blob: 0848292982a2315f9e491728afe2714ad767bca0 [file] [log] [blame]
John Johansen63e2b422010-07-29 14:48:03 -07001/*
2 * AppArmor security module
3 *
4 * This file contains AppArmor /sys/kernel/security/apparmor interface functions
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#include <linux/security.h>
16#include <linux/vmalloc.h>
17#include <linux/module.h>
18#include <linux/seq_file.h>
19#include <linux/uaccess.h>
20#include <linux/namei.h>
21
22#include "include/apparmor.h"
23#include "include/apparmorfs.h"
24#include "include/audit.h"
25#include "include/context.h"
26#include "include/policy.h"
27
28/**
29 * aa_simple_write_to_buffer - common routine for getting policy from user
30 * @op: operation doing the user buffer copy
31 * @userbuf: user buffer to copy data from (NOT NULL)
John Johansen3ed02ad2010-10-09 00:47:53 -070032 * @alloc_size: size of user buffer (REQUIRES: @alloc_size >= @copy_size)
John Johansen63e2b422010-07-29 14:48:03 -070033 * @copy_size: size of data to copy from user buffer
34 * @pos: position write is at in the file (NOT NULL)
35 *
36 * Returns: kernel buffer containing copy of user buffer data or an
37 * ERR_PTR on failure.
38 */
39static char *aa_simple_write_to_buffer(int op, const char __user *userbuf,
40 size_t alloc_size, size_t copy_size,
41 loff_t *pos)
42{
43 char *data;
44
John Johansen3ed02ad2010-10-09 00:47:53 -070045 BUG_ON(copy_size > alloc_size);
46
John Johansen63e2b422010-07-29 14:48:03 -070047 if (*pos != 0)
48 /* only writes from pos 0, that is complete writes */
49 return ERR_PTR(-ESPIPE);
50
51 /*
52 * Don't allow profile load/replace/remove from profiles that don't
53 * have CAP_MAC_ADMIN
54 */
55 if (!aa_may_manage_policy(op))
56 return ERR_PTR(-EACCES);
57
58 /* freed by caller to simple_write_to_buffer */
59 data = kvmalloc(alloc_size);
60 if (data == NULL)
61 return ERR_PTR(-ENOMEM);
62
63 if (copy_from_user(data, userbuf, copy_size)) {
64 kvfree(data);
65 return ERR_PTR(-EFAULT);
66 }
67
68 return data;
69}
70
71
72/* .load file hook fn to load policy */
73static ssize_t profile_load(struct file *f, const char __user *buf, size_t size,
74 loff_t *pos)
75{
76 char *data;
77 ssize_t error;
78
79 data = aa_simple_write_to_buffer(OP_PROF_LOAD, buf, size, size, pos);
80
81 error = PTR_ERR(data);
82 if (!IS_ERR(data)) {
83 error = aa_replace_profiles(data, size, PROF_ADD);
84 kvfree(data);
85 }
86
87 return error;
88}
89
90static const struct file_operations aa_fs_profile_load = {
Arnd Bergmann6038f372010-08-15 18:52:59 +020091 .write = profile_load,
92 .llseek = default_llseek,
John Johansen63e2b422010-07-29 14:48:03 -070093};
94
95/* .replace file hook fn to load and/or replace policy */
96static ssize_t profile_replace(struct file *f, const char __user *buf,
97 size_t size, loff_t *pos)
98{
99 char *data;
100 ssize_t error;
101
102 data = aa_simple_write_to_buffer(OP_PROF_REPL, buf, size, size, pos);
103 error = PTR_ERR(data);
104 if (!IS_ERR(data)) {
105 error = aa_replace_profiles(data, size, PROF_REPLACE);
106 kvfree(data);
107 }
108
109 return error;
110}
111
112static const struct file_operations aa_fs_profile_replace = {
Arnd Bergmann6038f372010-08-15 18:52:59 +0200113 .write = profile_replace,
114 .llseek = default_llseek,
John Johansen63e2b422010-07-29 14:48:03 -0700115};
116
117/* .remove file hook fn to remove loaded policy */
118static ssize_t profile_remove(struct file *f, const char __user *buf,
119 size_t size, loff_t *pos)
120{
121 char *data;
122 ssize_t error;
123
124 /*
125 * aa_remove_profile needs a null terminated string so 1 extra
126 * byte is allocated and the copied data is null terminated.
127 */
128 data = aa_simple_write_to_buffer(OP_PROF_RM, buf, size + 1, size, pos);
129
130 error = PTR_ERR(data);
131 if (!IS_ERR(data)) {
132 data[size] = 0;
133 error = aa_remove_profiles(data, size);
134 kvfree(data);
135 }
136
137 return error;
138}
139
140static const struct file_operations aa_fs_profile_remove = {
Arnd Bergmann6038f372010-08-15 18:52:59 +0200141 .write = profile_remove,
142 .llseek = default_llseek,
John Johansen63e2b422010-07-29 14:48:03 -0700143};
144
145/** Base file system setup **/
146
147static struct dentry *aa_fs_dentry __initdata;
148
149static void __init aafs_remove(const char *name)
150{
151 struct dentry *dentry;
152
153 dentry = lookup_one_len(name, aa_fs_dentry, strlen(name));
154 if (!IS_ERR(dentry)) {
155 securityfs_remove(dentry);
156 dput(dentry);
157 }
158}
159
160/**
161 * aafs_create - create an entry in the apparmor filesystem
162 * @name: name of the entry (NOT NULL)
163 * @mask: file permission mask of the file
164 * @fops: file operations for the file (NOT NULL)
165 *
166 * Used aafs_remove to remove entries created with this fn.
167 */
168static int __init aafs_create(const char *name, int mask,
169 const struct file_operations *fops)
170{
171 struct dentry *dentry;
172
173 dentry = securityfs_create_file(name, S_IFREG | mask, aa_fs_dentry,
174 NULL, fops);
175
176 return IS_ERR(dentry) ? PTR_ERR(dentry) : 0;
177}
178
179/**
180 * aa_destroy_aafs - cleanup and free aafs
181 *
182 * releases dentries allocated by aa_create_aafs
183 */
184void __init aa_destroy_aafs(void)
185{
186 if (aa_fs_dentry) {
187 aafs_remove(".remove");
188 aafs_remove(".replace");
189 aafs_remove(".load");
190
191 securityfs_remove(aa_fs_dentry);
192 aa_fs_dentry = NULL;
193 }
194}
195
196/**
197 * aa_create_aafs - create the apparmor security filesystem
198 *
199 * dentries created here are released by aa_destroy_aafs
200 *
201 * Returns: error on failure
202 */
203int __init aa_create_aafs(void)
204{
205 int error;
206
207 if (!apparmor_initialized)
208 return 0;
209
210 if (aa_fs_dentry) {
211 AA_ERROR("%s: AppArmor securityfs already exists\n", __func__);
212 return -EEXIST;
213 }
214
215 aa_fs_dentry = securityfs_create_dir("apparmor", NULL);
216 if (IS_ERR(aa_fs_dentry)) {
217 error = PTR_ERR(aa_fs_dentry);
218 aa_fs_dentry = NULL;
219 goto error;
220 }
221
222 error = aafs_create(".load", 0640, &aa_fs_profile_load);
223 if (error)
224 goto error;
225 error = aafs_create(".replace", 0640, &aa_fs_profile_replace);
226 if (error)
227 goto error;
228 error = aafs_create(".remove", 0640, &aa_fs_profile_remove);
229 if (error)
230 goto error;
231
232 /* TODO: add support for apparmorfs_null and apparmorfs_mnt */
233
234 /* Report that AppArmor fs is enabled */
235 aa_info_message("AppArmor Filesystem Enabled");
236 return 0;
237
238error:
239 aa_destroy_aafs();
240 AA_ERROR("Error creating AppArmor securityfs\n");
241 return error;
242}
243
244fs_initcall(aa_create_aafs);