Re: How to hook the system call?

On Wed, Nov 23, 2011 at 04:40:14PM +0800, Geraint Yang wrote:

Hello everyone,

I am going to hook a system call like 'read' or 'send' by modifying the sys_call_table, but it seems that the sys_call_table is in read only page, how can I set modify the sys_call_table ? Or if there any method that I can use to hook a system call in module without modify the kernel source?

There's a kernel module for "advanced rickrolling" that overwrites the open entry in the syscall table: https://github.com/fpletz/kernelroll It does some trickery to make the page writable first. HTH, Jonathan Neuschäfer