Re: Syscall table AKA hijacking syscalls

Libor Vanek
2004-01-02T15:39:13Z

>>I'm writing some project which needs to hijack some syscalls in VFS
>>layer. AFAIK in 2.6 is this "not-wanted" solution (even that there are
>>some very nasty ways of doing it - see
>>http://mail.nl.linux.org/kernelnewbies/2002-12/msg00266.html )
>>
>>Also I've found out that Linus stated that intercepting syscalls is "bad
>>thing" (load module a, load module b, unload module b => crash) but I
>>think that there are some very good reasons (and ways) to do it (see
>>http://syscalltrack.sourceforge.net ). My main reason to do it is that I
>>want my GPLed module to be able to modify some VFS syscalls without
>>patching and recompiling whole kernel and rebooting the machine.
>>
>>
>
>As part of the openxdsm-project we wrote an syscall-intercept module
>that "solves" the (load module a, load module b, unload module b =>
>crash) part by providing a common infrastructure for intercepting
>syscalls.
>
>
The code looks very nice'n'simple but it won't run on 2.6 because
mentioned hidden sys_call_table. But I can imagine that this with some
small tweaks can be integrated into 2.6 to provide generall
infrastructure for syscall hijacking when really needed.

--

Libor Vanek