lkml.org 
[lkml]   [2000]   [Feb]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: Capabilities bounding set oddities ?
Hi,

On Tue, 1 Feb 2000 00:30:56 +0100 (MET), BIONDI Philippe
<Philippe.BIONDI@enst-bretagne.fr> said:

> Why removing CAP_SYS_RAWIO from the cap_bset prevent anyone from mapping a
> raw block device but doesn't protect it from reading or writing ?

I assume by "mapping" you mean "binding". The rationale is simple: you
may want to grant normal, unprivileged users access to certain raw
devices, using normal filesystem permissions to control that access just
as you would do for any other device. However, you certainly do _not_
want unprivileged users to be able to unbind or rebind a raw device to
which they have access, because that would be equivalent to letting them
open any arbitrary block device.

For example, it would be a privileged operation to bind /dev/raw2 to
/dev/fd0, but you might then make /dev/raw2 accessible to any user in
the group "fd". Opening /dev/raw2 should _not_ allow that user to
rebind it to /dev/sda and read the entire raw hard disk!

--Stephen

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:56    [W:0.059 / U:0.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site