linux-kernel - Re: [PATCH 1/3] bpf: verifier: Accept dynptr mem as mem in helpers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAEf4Bza3ONHzV0OPu2q17g7Z6w4PD8hMAmjP6ov-hKstt7r55A@mail.gmail.com>
Date:   Wed, 3 May 2023 11:39:32 -0700
From:   Andrii Nakryiko <andrii.nakryiko@...il.com>
To:     Daniel Rosenberg <drosen@...gle.com>
Cc:     Alexei Starovoitov <alexei.starovoitov@...il.com>,
        Joanne Koong <joannelkoong@...il.com>,
        bpf <bpf@...r.kernel.org>, Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        John Fastabend <john.fastabend@...il.com>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <martin.lau@...ux.dev>,
        Song Liu <song@...nel.org>, Yonghong Song <yhs@...com>,
        KP Singh <kpsingh@...nel.org>,
        Stanislav Fomichev <sdf@...gle.com>,
        Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
        Shuah Khan <shuah@...nel.org>,
        Jonathan Corbet <corbet@....net>,
        Mykola Lysenko <mykolal@...com>,
        LKML <linux-kernel@...r.kernel.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@...r.kernel.org>,
        Android Kernel Team <kernel-team@...roid.com>
Subject: Re: [PATCH 1/3] bpf: verifier: Accept dynptr mem as mem in helpers

On Mon, May 1, 2023 at 6:12 PM Daniel Rosenberg <drosen@...gle.com> wrote:
>
> On Thu, Apr 6, 2023 at 3:13 PM Alexei Starovoitov
> <alexei.starovoitov@...il.com> wrote:
> >
> > +1
> > All of the DYNPTR_TYPE_FLAG_MASK flags cannot appear in type == reg->type
> > here.
> > They are either dynamic flags inside bpf_dynptr_kern->size
> > or in arg_type.
> > Like in bpf_dynptr_from_mem_proto.
>
> Looking at this a bit more, I believe this is to enforce packet
> restrictions for DYNPTR_TYPE_SKB and DYNPTR_TYPE_XDP. When a helper
> function alters a packet, dynptr slices of it are invalidated. If I
> remove that annotation entirely, then the invalid_data_slice family of
> tests fail. bpf_dynptr_from_mem_proto is fine since that's just local
> dynptrs, which don't have any extra limitations.


Ah, ok, thanks for investigating!