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kernel/linux-rt-4.4.41/security/apparmor/include/context.h 4.89 KB
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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 "policy.h"
  
  #define cred_cxt(X) (X)->security
  #define current_cxt() cred_cxt(current_cred())
  
  /* 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);
  struct aa_profile *aa_get_task_profile(struct task_struct *task);
  
  
  /**
   * 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_cxt(cred);
  	BUG_ON(!cxt || !cxt->profile);
  	return cxt->profile;
  }
  
  /**
   * __aa_task_profile - retrieve another task's profile
   * @task: task to query  (NOT NULL)
   *
   * Returns: @task's profile without incrementing its ref count
   *
   * If @task != current needs to be called in RCU safe critical section
   */
  static inline struct aa_profile *__aa_task_profile(struct task_struct *task)
  {
  	return aa_cred_profile(__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_profile(task));
  }
  
  /**
   * __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_cxt();
  	struct aa_profile *profile;
  	BUG_ON(!cxt || !cxt->profile);
  
  	if (PROFILE_INVALID(cxt->profile)) {
  		profile = aa_get_newest_profile(cxt->profile);
  		aa_replace_current_profile(profile);
  		aa_put_profile(profile);
  		cxt = current_cxt();
  	}
  
  	return cxt->profile;
  }
  
  /**
   * aa_clear_task_cxt_trans - clear transition tracking info from the cxt
   * @cxt: task context to clear (NOT NULL)
   */
  static inline void aa_clear_task_cxt_trans(struct aa_task_cxt *cxt)
  {
  	aa_put_profile(cxt->previous);
  	aa_put_profile(cxt->onexec);
  	cxt->previous = NULL;
  	cxt->onexec = NULL;
  	cxt->token = 0;
  }
  
  #endif /* __AA_CONTEXT_H */