From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D391DC83001 for ; Thu, 30 Apr 2020 06:30:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B70362186A for ; Thu, 30 Apr 2020 06:30:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726611AbgD3Gad (ORCPT ); Thu, 30 Apr 2020 02:30:33 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:40118 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726358AbgD3Gad (ORCPT ); Thu, 30 Apr 2020 02:30:33 -0400 Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 7246AD2AB6546329FFF5; Thu, 30 Apr 2020 14:30:30 +0800 (CST) Received: from [127.0.0.1] (10.166.215.154) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.487.0; Thu, 30 Apr 2020 14:30:28 +0800 Subject: Re: [PATCH] xfrm: policy: Only use mark as policy lookup key To: Steffen Klassert References: <20200421143149.45108-1-yuehaibing@huawei.com> <20200422093344.GY13121@gauss3.secunet.de> <1650fd55-dd70-f687-88b6-d32a04245915@huawei.com> <02a56d2c-8d27-f53a-d9e3-c25bd03677c8@huawei.com> CC: Xin Long , Herbert Xu , davem , , network dev , LKML , "Jamal Hadi Salim" From: Yuehaibing Message-ID: <895e1510-6946-3580-fb90-7da328432f07@huawei.com> Date: Thu, 30 Apr 2020 14:30:27 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.166.215.154] X-CFilter-Loop: Reflected Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2020/4/24 11:48, Yuehaibing wrote: > On 2020/4/23 17:43, Xin Long wrote: >> On Thu, Apr 23, 2020 at 4:41 PM Yuehaibing wrote: >>> >>> On 2020/4/23 14:37, Xin Long wrote: >>>> On Thu, Apr 23, 2020 at 10:26 AM Yuehaibing wrote: >>>>> >>>>> On 2020/4/22 23:41, Xin Long wrote: >>>>>> On Wed, Apr 22, 2020 at 8:18 PM Yuehaibing wrote: >>>>>>> >>>>>>> On 2020/4/22 17:33, Steffen Klassert wrote: >>>>>>>> On Tue, Apr 21, 2020 at 10:31:49PM +0800, YueHaibing wrote: >>>>>>>>> While update xfrm policy as follow: >>>>>>>>> >>>>>>>>> ip -6 xfrm policy update src fd00::1/128 dst fd00::2/128 dir in \ >>>>>>>>> priority 1 mark 0 mask 0x10 >>>>>>>>> ip -6 xfrm policy update src fd00::1/128 dst fd00::2/128 dir in \ >>>>>>>>> priority 2 mark 0 mask 0x00 >>>>>>>>> ip -6 xfrm policy update src fd00::1/128 dst fd00::2/128 dir in \ >>>>>>>>> priority 2 mark 0 mask 0x10 >>>>>>>>> >>>>>>>>> We get this warning: >>>>>>>>> >>>>>>>>> WARNING: CPU: 0 PID: 4808 at net/xfrm/xfrm_policy.c:1548 >>>>>>>>> Kernel panic - not syncing: panic_on_warn set ... >>>>>>>>> CPU: 0 PID: 4808 Comm: ip Not tainted 5.7.0-rc1+ #151 >>>>>>>>> Call Trace: >>>>>>>>> RIP: 0010:xfrm_policy_insert_list+0x153/0x1e0 >>>>>>>>> xfrm_policy_inexact_insert+0x70/0x330 >>>>>>>>> xfrm_policy_insert+0x1df/0x250 >>>>>>>>> xfrm_add_policy+0xcc/0x190 [xfrm_user] >>>>>>>>> xfrm_user_rcv_msg+0x1d1/0x1f0 [xfrm_user] >>>>>>>>> netlink_rcv_skb+0x4c/0x120 >>>>>>>>> xfrm_netlink_rcv+0x32/0x40 [xfrm_user] >>>>>>>>> netlink_unicast+0x1b3/0x270 >>>>>>>>> netlink_sendmsg+0x350/0x470 >>>>>>>>> sock_sendmsg+0x4f/0x60 >>>>>>>>> >>>>>>>>> Policy C and policy A has the same mark.v and mark.m, so policy A is >>>>>>>>> matched in first round lookup while updating C. However policy C and >>>>>>>>> policy B has same mark and priority, which also leads to matched. So >>>>>>>>> the WARN_ON is triggered. >>>>>>>>> >>>>>>>>> xfrm policy lookup should only be matched when the found policy has the >>>>>>>>> same lookup keys (mark.v & mark.m) no matter priority. >>>>>>>>> >>>>>>>>> Fixes: 7cb8a93968e3 ("xfrm: Allow inserting policies with matching mark and different priorities") >>>>>>>>> Signed-off-by: YueHaibing >>>>>>>>> --- >>>>>>>>> net/xfrm/xfrm_policy.c | 16 +++++----------- >>>>>>>>> 1 file changed, 5 insertions(+), 11 deletions(-) >>>>>>>>> >>>>>>>>> diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c >>>>>>>>> index 297b2fd..67d0469 100644 >>>>>>>>> --- a/net/xfrm/xfrm_policy.c >>>>>>>>> +++ b/net/xfrm/xfrm_policy.c >>>>>>>>> @@ -1436,13 +1436,7 @@ static void xfrm_policy_requeue(struct xfrm_policy *old, >>>>>>>>> static bool xfrm_policy_mark_match(struct xfrm_policy *policy, >>>>>>>>> struct xfrm_policy *pol) >>>>>>>>> { >>>>>>>>> - u32 mark = policy->mark.v & policy->mark.m; >>>>>>>>> - >>>>>>>>> - if (policy->mark.v == pol->mark.v && policy->mark.m == pol->mark.m) >>>>>>>>> - return true; >>>>>>>>> - >>>>>>>>> - if ((mark & pol->mark.m) == pol->mark.v && >>>>>>>>> - policy->priority == pol->priority) >>>>>>>> >>>>>>>> If you remove the priority check, you can't insert policies with matching >>>>>>>> mark and different priorities anymore. This brings us back the old bug. >>>>>>> >>>>>>> Yes, this is true. >>>>>>> >>>>>>>> >>>>>>>> I plan to apply the patch from Xin Long, this seems to be the right way >>>>>>>> to address this problem. >>>>>>> >>>>>>> That still brings an issue, update like this: >>>>>>> >>>>>>> policy A (mark.v = 1, mark.m = 0, priority = 1) >>>>>>> policy B (mark.v = 1, mark.m = 0, priority = 1) >>>>>>> >>>>>>> A and B will all in the list. >>>>>> I think this is another issue even before: >>>>>> 7cb8a93968e3 ("xfrm: Allow inserting policies with matching mark and >>>>>> different priorities") >>>>>> >>>>>>> >>>>>>> So should do this: >>>>>>> >>>>>>> static bool xfrm_policy_mark_match(struct xfrm_policy *policy, >>>>>>> struct xfrm_policy *pol) >>>>>>> { >>>>>>> - u32 mark = policy->mark.v & policy->mark.m; >>>>>>> - >>>>>>> - if (policy->mark.v == pol->mark.v && policy->mark.m == pol->mark.m) >>>>>>> - return true; >>>>>>> - >>>>>>> - if ((mark & pol->mark.m) == pol->mark.v && >>>>>>> + if ((policy->mark.v & policy->mark.m) == (pol->mark.v & pol->mark.m) && >>>>>>> policy->priority == pol->priority) >>>>>>> return true; >>>>>> "mark.v & mark.m" looks weird to me, it should be: >>>>>> ((something & mark.m) == mark.v) >>>>>> >>>>>> So why should we just do this here?: >>>>>> (policy->mark.v == pol->mark.v && policy->mark.m == pol->mark.m && >>>>>> policy->priority == pol->priority) >>>>> >>>>> >>>>> This leads to this issue: >>>>> >>>>> ip -6 xfrm policy add src fd00::1/128 dst fd00::2/128 dir in mark 0x00000001 mask 0x00000005 >>>>> ip -6 xfrm policy add src fd00::1/128 dst fd00::2/128 dir in mark 0x00000001 mask 0x00000003 >>>>> >>>>> the two policies will be in list, which should not be allowed. >>>> I think these are two different policies. >>>> For instance: >>>> mark = 0x1234567b will match the 1st one only. >>>> mark = 0x1234567d will match the 2st one only >>>> >>>> So these should have been allowed, no? >>> >>> If mark = 0x12345671, it may match different policy depends on the order of inserting, >>> >>> ip xfrm policy update src 172.16.2.0/24 dst 172.16.1.0/24 dir in ptype main \ >>> tmpl src 192.168.2.10 dst 192.168.1.20 proto esp mode tunnel mark 0x00000001 mask 0x00000005 >>> >>> ip xfrm policy update src 172.16.2.0/24 dst 172.16.1.0/24 dir in ptype main \ >>> tmpl src 192.168.2.100 dst 192.168.1.100 proto esp mode beet mark 0x00000001 mask 0x00000003 >>> >>> In fact, your case should use different priority to match. >> Sorry, but it does match your above policies now, like in xfrm_policy_match(), >> when fl->flowi_mark == 0x1234567b: >> >> (fl->flowi_mark & pol->mark.m) != pol->mark.v >> 0x1234567b & 0x00000005 == 0x00000001 >> >> and when fl->flowi_mark == 0x1234567d: >> 0x1234567d & 0x00000003 == 0x00000001 >> >> am I missing something? > > when fl->flowi_mark == 0x12345671 > > 0x12345671 & 0x00000005 == 0x00000001 > 0x12345671 & 0x00000003 == 0x00000001 > > This will match different policy depends on the order of policy inserting, it is not expected. > Steffen, any futher comment ? >> >> >>> >>>> >>>> I'm actually confused now. >>>> does the mask work against its own value, or the other value? >>>> as 'A == (mark.v&mark.m)' and '(A & mark.m) == mark.v' are different things. >>>> >>>> This can date back to Jamal's xfrm by MARK: >>>> >>>> https://lwn.net/Articles/375829/ >>>> >>>> where it does 'm->v & m->m' in xfrm_mark_get() and >>>> 'policy->mark.v & policy->mark.m' in xfrm_policy_insert() while >>>> it does '(A & pol->mark.m) == pol->mark.v' in other places. >>>> >>>> Now I'm thinking 'm->v & m->m' is meaningless, by which if we get >>>> a value != m->v, it means this mark can never be matched by any. >>>> >>>> policy A (mark.v = 1, mark.m = 0, priority = 1) >>>> policy B (mark.v = 1, mark.m = 0, priority = 1) >>>> >>>> So probably we should avoid this case by check m->v == (m->v & m->m) >>>> when adding a new policy. >>>> >>>> wdyt? >>>> >>> >> >> . >> > > > . >