linux-kernel - Re: [PATCH bpf-next v1 1/3] bpf, sockmap: avoid using sk

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: <20250227205641.n2zpm5yetkoopvcz@gmail.com>
Date: Thu, 27 Feb 2025 12:57:15 -0800
From: John Fastabend <john.fastabend@...il.com>
To: Cong Wang <xiyou.wangcong@...il.com>
Cc: Jiayuan Chen <jiayuan.chen@...ux.dev>, cong.wang@...edance.com,
	jakub@...udflare.com, davem@...emloft.net, edumazet@...gle.com,
	kuba@...nel.org, pabeni@...hat.com, horms@...nel.org,
	andrii@...nel.org, eddyz87@...il.com, mykolal@...com,
	ast@...nel.org, daniel@...earbox.net, martin.lau@...ux.dev,
	song@...nel.org, yonghong.song@...ux.dev, kpsingh@...nel.org,
	sdf@...ichev.me, haoluo@...gle.com, jolsa@...nel.org,
	shuah@...nel.org, mhal@...x.co, sgarzare@...hat.com,
	netdev@...r.kernel.org, bpf@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
	mrpre@....com,
	syzbot+dd90a702f518e0eac072@...kaller.appspotmail.com
Subject: Re: [PATCH bpf-next v1 1/3] bpf, sockmap: avoid using sk_socket
 after free

On 2025-02-27 11:45:53, Cong Wang wrote:
> On Wed, Feb 26, 2025 at 09:22:40PM +0800, Jiayuan Chen wrote:
> > Use RCU lock to protect sk_socket, preventing concurrent close and release
> > by another thread.
> > 
> > Because TCP/UDP are already within a relatively large critical section:
> > '''
> > ip_local_deliver_finish
> >   rcu_read_lock
> >   ip_protocol_deliver_rcu
> >       tcp_rcv/udp_rcv
> >   rcu_read_unlock
> > '''
> > 
> > Adding rcu_read_{un}lock() at the entrance and exit of sk_data_ready
> > will not increase performance overhead.
> > 
> > Reported-by: syzbot+dd90a702f518e0eac072@...kaller.appspotmail.com
> > Closes: https://lore.kernel.org/bpf/6734c033.050a0220.2a2fcc.0015.GAE@google.com/
> > Signed-off-by: Jiayuan Chen <jiayuan.chen@...ux.dev>
> 
> sock_def_readable() already acquires RCU read lock anyway.
> 
> Reviewed-by: Cong Wang <xiyou.wangcong@...il.com>

Thanks.

Reviewed-by: John Fastabend <john.fastabend@...il.com>