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From: Alexei Starovoitov <ast@fb.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>,
	Alexei Starovoitov <ast@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>,
	Daniel Borkmann <daniel@iogearbox.net>,
	"x86@kernel.org" <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: Wed, 9 Oct 2019 19:38:17 +0000	[thread overview]
Message-ID: <832aa9b3-8c7a-6304-ad09-e825a1c72e3a@fb.com> (raw)
In-Reply-To: <CAEf4Bzb2XEp2H26RonyPjvUqXB4qx6sc6KN_i74hu4bhPhhc4w@mail.gmail.com>

On 10/8/19 10:29 PM, Andrii Nakryiko wrote:
> 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?

yeah. that sucks that we forgot to check expected_attach_type for zero
when that field was introduced for networking progs.
I'll add new u32 to prog_load command instead. It's cleaner too.

  reply	other threads:[~2019-10-09 19:38 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
2019-10-09 19:38     ` Alexei Starovoitov [this message]
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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