Re: [RFC 0/8] Additional kmsg devices

From	Andy Lutomirski <luto@amacapital.net>
Newsgroups	linux.kernel
Subject	Re: [RFC 0/8] Additional kmsg devices
Date	2015-07-03 19:00 +0200
Message-ID	<pIctH-2x8-1@gated-at.bofh.it> (permalink)
References	<pI6Rj-7tK-3@gated-at.bofh.it> <pI7kl-7T6-7@gated-at.bofh.it> <pIaLg-1Di-19@gated-at.bofh.it>
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On Fri, Jul 3, 2015 at 8:09 AM, Marcin Niesluchowski
<m.niesluchow@samsung.com> wrote:
>
> * Message credibility: Lets imagine simple service which collects logs via
> unix sockets. There is no reliable way of identifying logging process.
> getsockopt() with SO_PEERCRED option would give pid form cred structure, but
> according to manual it may not be of actual logging process:
>   "The returned credentials are those that were in effect at the time of the
> call to connect(2) or socketpair(2)."
>       - select(7)

There's SCM_CREDENTIALS, which is dangerous, but it's dangerous in
exactly the same way that your patches are dangerous.  You're
collecting PID/TID when write(2) is called, and it's very easy to get
another process to call write(2) on your behalf, because write(2)
isn't supposed to collect credentials.

--Andy
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Thread

[RFC 0/8] Additional kmsg devices Marcin Niesluchowski <m.niesluchow@samsung.com> - 2015-07-03 13:00 +0200
  [RFC 4/8] kmsg: add function for adding and deleting additional buffers Marcin Niesluchowski <m.niesluchow@samsung.com> - 2015-07-03 13:00 +0200
  [RFC 8/8] kmsg: add ioctl for kmsg* devices operating on buffers Marcin Niesluchowski <m.niesluchow@samsung.com> - 2015-07-03 13:00 +0200
  Re: [RFC 0/8] Additional kmsg devices Marcin Niesluchowski <m.niesluchow@samsung.com> - 2015-07-03 17:10 +0200
    Re: [RFC 0/8] Additional kmsg devices Andy Lutomirski <luto@amacapital.net> - 2015-07-03 19:00 +0200
    Re: [RFC 0/8] Additional kmsg devices Karol Lewandowski <k.lewandowsk@samsung.com> - 2015-07-07 19:20 +0200

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