On 01/12/2016 07:56, Douglas R. Reno wrote:
Pierre Labastie wrote:
On 01/12/2016 04:38, Douglas R. Reno wrote:

Upon trying to run the newaliases command in the Configuration Information page, I'll get the following error:

newaliases: cannot open /etc/mail/aliases: Group writable file

For context, these are the commands that I ran (similar to the book):

renodr [ /sources ]$ su
root [ /sources ]# echo $(hostname) > /etc/mail/local-host-names
root [ /sources ]# cat > /etc/mail/aliases << "EOF"
> postmaster: root
root [ /sources ]# newaliases
newaliases: cannot open /etc/mail/aliases: Group writable file
root [ /sources ]#

In order to fix this, I had to run something similar to:

root [ /sources ]# chmod -v 644 /etc/mail/aliases
mode of '/etc/mail/aliases' changed from 0664 (rw-rw-r--) to 0644 (rw-r--r--)
root [ /sources ]# newaliases
/etc/mail/aliases: 2 aliases, longest 4 bytes, 31 bytes total

I propose adding the "chmod -v 644 /etc/mail/aliases" command to the book.

I'd like to ask for comments / suggestions before I put it in there myself.

I guess it is an "umask" problem. Normally, if your bash startup files are set as in the book, umask should be 022 when you are root, and no additional instruction should be necessary. OTOH, maybe su does not run the bash startup files...

As far as I can see after tracing it for a little bit, I can't find a line in /root/.bashrc, /etc/profile, /etc/bashrc, or /root/.bash_profile that accomplishes that. However, we do execute it in /etc/profile.d/umask.sh.

When I am "su"ed to root, my umask is 0022. If I use my normal user, my umask is 0002.

root [ ~ ]# umask

renodr [ /sources ]$ umask

I just verified that all of my bash startup files are identical to the ones in the book.

If I use "su", my umask as root is the same as that of pierre (0002)
If I use "su -", umask is correctly set to 0022 (but of course the working directory is changed to /root)
what I use in my scripts is
sudo -E sh << ROOT_EOF
<root commands>
If I do that, umask is 0022, and CWD is not changed. I cannot understand what makes the difference with su (I do not use this command, that's why...)


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