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authorLorenz Bauer <lmb@cloudflare.com>2020-06-29 10:56:25 +0100
committerAlexei Starovoitov <ast@kernel.org>2020-06-30 10:46:38 -0700
commit1b514239e85965cc4df085180a73dd91733135f7 (patch)
tree8a677a5b7ae15b977369200727eb37980ef300b4
parent951f38cf08350884e72e0936adf147a8d764cc5d (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.c3
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;