Re: access_ok inside kernelspace

Tigran Aivazian (tigran@sco.COM)
Tue, 19 Oct 1999 10:30:44 +0100 (BST)


On Tue, 19 Oct 1999, Ingo Molnar wrote:
> ... provided you are using/setting set_fs()/get_fs() properly. You'll
> obviously not go through the system call handler but call sys_open() or
> whatever directly from within kernel space.

calling sys_function() functions directly doesn't look right:

1. what if one was to do some accounting of the system calls. Not going
through the int 0x80 would break this.

2. what if one were to temporarily redirect some system calls to another
handler (like timetravel.o module does).

3. probably other "what-ifs".

So, it is better to ensure that either one can go through that gate as
many times as one wants or forbid it completely.

Matthew, if, as you say a specific Linux port disallows that, how are you
going to handle kernel/kmod.c and all the other occurrences where
_syscallX() is used from kernel space?

Regards,
Tigran.

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