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	net: ipv6: fix dst ref loop on input in seg6 lwt
Prevent a dst ref loop on input in seg6_iptunnel.
Fixes: af4a2209b1 ("ipv6: sr: use dst_cache in seg6_input")
Cc: David Lebrun <dlebrun@google.com>
Cc: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
			
			
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					 1 changed files with 12 additions and 2 deletions
				
			
		|  | @ -472,10 +472,18 @@ static int seg6_input_core(struct net *net, struct sock *sk, | |||
| { | ||||
| 	struct dst_entry *orig_dst = skb_dst(skb); | ||||
| 	struct dst_entry *dst = NULL; | ||||
| 	struct lwtunnel_state *lwtst; | ||||
| 	struct seg6_lwt *slwt; | ||||
| 	int err; | ||||
| 
 | ||||
| 	slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate); | ||||
| 	/* We cannot dereference "orig_dst" once ip6_route_input() or
 | ||||
| 	 * skb_dst_drop() is called. However, in order to detect a dst loop, we | ||||
| 	 * need the address of its lwtstate. So, save the address of lwtstate | ||||
| 	 * now and use it later as a comparison. | ||||
| 	 */ | ||||
| 	lwtst = orig_dst->lwtstate; | ||||
| 
 | ||||
| 	slwt = seg6_lwt_lwtunnel(lwtst); | ||||
| 
 | ||||
| 	local_bh_disable(); | ||||
| 	dst = dst_cache_get(&slwt->cache); | ||||
|  | @ -490,7 +498,9 @@ static int seg6_input_core(struct net *net, struct sock *sk, | |||
| 	if (!dst) { | ||||
| 		ip6_route_input(skb); | ||||
| 		dst = skb_dst(skb); | ||||
| 		if (!dst->error) { | ||||
| 
 | ||||
| 		/* cache only if we don't create a dst reference loop */ | ||||
| 		if (!dst->error && lwtst != dst->lwtstate) { | ||||
| 			local_bh_disable(); | ||||
| 			dst_cache_set_ip6(&slwt->cache, dst, | ||||
| 					  &ipv6_hdr(skb)->saddr); | ||||
|  |  | |||
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	 Justin Iurman
						Justin Iurman