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/*
* 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 "label.h"
#include "policy_ns.h"
#define cred_ctx(X) ((X)->security)
#define current_ctx() cred_ctx(current_cred())
/**
* struct aa_task_ctx - primary label for confined tasks
* @label: the current label (NOT NULL)
* @exec: label to transition to on next exec (MAYBE NULL)
* @previous: label the task may return to (MAYBE NULL)
* @token: magic value the task must know for returning to @previous
*
* Contains the task's current label (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_ctx {
struct aa_label *label;
struct aa_label *onexec;
struct aa_label *previous;
u64 token;
};
struct aa_task_ctx *aa_alloc_task_context(gfp_t flags);
void aa_free_task_context(struct aa_task_ctx *ctx);
void aa_dup_task_context(struct aa_task_ctx *new,
const struct aa_task_ctx *old);
int aa_replace_current_label(struct aa_label *label);
int aa_set_current_onexec(struct aa_label *label, bool stack);
int aa_set_current_hat(struct aa_label *label, u64 token);
int aa_restore_previous_label(u64 cookie);
struct aa_label *aa_get_task_label(struct task_struct *task);
/**
* aa_cred_raw_label - obtain cred's label
* @cred: cred to obtain label from (NOT NULL)
*
* Returns: confining label
*
* does NOT increment reference count
*/
static inline struct aa_label *aa_cred_raw_label(const struct cred *cred)
{
struct aa_task_ctx *ctx = cred_ctx(cred);
AA_BUG(!ctx || !ctx->label);
return ctx->label;
}
/**
* aa_get_newest_cred_label - obtain the newest label on a cred
* @cred: cred to obtain label from (NOT NULL)
*
* Returns: newest version of confining label
*/
static inline struct aa_label *aa_get_newest_cred_label(const struct cred *cred)
{
return aa_get_newest_label(aa_cred_raw_label(cred));
}
/**
* __aa_task_raw_label - retrieve another task's label
* @task: task to query (NOT NULL)
*
* Returns: @task's label without incrementing its ref count
*
* If @task != current needs to be called in RCU safe critical section
*/
static inline struct aa_label *__aa_task_raw_label(struct task_struct *task)
{
return aa_cred_raw_label(__task_cred(task));
}
/**
* __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)
{
return !unconfined(__aa_task_raw_label(task));
}
/**
* aa_current_raw_label - find the current tasks confining label
*
* Returns: up to date confining label or the ns unconfined label (NOT NULL)
*
* This fn will not update the tasks cred to the most up to date version
* of the label so it is safe to call when inside of locks.
*/
static inline struct aa_label *aa_current_raw_label(void)
{
return aa_cred_raw_label(current_cred());
}
/**
* aa_get_current_label - get the newest version of the current tasks label
*
* Returns: newest version of confining label (NOT NULL)
*
* This fn will not update the tasks cred, so it is safe inside of locks
*
* The returned reference must be put with aa_put_label()
*/
static inline struct aa_label *aa_get_current_label(void)
{
struct aa_label *l = aa_current_raw_label();
if (label_is_stale(l))
return aa_get_newest_label(l);
return aa_get_label(l);
}
#define __end_current_label_crit_section(X) end_current_label_crit_section(X)
/**
* end_label_crit_section - put a reference found with begin_current_label..
* @label: label reference to put
*
* Should only be used with a reference obtained with
* begin_current_label_crit_section and never used in situations where the
* task cred may be updated
*/
static inline void end_current_label_crit_section(struct aa_label *label)
{
if (label != aa_current_raw_label())
aa_put_label(label);
}
/**
* __begin_current_label_crit_section - current's confining label
*
* Returns: up to date confining label or the ns unconfined label (NOT NULL)
*
* safe to call inside locks
*
* The returned reference must be put with __end_current_label_crit_section()
* This must NOT be used if the task cred could be updated within the
* critical section between __begin_current_label_crit_section() ..
* __end_current_label_crit_section()
*/
static inline struct aa_label *__begin_current_label_crit_section(void)
{
struct aa_label *label = aa_current_raw_label();
if (label_is_stale(label))
label = aa_get_newest_label(label);
return label;
}
/**
* begin_current_label_crit_section - current's confining label and update it
*
* Returns: up to date confining label or the ns unconfined label (NOT NULL)
*
* Not safe to call inside locks
*
* The returned reference must be put with end_current_label_crit_section()
* This must NOT be used if the task cred could be updated within the
* critical section between begin_current_label_crit_section() ..
* end_current_label_crit_section()
*/
static inline struct aa_label *begin_current_label_crit_section(void)
{
struct aa_label *label = aa_current_raw_label();
if (label_is_stale(label)) {
label = aa_get_newest_label(label);
if (aa_replace_current_label(label) == 0)
/* task cred will keep the reference */
aa_put_label(label);
}
return label;
}
static inline struct aa_ns *aa_get_current_ns(void)
{
struct aa_label *label;
struct aa_ns *ns;
label = __begin_current_label_crit_section();
ns = aa_get_ns(labels_ns(label));
__end_current_label_crit_section(label);
return ns;
}
/**
* aa_clear_task_ctx_trans - clear transition tracking info from the ctx
* @ctx: task context to clear (NOT NULL)
*/
static inline void aa_clear_task_ctx_trans(struct aa_task_ctx *ctx)
{
aa_put_label(ctx->previous);
aa_put_label(ctx->onexec);
ctx->previous = NULL;
ctx->onexec = NULL;
ctx->token = 0;
}
#endif /* __AA_CONTEXT_H */
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