linux/drivers/block/drbd
Eric W. Biederman 38bf195398 connector/userns: replace netlink uses of cap_raised() with capable()
In 2009 Philip Reiser notied that a few users of netlink connector
interface needed a capability check and added the idiom
cap_raised(nsp->eff_cap, CAP_SYS_ADMIN) to a few of them, on the premise
that netlink was asynchronous.

In 2011 Patrick McHardy noticed we were being silly because netlink is
synchronous and removed eff_cap from the netlink_skb_params and changed
the idiom to cap_raised(current_cap(), CAP_SYS_ADMIN).

Looking at those spots with a fresh eye we should be calling
capable(CAP_SYS_ADMIN).  The only reason I can see for not calling capable
is that it once appeared we were not in the same task as the caller which
would have made calling capable() impossible.

In the initial user_namespace the only difference between between
cap_raised(current_cap(), CAP_SYS_ADMIN) and capable(CAP_SYS_ADMIN) are a
few sanity checks and the fact that capable(CAP_SYS_ADMIN) sets
PF_SUPERPRIV if we use the capability.

Since we are going to be using root privilege setting PF_SUPERPRIV seems
the right thing to do.

The motivation for this that patch is that in a child user namespace
cap_raised(current_cap(),...) tests your capabilities with respect to that
child user namespace not capabilities in the initial user namespace and
thus will allow processes that should be unprivielged to use the kernel
services that are only protected with cap_raised(current_cap(),..).

To fix possible user_namespace issues and to just clean up the code
replace cap_raised(current_cap(), CAP_SYS_ADMIN) with
capable(CAP_SYS_ADMIN).

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Acked-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: Andrew G. Morgan <morgan@kernel.org>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-10 23:21:39 -04:00
..
Kconfig drbd: Kconfig fix 2009-12-29 17:38:28 +01:00
Makefile drbd: remove tracing bits 2009-10-01 21:17:58 +02:00
drbd_actlog.c drbd: we should write meta data updates with FLUSH FUA 2011-06-30 09:23:46 +02:00
drbd_bitmap.c drbd: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:29 +08:00
drbd_int.h module_param: make bool parameters really bool (drivers & misc) 2012-01-13 09:32:20 +10:30
drbd_main.c module_param: make bool parameters really bool (drivers & misc) 2012-01-13 09:32:20 +10:30
drbd_nl.c connector/userns: replace netlink uses of cap_raised() with capable() 2012-05-10 23:21:39 -04:00
drbd_proc.c drbd: allow petabyte storage on 64bit arch 2011-03-10 11:43:24 +01:00
drbd_receiver.c drbd: when receive times out on meta socket, also check last receive time on data socket 2011-06-30 09:23:44 +02:00
drbd_req.c block: remove support for bio remapping from ->make_request 2011-09-12 12:12:01 +02:00
drbd_req.h drbd: fix warning 2011-05-24 10:38:33 +02:00
drbd_strings.c drbd: Rename enum drbd_state_ret_codes to enum drbd_state_rv 2011-03-10 11:36:18 +01:00
drbd_vli.h Fix common misspellings 2011-03-31 11:26:23 -03:00
drbd_worker.c drbd: Use the correct max_bio_size when creating resync requests 2011-06-30 09:23:40 +02:00
drbd_wrappers.h drbd: Get rid of unnecessary macros (2) 2011-03-10 11:36:15 +01:00