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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
zero-sugar-mainline-defconfig
Lorenz Bauer 2020-09-28 10:08:02 +01:00 committed by Alexei Starovoitov
parent efa90b5093
commit 6550f2dddf
2 changed files with 4 additions and 1 deletions
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2
kernel/bpf/verifier.c
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@ -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;

3
net/core/sock_map.c
View File

@ -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;