Re: [PATCH v3 1/1] bpf: Ensure correct locking around vulnerable function find_vpid()

[Lee Jones]

On Mon, 12 Sep 2022, Yonghong Song wrote:
> On 9/12/22 2:38 PM, Lee Jones wrote:
> > The documentation for find_vpid() clearly states:
> > 
> 
> No need for the above extra line.

The intentional blank formatting line?

The commit message would look worse without it.

Is this really a blocker?

> >    "Must be called with the tasklist_lock or rcu_read_lock() held."
> > 
> > Presently we do neither.
> 
> Presently we do neither for find_vpid() instance in bpf_task_fd_query().
> Add proper rcu_read_lock/unlock() to fix the issue.

I can expand this.

> > Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> > Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
> > Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> > Cc: John Fastabend <john.fastabend@xxxxxxxxx>
> > Cc: Andrii Nakryiko <andrii@xxxxxxxxxx>
> > Cc: Martin KaFai Lau <martin.lau@xxxxxxxxx>
> > Cc: Song Liu <song@xxxxxxxxxx>
> > Cc: Yonghong Song <yhs@xxxxxx>
> > Cc: KP Singh <kpsingh@xxxxxxxxxx>
> > Cc: Stanislav Fomichev <sdf@xxxxxxxxxx>
> > Cc: Hao Luo <haoluo@xxxxxxxxxx>
> > Cc: bpf@xxxxxxxxxxxxxxx
> > Fixes: 41bdc4b40ed6f ("bpf: introduce bpf subcommand BPF_TASK_FD_QUERY")
> > Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
> 
> Ack with above a few suggestions for the commit message.
> 
> Acked-by: Yonghong Song <yhs@xxxxxx>

-- 
Lee Jones [李琼斯]