Re: thoughts on kernel security issues

[Andrew Morton]

Dave Jones <davej@xxxxxxxxxx> wrote:
>
> On Wed, Jan 12, 2005 at 06:28:38PM -0800, Andrew Morton wrote:
>  
>  > IMO, local DoS holes are important mainly because buggy userspace
>  > applications allow remote users to get in and exploit them, and for that
>  > reason we of course need to fix them up.  Even though such an attacker
>  > could cripple the machine without exploiting such a hole.
>  > 
>  > For the above reasons I see no need to delay publication of local DoS holes
>  > at all.  The only thing for which we need to provide special processing is
>  > privilege escalation bugs.
>  > 
>  > Or am I missing something?
> 
> The problem is it depends on who you are, and what you're doing with Linux
> how much these things affect you.
> 
> A local DoS doesn't both me one squat personally, as I'm the only
> user of computers I use each day. An admin of a shell server or
> the like however would likely see this in a different light.
> (though it can be argued a mallet to the kneecaps of the user
>  responsible is more effective than any software update)

yup.  But there are so many ways to cripple a Linux box once you have local
access.  Another means which happens to be bug-induced doesn't seem
important.

> An information leak from kernel space may be equally as mundane to some,
> though terrifying to some admins. Would you want some process to be
> leaking your root password, credit card #, etc to some other users process ?
> 
> priveledge escalation is clearly the number one threat. Whilst some
> class 'remote root hole' higher risk than 'local root hole', far
> too often, we've had instances where execution of shellcode by
> overflowing some buffer in $crappyapp has led to a shell
> turning a local root into a remote root.

I'd place information leaks and privilege escalations into their own class,
way above "yet another local DoS".

A local privilege escalation hole should be viewed as seriously as a remote
privilege escalation hole, given the bugginess of userspace servers, yes?

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