[PATCH bpf v2 3/6] bpf: sockmap: check value of unused args to BPF_PROG_ATTACH

[Lorenz Bauer <lmb@xxxxxxxxxxxxxx>]

Using BPF_PROG_ATTACH on a sockmap program currently understands no
flags or replace_bpf_fd, but accepts any value. Return EINVAL instead.

Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
---
 net/core/sock_map.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 4c1123c749bb..db45c1453d39 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -70,6 +70,9 @@ int sock_map_get_from_fd(const union bpf_attr *attr, struct bpf_prog *prog)
 	struct fd f;
 	int ret;
 
+	if (attr->attach_flags || attr->replace_bpf_fd)
+		return -EINVAL;
+
 	f = fdget(ufd);
 	map = __bpf_map_get(f);
 	if (IS_ERR(map))
-- 
2.25.1