Re: [GIT PULL] kdbus for 4.1-rc1

Greg Kroah-Hartman
2015-04-23T18:56:41Z

On Thu, Apr 23, 2015 at 11:04:36AM -0700, Linus Torvalds wrote:
> On Thu, Apr 23, 2015 at 10:57 AM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > If somebody is printing something, it shouldn't matter if it's "lpr"
> > or "firefox http://horses.and.trannyporn.my.little.pony.com/" that
> > does the printing.
>
> And btw, it's not just "this is information that shouldn't be logged".
>
> It's literally "information that should not *ever* be used". I can
> easily see some phone manufacturer deciding to do "value add" by
> adding a special case where a special vendor system manager program
> gets a back door to some service, because it needs to access the
> camera for user identification at login time, so there's some magic
>
> if (!strcmp(client->pid_comm, "vendor-login-pr"))
> return ACCESS_OK;
>
> because "it was the simplest way to do this", and the programmer knew
> it was a hack, but he needed to get it working because he had a
> deadline yesterday.
>
> And then somebody figures this out, and makes an app that takes
> pictures on your phone surreptitiously.
>
> No, we can't protect against vendors doing stupid things, but we very
> much also shouldn't make the kernel have interfaces that basically
> encourage people to do stupid things because they make irrelevant and
> wrongheaded data available.

Doing access control based on comm and cmdline is horrid, I totally
agree. But right now, any process in the system can read any other
process's comm and cmdline value out of /proc today. So removing it
from the metadata is fine for kdbus, I can live with that, but it really
isn't "preventing" anything that's not already visible to everyone, so
if someone wanting to be "bad" could always still log it or do anything
else they wanted with it.

Doesn't syslog uses it today all over the place for logging stuff that
happens in the system?

Or am I missing something here?

thanks,

greg k-h