[debian] initrd (cramfs) + ssh server

[Jozsef Steger <steger@complex.elte.hu>]

Hi,

I am not a member of this list. I searched the archives in vain, though I
have a chellenging problem to solve. Hopefully, the task is already solved
by someone, in this case I would welcome a site where the solution can be
read about. Otherwise I would appreciate any other ideas.

I would like to make my computer able to start an ssh server from initrd.
The main idea is that during bootup from initrd the partition comtaining
the system is checked. If the fs is found inconsistent (e2fsck fails) ssh
server is started, to give a means of maintainance from remote.

I am using linux kernel version 2.4.26-386-1 for the test. Network is
configured well, the machine can be pinged from remote. But when it comes
to starting sshd it tells ---> Privilege separation user sshd does not
exist though in /etc/passwd sshd is already added.

For the creation of initrd image initrd-tools were used. mkinitrd was
modified. Some useful binaries and scripts were added and symlinks were
created to files that cannot be readonly (Eg. /var/run/sshd.pid).

My linuxrc contains:
-----------------------------------------------------------------------
#!/bin/sh
export PATH=/sbin:/bin

mount -nt proc proc proc
root=$(cat proc/sys/kernel/real-root-dev)
mount -nt devfs devfs /devfs
for module in ide-core ide-disk piix ide-detect ext3 jbd; do
 modprobe $module
done

ERROR=0
for part in part1 part3; do
 e2fsck -p /dev/ide/host2/bus0/target0/lun0/$part || ERROR=1
done

if [ $ERROR -eq 1 ]; then
 mount -nt tmpfs tmpfs /tmp
 touch /tmp/syslogd.pid
 touch /tmp/syslog
 /etc/sysklogd start

 modprobe e1000
 mount -nt devpts devpts /dev/pts
 echo myhostname > /proc/sys/kernel/hostname
 touch /tmp/ifstate
 mkdir /tmp/if-up.d /tmp/if-down.d /tmp/if-post-down.d /tmp/if-pre-up.d
 /etc/network/networking start
 touch /tmp/inetd.pid
 /etc/inetd start
 mkdir /tmp/sshd
 touch /tmp/sshd.pid
 cp -a /etc/passwd.ro /tmp/passwd
 cp -a /etc/shadow.ro /tmp/shadow
 cp -a /etc/group.ro /tmp/group
 cp -a /etc/gshadow.ro /tmp/gshadow
 /etc/ssh/ssh start
 # just to get stopped
 /bin/sh
 for k in sshd syslogd inetd; do
  /usr/bin/killall $k
 done
 umount -n /devfs
 umount -n /dev/pts
 umount -n /tmp
 echo 256 > proc/sys/kernel/real-root-dev
 mount -nt tmpfs tmpfs bin || mount -nt ramfs ramfs bin
 echo $root > bin/root
else
 umount -n /devfs
 echo 256 > proc/sys/kernel/real-root-dev
 mount -nt tmpfs tmpfs bin || mount -nt ramfs ramfs bin
 echo 8451 > bin/root
fi
-----------------------------------------------------------------------

Thank you for your kind help in advance.

Cheers,
  Jozsi