From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Alexei Starovoitov <ast@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>,
Daniel Borkmann <daniel@iogearbox.net>,
x86@kernel.org, Networking <netdev@vger.kernel.org>,
bpf <bpf@vger.kernel.org>, Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH bpf-next 09/10] bpf: disallow bpf_probe_read[_str] helpers
Date: Tue, 8 Oct 2019 22:29:08 -0700 [thread overview]
Message-ID: <CAEf4Bzb2XEp2H26RonyPjvUqXB4qx6sc6KN_i74hu4bhPhhc4w@mail.gmail.com> (raw)
In-Reply-To: <20191005050314.1114330-10-ast@kernel.org>
On Fri, Oct 4, 2019 at 10:04 PM Alexei Starovoitov <ast@kernel.org> wrote:
>
> Disallow bpf_probe_read() and bpf_probe_read_str() helpers in
> raw_tracepoint bpf programs that use in-kernel BTF to track
> types of memory accesses.
>
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
> ---
> kernel/trace/bpf_trace.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 52f7e9d8c29b..7c607f79f1bb 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -700,6 +700,8 @@ tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> case BPF_FUNC_map_peek_elem:
> return &bpf_map_peek_elem_proto;
> case BPF_FUNC_probe_read:
> + if (prog->expected_attach_type)
> + return NULL;
This can unintentionally disable bpf_probe_read/bpf_probe_read_str for
non-raw_tp programs that happened to specify non-zero
expected_attach_type, which we don't really validate for
kprobe/tp/perf_event/etc. So how about passing program type into
tracing_func_proto() so that we can have more granular control?
> return &bpf_probe_read_proto;
> case BPF_FUNC_ktime_get_ns:
> return &bpf_ktime_get_ns_proto;
> @@ -728,6 +730,8 @@ tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> case BPF_FUNC_get_prandom_u32:
> return &bpf_get_prandom_u32_proto;
> case BPF_FUNC_probe_read_str:
> + if (prog->expected_attach_type)
> + return NULL;
> return &bpf_probe_read_str_proto;
> #ifdef CONFIG_CGROUPS
> case BPF_FUNC_get_current_cgroup_id:
> --
> 2.20.0
>
next prev parent reply other threads:[~2019-10-09 5:29 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-05 5:03 [PATCH bpf-next 00/10] bpf: revolutionize bpf tracing Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 01/10] bpf: add typecast to raw_tracepoints to help BTF generation Alexei Starovoitov
2019-10-05 18:40 ` Andrii Nakryiko
2019-10-06 3:58 ` John Fastabend
2019-10-05 5:03 ` [PATCH bpf-next 02/10] bpf: add typecast to bpf helpers " Alexei Starovoitov
2019-10-05 18:41 ` Andrii Nakryiko
2019-10-06 4:00 ` John Fastabend
2019-10-05 5:03 ` [PATCH bpf-next 03/10] bpf: process in-kernel BTF Alexei Starovoitov
2019-10-06 6:36 ` Andrii Nakryiko
2019-10-06 23:49 ` Alexei Starovoitov
2019-10-07 0:20 ` Andrii Nakryiko
2019-10-09 20:51 ` Martin Lau
2019-10-10 3:43 ` Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 04/10] libbpf: auto-detect btf_id of raw_tracepoint Alexei Starovoitov
2019-10-07 23:41 ` Andrii Nakryiko
2019-10-09 2:26 ` Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 05/10] bpf: implement accurate raw_tp context access via BTF Alexei Starovoitov
2019-10-07 16:32 ` Alan Maguire
2019-10-09 3:59 ` Alexei Starovoitov
2019-10-08 0:35 ` Andrii Nakryiko
2019-10-09 3:30 ` Alexei Starovoitov
2019-10-09 4:01 ` Andrii Nakryiko
2019-10-09 5:10 ` Andrii Nakryiko
2019-10-10 3:54 ` Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 06/10] bpf: add support for BTF pointers to interpreter Alexei Starovoitov
2019-10-08 3:08 ` Andrii Nakryiko
2019-10-05 5:03 ` [PATCH bpf-next 07/10] bpf: add support for BTF pointers to x86 JIT Alexei Starovoitov
2019-10-05 6:03 ` Eric Dumazet
2019-10-09 17:38 ` Andrii Nakryiko
2019-10-09 17:46 ` Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 08/10] bpf: check types of arguments passed into helpers Alexei Starovoitov
2019-10-09 18:01 ` Andrii Nakryiko
2019-10-09 19:58 ` Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 09/10] bpf: disallow bpf_probe_read[_str] helpers Alexei Starovoitov
2019-10-09 5:29 ` Andrii Nakryiko [this message]
2019-10-09 19:38 ` Alexei Starovoitov
2019-10-05 5:03 ` [PATCH bpf-next 10/10] selftests/bpf: add kfree_skb raw_tp test Alexei Starovoitov
2019-10-09 5:36 ` Andrii Nakryiko
2019-10-09 17:37 ` Alexei Starovoitov
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