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From: ebiederm@xmission.com (Eric W. Biederman)
To: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Andrew Morton <akpm@osdl.org>, Ingo Molnar <mingo@elte.hu>,
tglx@linutronix.de, linux-kernel@vger.kernel.org,
selinux@tycho.nsa.gov, jmorris@namei.org
Subject: Re: [PATCH] sysctl selinux: Don't look at table->de
Date: Mon, 29 Jan 2007 10:43:07 -0700 [thread overview]
Message-ID: <m18xflloes.fsf@ebiederm.dsl.xmission.com> (raw)
In-Reply-To: <1170075866.8720.15.camel@moss-spartans.epoch.ncsc.mil> (Stephen Smalley's message of "Mon, 29 Jan 2007 08:04:26 -0500")
Stephen Smalley <sds@tycho.nsa.gov> writes:
> On Sun, 2007-01-28 at 12:21 -0700, Eric W. Biederman wrote:
>> With the sysctl cleanups sysctl is not really a part of proc
>> it just shows up there, and any path based approach will not
>> adequately describe the data as sysctl is essentially a
>> union mount underneath the covers. As designed this mechanism
>> is viewer dependent so trying to be path based gets even worse.
>>
>> However the permissions in sys_sysctl are currently immutable
>> and going through proc does not change the permission checks
>> when accessing sysctl. So we might as well stick with the well
>> defined sysctl sid, as that is what selinux uses when proc is
>> not compiled in.
>>
>> I.e. I see no hope for salvaging the selinux_proc_get_sid call
>> in selinux_sysctl so I'm removing it.
>>
>> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
>> ---
>> security/selinux/hooks.c | 8 ++------
>> 1 files changed, 2 insertions(+), 6 deletions(-)
>>
>> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
>> index 7b38372..3a36057 100644
>> --- a/security/selinux/hooks.c
>> +++ b/security/selinux/hooks.c
>> @@ -1438,12 +1438,8 @@ static int selinux_sysctl(ctl_table *table, int op)
>>
>> tsec = current->security;
>>
>> - rc = selinux_proc_get_sid(table->de, (op == 001) ?
>> - SECCLASS_DIR : SECCLASS_FILE, &tsid);
>> - if (rc) {
>> - /* Default to the well-defined sysctl SID. */
>> - tsid = SECINITSID_SYSCTL;
>> - }
>> + /* Use the well-defined sysctl SID. */
>> + tsid = SECINITSID_SYSCTL;
>>
>> /* The op values are "defined" in sysctl.c, thereby creating
>> * a bad coupling between this module and sysctl.c */
>
> NAK. Mapping all sysctls to a single security label prevents any kind
> of fine-grained security on sysctls, and current policies already make
> use of the current distinctions to limit access to particular sets of
> sysctls to particular processes. As is, I'd expect breakage of current
> systems running SELinux from this patch, because (confined) processes
> that formerly only required access to specific sysctl labels will
> suddenly run into denials on the generic fallback label.
Reasonable. There is the issue that your code already had this code
path for when /proc was compiled out.
> If the ctl_table supplied more information about the functional purpose
> and the security sensitivity of the sysctl, then we could leverage that
> information instead, as long as we can at least derive the current
> labelings from that information for compatibility.
What do information do you need to do need? Do you need extra fields in sysctl?
I am more than willing to help but I am not familiar enough with selinux
to do a reasonable job on my own.
Eric
next prev parent reply other threads:[~2007-01-29 17:44 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200701280106.l0S16CG3019873@shell0.pdx.osdl.net>
[not found] ` <20070127172410.2b041952.akpm@osdl.org>
[not found] ` <1169972718.17469.164.camel@localhost.localdomain>
[not found] ` <20070128003549.2ca38dc8.akpm@osdl.org>
[not found] ` <20070128093358.GA2071@elte.hu>
[not found] ` <20070128095712.GA6485@elte.hu>
[not found] ` <20070128100627.GA8416@elte.hu>
[not found] ` <20070128104548.a835d859.akpm@osdl.org>
2007-01-28 19:21 ` Eric W. Biederman
2007-01-29 13:04 ` Stephen Smalley
2007-01-29 15:23 ` James Morris
2007-01-29 17:55 ` Eric W. Biederman
2007-01-29 19:26 ` Stephen Smalley
2007-01-29 17:43 ` Eric W. Biederman [this message]
2007-01-29 18:43 ` Stephen Smalley
2007-01-29 19:08 ` Casey Schaufler
2007-01-29 20:07 ` Stephen Smalley
2007-01-30 10:25 ` Christoph Hellwig
2007-01-30 17:19 ` Casey Schaufler
2007-01-29 19:16 ` Eric W. Biederman
2007-01-29 23:28 ` Russell Coker
2007-02-06 21:16 ` [PATCH 1/2] sysctl: Add a parent entry to ctl_table and set the parent entry Eric W. Biederman
2007-02-06 21:21 ` [PATCH 2/2] sysctl: Restore the selinux path based label lookup for sysctls Eric W. Biederman
2007-02-07 18:24 ` Stephen Smalley
2007-02-07 21:12 ` Stephen Smalley
2007-02-07 21:54 ` Stephen Smalley
2007-02-07 22:21 ` Eric W. Biederman
2007-02-08 15:07 ` Stephen Smalley
2007-02-08 1:57 ` Eric W. Biederman
2007-02-08 15:01 ` Stephen Smalley
2007-02-08 17:53 ` Eric W. Biederman
2007-02-08 18:13 ` Stephen Smalley
2007-02-08 22:17 ` Eric W. Biederman
2007-02-08 22:51 ` [PATCH 0/5] sysctl cleanup selinux fixes Eric W. Biederman
2007-02-08 22:53 ` [PATCH 1/5] sysctl: Remove declaration of nonexistent sysctl_init() Eric W. Biederman
2007-02-08 22:54 ` [PATCH 2/5] sysctl: Set the parent field in the root sysctl table Eric W. Biederman
2007-02-08 22:55 ` [PATCH 3/5] sysctl: Fix the selinux_sysctl_get_sid Eric W. Biederman
2007-02-08 23:02 ` [PATCH 4/5] selinux: Enhance selinux to always ignore private inodes Eric W. Biederman
2007-02-08 23:04 ` [PATCH 5/5] sysctl: Hide the sysctl proc inodes from selinux Eric W. Biederman
2007-02-09 12:26 ` [PATCH 4/5] selinux: Enhance selinux to always ignore private inodes Stephen Smalley
2007-02-09 12:24 ` [PATCH 3/5] sysctl: Fix the selinux_sysctl_get_sid Stephen Smalley
2007-02-09 11:05 ` [PATCH 0/5] sysctl cleanup selinux fixes Andrew Morton
2007-02-09 18:09 ` Eric W. Biederman
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