20510f2f4e
Convert LSM into a static interface, as the ability to unload a security module is not required by in-tree users and potentially complicates the overall security architecture. Needlessly exported LSM symbols have been unexported, to help reduce API abuse. Parameters for the capability and root_plug modules are now specified at boot. The SECURITY_FRAMEWORK_VERSION macro has also been removed. In a nutshell, there is no safe way to unload an LSM. The modular interface is thus unecessary and broken infrastructure. It is used only by out-of-tree modules, which are often binary-only, illegal, abusive of the API and dangerous, e.g. silently re-vectoring SELinux. [akpm@linux-foundation.org: cleanups] [akpm@linux-foundation.org: USB Kconfig fix] [randy.dunlap@oracle.com: fix LSM kernel-doc] Signed-off-by: James Morris <jmorris@namei.org> Acked-by: Chris Wright <chrisw@sous-sol.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: "Serge E. Hallyn" <serue@us.ibm.com> Acked-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
113 lines
3.0 KiB
C
113 lines
3.0 KiB
C
/*
|
|
* Root Plug sample LSM module
|
|
*
|
|
* Originally written for a Linux Journal.
|
|
*
|
|
* Copyright (C) 2002 Greg Kroah-Hartman <greg@kroah.com>
|
|
*
|
|
* Prevents any programs running with egid == 0 if a specific USB device
|
|
* is not present in the system. Yes, it can be gotten around, but is a
|
|
* nice starting point for people to play with, and learn the LSM
|
|
* interface.
|
|
*
|
|
* If you want to turn this into something with a semblance of security,
|
|
* you need to hook the task_* functions also.
|
|
*
|
|
* See http://www.linuxjournal.com/article.php?sid=6279 for more information
|
|
* about this code.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License as
|
|
* published by the Free Software Foundation, version 2 of the
|
|
* License.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/security.h>
|
|
#include <linux/usb.h>
|
|
#include <linux/moduleparam.h>
|
|
|
|
/* flag to keep track of how we were registered */
|
|
static int secondary;
|
|
|
|
/* default is a generic type of usb to serial converter */
|
|
static int vendor_id = 0x0557;
|
|
static int product_id = 0x2008;
|
|
|
|
module_param(vendor_id, uint, 0400);
|
|
module_param(product_id, uint, 0400);
|
|
|
|
/* should we print out debug messages */
|
|
static int debug = 0;
|
|
|
|
module_param(debug, bool, 0600);
|
|
|
|
#define MY_NAME "root_plug"
|
|
|
|
#define root_dbg(fmt, arg...) \
|
|
do { \
|
|
if (debug) \
|
|
printk(KERN_DEBUG "%s: %s: " fmt , \
|
|
MY_NAME , __FUNCTION__ , \
|
|
## arg); \
|
|
} while (0)
|
|
|
|
static int rootplug_bprm_check_security (struct linux_binprm *bprm)
|
|
{
|
|
struct usb_device *dev;
|
|
|
|
root_dbg("file %s, e_uid = %d, e_gid = %d\n",
|
|
bprm->filename, bprm->e_uid, bprm->e_gid);
|
|
|
|
if (bprm->e_gid == 0) {
|
|
dev = usb_find_device(vendor_id, product_id);
|
|
if (!dev) {
|
|
root_dbg("e_gid = 0, and device not found, "
|
|
"task not allowed to run...\n");
|
|
return -EPERM;
|
|
}
|
|
usb_put_dev(dev);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct security_operations rootplug_security_ops = {
|
|
/* Use the capability functions for some of the hooks */
|
|
.ptrace = cap_ptrace,
|
|
.capget = cap_capget,
|
|
.capset_check = cap_capset_check,
|
|
.capset_set = cap_capset_set,
|
|
.capable = cap_capable,
|
|
|
|
.bprm_apply_creds = cap_bprm_apply_creds,
|
|
.bprm_set_security = cap_bprm_set_security,
|
|
|
|
.task_post_setuid = cap_task_post_setuid,
|
|
.task_reparent_to_init = cap_task_reparent_to_init,
|
|
|
|
.bprm_check_security = rootplug_bprm_check_security,
|
|
};
|
|
|
|
static int __init rootplug_init (void)
|
|
{
|
|
/* register ourselves with the security framework */
|
|
if (register_security (&rootplug_security_ops)) {
|
|
printk (KERN_INFO
|
|
"Failure registering Root Plug module with the kernel\n");
|
|
/* try registering with primary module */
|
|
if (mod_reg_security (MY_NAME, &rootplug_security_ops)) {
|
|
printk (KERN_INFO "Failure registering Root Plug "
|
|
" module with primary security module.\n");
|
|
return -EINVAL;
|
|
}
|
|
secondary = 1;
|
|
}
|
|
printk (KERN_INFO "Root Plug module initialized, "
|
|
"vendor_id = %4.4x, product id = %4.4x\n", vendor_id, product_id);
|
|
return 0;
|
|
}
|
|
|
|
security_initcall (rootplug_init);
|