[PATCH bpf-next 1/4] bpf: sockmap: enable map_update_elem from bpf_iter

[Lorenz Bauer]

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. Doing this allows calling map_update_elem on
sockmap from bpf_iter context, which uses BTF pointers.

Signed-off-by: Lorenz Bauer <l...@cloudflare.com>
---
 kernel/bpf/verifier.c | 2 +-
 net/core/sock_map.c   | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index d4ba29fb17a6..5bd0239da8b6 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -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;
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index e1f05e3fa1d0..497e7df466d4 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -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))
+               return -EINVAL;
+
        if (!sock_map_sk_is_suitable(sk))
                return -EOPNOTSUPP;
 
-- 
2.25.1