Re: [Coverity] Untrusted user data in kernel

From: Tomas Carnecky
Date: Fri Dec 17 2004 - 14:15:13 EST

linux-os wrote:
On Fri, 17 Dec 2004, Bill Davidsen wrote:

James Morris wrote:

On Fri, 17 Dec 2004, Patrick McHardy wrote:
That's what I meant, you need the capability to do anything bad :-)

Are you saying that processes with capability don't make mistakes? This isn't a bug related to untrusted users doing privileged operations, it's a case of using unchecked user data.

But isn't there always the possibility of "unchecked user data"?
I can, as root, do `cp /dev/zero /dev/mem` and have the most
spectacular crask you've evet seen. I can even make my file-
systems unrecoverable.

But the difference between you example (cp /dev/zero /dev/mem) and passing unchecked data to the kernel is... you _can_ check the data and do something about it if you discover that the data is not valid/within a range/whatever even if the user has full permissions.
No same person would do a 'cp /dev/zero /dev/mem', but passing bad data is more likely to happen, badly written userspace configuration tools etc.

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