Subject: Re: sshd and read-only filesystem
To: Christos Zoulas <>
From: Emmanuel Dreyfus <>
List: tech-security
Date: 07/10/2001 23:34:20
> | But it is a pain to be unable to use sshd with a read-only filesystem.
> But having dev readonly does not really work, does it? What happens
> when you try to write to /dev/null?

It works. Having the fs read-only does not mean you cannot write to

root@violette[/root]#mount -o ro /dev/sd0a /
root@violette[/root]#dd if=/dev/zero of=/dev/null count=100
100+0 records in
100+0 records out
51200 bytes transferred in 1 secs (51200 bytes/sec)

What you can't do with /dev/null is set the immutable flag on it. That
way you won't be able to write to it.

Emmanuel Dreyfus.  
Avec Windows 3.1 ils etaient au bord du gouffre...
Avec Windows 95 ils ont fait un grand bon en avant.