sudo can't access /etc/sudoers

[m0sia]

I copied the whole system to the new SDD, but sudo doesn't work.

# lsb_release -a
LSB Version: core-2.0-amd64:core-2.0-noarch:core-3.0-amd64:core-3.0-noarch:core-3.1-amd64:core-3.1-noarch:core-3.2-amd64:core-3.2-noarch:core-4.0-amd64:core-4.0-noarch
Distributor ID: Ubuntu
Description: Ubuntu 12.04.1 LTS
Release: 12.04
Codename: precise

# ls -la /etc/sudoers
-r--r----- 1 root root 723 Jan 31 2012 /etc/sudoers

# ls -la /usr/bin/sudo
-rwsr-xr-x 2 root root 71288 Jun 1 09:53 /usr/bin/sudo

# sudo
sudo: unable to open /etc/sudoers: Permission denied
sudo: no valid sudoers sources found, quitting
sudo: unable to initialize policy plugin

Please find strace log in attachment.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[igor (ibs0d)]

confirmed? but in 13.10