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

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Date:   Fri, 15 May 2020 16:39:57 +0800
From:   Yuehaibing <yuehaibing@...wei.com>
To:     <steffen.klassert@...unet.com>, <herbert@...dor.apana.org.au>,
        <davem@...emloft.net>, <kuba@...nel.org>
CC:     <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <lucien.xin@...il.com>
Subject: Re: [PATCH v2] xfrm: policy: Fix xfrm policy match


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@...wei.com>
> ---
> 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;
>