linux-kernel - Re: [RFC PATCH bpf-next RESEND 00/16] bpf: Checkpoint/Restore In eBPF (CRIB)

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

Message-ID: <CAADnVQLsqV2q3Ury+p3_6n4eph+TWAVRFSVWst803k6XV_qf6g@mail.gmail.com>
Date: Mon, 22 Jul 2024 17:58:04 -0700
From: Alexei Starovoitov <alexei.starovoitov@...il.com>
To: Kumar Kartikeya Dwivedi <memxor@...il.com>
Cc: Juntong Deng <juntong.deng@...look.com>, Alexei Starovoitov <ast@...nel.org>, 
	Daniel Borkmann <daniel@...earbox.net>, John Fastabend <john.fastabend@...il.com>, 
	Martin KaFai Lau <martin.lau@...ux.dev>, Eddy Z <eddyz87@...il.com>, Song Liu <song@...nel.org>, 
	Yonghong Song <yonghong.song@...ux.dev>, KP Singh <kpsingh@...nel.org>, 
	Stanislav Fomichev <sdf@...ichev.me>, Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>, 
	Andrii Nakryiko <andrii@...nel.org>, Andrei Vagin <avagin@...il.com>, snorcht@...il.com, 
	bpf <bpf@...r.kernel.org>, Network Development <netdev@...r.kernel.org>, 
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH bpf-next RESEND 00/16] bpf: Checkpoint/Restore In eBPF (CRIB)

On Mon, Jul 22, 2024 at 5:50 PM Kumar Kartikeya Dwivedi
<memxor@...il.com> wrote:
>
> >
> >   > Currently we cannot pass the pointer returned by the iterator next
> >   > method as argument to the KF_TRUSTED_ARGS kfuncs, because the pointer
> >   > returned by the iterator next method is not "valid".
>
> I've replied to this particular patch to explain what exact unsafety
> it might introduce.

What do you mean?
I think we can make the return value from iter_next() trusted in
certain cases.
For example bpf_iter_task_next() returns task_struct and it
can be safely marked as MEM_RCU, since the whole iterator is
KF_RCU_PROTECTED.