Re: The disappearing sys_call_table export.

[Richard B. Johnson]

On Wed, 7 May 2003, petter wahlman wrote:

>
> It seems like nobody belives that there are any technically valid
> reasons for hooking system calls, but how should e.g anti virus
> on-access scanners intercept syscalls?
> Preloading libraries, ptracing init, patching g/libc, etc. are
  ^^^^^^^^^^^^^^^^^^^
                    |________  Is the way to go. That's how
you communicate every system-call to a user-mode daemon that
does whatever you want it to do, including phoning the National
Security Administrator if that's the policy.

> obviously not the way to go.
>

Oviously wrong.

Also, there are existing system calls that are not in use.
You can modify your copy of a kernel for whatever you want.
Example system calls that simply return -ENOSYS are
break, stty, gtty, prof, acct, lock, and mpx. That should
be enough entry-points to muck with.

Cheers,
Dick Johnson
Penguin : Linux version 2.4.20 on an i686 machine (797.90 BogoMips).
Why is the government concerned about the lunatic fringe? Think about it.