The current libmount assumes that mount(8) and umount(8) are suid binaries. For this reason it implements internal rules which restrict what is allowed for non-root users. Unfortunately, it's out of reality for some use-cases where root permissions are no required. Nice example are fuse filesystems. So, the current situation is to call exit() always when mount, umount or libmount are unsure with non-root user rights. This patch removes the exit() call and replaces it with suid permissions drop, after that it continues as usually. It means after suid-drop all depend on kernel and no another security rule is used by libmount (simply because any rule is no more necessary). Example: old version: $ mount -t fuse.sshfs kzak@192.168.111.1:/home/kzak /home/kzak/mnt mount: only root can use "--types" option new version: $ mount -t fuse.sshfs kzak@192.168.111.1:/home/kzak /home/kzak/mnt kzak@192.168.111.1's password: $ findmnt /home/kzak/mnt TARGET SOURCE FSTYPE OPTIONS /home/kzak/mnt kzak@192.168.111.1:/home/kzak fuse.sshfs rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 $ umount /home/kzak/mnt $ echo $? 0 Note that fuse user umount is supported since v2.34 due to user_id= in kernel mount table. Signed-off-by: Karel Zak <kzak@redhat.com>