LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Yafang Shao <laoar.shao@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Petr Mladek <pmladek@suse.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	qiang.zhang@windriver.com, robdclark@chromium.org,
	Al Viro <viro@zeniv.linux.org.uk>,
	christian@brauner.io, Dietmar Eggemann <dietmar.eggemann@arm.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/5] kernel/sched: improve the BUILD_BUG_ON() in get_task_comm()
Date: Thu, 30 Sep 2021 20:43:43 +0800	[thread overview]
Message-ID: <CALOAHbANTC8vQ+f4q_YzFtYtd5Ffrm_nx8Y42552X1kXTCCS7Q@mail.gmail.com> (raw)
In-Reply-To: <202109291111.31671B6A6@keescook>

On Thu, Sep 30, 2021 at 2:12 AM Kees Cook <keescook@chromium.org> wrote:
>
> On Wed, Sep 29, 2021 at 11:50:34AM +0000, Yafang Shao wrote:
> > What we really want to guarantee is that the buf size can't be less than
> > TASK_COMM_LEN. While the size be greater than TASK_COMM_LEN is
> > acceptable.
>
> This makes sense when task_struct::comm is a pointer. (But I think it's
> not a good idea to do that.)
>

OK, I won't make this change.

> >
> > Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
> > ---
> >  include/linux/sched.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/linux/sched.h b/include/linux/sched.h
> > index b387b5943db4..959eaef248fc 100644
> > --- a/include/linux/sched.h
> > +++ b/include/linux/sched.h
> > @@ -1931,7 +1931,7 @@ static inline void set_task_comm(struct task_struct *tsk, const char *from)
> >
> >  extern char *__get_task_comm(char *to, size_t len, struct task_struct *tsk);
> >  #define get_task_comm(buf, tsk) ({                   \
> > -     BUILD_BUG_ON(sizeof(buf) != TASK_COMM_LEN);     \
> > +     BUILD_BUG_ON(sizeof(buf) < TASK_COMM_LEN);      \
> >       __get_task_comm(buf, sizeof(buf), tsk);         \
> >  })
> >
> > --
> > 2.17.1
> >
>
> --
> Kees Cook



-- 
Thanks
Yafang

  reply	other threads:[~2021-09-30 12:44 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-29 11:50 [PATCH 0/5] kthread: increase the size of kthread's comm Yafang Shao
2021-09-29 11:50 ` [PATCH 1/5] kernel: replace sizeof(task->comm) with TASK_COMM_LEN Yafang Shao
2021-09-29 18:09   ` Kees Cook
2021-09-30 12:27     ` Yafang Shao
2021-10-03  3:31   ` Al Viro
2021-10-03 14:14     ` Yafang Shao
2021-09-29 11:50 ` [PATCH 2/5] kernel/fork: allocate task->comm dynamicly Yafang Shao
2021-09-29 13:08   ` Yafang Shao
2021-09-29 18:11   ` Kees Cook
2021-09-30 12:41     ` Yafang Shao
2021-09-30 14:51       ` Petr Mladek
2021-10-01 11:58         ` Yafang Shao
2021-09-29 11:50 ` [PATCH 3/5] kernel/sched: improve the BUILD_BUG_ON() in get_task_comm() Yafang Shao
2021-09-29 18:12   ` Kees Cook
2021-09-30 12:43     ` Yafang Shao [this message]
2021-09-29 11:50 ` [PATCH 4/5] kernel: increase the size of kthread's comm Yafang Shao
2021-09-29 18:19   ` Kees Cook
2021-09-30 12:53     ` Yafang Shao
2021-09-29 11:50 ` [PATCH 5/5] kernel/kthread: show a warning if kthread's comm is still trucated Yafang Shao
2021-09-29 18:20   ` Kees Cook
2021-09-30 12:54     ` Yafang Shao
2021-09-30 15:17   ` Petr Mladek
2021-10-01 11:59     ` Yafang Shao
2021-10-03  3:41 ` [PATCH 0/5] kthread: increase the size of kthread's comm Al Viro
2021-10-03 14:20   ` Yafang Shao

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CALOAHbANTC8vQ+f4q_YzFtYtd5Ffrm_nx8Y42552X1kXTCCS7Q@mail.gmail.com \
    --to=laoar.shao@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=christian@brauner.io \
    --cc=dietmar.eggemann@arm.com \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mathieu.desnoyers@efficios.com \
    --cc=peterz@infradead.org \
    --cc=pmladek@suse.com \
    --cc=qiang.zhang@windriver.com \
    --cc=robdclark@chromium.org \
    --cc=valentin.schneider@arm.com \
    --cc=viro@zeniv.linux.org.uk \
    --subject='Re: [PATCH 3/5] kernel/sched: improve the BUILD_BUG_ON() in get_task_comm()' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).