Messages in this thread | | | Date | Tue, 12 Nov 2013 13:20:29 +0100 | Subject | Re: Partially Privileged Applications | From | Shahbaz Youssefi <> |
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Hi,
Thanks for the feedback. You are absolutely right and as I mentioned before, I came to realize that it would be hard to contain malicious code.
Nevertheless, honest mistakes shouldn't be a big problem. Currently, if you write a kernel module, you can cause havoc and the only thing preventing you from inserting a bad module is a `sudo`. For the honest people (regardless of noob or not), it would be the same. If you want to run a privileged application, you need a `sudo` and the implications are as good or as bad as inserting your own kernel module.
On Tue, Nov 12, 2013 at 12:56 PM, Levente Kurusa <levex@linux.com> wrote: > 2013-11-11 19:44 keltezéssel, Matthias Schniedermeyer írta: >> On 11.11.2013 14:05, Shahbaz Youssefi wrote: >>> On Sun, Nov 10, 2013 at 8:06 PM, Matthias Schniedermeyer <ms@citd.de> wrote: >>>> I don't see a way around "borders" (Papers please), otherwise you can't >>>> reject things you don't want, you have to check if that something that >>>> is to be done is allowed. For e.g. you would get around every >>>> permission-check, because the code you called is allowed to do >>>> everything. >>> >>> You're right actually. Proper linking solves the issue for "good people", >>> but I can't think of a not-dirty way for preventing bad calls from >>> "bad people". I may get back here if I do find a solution. > > Hi, > > What you describe in your blogpost already exists. It is called real-mode. > Imagine yourself as a userspace developer. You make an application and want > it to run as fast as possible and therefore you eliminate the mode-switches, which > do cost a lot of time. Your only way to stop them is by leaving out .text section > and only having the .privileged section. > > Also, think about the malicious software we had back in the DOS times. You caught one, > your computer or atleast your harddrive died. > > Another problem is the bad developer, they want to test out their application, but they > accidentally left out something. Just thinking about myself, I made lots of stupid mistakes > when I began development, if the CPU worked per your description, I would have bricked bunch of > computers. The whole point of separating kernelspace from userspace is not only the abstraction > of hardware, but the security as well. We want to protect the user from having the fear of bricking > his or her computer. > > By this, I don't mean to say that your idea is bad, but right now we can't just trust userspace > with 'God' powers. > > -- > Regards, > Levente Kurusa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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