In my previous post I followed documentation for VirtualBox to get USB working in my Virtual Machines (VM) and issued the following command: sudo usermod -G vboxusers mike. This command resulted in this error message when I subsequently tried to use the sudo command:
mike is not in the sudoers file. This incident will be reported.
I could no longer issue sudo commands – but all was not lost.
I decided to compare the user permissions on my now broken Linux Mint installation to the user permissions on my Ubuntu 11.10 VM that I had just installed (prior to running the command that broke things). I assumed that the settings between the two would be close enough – but given more time I probably have installed Linux Mint in a VM to make the comparison.
On broken Linux Mint system I issued the id username command:
id mike uid=1000(mike) gid=1000(mike) groups=1000(mike),125(vboxusers)
On my Ubuntu 11.10 VM I got a rather different result:
id mike uid=1000(mike) gid=1000(mike) groups=1000(mike),4(adm),20(dialout) ,24(cdrom),46(plugdev),116(lpadmin),118(admin),124(sambashare)
These permissions are contained in the file /etc/group and so I used the output from the Ubuntu VM as a guide to fixing permissions in /etc/group on Linux Mint. It should be noted that the Linux Mint and Ubuntu versions of /etc/group are not identical – so pay attention when editing this file.
To edit /etc/group I rebooted and selected the recovery mode option from the grub boot menu. I then chose the option to drop into a root prompt and supplied my user password as credentials.
I then edited /etc/group with nano and appended my username to the entries that I needed to correct.
sudo nano /etc/group
For example, I changed adm:x:4: to adm:x:4:mike. As you can see below the numerical sequence is not the same as for my Ubuntu VM but it is straight-forward enough to see which lines to append with your username.
#My amended /etc/group file on Linux Mint root:x:0: daemon:x:1: bin:x:2: sys:x:3: adm:x:4:mike tty:x:5: disk:x:6: lp:x:7: mail:x:8: news:x:9: uucp:x:10: man:x:12: proxy:x:13: kmem:x:15: dialout:x:20:mike fax:x:21: voice:x:22: cdrom:x:24:mike floppy:x:25: tape:x:26: sudo:x:27: audio:x:29:pulse dip:x:30: www-data:x:33: backup:x:34: operator:x:37: list:x:38: irc:x:39: src:x:40: gnats:x:41: shadow:x:42: utmp:x:43: video:x:44: sasl:x:45: plugdev:x:46:mike staff:x:50: games:x:60: users:x:100: nogroup:x:65534: libuuid:x:101: crontab:x:102: syslog:x:103: fuse:x:104: messagebus:x:105: mlocate:x:106: ssh:x:107: avahi-autoipd:x:108: avahi:x:109: netdev:x:110: bluetooth:x:111: lpadmin:x:112:mike ssl-cert:x:113: gdm:x:114: nopasswdlogin:x:115: pulse:x:116: pulse-access:x:117: utempter:x:118: rtkit:x:119: admin:x:120:mike saned:x:121: sambashare:x:122:mike mike:x:1000: couchdb:x:123: winbindd_priv:x:124: vboxusers:x:125:mike
All that was left to do was to reboot and the problem was fixed.