linux-kernel - Re: [PATCH 3/6] bpf: task_group_seq_get_next: fix the skip_if_dup

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]

Date:   Fri, 25 Aug 2023 15:49:35 -0700
From:   Yonghong Song <yonghong.song@...ux.dev>
To:     Oleg Nesterov <oleg@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Yonghong Song <yhs@...com>
Cc:     "Eric W. Biederman" <ebiederm@...ssion.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Kui-Feng Lee <kuifeng@...com>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <martin.lau@...nel.org>,
        bpf@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/6] bpf: task_group_seq_get_next: fix the
 skip_if_dup_files check



On 8/25/23 9:19 AM, Oleg Nesterov wrote:
> Unless I am notally confused it is wrong. We are going to return or
> skip next_task so we need to check next_task-files, not task->files.

Thanks for capturing this. This is indeed an oversight.

Acked-by: Yonghong Song <yonghong.song@...ux.dev>

> 
> Signed-off-by: Oleg Nesterov <oleg@...hat.com>
> ---
>   kernel/bpf/task_iter.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
> index 1589ec3faded..2264870ae3fc 100644
> --- a/kernel/bpf/task_iter.c
> +++ b/kernel/bpf/task_iter.c
> @@ -82,7 +82,7 @@ static struct task_struct *task_group_seq_get_next(struct bpf_iter_seq_task_comm
>   
>   	common->pid_visiting = *tid;
>   
> -	if (skip_if_dup_files && task->files == task->group_leader->files) {
> +	if (skip_if_dup_files && next_task->files == next_task->group_leader->files) {
>   		task = next_task;
>   		goto retry;
>   	}