diff options
| author | Jakub Sitnicki <jakub@cloudflare.com> | 2020-02-18 17:10:20 +0000 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2020-02-21 22:29:45 +0100 |
| commit | 9fed9000c5c6cacfcaaa48aff74818072ae294cc (patch) | |
| tree | 66854f14a43c09c2aea3c3c5e6e5ed93a65a1aea | |
| parent | 1d59f3bcee356caa933646dc45ff0836455535e8 (diff) | |
bpf: Allow selecting reuseport socket from a SOCKMAP/SOCKHASH
SOCKMAP & SOCKHASH now support storing references to listening
sockets. Nothing keeps us from using these map types a collection of
sockets to select from in BPF reuseport programs. Whitelist the map types
with the bpf_sk_select_reuseport helper.
The restriction that the socket has to be a member of a reuseport group
still applies. Sockets in SOCKMAP/SOCKHASH that don't have sk_reuseport_cb
set are not a valid target and we signal it with -EINVAL.
The main benefit from this change is that, in contrast to
REUSEPORT_SOCKARRAY, SOCK{MAP,HASH} don't impose a restriction that a
listening socket can be just one BPF map at the same time.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200218171023.844439-9-jakub@cloudflare.com
| -rw-r--r-- | kernel/bpf/verifier.c | 10 | ||||
| -rw-r--r-- | net/core/filter.c | 15 |
2 files changed, 17 insertions, 8 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 1cc945daa9c8..6d15dfbd4b88 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3693,14 +3693,16 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, if (func_id != BPF_FUNC_sk_redirect_map && func_id != BPF_FUNC_sock_map_update && func_id != BPF_FUNC_map_delete_elem && - func_id != BPF_FUNC_msg_redirect_map) + func_id != BPF_FUNC_msg_redirect_map && + func_id != BPF_FUNC_sk_select_reuseport) goto error; break; case BPF_MAP_TYPE_SOCKHASH: if (func_id != BPF_FUNC_sk_redirect_hash && func_id != BPF_FUNC_sock_hash_update && func_id != BPF_FUNC_map_delete_elem && - func_id != BPF_FUNC_msg_redirect_hash) + func_id != BPF_FUNC_msg_redirect_hash && + func_id != BPF_FUNC_sk_select_reuseport) goto error; break; case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY: @@ -3774,7 +3776,9 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, goto error; break; case BPF_FUNC_sk_select_reuseport: - if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) + if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY && + map->map_type != BPF_MAP_TYPE_SOCKMAP && + map->map_type != BPF_MAP_TYPE_SOCKHASH) goto error; break; case BPF_FUNC_map_peek_elem: diff --git a/net/core/filter.c b/net/core/filter.c index c180871e606d..77d2f471b3bb 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -8620,6 +8620,7 @@ struct sock *bpf_run_sk_reuseport(struct sock_reuseport *reuse, struct sock *sk, BPF_CALL_4(sk_select_reuseport, struct sk_reuseport_kern *, reuse_kern, struct bpf_map *, map, void *, key, u32, flags) { + bool is_sockarray = map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY; struct sock_reuseport *reuse; struct sock *selected_sk; @@ -8628,12 +8629,16 @@ BPF_CALL_4(sk_select_reuseport, struct sk_reuseport_kern *, reuse_kern, return -ENOENT; reuse = rcu_dereference(selected_sk->sk_reuseport_cb); - if (!reuse) - /* selected_sk is unhashed (e.g. by close()) after the - * above map_lookup_elem(). Treat selected_sk has already - * been removed from the map. + if (!reuse) { + /* reuseport_array has only sk with non NULL sk_reuseport_cb. + * The only (!reuse) case here is - the sk has already been + * unhashed (e.g. by close()), so treat it as -ENOENT. + * + * Other maps (e.g. sock_map) do not provide this guarantee and + * the sk may never be in the reuseport group to begin with. */ - return -ENOENT; + return is_sockarray ? -ENOENT : -EINVAL; + } if (unlikely(reuse->reuseport_id != reuse_kern->reuseport_id)) { struct sock *sk; |