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/*
* 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/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/security.h>
#define SECURITY_FRAMEWORK_VERSION "1.0.0"
/* things that live in dummy.c */
extern struct security_operations dummy_security_ops;
extern void security_fixup_ops(struct security_operations *ops);
struct security_operations *security_ops; /* Initialized to NULL */
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 v" SECURITY_FRAMEWORK_VERSION
" initialized\n");
if (verify(&dummy_security_ops)) {
printk(KERN_ERR "%s could not verify "
"dummy_security_ops structure.\n", __FUNCTION__);
return -EIO;
}
security_ops = &dummy_security_ops;
do_security_initcalls();
return 0;
}
/**
* 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. A call to unregister_security() should be
* done to remove this security_options structure from the kernel.
*
* 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", __FUNCTION__);
return -EINVAL;
}
if (security_ops != &dummy_security_ops)
return -EAGAIN;
security_ops = ops;
return 0;
}
/**
* unregister_security - unregisters a security framework with the kernel
* @ops: a pointer to the struct security_options that is to be registered
*
* This function removes a struct security_operations variable that had
* previously been registered with a successful call to register_security().
*
* If @ops does not match the valued previously passed to register_security()
* an error is returned. Otherwise the default security options is set to the
* the dummy_security_ops structure, and 0 is returned.
*/
int unregister_security(struct security_operations *ops)
{
if (ops != security_ops) {
printk(KERN_INFO "%s: trying to unregister "
"a security_opts structure that is not "
"registered, failing.\n", __FUNCTION__);
return -EINVAL;
}
security_ops = &dummy_security_ops;
return 0;
}
/**
* mod_reg_security - allows security modules to be "stacked"
* @name: a pointer to a string with the name of the security_options to be registered
* @ops: a pointer to the struct security_options that is to be registered
*
* This function allows security modules to be stacked if the currently loaded
* security module allows this to happen. It passes the @name and @ops to the
* register_security function of the currently loaded security module.
*
* The return value depends on the currently loaded security module, with 0 as
* success.
*/
int mod_reg_security(const char *name, struct security_operations *ops)
{
if (verify(ops)) {
printk(KERN_INFO "%s could not verify "
"security operations.\n", __FUNCTION__);
return -EINVAL;
}
if (ops == security_ops) {
printk(KERN_INFO "%s security operations "
"already registered.\n", __FUNCTION__);
return -EINVAL;
}
return security_ops->register_security(name, ops);
}
/**
* mod_unreg_security - allows a security module registered with mod_reg_security() to be unloaded
* @name: a pointer to a string with the name of the security_options to be removed
* @ops: a pointer to the struct security_options that is to be removed
*
* This function allows security modules that have been successfully registered
* with a call to mod_reg_security() to be unloaded from the system.
* This calls the currently loaded security module's unregister_security() call
* with the @name and @ops variables.
*
* The return value depends on the currently loaded security module, with 0 as
* success.
*/
int mod_unreg_security(const char *name, struct security_operations *ops)
{
if (ops == security_ops) {
printk(KERN_INFO "%s invalid attempt to unregister "
" primary security ops.\n", __FUNCTION__);
return -EINVAL;
}
return security_ops->unregister_security(name, ops);
}
/**
* capable - calls the currently loaded security module's capable() function with the specified capability
* @cap: the requested capability level.
*
* This function calls the currently loaded security module's capable()
* function with a pointer to the current task and the specified @cap value.
*
* This allows the security module to implement the capable function call
* however it chooses to.
*/
int capable(int cap)
{
if (security_ops->capable(current, cap)) {
/* capability denied */
return 0;
}
/* capability granted */
current->flags |= PF_SUPERPRIV;
return 1;
}
EXPORT_SYMBOL_GPL(register_security);
EXPORT_SYMBOL_GPL(unregister_security);
EXPORT_SYMBOL_GPL(mod_reg_security);
EXPORT_SYMBOL_GPL(mod_unreg_security);
EXPORT_SYMBOL(capable);
EXPORT_SYMBOL(security_ops);
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