Is writing to /dev/ramdom a security flaw (vserver project)

Jacques Gelinas (jack@solucorp.qc.ca)
Fri, 19 Oct 2001 17:23:09 -0500


I have announced a project (see my signature) to run several virtual servers
on a single box (single kernel as well). The vservers are real linux distribution
running in a chroot/chbind/chcontext and capability limited environment.

While looking at the kernel we found out that writing to /dev/random is
not controlled by any capability. We are providing a /dev/random in
the vservers with permission 644, so it can be used.

Is this a security issue if an administrator of a vserver is allowed to write
in /dev/random ?

Looking at the source, it seems that it just increase the entropy and should
not be an issue. I am no expert in randomness.

If this is an issue, then a capability must exist to limit that (CAP_SYS_ADMIN
I guess).

Thanks!

---------------------------------------------------------
Jacques Gelinas <jack@solucorp.qc.ca>
vserver: run general purpose virtual servers on one box, full speed!
http://www.solucorp.qc.ca/miscprj/s_context.hc
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