bpf: sockmap: Require attach_bpf_fd when detaching a program

The sockmap code currently ignores the value of attach_bpf_fd when
detaching a program. This is contrary to the usual behaviour of
checking that attach_bpf_fd represents the currently attached
program.

Ensure that attach_bpf_fd is indeed the currently attached
program. It turns out that all sockmap selftests already do this,
which indicates that this is unlikely to cause breakage.

Fixes: 604326b41a ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200629095630.7933-5-lmb@cloudflare.com
This commit is contained in:
Lorenz Bauer
2020-06-29 10:56:28 +01:00
committed by Alexei Starovoitov
parent 9b2b09717e
commit bb0de3131f
4 changed files with 70 additions and 8 deletions

View File

@@ -430,6 +430,19 @@ static inline void psock_set_prog(struct bpf_prog **pprog,
bpf_prog_put(prog);
}
static inline int psock_replace_prog(struct bpf_prog **pprog,
struct bpf_prog *prog,
struct bpf_prog *old)
{
if (cmpxchg(pprog, old, prog) != old)
return -ENOENT;
if (old)
bpf_prog_put(old);
return 0;
}
static inline void psock_progs_drop(struct sk_psock_progs *progs)
{
psock_set_prog(&progs->msg_parser, NULL);