Re: [PATCH v2] kmsg: Honor dmesg_restrict sysctl on /dev/kmsg

From: Josh Boyer
Date: Wed Apr 24 2013 - 18:01:27 EST

On Wed, Apr 24, 2013 at 02:30:53PM -0700, Linus Torvalds wrote:
> On Wed, Apr 24, 2013 at 1:35 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> >
> > That said, I much prefer doing the privilege test at read time since
> > that means passing a file descriptor to another process doesn't mean
> > the new process can just continue reading.
> Bullshit.
> That's exactly the wrong kind of thinking. If you had privileges to
> open something, and you pass it off, it's *your* choice.
> In contrast, the "anybody can open, but some people can read/write"
> has several times resulted in real security issues. Notably the whole
> "open something, then fool a suid program to write its error message
> to it".
> This whole discussion has been f*cking moronic. The "security"
> arguments have been utter shite with clearly no thinking behind it,
> the feature is total crap (people need dmesg to do basic bug
> reporting), and I'm seriously considering just getting rid of this
> idiotic dmesg_restrict thing entirely. Your comment is the very
> epitome of bad security thinking.

I was just trying to get the 3 interfaces all honoring the same thing.

Let this be a lesson to you all: I am the harbinger of security
features removal. If you see me sending patches, run away or I might
accidentally cross the streams and make your feature undergo total
protonic reversal.

Now if only I could use this power for good, like somehow getting Linus
to remove capabilities entirely...

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