John Johansen | 63e2b42 | 2010-07-29 14:48:03 -0700 | [diff] [blame] | 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) |
John Johansen | 3ed02ad | 2010-10-09 00:47:53 -0700 | [diff] [blame] | 32 | * @alloc_size: size of user buffer (REQUIRES: @alloc_size >= @copy_size) |
John Johansen | 63e2b42 | 2010-07-29 14:48:03 -0700 | [diff] [blame] | 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 | |
John Johansen | 3ed02ad | 2010-10-09 00:47:53 -0700 | [diff] [blame] | 45 | BUG_ON(copy_size > alloc_size); |
| 46 | |
John Johansen | 63e2b42 | 2010-07-29 14:48:03 -0700 | [diff] [blame] | 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 = { |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 91 | .write = profile_load, |
| 92 | .llseek = default_llseek, |
John Johansen | 63e2b42 | 2010-07-29 14:48:03 -0700 | [diff] [blame] | 93 | }; |
| 94 | |
| 95 | /* .replace file hook fn to load and/or replace policy */ |
| 96 | static 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 | |
| 112 | static const struct file_operations aa_fs_profile_replace = { |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 113 | .write = profile_replace, |
| 114 | .llseek = default_llseek, |
John Johansen | 63e2b42 | 2010-07-29 14:48:03 -0700 | [diff] [blame] | 115 | }; |
| 116 | |
| 117 | /* .remove file hook fn to remove loaded policy */ |
| 118 | static 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 | |
| 140 | static const struct file_operations aa_fs_profile_remove = { |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 141 | .write = profile_remove, |
| 142 | .llseek = default_llseek, |
John Johansen | 63e2b42 | 2010-07-29 14:48:03 -0700 | [diff] [blame] | 143 | }; |
| 144 | |
| 145 | /** Base file system setup **/ |
| 146 | |
| 147 | static struct dentry *aa_fs_dentry __initdata; |
| 148 | |
| 149 | static 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 | */ |
| 168 | static 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 | */ |
| 184 | void __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 | */ |
James Morris | 3417d8d | 2011-08-17 11:05:21 +1000 | [diff] [blame] | 203 | static int __init aa_create_aafs(void) |
John Johansen | 63e2b42 | 2010-07-29 14:48:03 -0700 | [diff] [blame] | 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 | |
| 238 | error: |
| 239 | aa_destroy_aafs(); |
| 240 | AA_ERROR("Error creating AppArmor securityfs\n"); |
| 241 | return error; |
| 242 | } |
| 243 | |
| 244 | fs_initcall(aa_create_aafs); |