From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>
Cc: "Toke Høiland-Jørgensen" <toke@redhat.com>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Martin KaFai Lau" <kafai@fb.com>,
"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
"John Fastabend" <john.fastabend@gmail.com>,
"KP Singh" <kpsingh@kernel.org>,
"Stanislav Fomichev" <sdf@google.com>,
"David S. Miller" <davem@davemloft.net>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
"Andrea Arcangeli" <aarcange@redhat.com>,
"Clark Williams" <williams@redhat.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH bpf v2 1/2] bpf: enforce that struct_ops programs be GPL-only
Date: Thu, 25 Mar 2021 22:11:21 +0100 [thread overview]
Message-ID: <20210325211122.98620-1-toke@redhat.com> (raw)
With the introduction of the struct_ops program type, it became possible to
implement kernel functionality in BPF, making it viable to use BPF in place
of a regular kernel module for these particular operations.
Thus far, the only user of this mechanism is for implementing TCP
congestion control algorithms. These are clearly marked as GPL-only when
implemented as modules (as seen by the use of EXPORT_SYMBOL_GPL for
tcp_register_congestion_control()), so it seems like an oversight that this
was not carried over to BPF implementations. Since this is the only user
of the struct_ops mechanism, just enforcing GPL-only for the struct_ops
program type seems like the simplest way to fix this.
v2: Move check to the top of check_struct_ops_btf_id().
Fixes: 0baf26b0fcd7 ("bpf: tcp: Support tcp_congestion_ops in bpf")
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
kernel/bpf/verifier.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 44e4ec1640f1..3a738724a380 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -12158,6 +12158,11 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
u32 btf_id, member_idx;
const char *mname;
+ if (!prog->gpl_compatible) {
+ verbose(env, "struct ops programs must have a GPL compatible license\n");
+ return -EINVAL;
+ }
+
btf_id = prog->aux->attach_btf_id;
st_ops = bpf_struct_ops_find(btf_id);
if (!st_ops) {
--
2.31.0
next reply other threads:[~2021-03-25 21:12 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 21:11 Toke Høiland-Jørgensen [this message]
2021-03-25 21:11 ` [PATCH bpf v2 2/2] bpf/selftests: test that kernel rejects a TCP CC with an invalid license Toke Høiland-Jørgensen
2021-03-25 22:58 ` Martin KaFai Lau
2021-03-26 4:04 ` Andrii Nakryiko
2021-03-26 9:43 ` Toke Høiland-Jørgensen
2021-03-26 18:14 ` Andrii Nakryiko
2021-03-26 18:25 ` Toke Høiland-Jørgensen
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