Hi Grzegorz,
   To my knowledge if we try write to a read only area ,the kernel gives an OOPS.As I stated in the question,the module does not give me any errors.I have disabled page protections before writing to sys_call_table. I believe that is enough to make the sys_call_table RW. What do you think?


On Fri, Jan 25, 2013 at 6:58 PM, Paul Davies C <pauldaviesc@gmail.com> wrote:
Hi,
  [1] is the module I wrote for intercepting the system call fork(). I have taken the conventional way of hooking the system call. Firstly I found out the address of the sys_call_table from the System.map. Then I used it in the module to substitute for the original fork() with my own version of fork.My version does nothing more than printing a message and returning the original fork(). It didn't  gave any errors when loaded to kernel using the insmod.  However it seems that the module had no affect on the sys_call_table[] since the fork() is working perfectly after the insertion of module and it does not show me the message it was supposed to print. Can someone figure out the problem? I am using 3.2.0-4-686 version of kernel.
[1]  http://pastebin.com/aWN3jdQU

--
Regards,
Paul Davies C
vivafoss.blogspot.com



--
Regards,
Paul Davies C
vivafoss.blogspot.com