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From: Daniel De Graaf <dgdegra@tycho.nsa.gov>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xen.org
Subject: Re: [PATCH 11/15] flask: improve unknown permission handling
Date: Fri, 17 Jun 2016 13:02:58 -0400	[thread overview]
Message-ID: <7f165a2b-9c57-bd2e-b751-5a1b26460b3a@tycho.nsa.gov> (raw)
In-Reply-To: <20160617154548.GF1340@char.us.oracle.com>

On 06/17/2016 11:45 AM, Konrad Rzeszutek Wilk wrote:
> On Thu, Jun 09, 2016 at 10:47:14AM -0400, Daniel De Graaf wrote:
>> When an unknown domctl, sysctl, or other operation is encountered in the
>> FLASK security server, use the allow_unknown bit in the security policy
>> to decide if the permission should be allowed or denied.  This bit is
>> off by default, but it can be set by using checkpolicy -U allow when
>> compiling the policy.  This allows new operations to be tested without
>> needing to immediately add security checks; however, it is not flexible
>> enough to avoid adding the actual permission checks.  An error message
>> is printed to the hypervisor console when this fallback is encountered.
>
> .. and the operation is permitted.

The error message is printed either way (with a different priority).  Were
you suggesting I expand this explanation to include both the error and
warning messages separately?

>>
>> Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
>> ---
>>  xen/xsm/flask/hooks.c            | 44 +++++++++++++++++++++++++---------------
>>  xen/xsm/flask/include/security.h |  2 ++
>>  xen/xsm/flask/ss/policydb.c      |  1 +
>>  xen/xsm/flask/ss/policydb.h      |  6 ++++++
>>  xen/xsm/flask/ss/services.c      |  5 +++++
>>  5 files changed, 42 insertions(+), 16 deletions(-)
>>
>> diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
>> index a8d45e7..3ab3fbf 100644
>> --- a/xen/xsm/flask/hooks.c
>> +++ b/xen/xsm/flask/hooks.c
>> @@ -136,6 +136,23 @@ static int get_irq_sid(int irq, u32 *sid, struct avc_audit_data *ad)
>>      return 0;
>>  }
>>
>> +static int avc_unknown_permission(const char *name, int id)
>> +{
>> +    int rc;
>
> I would add a new line here.

OK

>> +    if ( !flask_enforcing || security_get_allow_unknown() )
>> +    {
>> +        printk(XENLOG_G_WARNING "FLASK: Allowing unknown %s: %d.\n", name, id);
>> +        rc = 0;
>> +    }
>> +    else
>> +    {
>> +        printk(XENLOG_G_ERR "FLASK: Denying unknown %s: %d.\n", name, id);
>> +        rc = -EPERM;
>> +    }
>> +
>> +    return rc;
>> +}
>> +
>
> The rest looks OK, but I have a question: Is this how Linux operates?

Yes; selinux_nlmsg_perm for an unknown netlink message seems to be an
example there.

-- 
Daniel De Graaf
National Security Agency

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  reply	other threads:[~2016-06-17 17:02 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-09 14:47 [PATCH 00/15] XSM/FLASK updates for 4.8 Daniel De Graaf
2016-06-09 14:47 ` [PATCH 01/15] flask/policy: split into modules Daniel De Graaf
2016-06-14 18:55   ` Konrad Rzeszutek Wilk
2016-06-20  5:15   ` Doug Goldstein
2016-06-09 14:47 ` [PATCH 02/15] flask/policy: split out rules for system_r Daniel De Graaf
2016-06-14 19:08   ` Konrad Rzeszutek Wilk
2016-06-20  5:21   ` Doug Goldstein
2016-06-09 14:47 ` [PATCH 03/15] flask/policy: move user definitions and constraints into modules Daniel De Graaf
2016-06-17 15:28   ` Konrad Rzeszutek Wilk
2016-06-17 16:49     ` Daniel De Graaf
2016-06-20  5:22   ` Doug Goldstein
2016-06-09 14:47 ` [PATCH 04/15] flask/policy: remove unused support for binary modules Daniel De Graaf
2016-06-20  5:22   ` Doug Goldstein
2016-06-09 14:47 ` [PATCH 05/15] flask/policy: xenstore stubdom policy Daniel De Graaf
2016-06-17 15:34   ` Konrad Rzeszutek Wilk
2016-06-20  5:22   ` Doug Goldstein
2016-06-09 14:47 ` [PATCH 06/15] flask/policy: remove unused example Daniel De Graaf
2016-06-17 15:34   ` Konrad Rzeszutek Wilk
2016-06-20  5:23   ` Doug Goldstein
2016-06-09 14:47 ` [PATCH 07/15] flask: unify {get, set}vcpucontext permissions Daniel De Graaf
2016-06-17 15:37   ` Konrad Rzeszutek Wilk
2016-06-09 14:47 ` [PATCH 08/15] flask: remove unused secondary context in ocontext Daniel De Graaf
2016-06-09 16:01   ` Jan Beulich
2016-06-09 16:38     ` Daniel De Graaf
2016-06-09 14:47 ` [PATCH 09/15] flask: remove unused AVC callback functions Daniel De Graaf
2016-06-09 14:47 ` [PATCH 10/15] flask: remove xen_flask_userlist operation Daniel De Graaf
2016-06-09 16:07   ` Jan Beulich
2016-06-09 16:43     ` Daniel De Graaf
2016-06-10  6:51       ` Jan Beulich
2016-06-10 13:08         ` Daniel De Graaf
2016-06-10 14:28           ` Jan Beulich
2016-06-09 14:47 ` [PATCH 11/15] flask: improve unknown permission handling Daniel De Graaf
2016-06-17 15:45   ` Konrad Rzeszutek Wilk
2016-06-17 17:02     ` Daniel De Graaf [this message]
2016-06-17 17:13       ` Konrad Rzeszutek Wilk
2016-06-17 17:20         ` Daniel De Graaf
2016-06-09 14:47 ` [PATCH 12/15] xen/xsm: remove .xsm_initcall.init section Daniel De Graaf
2016-06-09 15:14   ` Andrew Cooper
2016-06-09 16:11   ` Jan Beulich
2016-06-09 16:42     ` Daniel De Graaf
2016-06-17 15:50   ` Konrad Rzeszutek Wilk
2016-06-17 17:04     ` Daniel De Graaf
2016-06-17 17:14       ` Konrad Rzeszutek Wilk
2016-06-17 17:18         ` Daniel De Graaf
2016-06-17 17:21           ` Konrad Rzeszutek Wilk
2016-06-17 23:17             ` Daniel De Graaf
2016-06-09 14:47 ` [PATCH 13/15] xsm: annotate setup functions with __init Daniel De Graaf
2016-06-09 15:15   ` Andrew Cooper
2016-06-09 14:47 ` [PATCH 14/15] xsm: clean up unregistration Daniel De Graaf
2016-06-09 15:16   ` Andrew Cooper
2016-06-17 15:51   ` Konrad Rzeszutek Wilk
2016-06-09 14:47 ` [PATCH 15/15] xsm: add a default policy to .init.data Daniel De Graaf
2016-06-09 15:30   ` Andrew Cooper
2016-06-09 16:58     ` Daniel De Graaf
2016-06-10  7:15       ` Jan Beulich
2016-06-09 16:15   ` Jan Beulich
2016-06-09 16:53     ` Daniel De Graaf
2016-06-09 21:54       ` Doug Goldstein
2016-06-10 14:50         ` Daniel De Graaf
2016-06-10  6:53       ` Jan Beulich
2016-06-17 15:54   ` Konrad Rzeszutek Wilk
2016-06-17 16:00 ` [PATCH 00/15] XSM/FLASK updates for 4.8 Konrad Rzeszutek Wilk
2016-06-20  5:40 ` Doug Goldstein

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