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From: Lorenz Bauer <lmb@cloudflare.com>
To: Martin KaFai Lau <kafai@fb.com>
Cc: bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Kernel Team <kernel-team@fb.com>,
	Networking <netdev@vger.kernel.org>
Subject: Re: [PATCH v4 bpf-next 07/13] bpf: selftest: Add ref_tracking verifier test for bpf_skc casting
Date: Fri, 25 Sep 2020 09:30:23 +0100	[thread overview]
Message-ID: <CACAyw99gZoQFErqL73sD9rvY4OPK6fDyE7ED5U0wHE7TGe-8Ug@mail.gmail.com> (raw)
In-Reply-To: <20200925000421.3857616-1-kafai@fb.com>

On Fri, 25 Sep 2020 at 01:04, Martin KaFai Lau <kafai@fb.com> wrote:
>
> The patch tests for:
> 1. bpf_sk_release() can be called on a tcp_sock btf_id ptr.
>
> 2. Ensure the tcp_sock btf_id pointer cannot be used
>    after bpf_sk_release().
>
> Signed-off-by: Martin KaFai Lau <kafai@fb.com>

Acked-by: Lorenz Bauer <lmb@cloudflare.com>

> ---
>  .../selftests/bpf/verifier/ref_tracking.c     | 47 +++++++++++++++++++
>  1 file changed, 47 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/verifier/ref_tracking.c b/tools/testing/selftests/bpf/verifier/ref_tracking.c
> index 056e0273bf12..006b5bd99c08 100644
> --- a/tools/testing/selftests/bpf/verifier/ref_tracking.c
> +++ b/tools/testing/selftests/bpf/verifier/ref_tracking.c
> @@ -854,3 +854,50 @@
>         .errstr = "Unreleased reference",
>         .result = REJECT,
>  },
> +{
> +       "reference tracking: bpf_sk_release(btf_tcp_sock)",
> +       .insns = {
> +       BPF_SK_LOOKUP(sk_lookup_tcp),
> +       BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
> +       BPF_EXIT_INSN(),
> +       BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
> +       BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
> +       BPF_EMIT_CALL(BPF_FUNC_skc_to_tcp_sock),
> +       BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3),
> +       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
> +       BPF_EMIT_CALL(BPF_FUNC_sk_release),
> +       BPF_EXIT_INSN(),
> +       BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
> +       BPF_EMIT_CALL(BPF_FUNC_sk_release),
> +       BPF_EXIT_INSN(),
> +       },
> +       .prog_type = BPF_PROG_TYPE_SCHED_CLS,
> +       .result = ACCEPT,
> +       .result_unpriv = REJECT,
> +       .errstr_unpriv = "unknown func",
> +},
> +{
> +       "reference tracking: use ptr from bpf_skc_to_tcp_sock() after release",
> +       .insns = {
> +       BPF_SK_LOOKUP(sk_lookup_tcp),
> +       BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
> +       BPF_EXIT_INSN(),
> +       BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
> +       BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
> +       BPF_EMIT_CALL(BPF_FUNC_skc_to_tcp_sock),
> +       BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3),
> +       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
> +       BPF_EMIT_CALL(BPF_FUNC_sk_release),
> +       BPF_EXIT_INSN(),
> +       BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
> +       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
> +       BPF_EMIT_CALL(BPF_FUNC_sk_release),
> +       BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_7, 0),
> +       BPF_EXIT_INSN(),
> +       },
> +       .prog_type = BPF_PROG_TYPE_SCHED_CLS,
> +       .result = REJECT,
> +       .errstr = "invalid mem access",
> +       .result_unpriv = REJECT,
> +       .errstr_unpriv = "unknown func",
> +},
> --
> 2.24.1
>


-- 
Lorenz Bauer  |  Systems Engineer
6th Floor, County Hall/The Riverside Building, SE1 7PB, UK

www.cloudflare.com

  reply	other threads:[~2020-09-25  8:30 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-25  0:03 [PATCH v4 bpf-next 00/13] bpf: Enable bpf_skc_to_* sock casting helper to networking prog type Martin KaFai Lau
2020-09-25  0:03 ` [PATCH v4 bpf-next 01/13] bpf: Move the PTR_TO_BTF_ID check to check_reg_type() Martin KaFai Lau
2020-09-25  8:22   ` Lorenz Bauer
2020-09-25 13:36   ` John Fastabend
2020-09-25  0:03 ` [PATCH v4 bpf-next 02/13] bpf: Enable bpf_skc_to_* sock casting helper to networking prog type Martin KaFai Lau
2020-09-25  8:26   ` Lorenz Bauer
2020-09-25 13:18     ` Martin KaFai Lau
2020-09-25 13:50       ` Lorenz Bauer
2020-09-25 15:47         ` Alexei Starovoitov
2020-09-25 14:21   ` John Fastabend
2020-09-25  0:03 ` [PATCH v4 bpf-next 03/13] bpf: Change bpf_sk_release and bpf_sk_*cgroup_id to accept ARG_PTR_TO_BTF_ID_SOCK_COMMON Martin KaFai Lau
2020-09-25  0:04 ` [PATCH v4 bpf-next 04/13] bpf: Change bpf_sk_storage_*() " Martin KaFai Lau
2020-09-25  0:04 ` [PATCH v4 bpf-next 05/13] bpf: Change bpf_tcp_*_syncookie " Martin KaFai Lau
2020-09-25  0:04 ` [PATCH v4 bpf-next 06/13] bpf: Change bpf_sk_assign " Martin KaFai Lau
2020-09-25  0:04 ` [PATCH v4 bpf-next 07/13] bpf: selftest: Add ref_tracking verifier test for bpf_skc casting Martin KaFai Lau
2020-09-25  8:30   ` Lorenz Bauer [this message]
2020-09-25  0:04 ` [PATCH v4 bpf-next 08/13] bpf: selftest: Move sock_fields test into test_progs Martin KaFai Lau
2020-09-25  0:04 ` [PATCH v4 bpf-next 09/13] bpf: selftest: Adapt sock_fields test to use skel and global variables Martin KaFai Lau
2020-09-25  0:04 ` [PATCH v4 bpf-next 10/13] bpf: selftest: Use network_helpers in the sock_fields test Martin KaFai Lau
2020-09-25  0:04 ` [PATCH v4 bpf-next 11/13] bpf: selftest: Use bpf_skc_to_tcp_sock() " Martin KaFai Lau
2020-09-25  0:04 ` [PATCH v4 bpf-next 12/13] bpf: selftest: Remove enum tcp_ca_state from bpf_tcp_helpers.h Martin KaFai Lau
2020-09-25  0:04 ` [PATCH v4 bpf-next 13/13] bpf: selftest: Add test_btf_skc_cls_ingress Martin KaFai Lau
2020-09-25 16:24   ` John Fastabend
2020-09-25 17:58     ` Martin KaFai Lau
2020-09-25  9:40 ` [PATCH v4 bpf-next 00/13] bpf: Enable bpf_skc_to_* sock casting helper to networking prog type Lorenz Bauer
2020-09-25 23:22 ` Alexei Starovoitov

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