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 #define cred_cxt(X) (X)->security
  25 #define current_cxt() cred_cxt(current_cred())
  26
  27 /* struct aa_file_cxt - the AppArmor context the file was opened in
  28  * @perms: the permission the file was opened with
  29  *
  30  * The file_cxt could currently be directly stored in file->f_security
  31  * as the profile reference is now stored in the f_cred.  However the
  32  * cxt struct will expand in the future so we keep the struct.
  33  */
  34 struct aa_file_cxt {
  35         u16 allow;
  36 };
  37
  38 /**
  39  * aa_alloc_file_context - allocate file_cxt
  40  * @gfp: gfp flags for allocation
  41  *
  42  * Returns: file_cxt or NULL on failure
  43  */
  44 static inline struct aa_file_cxt *aa_alloc_file_context(gfp_t gfp)
  45 {
  46         return kzalloc(sizeof(struct aa_file_cxt), gfp);
  47 }
  48
  49 /**
  50  * aa_free_file_context - free a file_cxt
  51  * @cxt: file_cxt to free  (MAYBE_NULL)
  52  */
  53 static inline void aa_free_file_context(struct aa_file_cxt *cxt)
  54 {
  55         if (cxt)
  56                 kzfree(cxt);
  57 }
  58
  59 /**
  60  * struct aa_task_cxt - primary label for confined tasks
  61  * @profile: the current profile   (NOT NULL)
  62  * @exec: profile to transition to on next exec  (MAYBE NULL)
  63  * @previous: profile the task may return to     (MAYBE NULL)
  64  * @token: magic value the task must know for returning to @previous_profile
  65  *
  66  * Contains the task's current profile (which could change due to
  67  * change_hat).  Plus the hat_magic needed during change_hat.
  68  *
  69  * TODO: make so a task can be confined by a stack of contexts
  70  */
  71 struct aa_task_cxt {
  72         struct aa_profile *profile;
  73         struct aa_profile *onexec;
  74         struct aa_profile *previous;
  75         u64 token;
  76 };
  77
  78 struct aa_task_cxt *aa_alloc_task_context(gfp_t flags);
  79 void aa_free_task_context(struct aa_task_cxt *cxt);
  80 void aa_dup_task_context(struct aa_task_cxt *new,
  81                          const struct aa_task_cxt *old);
  82 int aa_replace_current_profile(struct aa_profile *profile);
  83 int aa_set_current_onexec(struct aa_profile *profile);
  84 int aa_set_current_hat(struct aa_profile *profile, u64 token);
  85 int aa_restore_previous_profile(u64 cookie);
  86 struct aa_profile *aa_get_task_profile(struct task_struct *task);
  87
  88
  89 /**
  90  * aa_cred_profile - obtain cred's profiles
  91  * @cred: cred to obtain profiles from  (NOT NULL)
  92  *
  93  * Returns: confining profile
  94  *
  95  * does NOT increment reference count
  96  */
  97 static inline struct aa_profile *aa_cred_profile(const struct cred *cred)
  98 {
  99         struct aa_task_cxt *cxt = cred_cxt(cred);
 100         BUG_ON(!cxt || !cxt->profile);
 101         return cxt->profile;
 102 }
 103
 104 /**
 105  * __aa_task_profile - retrieve another task's profile
 106  * @task: task to query  (NOT NULL)
 107  *
 108  * Returns: @task's profile without incrementing its ref count
 109  *
 110  * If @task != current needs to be called in RCU safe critical section
 111  */
 112 static inline struct aa_profile *__aa_task_profile(struct task_struct *task)
 113 {
 114         return aa_cred_profile(__task_cred(task));
 115 }
 116
 117 /**
 118  * __aa_task_is_confined - determine if @task has any confinement
 119  * @task: task to check confinement of  (NOT NULL)
 120  *
 121  * If @task != current needs to be called in RCU safe critical section
 122  */
 123 static inline bool __aa_task_is_confined(struct task_struct *task)
 124 {
 125         return !unconfined(__aa_task_profile(task));
 126 }
 127
 128 /**
 129  * __aa_current_profile - find the current tasks confining profile
 130  *
 131  * Returns: up to date confining profile or the ns unconfined profile (NOT NULL)
 132  *
 133  * This fn will not update the tasks cred to the most up to date version
 134  * of the profile so it is safe to call when inside of locks.
 135  */
 136 static inline struct aa_profile *__aa_current_profile(void)
 137 {
 138         return aa_cred_profile(current_cred());
 139 }
 140
 141 /**
 142  * aa_current_profile - find the current tasks confining profile and do updates
 143  *
 144  * Returns: up to date confining profile or the ns unconfined profile (NOT NULL)
 145  *
 146  * This fn will update the tasks cred structure if the profile has been
 147  * replaced.  Not safe to call inside locks
 148  */
 149 static inline struct aa_profile *aa_current_profile(void)
 150 {
 151         const struct aa_task_cxt *cxt = current_cxt();
 152         struct aa_profile *profile;
 153         BUG_ON(!cxt || !cxt->profile);
 154
 155         if (PROFILE_INVALID(cxt->profile)) {
 156                 profile = aa_get_newest_profile(cxt->profile);
 157                 aa_replace_current_profile(profile);
 158                 aa_put_profile(profile);
 159                 cxt = current_cxt();
 160         }
 161
 162         return cxt->profile;
 163 }
 164
 165 /**
 166  * aa_clear_task_cxt_trans - clear transition tracking info from the cxt
 167  * @cxt: task context to clear (NOT NULL)
 168  */
 169 static inline void aa_clear_task_cxt_trans(struct aa_task_cxt *cxt)
 170 {
 171         aa_put_profile(cxt->previous);
 172         aa_put_profile(cxt->onexec);
 173         cxt->previous = NULL;
 174         cxt->onexec = NULL;
 175         cxt->token = 0;
 176 }
 177
 178 #endif /* __AA_CONTEXT_H */