Commit 6550f2dd authored by Lorenz Bauer's avatar Lorenz Bauer Committed by Alexei Starovoitov
Browse files

bpf: sockmap: Enable map_update_elem from bpf_iter 



Allow passing a pointer to a BTF struct sock_common* when updating
a sockmap or sockhash. Since BTF pointers can fault and therefore be
NULL at runtime we need to add an additional !sk check to
sock_map_update_elem. Since we may be passed a request or timewait
socket we also need to check sk_fullsock. Doing this allows calling
map_update_elem on sockmap from bpf_iter context, which uses
BTF pointers.

Signed-off-by: default avatarLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200928090805.23343-2-lmb@cloudflare.com
parent efa90b50

kernel/bpf/verifier.c

+1 −1
Original line number Diff line number Diff line
@@ -3943,7 +3943,7 @@ static int resolve_map_arg_type(struct bpf_verifier_env *env, 
	case BPF_MAP_TYPE_SOCKMAP:

	case BPF_MAP_TYPE_SOCKHASH:

		if (*arg_type == ARG_PTR_TO_MAP_VALUE) {

			*arg_type = ARG_PTR_TO_SOCKET;

			*arg_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON;

		} else {

			verbose(env, "invalid arg_type for sockmap/sockhash\n");

			return -EINVAL;

net/core/sock_map.c

+3 −0
Original line number Diff line number Diff line
@@ -610,6 +610,9 @@ static int sock_map_update_elem(struct bpf_map *map, void *key, 
	struct sock *sk = (struct sock *)value;

	int ret;



	if (unlikely(!sk || !sk_fullsock(sk)))

		return -EINVAL;



	if (!sock_map_sk_is_suitable(sk))

		return -EOPNOTSUPP;