path: root/security/security.c

/*
 * Security plug functions
 *
 * Copyright (C) 2001 WireX Communications, Inc <chris@wirex.com>
 * Copyright (C) 2001-2002 Greg Kroah-Hartman <greg@kroah.com>
 * Copyright (C) 2001 Networks Associates Technology, Inc <ssmalley@nai.com>
 *
 *	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; either version 2 of the License, or
 *	(at your option) any later version.
 */

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/security.h>

/* Boot-time LSM user choice */
static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1];

/* things that live in capability.c */
extern struct security_operations default_security_ops;
extern void security_fixup_ops(struct security_operations *ops);

struct security_operations *security_ops;	/* Initialized to NULL */

/* amount of vm to protect from userspace access */
unsigned long mmap_min_addr = CONFIG_SECURITY_DEFAULT_MMAP_MIN_ADDR;

static inline int verify(struct security_operations *ops)
{
	/* verify the security_operations structure exists */
	if (!ops)
		return -EINVAL;
	security_fixup_ops(ops);
	return 0;
}

static void __init do_security_initcalls(void)
{
	initcall_t *call;
	call = __security_initcall_start;
	while (call < __security_initcall_end) {
		(*call) ();
		call++;
	}
}

/**
 * security_init - initializes the security framework
 *
 * This should be called early in the kernel initialization sequence.
 */
int __init security_init(void)
{
	printk(KERN_INFO "Security Framework initialized\n");

	security_fixup_ops(&default_security_ops);
	security_ops = &default_security_ops;
	do_security_initcalls();

	return 0;
}

/* Save user chosen LSM */
static int __init choose_lsm(char *str)
{
	strncpy(chosen_lsm, str, SECURITY_NAME_MAX);
	return 1;
}
__setup("security=", choose_lsm);

/**
 * security_module_enable - Load given security module on boot ?
 * @ops: a pointer to the struct security_operations that is to be checked.
 *
 * Each LSM must pass this method before registering its own operations
 * to avoid security registration races. This method may also be used
 * to check if your LSM is currently loaded during kernel initialization.
 *
 * Return true if:
 *	-The passed LSM is the one chosen by user at boot time,
 *	-or user didsn't specify a specific LSM and we're the first to ask
 *	 for registeration permissoin,
 *	-or the passed LSM is currently loaded.
 * Otherwise, return false.
 */
int __init security_module_enable(struct security_operations *ops)
{
	if (!*chosen_lsm)
		strncpy(chosen_lsm, ops->name, SECURITY_NAME_MAX);
	else if (strncmp(ops->name, chosen_lsm, SECURITY_NAME_MAX))
		return 0;

	return 1;
}

/**
 * register_security - registers a security framework with the kernel
 * @ops: a pointer to the struct security_options that is to be registered
 *
 * This function is to allow a security module to register itself with the
 * kernel security subsystem.  Some rudimentary checking is done on the @ops
 * value passed to this function. You'll need to check first if your LSM
 * is allowed to register its @ops by calling security_module_enable(@ops).
 *
 * If there is already a security module registered with the kernel,
 * an error will be returned.  Otherwise 0 is returned on success.
 */
int register_security(struct security_operations *ops)
{
	if (verify(ops)) {
		printk(KERN_DEBUG "%s could not verify "
		       "security_operations structure.\n", __func__);
		return -EINVAL;
	}

	if (security_ops != &default_security_ops)
		return -EAGAIN;

	security_ops = ops;

	return 0;
}

/* Security operations */

int security_ptrace_may_access(struct task_struct *child, unsigned int mode)
{
	return security_ops->ptrace_may_access(child, mode);
}

int security_ptrace_traceme(struct task_struct *parent)
{
	return security_ops->ptrace_traceme(parent);
}

int security_capget(struct task_struct *target,
		     kernel_cap_t *effective,
		     kernel_cap_t *inheritable,
		     kernel_cap_t *permitted)
{
	return security_ops->capget(target, effective, inheritable, permitted);
}

int security_capset_check(struct task_struct *target,
			   kernel_cap_t *effective,
			   kernel_cap_t *inheritable,