Re: [PATCH v2] xfrm: policy: Fix xfrm policy match

From: Yuehaibing
Date: Fri May 15 2020 - 04:40:05 EST



Friendly ping...

Any plan for this issue?

On 2020/4/22 20:53, 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 if the found policy has the
> same lookup keys (mark.v & mark.m) and priority.
>
> Fixes: 7cb8a93968e3 ("xfrm: Allow inserting policies with matching mark and different priorities")
> Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
> ---
> v2: policy matched while have same mark and priority
> ---
> net/xfrm/xfrm_policy.c | 15 +++++----------
> 1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
> index 297b2fdb3c29..2a0d7f5e6545 100644
> --- a/net/xfrm/xfrm_policy.c
> +++ b/net/xfrm/xfrm_policy.c
> @@ -1436,12 +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 &&
> + if ((policy->mark.v & policy->mark.m) == (pol->mark.v & pol->mark.m) &&
> policy->priority == pol->priority)
> return true;
>
> @@ -1628,7 +1623,7 @@ __xfrm_policy_bysel_ctx(struct hlist_head *chain, u32 mark, u32 if_id,
> hlist_for_each_entry(pol, chain, bydst) {
> if (pol->type == type &&
> pol->if_id == if_id &&
> - (mark & pol->mark.m) == pol->mark.v &&
> + mark == (pol->mark.m & pol->mark.v) &&
> !selector_cmp(sel, &pol->selector) &&
> xfrm_sec_ctx_match(ctx, pol->security))
> return pol;
> @@ -1726,7 +1721,7 @@ struct xfrm_policy *xfrm_policy_byid(struct net *net, u32 mark, u32 if_id,
> hlist_for_each_entry(pol, chain, byidx) {
> if (pol->type == type && pol->index == id &&
> pol->if_id == if_id &&
> - (mark & pol->mark.m) == pol->mark.v) {
> + mark == (pol->mark.m & pol->mark.v)) {
> xfrm_pol_hold(pol);
> if (delete) {
> *err = security_xfrm_policy_delete(
> @@ -1898,7 +1893,7 @@ static int xfrm_policy_match(const struct xfrm_policy *pol,
>
> if (pol->family != family ||
> pol->if_id != if_id ||
> - (fl->flowi_mark & pol->mark.m) != pol->mark.v ||
> + fl->flowi_mark != (pol->mark.m & pol->mark.v) ||
> pol->type != type)
> return ret;
>
> @@ -2177,7 +2172,7 @@ static struct xfrm_policy *xfrm_sk_policy_lookup(const struct sock *sk, int dir,
>
> match = xfrm_selector_match(&pol->selector, fl, family);
> if (match) {
> - if ((sk->sk_mark & pol->mark.m) != pol->mark.v ||
> + if (sk->sk_mark != (pol->mark.m & pol->mark.v) ||
> pol->if_id != if_id) {
> pol = NULL;
> goto out;
>