John Johansen | c75afcd | 2010-07-29 14:47:59 -0700 | [diff] [blame] | 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 */ |