From: Hou Tao <houtao1@huawei.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Yonghong Song <yhs@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Network Development <netdev@vger.kernel.org>,
bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf-next v4 2/2] bpf: disallow BPF_LOG_KERNEL log level for bpf(BPF_BTF_LOAD)
Date: Thu, 2 Dec 2021 11:42:00 +0800 [thread overview]
Message-ID: <d8328f48-bce7-b19b-53db-ccee3cc3322a@huawei.com> (raw)
In-Reply-To: <CAADnVQ+LDW+K_3czmiTcU4CtONxM+eTkyuwwra5hGTqAXTCcZw@mail.gmail.com>
Hi,
On 12/2/2021 1:42 AM, Alexei Starovoitov wrote:
> On Tue, Nov 30, 2021 at 11:19 PM Hou Tao <houtao1@huawei.com> wrote:
>> BPF_LOG_KERNEL is only used internally, so disallow bpf_btf_load()
>> to set log level as BPF_LOG_KERNEL. The same checking has already
>> been done in bpf_check(), so factor out a helper to check the
>> validity of log attributes and use it in both places.
>>
>>
snip
>> - ret = -EINVAL;
>> /* log attributes have to be sane */
>> - if (log->len_total < 128 || log->len_total > UINT_MAX >> 2 ||
>> - !log->level || !log->ubuf || log->level & ~BPF_LOG_MASK)
>> + if (!bpf_verifier_log_attr_valid(log, UINT_MAX >> 2)) {
>> + ret = -EINVAL;
> It's actually quite bad that we have this discrepancy in limits.
> I've already sent a patch to make them the same.
> It was a pain to debug.
> https://lore.kernel.org/bpf/20211124060209.493-7-alexei.starovoitov@gmail.com/
> "
> Otherwise tools that progressively increase log size and use the same log
> for BTF loading and program loading will be hitting hard to debug EINVAL.
> "
OK. Will send a single patch to handle that based on your patch set.
Regards,
Tao
prev parent reply other threads:[~2021-12-02 3:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-01 7:34 [PATCH bpf-next v4 0/2] clean-up for BPF_LOG_KERNEL log level Hou Tao
2021-12-01 7:34 ` [PATCH bpf-next v4 1/2] bpf: clean-up bpf_verifier_vlog() " Hou Tao
2021-12-01 17:50 ` Alexei Starovoitov
2021-12-01 7:34 ` [PATCH bpf-next v4 2/2] bpf: disallow BPF_LOG_KERNEL log level for bpf(BPF_BTF_LOAD) Hou Tao
2021-12-01 17:42 ` Alexei Starovoitov
2021-12-02 3:42 ` Hou Tao [this message]
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