From: Yuehaibing <yuehaibing@huawei.com>
To: Xin Long <lucien.xin@gmail.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
davem <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>,
network dev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] xfrm: policy: Fix xfrm policy match
Date: Mon, 25 May 2020 11:04:58 +0800 [thread overview]
Message-ID: <f82b038f-776e-a87a-d46b-173d238531ba@huawei.com> (raw)
In-Reply-To: <CADvbK_e8ixjGGHRK9A4HcXDGKYcNykneUHzHiE8sQ4ojDz+e-g@mail.gmail.com>
On 2020/5/23 17:02, Xin Long wrote:
> On Fri, May 22, 2020 at 8:39 PM Yuehaibing <yuehaibing@huawei.com> wrote:
>>
>> On 2020/5/22 13:49, Xin Long wrote:
>>> On Fri, May 22, 2020 at 9:45 AM Yuehaibing <yuehaibing@huawei.com> wrote:
>>>>
>>>> On 2020/5/21 14:49, Xin Long wrote:
>>>>> On Tue, May 19, 2020 at 4:53 PM Steffen Klassert
>>>>> <steffen.klassert@secunet.com> wrote:
>>>>>>
>>>>>> On Fri, May 15, 2020 at 04:39:57PM +0800, Yuehaibing wrote:
>>>>>>>
>>>>>>> Friendly ping...
>>>>>>>
>>>>>>> Any plan for this issue?
>>>>>>
>>>>>> There was still no consensus between you and Xin on how
>>>>>> to fix this issue. Once this happens, I consider applying
>>>>>> a fix.
>>>>>>
>>>>> Sorry, Yuehaibing, I can't really accept to do: (A->mark.m & A->mark.v)
>>>>> I'm thinking to change to:
>>>>>
>>>>> 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 (policy->mark.v == pol->mark.v &&
>>>>> + (policy->mark.m == pol->mark.m ||
>>>>> + policy->priority == pol->priority))
>>>>> return true;
>>>>>
>>>>> return false;
>>>>>
>>>>> which means we consider (the same value and mask) or
>>>>> (the same value and priority) as the same one. This will
>>>>> cover both problems.
>>>>
>>>> policy A (mark.v = 0x1011, mark.m = 0x1011, priority = 1)
>>>> policy B (mark.v = 0x1001, mark.m = 0x1001, priority = 1)
>>> I'd think these are 2 different policies.
>>>
>>>>
>>>> when fl->flowi_mark == 0x12341011, in xfrm_policy_match() do check like this:
>>>>
>>>> (fl->flowi_mark & pol->mark.m) != pol->mark.v
>>>>
>>>> 0x12341011 & 0x1011 == 0x00001011
>>>> 0x12341011 & 0x1001 == 0x00001001
>>>>
>>>> This also match different policy depends on the order of policy inserting.
>>> Yes, this may happen when a user adds 2 policies like that.
>>> But I think this's a problem that the user doesn't configure it well,
>>> 'priority' should be set.
>>> and this can not be avoided, also such as:
>>>
>>> policy A (mark.v = 0xff00, mark.m = 0x1000, priority = 1)
>>> policy B (mark.v = 0x00ff, mark.m = 0x0011, priority = 1)
>>>
>>> try with 0x12341011
>>>
>>> So just be it, let users decide.
>>
>> Ok, this make sense.
> Thanks Yuehaibing, it's good we're on the same page now.
>
> Just realized the patch I created above won't work for the case:
>
> policy A (mark.v = 0x10, mark.m = 0, priority = 1)
> policy B (mark.v = 0x1, mark.m = 0, priority = 2)
> policy C (mark.v = 0x10, mark.m = 0, priority = 2)
>
> when policy C is being added, the warning still occurs.
Do you means this:
policy A (mark.v = 0x10, mark.m = 0, priority = 1)
policy B (mark.v = 0x10, mark.m = 1, priority = 2)
policy C (mark.v = 0x10, mark.m = 0, priority = 2)
>
> So I will just check value and priority:
> - 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 == pol->mark.v &&
> policy->priority == pol->priority)
> return true;
>
> This allows two policies like this exist:
>
> policy A (mark.v = 0x10, mark.m = 0, priority = 1)
> policy C (mark.v = 0x10, mark.m = 0, priority = 2)
>
> But I don't think it's a problem.
Agreed.
>
> .
>
prev parent reply other threads:[~2020-05-25 3:05 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-21 14:31 [PATCH] xfrm: policy: Only use mark as policy lookup key YueHaibing
2020-04-22 9:33 ` Steffen Klassert
2020-04-22 12:18 ` Yuehaibing
2020-04-22 15:41 ` Xin Long
2020-04-22 15:54 ` Xin Long
2020-04-23 2:25 ` Yuehaibing
2020-04-23 6:37 ` Xin Long
2020-04-23 8:40 ` Yuehaibing
2020-04-23 9:43 ` Xin Long
2020-04-24 3:48 ` Yuehaibing
2020-04-30 6:30 ` Yuehaibing
2020-04-22 12:53 ` [PATCH v2] xfrm: policy: Fix xfrm policy match YueHaibing
2020-05-15 8:39 ` Yuehaibing
2020-05-19 8:53 ` Steffen Klassert
2020-05-21 6:49 ` Xin Long
2020-05-22 1:45 ` Yuehaibing
2020-05-22 5:49 ` Xin Long
2020-05-22 12:39 ` Yuehaibing
2020-05-23 9:02 ` Xin Long
2020-05-25 3:04 ` Yuehaibing [this message]
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