# Re: \[RFC 0/8\] Additional kmsg devices

- From: Andy Lutomirski \<hidden\>
- Date: 2015-07-03 16:58:20 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2015/07/4527277
- Thread: https://ratatoskr.run/linux-api/2015/07/4527040/t.md

```text
On Fri, Jul 3, 2015 at 8:09 AM, Marcin Niesluchowski
[ref] 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
```