[Gllug] Time Travel on Linux

[Daniel P. Berrange]

On Sun, Oct 23, 2005 at 03:45:28PM +0100, Richard Jones wrote:
> Does anyone know if there's a modern version of this:
> 
> http://www.ussg.iu.edu/hypermail/linux/kernel/9806.1/0940.html

Creating a new kernel space version of it would be pretty much
impossible with a stock kernel, since sys_call_table is no longer
exported to modules (a good thing BTW, since its primary use was
letting rootkits override various system calls ;-) 

That said, if you can identify which system calls you wish to
override, it would be reasonably straightforware to create a 
library you could LD_PRELOAD to wrap around the corresponding
GLibC functions.

> 
> <quote>
>   For those who do not know what I am talking about - Time Travel is a
>   kernel module (2.1.x only) that can be used to simulate the
>   environment with shifted (in any direction) concept of time, both in
>   the sense of system time and filesystem-related timestamps.
>   
>   Amongst bad uses of Time Travel is bypassing license limitations of
>   commercial time-restricted demos. Such use is not encouraged! ;)
> </quote>

Then, just set the LD_PRELOAD when running the license damaged software ;-)

Dan.
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