Re: siteXX.tgz with /home/user/.ssh/authorized_keys results in empty file

From: Theo Buehler <theo@math.ethz.ch>
Cc:
Bcc:
Subject: Fwd: siteXX.tgz with /home/user/.ssh/authorized_keys results in empty
file
Reply-To:
In-Reply-To: <f34cb3c3904e4804e52555201c297f97.squirrel@mail.kagu-tsuchi.com>

On Mon, May 29, 2017 at 07:16:06PM -0400, trondd wrote:
> On Mon, May 29, 2017 5:47 pm, Erling Westenvik wrote:
> > What is going on? Why is the process extracting siteXX.tgz
> > treating /mnt/home/user/.ssh different than /mnt/root/.ssh?

[...]

> My guess is this is an install. The installer seems to unpack the sets
> first. Including the site taball. Then, if you created a new user,
> copies the /etc/skel/ files over, overwriting your authorized_keys file.
> You'll need to use install.site or /etc/rc.firsttime
>
> Root is different because root's files are part of the distribution sets.

Populating the $ADMIN's $_home with some files from siteXX.tgz looks
like a legitimate use case to me, especially for authorized_keys, but
also for the dotfiles in /etc/skel.

How about not overwriting already existing files?

Index: install.sub
===================================================================
RCS file: /var/cvs/src/distrib/miniroot/install.sub,v
retrieving revision 1.1011
diff -u -p -r1.1011 install.sub
--- install.sub 28 May 2017 09:24:56 -0000 1.1011
+++ install.sub 30 May 2017 00:18:16 -0000
@@ -2919,7 +2919,7 @@ do_install(){

_home=/mnt$_home
mkdir -p $_home
- (cd /mnt/etc/skel; cp -pR . $_home)
+ (cd /mnt/etc/skel; pax -rw -k -pe . $_home)
(umask 077 && sed "s,^To: root\$,To: ${ADMIN_NAME} <${ADMIN}>," \
/mnt/var/mail/root >/mnt/var/mail/$ADMIN )
chown -R 1000:1000 $_home /mnt/var/mail/$ADMIN