linux/security/apparmor/include/context.h
John Johansen c75afcd153 AppArmor: contexts used in attaching policy to system objects
AppArmor contexts attach profiles and state to tasks, files, etc. when
a direct profile reference is not sufficient.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-08-02 15:35:12 +10:00

155 lines
4.3 KiB
C

/*
* AppArmor security module
*
* This file contains AppArmor contexts used to associate "labels" to objects.
*
* Copyright (C) 1998-2008 Novell/SUSE
* Copyright 2009-2010 Canonical Ltd.
*
* 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.
*/
#ifndef __AA_CONTEXT_H
#define __AA_CONTEXT_H
#include <linux/cred.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include "policy.h"
/* struct aa_file_cxt - the AppArmor context the file was opened in
* @perms: the permission the file was opened with
*
* The file_cxt could currently be directly stored in file->f_security
* as the profile reference is now stored in the f_cred. However the
* cxt struct will expand in the future so we keep the struct.
*/
struct aa_file_cxt {
u16 allow;
};
/**
* aa_alloc_file_context - allocate file_cxt
* @gfp: gfp flags for allocation
*
* Returns: file_cxt or NULL on failure
*/
static inline struct aa_file_cxt *aa_alloc_file_context(gfp_t gfp)
{
return kzalloc(sizeof(struct aa_file_cxt), gfp);
}
/**
* aa_free_file_context - free a file_cxt
* @cxt: file_cxt to free (MAYBE_NULL)
*/
static inline void aa_free_file_context(struct aa_file_cxt *cxt)
{
if (cxt)
kzfree(cxt);
}
/**
* struct aa_task_cxt - primary label for confined tasks
* @profile: the current profile (NOT NULL)
* @exec: profile to transition to on next exec (MAYBE NULL)
* @previous: profile the task may return to (MAYBE NULL)
* @token: magic value the task must know for returning to @previous_profile
*
* Contains the task's current profile (which could change due to
* change_hat). Plus the hat_magic needed during change_hat.
*
* TODO: make so a task can be confined by a stack of contexts
*/
struct aa_task_cxt {
struct aa_profile *profile;
struct aa_profile *onexec;
struct aa_profile *previous;
u64 token;
};
struct aa_task_cxt *aa_alloc_task_context(gfp_t flags);
void aa_free_task_context(struct aa_task_cxt *cxt);
void aa_dup_task_context(struct aa_task_cxt *new,
const struct aa_task_cxt *old);
int aa_replace_current_profile(struct aa_profile *profile);
int aa_set_current_onexec(struct aa_profile *profile);
int aa_set_current_hat(struct aa_profile *profile, u64 token);
int aa_restore_previous_profile(u64 cookie);
/**
* __aa_task_is_confined - determine if @task has any confinement
* @task: task to check confinement of (NOT NULL)
*
* If @task != current needs to be called in RCU safe critical section
*/
static inline bool __aa_task_is_confined(struct task_struct *task)
{
struct aa_task_cxt *cxt = __task_cred(task)->security;
BUG_ON(!cxt || !cxt->profile);
if (unconfined(aa_newest_version(cxt->profile)))
return 0;
return 1;
}
/**
* aa_cred_profile - obtain cred's profiles
* @cred: cred to obtain profiles from (NOT NULL)
*
* Returns: confining profile
*
* does NOT increment reference count
*/
static inline struct aa_profile *aa_cred_profile(const struct cred *cred)
{
struct aa_task_cxt *cxt = cred->security;
BUG_ON(!cxt || !cxt->profile);
return aa_newest_version(cxt->profile);
}
/**
* __aa_current_profile - find the current tasks confining profile
*
* Returns: up to date confining profile or the ns unconfined profile (NOT NULL)
*
* This fn will not update the tasks cred to the most up to date version
* of the profile so it is safe to call when inside of locks.
*/
static inline struct aa_profile *__aa_current_profile(void)
{
return aa_cred_profile(current_cred());
}
/**
* aa_current_profile - find the current tasks confining profile and do updates
*
* Returns: up to date confining profile or the ns unconfined profile (NOT NULL)
*
* This fn will update the tasks cred structure if the profile has been
* replaced. Not safe to call inside locks
*/
static inline struct aa_profile *aa_current_profile(void)
{
const struct aa_task_cxt *cxt = current_cred()->security;
struct aa_profile *profile;
BUG_ON(!cxt || !cxt->profile);
profile = aa_newest_version(cxt->profile);
/*
* Whether or not replacement succeeds, use newest profile so
* there is no need to update it after replacement.
*/
if (unlikely((cxt->profile != profile)))
aa_replace_current_profile(profile);
return profile;
}
#endif /* __AA_CONTEXT_H */