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From: YiFei Zhu <zhuyifei1999@gmail.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: containers@lists.linux.dev, bpf <bpf@vger.kernel.org>,
	 YiFei Zhu <yifeifz2@illinois.edu>,
	LSM List <linux-security-module@vger.kernel.org>,
	 Alexei Starovoitov <ast@kernel.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	 Andy Lutomirski <luto@amacapital.net>,
	Austin Kuo <hckuo2@illinois.edu>,
	 Claudio Canella <claudio.canella@iaik.tugraz.at>,
	Daniel Borkmann <daniel@iogearbox.net>,
	 Daniel Gruss <daniel.gruss@iaik.tugraz.at>,
	Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
	 Giuseppe Scrivano <gscrivan@redhat.com>,
	Hubertus Franke <frankeh@us.ibm.com>,
	Jann Horn <jannh@google.com>,
	 Jinghao Jia <jinghao7@illinois.edu>,
	Josep Torrellas <torrella@illinois.edu>,
	 Kees Cook <keescook@chromium.org>,
	Sargun Dhillon <sargun@sargun.me>, Tianyin Xu <tyxu@illinois.edu>,
	 Tobin Feldman-Fitzthum <tobin@ibm.com>,
	Tom Hromatka <tom.hromatka@oracle.com>,
	Will Drewry <wad@chromium.org>
Subject: Re: [RFC PATCH bpf-next seccomp 10/12] seccomp-ebpf: Add ability to read user memory
Date: Thu, 13 May 2021 00:26:19 -0500	[thread overview]
Message-ID: <CABqSeAR9rgARxYGYUVZQgZ0a-wqZxy-qeoVpu495XHxpj0Ku=A@mail.gmail.com> (raw)
In-Reply-To: <20210512223626.olex7ewf6xd6m2c4@ast-mbp.dhcp.thefacebook.com>

On Wed, May 12, 2021 at 5:36 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
> Typically the verifier does all the checks at load time to avoid
> run-time overhead during program execution. Then at attach time we
> check that attach parameters provided at load time match exactly
> to those at attach time. ifindex, attach_btf_id, etc fall into this category.
> Doing something similar it should be possible to avoid
> doing get_dumpable() at run-time.

Do you mean to move the check of dumpable to load time instead of
runtime? I do not think that makes sense. A process may arbitrarily
set its dumpable attribute during execution via prctl. A process could
do set itself to non-dumpable, before interacting with sensitive
information that would better not be possible to be dumped (eg.
ssh-agent does this [1]). Therefore, being dumpable at one point in
time does not indicate anything about whether it stays dumpable at a
later point in time. Besides, seccomp filters are inherited across
clone and exec, attaching to many tasks with no option to detach. What
should the load-time check of task dump-ability be against? The
current task may only be the tip of an iceburg.

[1] https://github.com/openssh/openssh-portable/blob/2dc328023f60212cd29504fc05d849133ae47355/ssh-agent.c#L1398

YiFei Zhu

  reply	other threads:[~2021-05-13  5:26 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-10 17:22 [RFC PATCH bpf-next seccomp 00/12] eBPF seccomp filters YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 01/12] seccomp: Move no_new_privs check to after prepare_filter YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 02/12] bpf, seccomp: Add eBPF filter capabilities YiFei Zhu
2021-05-11 10:59   ` kernel test robot
2021-05-11 16:40   ` kernel test robot
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 03/12] seccomp, ptrace: Add a mechanism to retrieve attached eBPF seccomp filters YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 04/12] libbpf: recognize section "seccomp" YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 05/12] samples/bpf: Add eBPF seccomp sample programs YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 06/12] lsm: New hook seccomp_extended YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 07/12] bpf/verifier: allow restricting direct map access YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 08/12] seccomp-ebpf: restrict filter to almost cBPF if LSM request such YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 09/12] yama: (concept) restrict seccomp-eBPF with ptrace_scope YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 10/12] seccomp-ebpf: Add ability to read user memory YiFei Zhu
2021-05-11  2:04   ` Alexei Starovoitov
2021-05-11  7:14     ` YiFei Zhu
2021-05-11  7:14       ` YiFei Zhu
2021-05-12 22:36       ` Alexei Starovoitov
2021-05-13  5:26         ` YiFei Zhu [this message]
2021-05-13  5:26           ` YiFei Zhu
2021-05-13 14:53           ` Andy Lutomirski
2021-05-13 17:12             ` YiFei Zhu
2021-05-13 17:12               ` YiFei Zhu
2021-05-13 17:15               ` Andy Lutomirski
2021-05-13 17:15                 ` Andy Lutomirski
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 11/12] bpf/verifier: support NULL-able ptr to BTF ID as helper argument YiFei Zhu
2021-05-10 17:22 ` [RFC PATCH bpf-next seccomp 12/12] seccomp-ebpf: support task storage from BPF-LSM, defaulting to group leader YiFei Zhu
2021-05-11  1:58   ` Alexei Starovoitov
2021-05-11  5:44     ` YiFei Zhu
2021-05-11  5:44       ` YiFei Zhu
2021-05-12 21:56       ` Alexei Starovoitov
2021-05-10 17:47 ` [RFC PATCH bpf-next seccomp 00/12] eBPF seccomp filters Andy Lutomirski
2021-05-10 17:47   ` Andy Lutomirski
2021-05-11  5:21   ` YiFei Zhu
2021-05-11  5:21     ` YiFei Zhu
2021-05-15 15:49     ` Andy Lutomirski
2021-05-20  9:05       ` Christian Brauner
     [not found]     ` <fffbea8189794a8da539f6082af3de8e@DM5PR11MB1692.namprd11.prod.outlook.com>
2021-05-16  8:38       ` Tianyin Xu
2021-05-17 15:40         ` Tycho Andersen
2021-05-17 17:07         ` Sargun Dhillon
2021-05-17 17:07           ` Sargun Dhillon
     [not found]         ` <108b4b9c2daa4123805d2b92cf51374b@DM5PR11MB1692.namprd11.prod.outlook.com>
2021-05-20  8:16           ` Tianyin Xu
2021-05-20  8:56             ` Christian Brauner
2021-05-20  9:37               ` Christian Brauner
2021-06-01 19:55               ` Kees Cook
2021-06-09  6:32                 ` Jinghao Jia
2021-06-09  6:27               ` Jinghao Jia
     [not found]             ` <00fe481c572d486289bc88780f48e88f@DM5PR11MB1692.namprd11.prod.outlook.com>
2021-05-20 22:13               ` Tianyin Xu
     [not found]         ` <eae2a0e5038b41c4af87edcb3d4cdc13@DM5PR11MB1692.namprd11.prod.outlook.com>
2021-05-20  8:22           ` Tianyin Xu
2021-05-24 18:55             ` Sargun Dhillon
2021-05-24 18:55               ` Sargun Dhillon

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