Hey VPP-ers,
I have posted a suggested solution to this issue here:
https://gerrit.fd.io/r/c/vpp/+/35896
Feel free to review!
jdl
On Mon, Apr 4, 2022 at 12:45 PM Jon Loeliger via lists.fd.io <jdl=
[email protected]> wrote:
> Folks,
>
> I have a scenario where setting up a Wireguard interface and peer causes
> VPP
> to segfault. I think the situation is simply that the function
>
> always_inline uword
> wg_output_tun_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
> vlib_frame_t *frame, u8 is_ip4, u16 async_next_node)
>
> fails to find a proper peer for an adj_index of a packet in this code:
>
> adj_index = vnet_buffer (b[0])->ip.adj_index[VLIB_TX];
>
> if (PREDICT_FALSE (last_adj_index != adj_index))
> {
> peeri = wg_peer_get_by_adj_index (adj_index);
> peer = wg_peer_get (peeri);
> }
>
> Should it instead see a lack of peer (and route?) and thus simply
> drop the packet instead?
>
> The segfault happens in wg_peer_get_by_adj_index() because a
> NULL vector was never established with a peer:
>
> static inline index_t
> wg_peer_get_by_adj_index (index_t ai)
> {
> return (wg_peer_by_adj_index[ai]);
> }
>
> That should have been setup here:
>
> wg_peer_if_adj_change (index_t peeri, void *data)
> {
> adj_index_t *adj_index = data;
> adj_midchain_fixup_t fixup;
> ip_adjacency_t *adj;
> wg_peer_t *peer;
> fib_prefix_t *allowed_ip;
>
> adj = adj_get (*adj_index);
>
> peer = wg_peer_get (peeri);
> vec_foreach (allowed_ip, peer->allowed_ips)
> {
> if (fib_prefix_is_cover_addr_46 (allowed_ip,
> &adj->sub_type.nbr.next_hop))
> {
> vec_add1 (peer->adj_indices, *adj_index);
> vec_validate_init_empty (wg_peer_by_adj_index, *adj_index,
> INDEX_INVALID);
> wg_peer_by_adj_index[*adj_index] = peer - wg_peer_pool;
>
>
> Dumping core by an invalid vector reference of wg_peer_by_adj_index[] is
> a poor way to tell me that a route isn't set up properly? :-). My question
> is,
> where should we catch this error and prevent that?
>
> Thanks,
> jdl
>
>
>
>
>
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