Mount USB drive with write permissions for everyone or specific user

  • I know there are similar questions but I get some specific problem I can't overcome.

    I have:

    • HDD split into two partitions. /dev/sdb1 and /dev/sdb2. sdb1 is NTFS and I don't need it. I need sdb2 which is fat32.
    • Ubuntu 12.04.1 LTS (server)

    I want:

    Ultimately I need a perma-mount /dev/sdb2 to /home/storage with access right (rw) for the user media.

    Problems I'm facing:

    1) Using manual mount from command line.

    If I just use

    server# sudo mount /dev/sdb2 /home/storage
    

    It mounts but the /home/storage receives root as owner and group and doesn't allow media user to write there.

    If i use mount command without sudo as the user media - i'm not allowed. Says only root can use mount.

    If I use mount with options: server# sudo mount /dev/sdb2 /home/storage -o umask=000 I get what I need. A bit overdone of course, since the storage folder becomes writable for everyone. BUT - that is manually mounted - now i need it to remount on every reboot.

    2) Remounting on reboot - using fstab

    So I thought I'll be fine if I use fstab to mount this partition (/dev/sdb2) every time i reboot. The fstab line I added:

    UUID=8C52-C1CD /home/storage auto user,umask=000,utf8,noauto 0 0

    got uuid with blkid. The fs type auto i changed few times...tried vfat too, but always on the reboot ubuntu stops when processing fstab (as i think) with the message (took from the log):

    fsck from util-linux 2.20.1 /dev/sda5: clean, 120559/10969088 files, 19960144/43861504 blocks mount: unknown filesystem type 'static' mountall: mount /etc/fstab: [772] terminated with status 32 mountall: Filesystem could not be mounted: /etc/fstab: Skipping /etc/fstab: at user request

    And also - sudo mount -a never really does anything.

    What am I doing wrong? I do suspect I messed up something:)

    UPDATE:

    As it seems - fstab should hold only mounts for static drives, not any sort of usb stuff. I'm puzzled how then this works with all the people posting on the net their success stories...

    however..if this is not possible - i would like to know how to remount my usb after every reboot...if not with fstab - than how?:)

    I think you should post all of fstab for review, and not just one line. As for the right permissions, run `id media` and use `uid=` and `gid=` and `umask=027`options.

    Is there some reason you need to use FAT ? If not, I would back up the data and use a linux native file system. You can then set ownership and permissions.

    @mikewhatever thanks but it's working strangely actually... well..not really:)

    @bodhi.zazen did more reading... seams like on ubuntu 12 fstab should have only mounts for static drives. not any usb...

  • CacheXT

    CacheXT Correct answer

    7 years ago

    Your problem seems to be about the permissions you have set. FAT / FAT32 formatted drives don't support file permissions. The permissions for everything are determined by how the drive is mounted. When you set the permission open it worked when you

    server# sudo mount /dev/sdb2 /home/storage -o umask=000
    

    As for it not auto mounting on reboot

    UUID=8C52-C1CD /home/storage auto user,umask=000,utf8, -->noauto<-- 0 0
    

    The "noauto" makes this NOT automatically mount when the system starts and parses the /etc/fstab file. Remove that option and it will mount on startup. You can set the permissions on the mount point once it's mounted with chmod or specify them in /etc/fstab.

    If you need the media user to access it, you can set the permissions to 764, and add them to the security group. Root always has access to everything.

    see http://www.linux.org/threads/file-permissions-chmod.4094/ for some examples of propper file permissions

    On a side note, bodhi.zazen made a good point Is there some reason you need to use FAT ? If not, I would back up the data and use a linux native file system. You can then set ownership and permissions.

    `-o umask=000` is it!! Thank you!

  • You can also run

    sudo chmod 0777 /home/storage
    

    Since FAT drives don't have permissions, linux applies the permission of the mount point to the entire drive.

    Never apply R+W+X permissions for every user.. This would allow anyone or anything to access,execute,delete,modify storage and its contents....

    On most operating systems, USB drives are mounted so any user can modify the contents. If you are a server admin in a situation where this could be an issue, I wouldn't have to tell you what 0777 means.

    Drives are never mounted by default to allow all users, This is why they have groups and permissions. Either way its always safer to show a better security mod as people will simply copy and paste without knowing better

  • Unless overridden by mount options GID= or UID= the owner and permissions of the mount point upon mounting become those of the filesystem tree being mounted.

    So if /dev/sdb1 contains an ext4 filesystem (say a backup) owned by user then user will become the owner of the mount point upon successful mount.

    Starting off we have an empty folder 'backup' to serve as the mount point, and is owned by root.

    # ls -alR /mnt
    /mnt/:
    drwxr-x---  5 root root 4096 May 30 20:59 ./
    drwxr-xr-x  3 root root 4096 Dec  5  2015 ../
    drwx------  2 root root 4096 Jan  1 07:45 backup/
    
    /mnt/backup:
    drwx------  2 root root 4096 Jan  1 07:45 .
    drwxr-x---  5 root root 4096 May 30 20:59 ..
    

    now we mount /dev/sdb1 (read-only)

    # mount -o ro /dev/sdb1 /mnt/backup
    

    and lets see...

    # ls -alR
    /mnt/:
    drwxr-x---  5 root root 4096 May 30 20:59 ./
    drwxr-xr-x  3 root root 4096 Dec  5  2015 ../
    drwx------  2 user user 4096 Jan  1 07:45 backup/
    
    /mnt/backup:
    drwx------  2 user user 4096 Jan  1 07:45 .
    drwxr-x---  5 root root 4096 May 30 20:59 ..
    -rw-------  1 user user 252076021760 Jun  9 21:11 backup.tar
    

    Now if you've got an empty drive and you want to mount it for 'user' as an extension of 'user's disk space, mount the drive as root, chown the root of the mount to 'user' and unmount.

    The next time the filesystem is mounted (by root or anyone as per fstab) the owner of the mount will be 'user'.

  • If you do have external storage device connected to your Linux box with NTFS, make sure that the filesystem is clean.

    Before you mount the storage to your Linux box:

    1. Run the below command

      ntfsfix /dev/storagedevice ( like sdb1 or sdc1 )  
      
    2. Reboot your Linux box

    3. Mount the external storage by running the command:

      mount -o rw /dev/storagedevice /media/ 
      

      or

      mount -o rw /dev/storagedevice /mnt/ 
      

      or mount the storagedevice via GUI.

    What is your reasoning behind each of these steps?

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Content dated before 6/26/2020 9:53 AM