Re: [Jailkit-users] How to fix jailkit problems with /dev/null in FreeBSD

[Olivier Sessink]

On 05/29/2012 04:33 PM, Jordi Moles Blanco wrote:

> 3. You copy /dev/null in the jail "the FreeBSD way", that is,
> 
> cp /dev/null /jailkitpath/dev/null

I know little about FreeBSD, but on Linux you cannot copy devices with
cp. You have to create a device with mknod.

> Well... although this /dev/null thing allows you to run some binaries,
> it fails when for example you want to use git. The reason is because it
> needs /dev/urandom and that doesn't exist in FreeBSD. Actually, we do
> have /dev/urandom
> 
> but...
> 
> # ls -la /dev/urandom
> lrwxr-xr-x  1 root  wheel  6 Nov  3  2011 /dev/urandom -> random
> 
> it's a mere link...
> 
> which causes problems because
> 
> /dev/random doesn't work the same way as /dev/urandom
> 
> in order to fix this...
> 
> we have to literally copy /dev/random into the jail, again with "cp" and
> not "jk_cp"
> 
> cp /dev/random /jailkitpath/dev/urandom
> cp /dev/random /jailkitpath/dev/random
> actually, you have to run these commands and then "ctrl+c", that is,
> cancel the commands, after a second or two. If you don't do that, the
> "cp" command will continue to create random numbers and store them in
> the /jailkitpath/dev/random file.

again, use mknod and not cp them. Copy them will indeed copy the
contents, and not create a device.

Olivier

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