Simply use <asm/uaccess.h> int access_ok(int type, const void * address, unsigned long size) This checks whether the address is a userspace address, but does not guarantee that the address is relevant with the desired process. Also I know that put_user, get_user (described in same header) already do the access_ok check. Lastly, this information applies for the 2.4 kernel. Thanks, Bahadir On Fri, 28 Jan 2005 08:52:09 +0100, Jan Hudec <bulb@xxxxxx> wrote: > On Fri, Jan 28, 2005 at 01:06:21 +0100, Bernd Petrovitsch wrote: > > On Thu, 2005-01-27 at 09:14 -0800, Rock Gordon wrote: > > > If I'm given a particular address, how do I test > > > whether that address is from userspace or from kernel > > > space? > > > > You don't. > > > > > I need to make these decisions from either inside a > > > kernel module or a userspace program. The idea is I > > > use memcpy() in the user-user version, > > > copy_from/to_user in the kernel-kernel version, and > > > prohibit the others. > > > > You need to know where the address is from and use the correct function. > > If the interface is defined as taking userland address, than kernel > function passing a kernel address in is responsible for calling > set_fs(KERNEL_DS) before and undoing it after. That way the > copy_to/from_user does not complain. > > ------------------------------------------------------------------------------- > Jan 'Bulb' Hudec <bulb@xxxxxx> > > > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
