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On Wednesday, 1 May 2019 03:32:21 BST Bill Kenworthy wrote: |
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> Got sidetracked - turns out fuse and exfat on usb do not play well with |
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> mounts as a user due to changes late last year. It can now only be |
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> mounted/unmounted by root. |
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> |
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> The second part (also due to fuse) is that to stop fuse (silently as ls |
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> still showed the execute bit set) from interfering with execution of |
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> files on the mounted device) it must be mounted as the user under a user |
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> owned directory such as /home/user (mount cannot deal with this - it did |
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> in the past, but something has changed). So the solution is to mount |
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> via root as the user you want (via sudo) under a mount point in the |
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> users home. This may all be unique to fuse-exfat, and which versions of |
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> everything involved as I saw one email on the mechanics of the changes |
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> saying fat is handled a little differently due to a different use |
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> scenario. And ext2/3/4 etc don't have the problem at all. Auto-mount |
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> on device plugin still doesn't happen so thats next on my list. |
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> |
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> /etc/fstab: |
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> |
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> /dev/sda1 /home/myuser/mnt auto |
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> rw,auto,exec,uid=1000,gid=1000,users,user=myuser 0 0 |
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> |
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> |
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> BillK |
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|
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exFAT and VFAT are mounted with different permissions by udisks, without |
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overriding options in fstab or command line. |
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|
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A random file in exFAT: |
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|
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$ stat /run/media/michael/VERBATIM32G/blah |
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File: /run/media/michael/VERBATIM32G/blah |
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Size: 32768 Blocks: 64 IO Block: 4096 regular file |
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Device: 811h/2065d Inode: 19 Links: 1 |
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Access: (0777/-rwxrwxrwx) Uid: ( 1000/ michael) Gid: ( 1002/ michael) |
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Access: 2018-06-08 11:20:50.000000000 +0100 |
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Modify: 2015-08-24 12:50:56.000000000 +0100 |
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Change: 2015-08-24 12:50:56.000000000 +0100 |
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Birth: - |
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|
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A random file in FAT: |
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|
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$ stat /run/media/michael/CRUCIAL-8G/blah |
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File: /run/media/michael/CRUCIAL-8G/blah |
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Size: 1731366 Blocks: 3384 IO Block: 4096 regular file |
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Device: 810h/2064d Inode: 124 Links: 1 |
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Access: (0644/-rw-r--r--) Uid: ( 1000/ michael) Gid: ( 1002/ michael) |
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Access: 2019-04-08 01:00:00.000000000 +0100 |
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Modify: 2007-08-25 22:46:42.000000000 +0100 |
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Change: 2019-04-08 14:04:54.000000000 +0100 |
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Birth: - |
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|
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Ditto for directories. |
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|
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exFAT: |
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|
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$ stat /run/media/michael/VERBATIM32G/Foo |
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File: /run/media/michael/VERBATIM32G/Foo |
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Size: 32768 Blocks: 64 IO Block: 4096 directory |
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Device: 811h/2065d Inode: 24 Links: 1 |
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Access: (0777/drwxrwxrwx) Uid: ( 1000/ michael) Gid: ( 1002/ michael) |
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Access: 2018-02-11 17:22:52.000000000 +0000 |
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Modify: 2018-02-11 17:22:54.000000000 +0000 |
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Change: 2018-02-11 17:22:54.000000000 +0000 |
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Birth: - |
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|
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|
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FAT: |
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|
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$ stat /run/media/michael/CRUCIAL-8G/Foo |
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File: /run/media/michael/CRUCIAL-8G/Foo |
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Size: 4096 Blocks: 8 IO Block: 4096 directory |
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Device: 810h/2064d Inode: 79 Links: 2 |
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Access: (0755/drwxr-xr-x) Uid: ( 1000/ michael) Gid: ( 1002/ michael) |
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Access: 2019-04-08 01:00:00.000000000 +0100 |
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Modify: 2019-04-08 14:43:26.000000000 +0100 |
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Change: 2019-04-08 14:43:26.000000000 +0100 |
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Birth: - |
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|
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The mount options are different as shown below. |
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|
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exFAT: |
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|
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$ findmnt -oOPTIONS /dev/sdb1 |
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OPTIONS |
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rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other, |
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blksize=4096 |
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|
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FAT: |
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|
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$ findmnt -oOPTIONS /dev/sdb |
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OPTIONS |
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rw,nosuid,nodev,relatime,uid=1000,gid=1002,fmask=0022,dmask=0022,codepage=437, |
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iocharset=iso8859-1,shortname=mixed,showexec,utf8,flush,errors=remount-ro |
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|
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|
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In the above examples I used udisksctl to mount the devices. I understand |
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Gnome expose via Gvfs an API to handle I/O to block devices, which desktop |
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applications can plug into without performing raw kernel calls to hardware |
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devices (like e.g. /bin/mount does). I don't run Gnome and am not familiar |
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with its internals to know how similar it is with udisksctl. |
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|
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Regarding mounting with udisksctl I don't know why exFAT and VFAT are |
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different, but the udisksctl man page provides this revealing information on |
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the mount permissions allowed: |
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|
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The device will be mounted with a safe set of default options. You |
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can influence the options passed to the mount(8) command with |
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--options. Note that only safe options are allowed - requests with |
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inherently unsafe options such as suid or dev that would allow the |
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caller to gain additional privileges, are rejected. |
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|
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HTH. |
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-- |
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Regards, |
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Mick |
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