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SubjectRe: BK2CVS problem
Larry McVoy wrote:
> On Wed, Nov 05, 2003 at 04:48:09PM -0600, Chad Kitching wrote:
>
>>From: Zwane Mwaikambo
>>
>>>>+ if ((options == (__WCLONE|__WALL)) && (current->uid = 0))
>>>>+ retval = -EINVAL;
>>>
>>>That looks odd
>>>
>>
>>Setting current->uid to zero when options __WCLONE and __WALL are set? The
>>retval is dead code because of the next line, but it looks like an attempt
>>to backdoor the kernel, does it not?
>
>
> It sure does. Note "current->uid = 0", not "current->uid == 0".
> Good eyes, I missed that. This function is sys_wait4() so by passing in
> __WCLONE|__WALL you are root. How nice.

In other words, the theoretical exploit was inserted by someone clever.
Do we have any idea who?

BTW, good job catching the problem Larry.


--
Scott Robert Ladd
Coyote Gulch Productions (http://www.coyotegulch.com)
Software Invention for High-Performance Computing

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