From: Peter Zijlstra <peterz@infradead.org>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>, Andi Kleen <ak@linux.intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
"Schaufler, Casey" <casey.schaufler@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"Woodhouse, David" <dwmw@amazon.co.uk>,
Oleg Nesterov <oleg@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCH v3 1/3] ptrace: Provide ___ptrace_may_access() that can be applied on arbitrary tasks
Date: Wed, 5 Sep 2018 21:03:08 +0200 [thread overview]
Message-ID: <20180905190308.GD24082@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20180905184018.GC11625@redhat.com>
On Wed, Sep 05, 2018 at 02:40:18PM -0400, Andrea Arcangeli wrote:
> [ 1838.769917] <<EOE>> [<ffffffff816391e5>] avc_compute_av+0x126/0x1b5
That does read_lock(), which is not allowed from scheduler context.
> [ 1838.777125] [<ffffffff810b842e>] ? walk_tg_tree_from+0xbe/0x110
> [ 1838.783828] [<ffffffff8128b9c4>] avc_has_perm_noaudit+0xc4/0x110
In current code this can end up in avc_update_node() which uses
spin_lock(), which is a bug from scheduler context.o
> [ 1838.790628] [<ffffffff8128f1fb>] cred_has_capability+0x6b/0x120
> [ 1838.797331] [<ffffffff810db71c>] ? ktime_get+0x4c/0xd0
> [ 1838.803160] [<ffffffff810e167b>] ? clockevents_program_event+0x6b/0xf0
> [ 1838.810532] [<ffffffff8128f2de>] selinux_capable+0x2e/0x40
> [ 1838.816748] [<ffffffff81288f65>] security_capable_noaudit+0x15/0x20
> [ 1838.823829] [<ffffffff8108b975>] has_ns_capability_noaudit+0x15/0x20
> [ 1838.831014] [<ffffffff8108bc55>] ptrace_has_cap+0x35/0x40
> [ 1838.837126] [<ffffffff8108c717>] ___ptrace_may_access+0xa7/0x1e0
> [ 1838.843925] [<ffffffff8163f0ae>] __schedule+0x26e/0xa00
> [ 1838.849855] [<ffffffff81640949>] schedule_preempt_disabled+0x29/0x70
> [ 1838.857041] [<ffffffff810d9324>] cpu_startup_entry+0x184/0x290
> [ 1838.863637] [<ffffffff8104891a>] start_secondary+0x1da/0x250
So yes, looks like all that security LSM nonsense isn't going to work
here.
next prev parent reply other threads:[~2018-09-05 19:03 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-31 20:56 [PATCH] x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation Jiri Kosina
2018-09-03 8:51 ` Jiri Kosina
2018-09-03 12:45 ` [PATCH v2 0/3] Harden spectrev2 userspace-userspace protection Jiri Kosina
2018-09-04 14:23 ` [PATCH v3 " Jiri Kosina
2018-09-04 14:40 ` [PATCH v3 1/3] ptrace: Provide ___ptrace_may_access() that can be applied on arbitrary tasks Jiri Kosina
2018-09-04 16:13 ` Thomas Gleixner
2018-09-04 16:21 ` Thomas Gleixner
2018-09-04 17:26 ` Tim Chen
2018-09-04 17:35 ` Jiri Kosina
2018-09-04 18:10 ` Schaufler, Casey
2018-09-04 18:48 ` Jiri Kosina
2018-09-04 23:26 ` Tim Chen
2018-09-05 6:22 ` Jiri Kosina
2018-09-05 15:58 ` Andi Kleen
2018-09-05 18:04 ` Andrea Arcangeli
2018-09-05 18:29 ` Jiri Kosina
2018-09-05 18:40 ` Andrea Arcangeli
2018-09-05 18:42 ` Jiri Kosina
2018-09-05 19:03 ` Peter Zijlstra [this message]
2018-09-05 19:27 ` Schaufler, Casey
2018-09-05 20:02 ` Jiri Kosina
2018-09-05 18:26 ` Thomas Gleixner
2018-09-05 18:35 ` Jiri Kosina
2018-09-04 23:37 ` Andrea Arcangeli
2018-09-05 1:00 ` Schaufler, Casey
2018-09-05 2:38 ` Andrea Arcangeli
2018-09-05 8:00 ` Peter Zijlstra
2018-09-05 15:37 ` Schaufler, Casey
2018-09-05 7:51 ` Peter Zijlstra
2018-09-04 14:42 ` [PATCH v3 2/3] x86/speculation: apply IBPB more strictly to avoid cross-process data leak Jiri Kosina
2018-09-04 16:18 ` Thomas Gleixner
2018-09-05 7:59 ` Peter Zijlstra
2018-09-05 8:02 ` Jiri Kosina
2018-09-05 9:40 ` Peter Zijlstra
2018-09-05 7:52 ` Peter Zijlstra
2018-09-05 7:55 ` Jiri Kosina
2018-09-04 14:42 ` [PATCH v3 3/3] x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation Jiri Kosina
-- strict thread matches above, loose matches on Subject: below --
2018-09-04 14:24 [PATCH v3 1/3] ptrace: Provide ___ptrace_may_access() that can be applied on arbitrary tasks Jiri Kosina
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