Re: [CHECKER] security rules? (and 2.4.5-ac4 security bug)

[Dawson Engler]

> Indeed; the bug in the uuid_strategy which you pointed out in the
> random driver wasn't caused by the fact that we were using a
> user-specified length (since the length was being capped to a maximum
> value of 16).  The security bug was that the test was done on a signed
> value, and copy_to_user() takes an unsigned value.
> 
> So your checker found a real bug, but it wasn't the one that the
> checker thought it was.  :-)

No, it was the bug the checker thought it was: a signed integer from
user space that had only been upper-bound checked.  If the value had
been unsigned, or had been checked in a range lower_bound < x <
upper_bound there woulnd't have been a message.

But I certainly concede that the message could be more informative.

Dawson