From e4ff5aa469403462091eb22e2b0843b894167e10 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Wed, 9 Dec 2020 14:57:39 +0100 Subject: [PATCH] netdevsim: Add debugfs toggle to reject BPF programs in verifier MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This adds a new debugfs toggle ('bpf_bind_verifier_accept') that can be used to make netdevsim reject BPF programs from being accepted by the verifier. If this toggle (which defaults to true) is set to false, nsim_bpf_verify_insn() will return EOPNOTSUPP on the last instruction (after outputting the 'Hello from netdevsim' verifier message). This makes it possible to check the verification callback in the driver from test_offload.py in selftests, since the verifier now clears the verifier log on a successful load, hiding the message from the driver. Fixes: 6f8a57ccf851 ("bpf: Make verifier log more relevant by default") Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Daniel Borkmann Acked-by: Jakub Kicinski Link: https://lore.kernel.org/bpf/160752225964.110217.12584017165318065332.stgit@toke.dk --- drivers/net/netdevsim/bpf.c | 12 ++++++++++-- drivers/net/netdevsim/netdevsim.h | 1 + 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/net/netdevsim/bpf.c b/drivers/net/netdevsim/bpf.c index 85546664bdd5..90aafb56f140 100644 --- a/drivers/net/netdevsim/bpf.c +++ b/drivers/net/netdevsim/bpf.c @@ -63,15 +63,20 @@ static int nsim_bpf_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn) { struct nsim_bpf_bound_prog *state; + int ret = 0; state = env->prog->aux->offload->dev_priv; if (state->nsim_dev->bpf_bind_verifier_delay && !insn_idx) msleep(state->nsim_dev->bpf_bind_verifier_delay); - if (insn_idx == env->prog->len - 1) + if (insn_idx == env->prog->len - 1) { pr_vlog(env, "Hello from netdevsim!\n"); - return 0; + if (!state->nsim_dev->bpf_bind_verifier_accept) + ret = -EOPNOTSUPP; + } + + return ret; } static int nsim_bpf_finalize(struct bpf_verifier_env *env) @@ -595,6 +600,9 @@ int nsim_bpf_dev_init(struct nsim_dev *nsim_dev) &nsim_dev->bpf_bind_accept); debugfs_create_u32("bpf_bind_verifier_delay", 0600, nsim_dev->ddir, &nsim_dev->bpf_bind_verifier_delay); + nsim_dev->bpf_bind_verifier_accept = true; + debugfs_create_bool("bpf_bind_verifier_accept", 0600, nsim_dev->ddir, + &nsim_dev->bpf_bind_verifier_accept); return 0; } diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h index 827fc80f50a0..c4e7ad2a1964 100644 --- a/drivers/net/netdevsim/netdevsim.h +++ b/drivers/net/netdevsim/netdevsim.h @@ -189,6 +189,7 @@ struct nsim_dev { struct dentry *take_snapshot; struct bpf_offload_dev *bpf_dev; bool bpf_bind_accept; + bool bpf_bind_verifier_accept; u32 bpf_bind_verifier_delay; struct dentry *ddir_bpf_bound_progs; u32 prog_id_gen;