lkml.org 
[lkml]   [2015]   [Mar]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] capabilities: Ambient capability set V2
    On Fri, Mar 06, 2015 at 11:02:43AM -0800, Andy Lutomirski wrote:
    > On Fri, Mar 6, 2015 at 10:53 AM, Christoph Lameter <cl@linux.com> wrote:
    > > On Fri, 6 Mar 2015, Serge E. Hallyn wrote:
    > >
    > >> Sorry, something about that patch-patch didn't make sense to me, but I
    > >> need to look more closely. My objection was that you were able to get the
    > >> pA capabilities into pP without them being in your pI. Your proposed
    > >> change didn't seem like it would fix that.
    > >
    > > Just tried to fix that. Could it be that cap_inherited is never set even
    > > for a binary that has
    > >
    > > christoph@fujitsu-haswell:~$ getcap ambient_test
    > >
    > > ambient_test = cap_setpcap,cap_net_admin,cap_net_raw,cap_sys_nice+eip
    >
    > I think that's right. fI doesn't set pI.

    Right. The idea is that for the running binary to get capability x in its
    pP, its privileged ancestor must have set x in pI, and the binary itself
    must be trusted with x in fI.

    What we are doing is allowing bypassing fI using pA, without bypassing the
    requirement for x to be in pI. Since pI is intended to be filled (for
    instance) at login based on username/group, pI generally does not get cleared.
    At the same time, any software which thinks it is running untrusted code
    safely without privilege by clearing pI and pP won't be fooled by pA.

    -serge


    \
     
     \ /
      Last update: 2015-03-06 21:21    [W:4.278 / U:0.132 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site