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!
next prev 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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