround that sets a 
>> permission to allows anyone to change content on the floppy.  This 
>> was inspired by comment #11 at Floppies mount fine, but can't seem to 
>> edit them in Xubuntu 14.04 
>> <http://ubuntuforums.org/showthread.php?t=2222487&page=2>.
>>
>> The sloppy workaround in my case is to add this line to /etc/fstab:
>> /dev/fd0 /media/user1/disk vfat 
>> rw,nosuid,nodev,uhelper=udisks2,user,noauto,umask=0 0 0
>>
>> This will work fine in a one-user installation, but it fails in a 
>> multi-user installation.  With user2 as the logged in user, clicking 
>> on Floppy Disk in pcmanfm to mount it causes the error:
>>     The specified directory '/media/user1/disk' is not valid.
>>
>> I would be happy to hear about it if someone can come up with an 
>> improved workaround!
>>
> Hi
> It should be possible to run:
>
> sudo umount /path/to/floppy
> sudo mkdir /media/floppy
>
> fd0 was taken from your e-mail... it may be different on other systems..
> sudo mount -o users /dev/fd0 /media/floppy
>

Thanks to Israel and Andre for the ideas.

The best solutions would probably involve chown as Andre suggested in 
his first reply, and if I knew how, an upstart job that runs when 
/dev/fd0 is mounted.  This could be made to align with expected 
behavior, such as one sees with a usb flash drive.

But taking the path of least resistance, I seized a piece of Israel's 
idea above, creating /media/floppy.  Then I set Change Content: Anyone 
permission for that.  And finally revised my addition to fstab thus:
/dev/fd0 /media/floppy vfat 
rw,nosuid,nodev,uhelper=udisks2,user,noauto,umask=0 0 0

This seems to work OK in multiple-user setups, so that is a better 
workaround.

As a footnote: The Filesystem Hierarchy Standard, if that is still 
current, says that /media/floppy should exist, but it does not here in a 
default installation.  See 
http://www.pathname.com/fhs/pub/fhs-2.3.html#MEDIAMOUNTPOINT
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