Messages in this thread | | | From | Xin Long <> | Date | Wed, 22 Apr 2020 23:41:37 +0800 | Subject | Re: [PATCH] xfrm: policy: Only use mark as policy lookup key |
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On Wed, Apr 22, 2020 at 8:18 PM Yuehaibing <yuehaibing@huawei.com> 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 <yuehaibing@huawei.com> > >> --- > >> 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)
> > > > > > > . > > >
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