Have drwxrwxrwx permissions on folder, but after mounting to it it becomes drwxr-xr-x which disalows members of the group to write. How do I fix it?

Question

I have a folder under /mnt/ with drwxrwxrwx permissions and under root:root

I then mount a USB drive (exFAT) to this folder and it becomes drwxr-xr-x

The issue is that now I cannot scp to that folder via WinSCP since there is no permission for group to write to folder, and I am unable to scp as root user.

I am mounting the drive via fstab with the following:

/dev/sdb2       /mnt/USB    exfat   defaults,dmask=0000,umask=0000,rw       0       0

How do I either: 1) Give permission to group write or 2) Mount it as a non root user so that that user can write?

ive attempted chown and chmod to no avail. Chown even when run as root returns Operation not permitted

I am able to write to the mount as root user when in SSH (such as mkdir), so the mount is writable, but only by root.

Answer 1

ExFAT filesystems don't support Unix permissions. The Unix permissions are set at mount time.

The ownership/permissions of the mountpoint (/mnt/USB) has nothing to do with whatever gets mounted over it. It's just a placeholder in the file tree.

To fix it now, try:

sudo mount -o remount,umask=0,dmask=0,fmask=0,uid=$(id -u),gid=$(id -g) /dev/sdb2 /mnt/USB

Update your /etc/fstab entry to add the fmask=0 and uid= and gid= options. You'll have to hard-code your UID and GID, with the values from id -u;id -g.