From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zefan Li Subject: Re: [PATCH v2 2/3] sched: add a macro to define bitops for task atomic flags Date: Tue, 23 Sep 2014 14:52:50 +0800 Message-ID: <542118C2.6030302@huawei.com> References: <54210D3F.2090409@huawei.com> <54210D7B.8030103@huawei.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Kees Cook Cc: Tejun Heo , Peter Zijlstra , Ingo Molnar , Tetsuo Handa , Miao Xie , LKML , Cgroups >> -static inline bool task_no_new_privs(struct task_struct *p) >> -{ >> - return test_bit(PFA_NO_NEW_PRIVS, &p->atomic_flags); >> -} >> - >> -static inline void task_set_no_new_privs(struct task_struct *p) >> -{ >> - set_bit(PFA_NO_NEW_PRIVS, &p->atomic_flags); >> -} >> +#define TASK_PFA_BITOPS(name, func) \ >> +static inline bool task_##func(struct task_struct *p) \ >> +{ return test_bit(PFA_##name, &p->atomic_flags); } \ >> + \ >> +static inline void task_set_##func(struct task_struct *p) \ >> +{ set_bit(PFA_##name, &p->atomic_flags); } \ >> + \ >> +static inline void task_clear_##func(struct task_struct *p) \ >> +{ clear_bit(PFA_##name, &p->atomic_flags); } >> + >> +TASK_PFA_BITOPS(NO_NEW_PRIVS, no_new_privs) > > One thing I don't like about this is that task_clear_no_new_privs() > ends up getting defined, and it should absolutely never be used. NNP > should never be cleared or there could be security issues. I realize > this isn't a very useful nit-pick, but I'd rather the function wasn't > even available for someone to accidentally use. Maybe break up the > macro with some kind of "write only" version like: > > #define TASK_PFA_BITOPS_WO(name, func) \ > static inline bool task_##func(struct task_struct *p) \ > { return test_bit(PFA_##name, &p->atomic_flags); } \ > static inline void task_set_##func(struct task_struct *p) \ > { set_bit(PFA_##name, &p->atomic_flags); } > > #define TASK_PFA_BITOPS(name, func) \ > TASK_PFA_BITOPS_WO(name, func); \ > static inline void task_clear_##func(struct task_struct *p) \ > { clear_bit(PFA_##name, &p->atomic_flags); } > > TASK_PFA_BITOPS_WO(NO_NEW_PRIVS, no_new_privs) > > And then all the new users can use TASK_PFA_BITOPS() normally since > they expect to use "clear"? > Now I'm inclined to do this: +#define TASK_PFA_TEST(name, func) \ + static inline bool task_##func(struct task_struct *p) \ + { return test_bit(PFA_##name, &p->atomic_flags); } +#define TASK_PFA_SET(name, func) \ + static inline void task_set_##func(struct task_struct *p) \ + { set_bit(PFA_##name, &p->atomic_flags); } +#define TASK_PFA_CLEAR(name, func) \ + static inline void task_clear_##func(struct task_struct *p) \ + { clear_bit(PFA_##name, &p->atomic_flags); } + +TASK_PFA_TEST(NO_NEW_PRIVS, no_new_privs) +TASK_PFA_SET(NO_NEW_PRIVS, no_new_privs) From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754064AbaIWGw7 (ORCPT ); Tue, 23 Sep 2014 02:52:59 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:32490 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753287AbaIWGw5 (ORCPT ); Tue, 23 Sep 2014 02:52:57 -0400 Message-ID: <542118C2.6030302@huawei.com> Date: Tue, 23 Sep 2014 14:52:50 +0800 From: Zefan Li User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: Kees Cook CC: Tejun Heo , Peter Zijlstra , "Ingo Molnar" , Tetsuo Handa , Miao Xie , LKML , Cgroups Subject: Re: [PATCH v2 2/3] sched: add a macro to define bitops for task atomic flags References: <54210D3F.2090409@huawei.com> <54210D7B.8030103@huawei.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.18.230] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A02020A.542118C7.013E,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 031cd62a07534d2b9da7b36be43eaab1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> -static inline bool task_no_new_privs(struct task_struct *p) >> -{ >> - return test_bit(PFA_NO_NEW_PRIVS, &p->atomic_flags); >> -} >> - >> -static inline void task_set_no_new_privs(struct task_struct *p) >> -{ >> - set_bit(PFA_NO_NEW_PRIVS, &p->atomic_flags); >> -} >> +#define TASK_PFA_BITOPS(name, func) \ >> +static inline bool task_##func(struct task_struct *p) \ >> +{ return test_bit(PFA_##name, &p->atomic_flags); } \ >> + \ >> +static inline void task_set_##func(struct task_struct *p) \ >> +{ set_bit(PFA_##name, &p->atomic_flags); } \ >> + \ >> +static inline void task_clear_##func(struct task_struct *p) \ >> +{ clear_bit(PFA_##name, &p->atomic_flags); } >> + >> +TASK_PFA_BITOPS(NO_NEW_PRIVS, no_new_privs) > > One thing I don't like about this is that task_clear_no_new_privs() > ends up getting defined, and it should absolutely never be used. NNP > should never be cleared or there could be security issues. I realize > this isn't a very useful nit-pick, but I'd rather the function wasn't > even available for someone to accidentally use. Maybe break up the > macro with some kind of "write only" version like: > > #define TASK_PFA_BITOPS_WO(name, func) \ > static inline bool task_##func(struct task_struct *p) \ > { return test_bit(PFA_##name, &p->atomic_flags); } \ > static inline void task_set_##func(struct task_struct *p) \ > { set_bit(PFA_##name, &p->atomic_flags); } > > #define TASK_PFA_BITOPS(name, func) \ > TASK_PFA_BITOPS_WO(name, func); \ > static inline void task_clear_##func(struct task_struct *p) \ > { clear_bit(PFA_##name, &p->atomic_flags); } > > TASK_PFA_BITOPS_WO(NO_NEW_PRIVS, no_new_privs) > > And then all the new users can use TASK_PFA_BITOPS() normally since > they expect to use "clear"? > Now I'm inclined to do this: +#define TASK_PFA_TEST(name, func) \ + static inline bool task_##func(struct task_struct *p) \ + { return test_bit(PFA_##name, &p->atomic_flags); } +#define TASK_PFA_SET(name, func) \ + static inline void task_set_##func(struct task_struct *p) \ + { set_bit(PFA_##name, &p->atomic_flags); } +#define TASK_PFA_CLEAR(name, func) \ + static inline void task_clear_##func(struct task_struct *p) \ + { clear_bit(PFA_##name, &p->atomic_flags); } + +TASK_PFA_TEST(NO_NEW_PRIVS, no_new_privs) +TASK_PFA_SET(NO_NEW_PRIVS, no_new_privs)