From: sdf@google.com
To: Peilin Ye <yepeilin.cs@gmail.com>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>,
Andrii Nakryiko <andrii@kernel.org>,
Alexei Starovoitov <ast@kernel.org>, bpf <bpf@vger.kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
davem@davemloft.net, haoluo@google.com, hawk@kernel.org,
John Fastabend <john.fastabend@gmail.com>,
jolsa@kernel.org, KP Singh <kpsingh@kernel.org>,
kuba@kernel.org, lkml <linux-kernel@vger.kernel.org>,
llvm@lists.linux.dev, martin.lau@linux.dev, nathan@kernel.org,
Nick Desaulniers <ndesaulniers@google.com>,
Networking <netdev@vger.kernel.org>, Song Liu <song@kernel.org>,
syzkaller-bugs@googlegroups.com, Tom Rix <trix@redhat.com>,
Yonghong Song <yhs@fb.com>, Peilin Ye <peilin.ye@bytedance.com>
Subject: Re: [syzbot] WARNING in bpf_verifier_vlog
Date: Fri, 9 Sep 2022 14:43:18 -0700 [thread overview]
Message-ID: <YxuzdhmaHeyycyRi@google.com> (raw)
In-Reply-To: <20220909211540.GA11304@bytedance>
On 09/09, Peilin Ye wrote:
> Hi all,
> On Fri, Sep 09, 2022 at 12:54:06PM -0700, sdf@google.com wrote:
> > On 09/09, Benjamin Tissoires wrote:
> > Yeah, good point. I've run the repro. I think the issue is that
> > syzkaller is able to pass btf with a super long random name which
> > then hits BPF_VERIFIER_TMP_LOG_SIZE while printing the verifier
> > log line. Seems like a non-issue to me, but maybe we need to
> > add some extra validation..
> In btf_func_proto_check_meta():
> if (t->name_off) {
> btf_verifier_log_type(env, t, "Invalid name");
> return -EINVAL;
> }
> In the verifier log, maybe we should just say that
> BTF_KIND_FUNC_PROTO "must
> not have a name" [1], instead of printing out the user-provided
> (potentially very long) name and say it's "Invalid" ?
> Similarly, for name-too-long errors, should we truncate the name to
> KSYM_NAME_LEN bytes (see __btf_name_valid()) in the log ?
Both suggestions sound good to me. Care to cook and send a patch with a
fix?
> [1] commit 2667a2626f4d ("bpf: btf: Add BTF_KIND_FUNC and
> BTF_KIND_FUNC_PROTO")
> Thanks,
> Peilin Ye
next prev parent reply other threads:[~2022-09-09 21:43 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-09 4:19 [syzbot] WARNING in bpf_verifier_vlog syzbot
2022-09-09 16:37 ` sdf
2022-09-09 16:52 ` Benjamin Tissoires
2022-09-09 19:54 ` sdf
2022-09-09 21:15 ` Peilin Ye
2022-09-09 21:43 ` sdf [this message]
2022-09-09 21:57 ` Peilin Ye
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