Re: [PATCH net-next 1/1] netfilter: flowtable: Make sure dst_cache is valid before using it

[Roi Dayan]

On 2021-04-11 1:58 PM, Pablo Neira Ayuso wrote:

Hi Roi,

On Sun, Apr 11, 2021 at 11:13:34AM +0300, Roi Dayan wrote:

It could be dst_cache was not set so check it's not null before using
it.

Could you give a try to this fix?

net/sched/act_ct.c leaves the xmit_type as FLOW_OFFLOAD_XMIT_UNSPEC
since it does not cache a route.

Thanks.

what do you mean? FLOW_OFFLOAD_XMIT_UNSPEC doesn't exists so default 0
is set.

do you suggest adding that enum option as 0?

this is the current xmit_type enum

enum flow_offload_xmit_type {
       FLOW_OFFLOAD_XMIT_NEIGH         = 0,
       FLOW_OFFLOAD_XMIT_XFRM,
       FLOW_OFFLOAD_XMIT_DIRECT,
};

Fixes: 8b9229d15877 ("netfilter: flowtable: dst_check() from garbage collector 
path")
Signed-off-by: Roi Dayan <r...@nvidia.com>
---
  net/netfilter/nf_flow_table_core.c | 2 ++
  1 file changed, 2 insertions(+)

diff --git a/net/netfilter/nf_flow_table_core.c 
b/net/netfilter/nf_flow_table_core.c
index 76573bae6664..e426077aaed1 100644
--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
@@ -410,6 +410,8 @@ static bool flow_offload_stale_dst(struct 
flow_offload_tuple *tuple)
        if (tuple->xmit_type == FLOW_OFFLOAD_XMIT_NEIGH ||
            tuple->xmit_type == FLOW_OFFLOAD_XMIT_XFRM) {
                dst = tuple->dst_cache;
+               if (!dst)
+                       return false;
                if (!dst_check(dst, tuple->dst_cookie))
                        return true;
        }
--
2.26.2