security/apparmor/include/context.h

   1 /*
   2  * AppArmor security module
   3  *
   4  * This file contains AppArmor contexts used to associate "labels" to objects.
   5  *
   6  * Copyright (C) 1998-2008 Novell/SUSE
   7  * Copyright 2009-2010 Canonical Ltd.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation, version 2 of the
  12  * License.
  13  */
  14
  15 #ifndef __AA_CONTEXT_H
  16 #define __AA_CONTEXT_H
  17
  18 #include <linux/cred.h>
  19 #include <linux/slab.h>
  20 #include <linux/sched.h>
  21
  22 #include "policy.h"
  23
  24 /* struct aa_file_cxt - the AppArmor context the file was opened in
  25  * @perms: the permission the file was opened with
  26  *
  27  * The file_cxt could currently be directly stored in file->f_security
  28  * as the profile reference is now stored in the f_cred.  However the
  29  * cxt struct will expand in the future so we keep the struct.
  30  */
  31 struct aa_file_cxt {
  32         u16 allow;
  33 };
  34
  35 /**
  36  * aa_alloc_file_context - allocate file_cxt
  37  * @gfp: gfp flags for allocation
  38  *
  39  * Returns: file_cxt or NULL on failure
  40  */
  41 static inline struct aa_file_cxt *aa_alloc_file_context(gfp_t gfp)
  42 {
  43         return kzalloc(sizeof(struct aa_file_cxt), gfp);
  44 }
  45
  46 /**
  47  * aa_free_file_context - free a file_cxt
  48  * @cxt: file_cxt to free  (MAYBE_NULL)
  49  */
  50 static inline void aa_free_file_context(struct aa_file_cxt *cxt)
  51 {
  52         if (cxt)
  53                 kzfree(cxt);
  54 }
  55
  56 /**
  57  * struct aa_task_cxt - primary label for confined tasks
  58  * @profile: the current profile   (NOT NULL)
  59  * @exec: profile to transition to on next exec  (MAYBE NULL)
  60  * @previous: profile the task may return to     (MAYBE NULL)
  61  * @token: magic value the task must know for returning to @previous_profile
  62  *
  63  * Contains the task's current profile (which could change due to
  64  * change_hat).  Plus the hat_magic needed during change_hat.
  65  *
  66  * TODO: make so a task can be confined by a stack of contexts
  67  */
  68 struct aa_task_cxt {
  69         struct aa_profile *profile;
  70         struct aa_profile *onexec;
  71         struct aa_profile *previous;
  72         u64 token;
  73 };
  74
  75 struct aa_task_cxt *aa_alloc_task_context(gfp_t flags);
  76 void aa_free_task_context(struct aa_task_cxt *cxt);
  77 void aa_dup_task_context(struct aa_task_cxt *new,
  78                          const struct aa_task_cxt *old);
  79 int aa_replace_current_profile(struct aa_profile *profile);
  80 int aa_set_current_onexec(struct aa_profile *profile);
  81 int aa_set_current_hat(struct aa_profile *profile, u64 token);
  82 int aa_restore_previous_profile(u64 cookie);
  83
  84 /**
  85  * __aa_task_is_confined - determine if @task has any confinement
  86  * @task: task to check confinement of  (NOT NULL)
  87  *
  88  * If @task != current needs to be called in RCU safe critical section
  89  */
  90 static inline bool __aa_task_is_confined(struct task_struct *task)
  91 {
  92         struct aa_task_cxt *cxt = __task_cred(task)->security;
  93
  94         BUG_ON(!cxt || !cxt->profile);
  95         if (unconfined(aa_newest_version(cxt->profile)))
  96                 return 0;
  97
  98         return 1;
  99 }
 100
 101 /**
 102  * aa_cred_profile - obtain cred's profiles
 103  * @cred: cred to obtain profiles from  (NOT NULL)
 104  *
 105  * Returns: confining profile
 106  *
 107  * does NOT increment reference count
 108  */
 109 static inline struct aa_profile *aa_cred_profile(const struct cred *cred)
 110 {
 111         struct aa_task_cxt *cxt = cred->security;
 112         BUG_ON(!cxt || !cxt->profile);
 113         return aa_newest_version(cxt->profile);
 114 }
 115
 116 /**
 117  * __aa_current_profile - find the current tasks confining profile
 118  *
 119  * Returns: up to date confining profile or the ns unconfined profile (NOT NULL)
 120  *
 121  * This fn will not update the tasks cred to the most up to date version
 122  * of the profile so it is safe to call when inside of locks.
 123  */
 124 static inline struct aa_profile *__aa_current_profile(void)
 125 {
 126         return aa_cred_profile(current_cred());
 127 }
 128
 129 /**
 130  * aa_current_profile - find the current tasks confining profile and do updates
 131  *
 132  * Returns: up to date confining profile or the ns unconfined profile (NOT NULL)
 133  *
 134  * This fn will update the tasks cred structure if the profile has been
 135  * replaced.  Not safe to call inside locks
 136  */
 137 static inline struct aa_profile *aa_current_profile(void)
 138 {
 139         const struct aa_task_cxt *cxt = current_cred()->security;
 140         struct aa_profile *profile;
 141         BUG_ON(!cxt || !cxt->profile);
 142
 143         profile = aa_newest_version(cxt->profile);
 144         /*
 145          * Whether or not replacement succeeds, use newest profile so
 146          * there is no need to update it after replacement.
 147          */
 148         if (unlikely((cxt->profile != profile)))
 149                 aa_replace_current_profile(profile);
 150
 151         return profile;
 152 }
 153
 154 #endif /* __AA_CONTEXT_H */