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63e2b423 JJ |
1 | /* |
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) | |
3ed02ada | 32 | * @alloc_size: size of user buffer (REQUIRES: @alloc_size >= @copy_size) |
63e2b423 JJ |
33 | * @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 | */ | |
39 | static 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 | ||
3ed02ada JJ |
45 | BUG_ON(copy_size > alloc_size); |
46 | ||
63e2b423 JJ |
47 | 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 */ | |
73 | static 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 | ||
90 | static const struct file_operations aa_fs_profile_load = { | |
91 | .write = profile_load | |
92 | }; | |
93 | ||
94 | /* .replace file hook fn to load and/or replace policy */ | |
95 | static ssize_t profile_replace(struct file *f, const char __user *buf, | |
96 | size_t size, loff_t *pos) | |
97 | { | |
98 | char *data; | |
99 | ssize_t error; | |
100 | ||
101 | data = aa_simple_write_to_buffer(OP_PROF_REPL, buf, size, size, pos); | |
102 | error = PTR_ERR(data); | |
103 | if (!IS_ERR(data)) { | |
104 | error = aa_replace_profiles(data, size, PROF_REPLACE); | |
105 | kvfree(data); | |
106 | } | |
107 | ||
108 | return error; | |
109 | } | |
110 | ||
111 | static const struct file_operations aa_fs_profile_replace = { | |
112 | .write = profile_replace | |
113 | }; | |
114 | ||
115 | /* .remove file hook fn to remove loaded policy */ | |
116 | static ssize_t profile_remove(struct file *f, const char __user *buf, | |
117 | size_t size, loff_t *pos) | |
118 | { | |
119 | char *data; | |
120 | ssize_t error; | |
121 | ||
122 | /* | |
123 | * aa_remove_profile needs a null terminated string so 1 extra | |
124 | * byte is allocated and the copied data is null terminated. | |
125 | */ | |
126 | data = aa_simple_write_to_buffer(OP_PROF_RM, buf, size + 1, size, pos); | |
127 | ||
128 | error = PTR_ERR(data); | |
129 | if (!IS_ERR(data)) { | |
130 | data[size] = 0; | |
131 | error = aa_remove_profiles(data, size); | |
132 | kvfree(data); | |
133 | } | |
134 | ||
135 | return error; | |
136 | } | |
137 | ||
138 | static const struct file_operations aa_fs_profile_remove = { | |
139 | .write = profile_remove | |
140 | }; | |
141 | ||
142 | /** Base file system setup **/ | |
143 | ||
144 | static struct dentry *aa_fs_dentry __initdata; | |
145 | ||
146 | static void __init aafs_remove(const char *name) | |
147 | { | |
148 | struct dentry *dentry; | |
149 | ||
150 | dentry = lookup_one_len(name, aa_fs_dentry, strlen(name)); | |
151 | if (!IS_ERR(dentry)) { | |
152 | securityfs_remove(dentry); | |
153 | dput(dentry); | |
154 | } | |
155 | } | |
156 | ||
157 | /** | |
158 | * aafs_create - create an entry in the apparmor filesystem | |
159 | * @name: name of the entry (NOT NULL) | |
160 | * @mask: file permission mask of the file | |
161 | * @fops: file operations for the file (NOT NULL) | |
162 | * | |
163 | * Used aafs_remove to remove entries created with this fn. | |
164 | */ | |
165 | static int __init aafs_create(const char *name, int mask, | |
166 | const struct file_operations *fops) | |
167 | { | |
168 | struct dentry *dentry; | |
169 | ||
170 | dentry = securityfs_create_file(name, S_IFREG | mask, aa_fs_dentry, | |
171 | NULL, fops); | |
172 | ||
173 | return IS_ERR(dentry) ? PTR_ERR(dentry) : 0; | |
174 | } | |
175 | ||
176 | /** | |
177 | * aa_destroy_aafs - cleanup and free aafs | |
178 | * | |
179 | * releases dentries allocated by aa_create_aafs | |
180 | */ | |
181 | void __init aa_destroy_aafs(void) | |
182 | { | |
183 | if (aa_fs_dentry) { | |
184 | aafs_remove(".remove"); | |
185 | aafs_remove(".replace"); | |
186 | aafs_remove(".load"); | |
187 | ||
188 | securityfs_remove(aa_fs_dentry); | |
189 | aa_fs_dentry = NULL; | |
190 | } | |
191 | } | |
192 | ||
193 | /** | |
194 | * aa_create_aafs - create the apparmor security filesystem | |
195 | * | |
196 | * dentries created here are released by aa_destroy_aafs | |
197 | * | |
198 | * Returns: error on failure | |
199 | */ | |
200 | int __init aa_create_aafs(void) | |
201 | { | |
202 | int error; | |
203 | ||
204 | if (!apparmor_initialized) | |
205 | return 0; | |
206 | ||
207 | if (aa_fs_dentry) { | |
208 | AA_ERROR("%s: AppArmor securityfs already exists\n", __func__); | |
209 | return -EEXIST; | |
210 | } | |
211 | ||
212 | aa_fs_dentry = securityfs_create_dir("apparmor", NULL); | |
213 | if (IS_ERR(aa_fs_dentry)) { | |
214 | error = PTR_ERR(aa_fs_dentry); | |
215 | aa_fs_dentry = NULL; | |
216 | goto error; | |
217 | } | |
218 | ||
219 | error = aafs_create(".load", 0640, &aa_fs_profile_load); | |
220 | if (error) | |
221 | goto error; | |
222 | error = aafs_create(".replace", 0640, &aa_fs_profile_replace); | |
223 | if (error) | |
224 | goto error; | |
225 | error = aafs_create(".remove", 0640, &aa_fs_profile_remove); | |
226 | if (error) | |
227 | goto error; | |
228 | ||
229 | /* TODO: add support for apparmorfs_null and apparmorfs_mnt */ | |
230 | ||
231 | /* Report that AppArmor fs is enabled */ | |
232 | aa_info_message("AppArmor Filesystem Enabled"); | |
233 | return 0; | |
234 | ||
235 | error: | |
236 | aa_destroy_aafs(); | |
237 | AA_ERROR("Error creating AppArmor securityfs\n"); | |
238 | return error; | |
239 | } | |
240 | ||
241 | fs_initcall(aa_create_aafs); |