This is a note to let you know that I've just added the patch titled bpf: Enforce that struct_ops programs be GPL-only to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bpf-enforce-that-struct_ops-programs-be-gpl-only.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 12aa8a9467b354ef893ce0fc5719a4de4949a9fb Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@xxxxxxxxxx> Date: Fri, 26 Mar 2021 11:03:13 +0100 Subject: bpf: Enforce that struct_ops programs be GPL-only MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Toke Høiland-Jørgensen <toke@xxxxxxxxxx> commit 12aa8a9467b354ef893ce0fc5719a4de4949a9fb upstream. 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. Fixes: 0baf26b0fcd7 ("bpf: tcp: Support tcp_congestion_ops in bpf") Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx> Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Acked-by: Martin KaFai Lau <kafai@xxxxxx> Link: https://lore.kernel.org/bpf/20210326100314.121853-1-toke@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/bpf/verifier.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -11429,6 +11429,11 @@ static int check_struct_ops_btf_id(struc 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) { Patches currently in stable-queue which might be from toke@xxxxxxxxxx are queue-5.10/mac80211-fix-txq-ac-confusion.patch queue-5.10/bpf-enforce-that-struct_ops-programs-be-gpl-only.patch