From: Cong Wang <xiyou.wangcong@gmail.com>
To: Bryan Jacobs <its@easytoremember.us>
Cc: linux-kernel@vger.kernel.org
Subject: Re: /proc/[pid]/mem write implications
Date: Sun, 29 Jan 2012 11:36:21 +0800 [thread overview]
Message-ID: <4F24BEB5.5070402@gmail.com> (raw)
In-Reply-To: <20120128203250.090abec6@easytoremember.us>
On 01/29/2012 09:32 AM, Bryan Jacobs wrote:
> Dear LKML,
>
> I have a few questions on the recent change to allow writing
> to /proc/[pid]/mem. If I understand correctly, the recent
> privilege-escalation vulnerability was fundamentally caused by
> incorrectly verifying that the memory being written to by a process was
> its own. The goal was to only allow processes to write to their own
> memory space - this was deemed harmless.
Well, the more fundamental vulnerability is the check was done in
write(2) instead of open(2), which leaves a window for exploits.
>
> But I think that allowing arbitrary processes to write to **their own**
> memory via a file descriptor might in itself be problematic. Please,
> help me understand how this is safe.
You will have a sysctl to control if it is writable.
Thanks.
next prev parent reply other threads:[~2012-01-29 3:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-29 1:32 /proc/[pid]/mem write implications Bryan Jacobs
2012-01-29 3:36 ` Cong Wang [this message]
2012-01-29 14:19 ` Alan Cox
2012-01-30 8:10 ` Indan Zupancic
2012-01-29 14:21 ` Alan Cox
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=4F24BEB5.5070402@gmail.com \
--to=xiyou.wangcong@gmail.com \
--cc=its@easytoremember.us \
--cc=linux-kernel@vger.kernel.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).