Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756288Ab3IPO0y (ORCPT ); Mon, 16 Sep 2013 10:26:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50750 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755754Ab3IPO0u (ORCPT ); Mon, 16 Sep 2013 10:26:50 -0400 Date: Mon, 16 Sep 2013 16:20:35 +0200 From: Oleg Nesterov To: John Johansen Cc: Richard Guy Briggs , linux-kernel@vger.kernel.org Subject: [PATCH] apparmor: remove the "task" arg from may_change_ptraced_domain() Message-ID: <20130916142035.GA26661@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2869 Lines: 82 Unless task == current ptrace_parent(task) is not safe even under rcu_read_lock() and most of the current users are not right. So may_change_ptraced_domain(task) looks wrong as well. However it is always called with task == current so the code is actually fine. Remove this argument to make this fact clear. Note: perhaps we should simply kill ptrace_parent(), it buys almost nothing. And it is obviously racy, perhaps this should be fixed. Signed-off-by: Oleg Nesterov --- security/apparmor/domain.c | 14 ++++++-------- 1 files changed, 6 insertions(+), 8 deletions(-) diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c index 26c607c..8423558 100644 --- a/security/apparmor/domain.c +++ b/security/apparmor/domain.c @@ -50,23 +50,21 @@ void aa_free_domain_entries(struct aa_domain *domain) /** * may_change_ptraced_domain - check if can change profile on ptraced task - * @task: task we want to change profile of (NOT NULL) * @to_profile: profile to change to (NOT NULL) * - * Check if the task is ptraced and if so if the tracing task is allowed + * Check if current is ptraced and if so if the tracing task is allowed * to trace the new domain * * Returns: %0 or error if change not allowed */ -static int may_change_ptraced_domain(struct task_struct *task, - struct aa_profile *to_profile) +static int may_change_ptraced_domain(struct aa_profile *to_profile) { struct task_struct *tracer; struct aa_profile *tracerp = NULL; int error = 0; rcu_read_lock(); - tracer = ptrace_parent(task); + tracer = ptrace_parent(current); if (tracer) /* released below */ tracerp = aa_get_task_profile(tracer); @@ -477,7 +475,7 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm) } if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) { - error = may_change_ptraced_domain(current, new_profile); + error = may_change_ptraced_domain(new_profile); if (error) { aa_put_profile(new_profile); goto audit; @@ -690,7 +688,7 @@ int aa_change_hat(const char *hats[], int count, u64 token, bool permtest) } } - error = may_change_ptraced_domain(current, hat); + error = may_change_ptraced_domain(hat); if (error) { info = "ptraced"; error = -EPERM; @@ -829,7 +827,7 @@ int aa_change_profile(const char *ns_name, const char *hname, bool onexec, } /* check if tracing task is allowed to trace target domain */ - error = may_change_ptraced_domain(current, target); + error = may_change_ptraced_domain(target); if (error) { info = "ptrace prevents transition"; goto audit; -- 1.5.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/