Subject: Re: sshd and read-only filesystem
To: None <>
From: Christos Zoulas <>
List: tech-security
Date: 07/10/2001 21:53:52
In article <1ewcs1w.1a209xy1pz2xpiM@[]>,
Emmanuel Dreyfus <> wrote:
>> | 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.

Interesting... Writing to writable files on a readonly filesystem is
dissallowed. What happens to the mtime of the device?