Messages in this thread | | | From | Xin Long <> | Date | Wed, 22 Apr 2020 23:54:03 +0800 | Subject | Re: [PATCH] xfrm: policy: Only use mark as policy lookup key |
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On Wed, Apr 22, 2020 at 11:41 PM Xin Long <lucien.xin@gmail.com> wrote: > > 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?: *shouldn't, sorry ;D
> (policy->mark.v == pol->mark.v && policy->mark.m == pol->mark.m && > policy->priority == pol->priority) > > > > > > > > > > > > > . > > > > >
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