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From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
	security@kernel.org
Subject: Re: [PATCH] prctl: fix PR_SET_MM_AUXV kernel stack leak
Date: Mon, 15 Mar 2021 01:18:27 +0300	[thread overview]
Message-ID: <YE6LswIxL1N+8AS4@grain> (raw)
In-Reply-To: <YE53QiJuxsCUeoiu@localhost.localdomain>

On Sun, Mar 14, 2021 at 11:51:14PM +0300, Alexey Dobriyan wrote:
> 	prctl(PR_SET_MM, PR_SET_MM_AUXV, addr, 1);
> 
> will copy 1 byte from userspace to (quite big) on-stack array
> and then stash everything to mm->saved_auxv.
> AT_NULL terminator will be inserted at the very end.
> 
> /proc/*/auxv handler will find that AT_NULL terminator
> and copy original stack contents to userspace.
> 
> This devious scheme requires CAP_SYS_RESOURCE.
> 
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> ---

Thanks for catching up, Alexey!

  parent reply	other threads:[~2021-03-14 22:19 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-14 20:51 [PATCH] prctl: fix PR_SET_MM_AUXV kernel stack leak Alexey Dobriyan
2021-03-14 21:40 ` Linus Torvalds
2021-03-14 22:24   ` Cyrill Gorcunov
2021-03-15  6:00   ` auxv stuff (Re: [PATCH] prctl: fix PR_SET_MM_AUXV kernel stack leak) Alexey Dobriyan
2021-03-15  6:42     ` Cyrill Gorcunov
2021-03-16 18:50       ` Alexey Dobriyan
2021-03-16 18:51         ` Cyrill Gorcunov
2021-03-14 22:18 ` Cyrill Gorcunov [this message]
2021-03-15 10:29 ` [PATCH] prctl: fix PR_SET_MM_AUXV kernel stack leak Dan Carpenter
2021-03-15 13:30   ` Alexey Dobriyan
2021-03-15 12:08 ` Oleg Nesterov
2021-03-15 12:54   ` Cyrill Gorcunov
2021-03-15 13:19     ` Oleg Nesterov
2021-03-15 13:52       ` Cyrill Gorcunov

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