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From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Alistair Popple <apopple@nvidia.com>,
	Byungchul Park <byungchul@sk.com>,
	David Hildenbrand <david@kernel.org>,
	Gregory Price <gourry@gourry.net>,
	Joshua Hahn <joshua.hahnjy@gmail.com>,
	Matthew Brost <matthew.brost@intel.com>,
	Rakie Kim <rakie.kim@sk.com>,
	Ying Huang <ying.huang@linux.alibaba.com>,
	Zi Yan <ziy@nvidia.com>, Jann Horn <jannh@google.com>,
	Kees Cook <kees@kernel.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/migrate: find_mm_struct: fix race between security checks and suid exec
Date: Tue, 26 May 2026 19:07:30 +0200	[thread overview]
Message-ID: <ahXTUjrU44xKuofI@redhat.com> (raw)
In-Reply-To: <20260526094242.adf161e66ee7adbb445d81ee@linux-foundation.org>

On 05/26, Andrew Morton wrote:
>
> On Tue, 26 May 2026 16:42:11 +0200 Oleg Nesterov <oleg@redhat.com> wrote:
>
> > The target task can execute a setuid binary between ptrace_may_access()
> > and get_task_mm(). Protect this critical section with exec_update_lock.
> >
> > I don't think cpuset_mems_allowed(task) should be called under
> > exec_update_lock, but this patch just tries to add the minimal fix.
> >
> > Perhaps we can later add a common helper which can be used by
> > find_mm_struct() and kernel_migrate_pages().
> >
>
> Thanks.  Sashiko thinks we should fix kernel_migrate_pages() also:
> 	https://sashiko.dev/#/patchset/ahWxQ3JxdR5ff2qf@redhat.com

Of course ;) That is why I have already sent

	[PATCH 0/4] mm/mempolicy: kernel_migrate_pages: fix race between security checks and suid exec
	https://lore.kernel.org/all/ahMt6xyUNnacZU8-@redhat.com/

and mentioned this in 0/4.

Sashiko has concern about 3/4 in the series above.

I personally do not think this is a problem... Without hidepid != 0
/proc/pid/status reports the same "info leak".

But may be I am wrong. Still waiting for review from maintainers.

Oleg.



  reply	other threads:[~2026-05-26 17:08 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-26 14:42 [PATCH] mm/migrate: find_mm_struct: fix race between security checks and suid exec Oleg Nesterov
2026-05-26 16:42 ` Andrew Morton
2026-05-26 17:07   ` Oleg Nesterov [this message]
2026-05-26 20:24 ` Andrew Morton
2026-05-27 10:02   ` Oleg Nesterov
2026-05-27 18:14 ` Gregory Price

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