Why doesn't sudo -E keep my $HOME environment variable?

Question

On my Red Hat machine, when I run the command echo $HOME with my normal user account, I get /home/snrub. When I run the command sudo vim foo.txt and inside vim I type echo $HOME I get /root returned. I want it to return /home/snrub instead so that it will parse my cool Vim plugins, even when I'm editing a file with sudo. According to the sudo manpage, the -E or -H options should work, but if I run sudo -E vim foo.txt or sudo -H vim foo.txt or sudo -EH vim foo.txt they all still don't parse my home .vimrc file and return /root when I type echo $HOME.

I have also tried adding the following line to the sudoers file, and saving:

Defaults   env_keep += "HOME"

Still not working. If I run sudo vim foo.txt and then inside Vim type echo $HOME it still says /root. Similarly (and to verify that this is not strictly an issue with Vim), if I type sudo emacs foo.txt and press Enter, then type Alt-X, type getenv and press Enter, then type HOME and press Enter, it will still return /root. How do I make it return /home/snrub?

Answer 1

As a security precaution, sudo resets a list of environment variables (TERM, PATH, HOME, MAIL, SHELL, LOGNAME, USER, USERNAME and SUDO_*) under the env_reset option, which is enabled by default. In order for HOME to carry over from your user account to a sudo environment, you would have to either:

• use the SETENV tag on the sudo rule along with the -E option, or

• specifically unset the env_reset option.

Additionally ensure that always_set_home is off (which it is by default).

See the sudoers man page for all the details and interactions.