Commit 6550f2dd authored Sep 28, 2020 by Lorenz Bauer Committed by Alexei Starovoitov Sep 28, 2020

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: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei 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;

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