At 08:30 29/04/02, Rolf Fokkens wrote:
>On Monday 29 April 2002 09:23, Thomas 'Dent' Mirlacher wrote:
> > the capable call is sthell there, but with the module_lock
> > kind or redundant.
>
>once set module_lock cannot be cleared, not even by root. This differs from
>the CAP_SYS_MODULE which can be activated by root, if I'm correct.
>
>module_lock is only a suggestion, w/o /dev/kmem write locking or even
>locking writes on other /dev/.. or doing mounts it won't be full proof.
*sigh*
RTFM man 2 sysctl
With your patch applied AND module_lock set to 1, anyone with sufficient
privileges could still do:
#include <linux/unistd.h>
#include <linux/types.h>
#include <linux/sysctl.h>
_syscall1(int, _sysctl, struct __sysctl_args *, args);
#define SIZE(x) sizeof(x)/sizeof(x[0])
int main(void)
{
int name[] = { CTL_KERN, KERN_MODPROBE };
int hack = 0;
struct __sysctl_args args = { name, SIZE(name), 0, 0,
&hack, sizeof(hack) };
if (_sysctl(&args)) {
perror("sysctl failed");
exit(1);
}
printf("module_lock has been zeroed! Muahaha!");
return 0;
}
Good bye module_lock! /me waves
What was that about not being able to zero it again...?
Best regards,
Anton
-- "I've not lost my mind. It's backed up on tape somewhere." - Unknown -- Anton Altaparmakov <aia21 at cantab.net> (replace at with @) Linux NTFS Maintainer / IRC: #ntfs on irc.openprojects.net WWW: http://linux-ntfs.sf.net/ & http://www-stu.christs.cam.ac.uk/~aia21/- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Tue Apr 30 2002 - 22:00:17 EST