Automount file permissions

[cefn]

I have found myself in a situation where I am not permitted to read automounted filesystems and I can't fathom why. I recently changed the uid and gid of my user account (username=cefn) from 1001:1001 to 1000:1000 which might be related, but since then I have also run the following to change all files which were previously owned by 1001 to be swapped to 1000...

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sudo find / -user 1001 -exec chown -h cefn {} \;
sudo find / -group 1001 -exec chgrp -h cefn {} \;

For example in PCManFM there is a partition mounted from an SD Card named 'fat32', but clicking on it triggers a dialog

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The specified directory '/media/cefn/fat32' is not valid

or if I try to ls it...

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ls -la /media/cefn/fat32/
ls: cannot access '/media/cefn/fat32/': Permission denied
cefn@cefn-xenial-toshiba:~$ ls -la /media/cefn/fat32/Sky
ls: cannot access '/media/cefn/fat32/Sky': Permission denied

But the filesystems seem to have the right sort of visibility if I run with sudo...

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sudo ls -la /media/cefn/
total 24
drwxr-x---+ 5 root root 4096 Jan  1 13:29 .
drwxr-xr-x  4 root root 4096 Jan  1 11:58 ..
drwxr-xr-x  9 root root 4096 Dec 31 17:28 96e93dc8-b388-482e-bab1-1ac4a7ce35e4
drwxr-xr-x  4 cefn cefn 8192 Jan  1  1970 fat32
drwxr-xr-x  3 root root 4096 Dec 30 00:35 lubuntu-root

Any thoughts how I can get back to a normal situation where I can read automounted filesystems again? Where is the failure happening?

[drooly]

well it sounds like you messed up your permissions pretty well.
every command that starts with sudo and contains '/' should be treated with the utmost respect.
and should be executed only when 100% sure what it does.

so much from mr hindsight.

save your data (i guess you canstill access it with root privileges?) and reinstall.

[cefn]

Turned out to be fixed after launching a 'repair' session from Grub, choosing a root shell and removing the /media/cefn directory (and whatever broken cruft and permissions were there).

After re-logging in as cefn the /media/cefn folder was re-created and no longer broken. The weird thing was being unable to identify what was different with the new one. It now looks like the below which looks entirely identical...

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sudo ls -la /media/cefn/
total 24
drwxr-x---+ 5 root root 4096 Jan  2 01:54 .
drwxr-xr-x  4 root root 4096 Jan  1 14:09 ..
drwxr-xr-x  9 root root 4096 Dec 31 17:28 96e93dc8-b388-482e-bab1-1ac4a7ce35e4
drwxr-xr-x  4 cefn cefn 8192 Jan  1  1970 fat32
drwxr-xr-x  3 root root 4096 Dec 30 00:35 lubuntu-root