diff options
| author | Lorenz Bauer <lmb@cloudflare.com> | 2020-06-29 10:56:25 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-06-30 10:46:38 -0700 |
| commit | 1b514239e85965cc4df085180a73dd91733135f7 (patch) | |
| tree | 8a677a5b7ae15b977369200727eb37980ef300b4 | |
| parent | 951f38cf08350884e72e0936adf147a8d764cc5d (diff) | |
bpf: flow_dissector: Check value of unused flags to BPF_PROG_ATTACH
Using BPF_PROG_ATTACH on a flow dissector program supports neither
target_fd, attach_flags or replace_bpf_fd but accepts any value.
Enforce that all of them are zero. This is fine for replace_bpf_fd
since its presence is indicated by BPF_F_REPLACE. It's more
problematic for target_fd, since zero is a valid fd. Should we
want to use the flag later on we'd have to add an exception for
fd 0. The alternative is to force a value like -1. This requires
more changes to tests. There is also precedent for using 0,
since bpf_iter uses this for target_fd as well.
Fixes: b27f7bb590ba ("flow_dissector: Move out netns_bpf prog callbacks")
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200629095630.7933-2-lmb@cloudflare.com
| -rw-r--r-- | kernel/bpf/net_namespace.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c index 7a34a8caf954..03045f45afec 100644 --- a/kernel/bpf/net_namespace.c +++ b/kernel/bpf/net_namespace.c @@ -209,6 +209,9 @@ int netns_bpf_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) struct net *net; int ret; + if (attr->target_fd || attr->attach_flags || attr->replace_bpf_fd) + return -EINVAL; + type = to_netns_bpf_attach_type(attr->attach_type); if (type < 0) return -EINVAL; |