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 #include <linux/capability.h> 22 23 #include "include/apparmor.h" 24 #include "include/apparmorfs.h" 25 #include "include/audit.h" 26 #include "include/context.h" 27 #include "include/policy.h" 28 29 /** 30 * aa_simple_write_to_buffer - common routine for getting policy from user 31 * @op: operation doing the user buffer copy 32 * @userbuf: user buffer to copy data from (NOT NULL) 33 * @alloc_size: size of user buffer (REQUIRES: @alloc_size >= @copy_size) 34 * @copy_size: size of data to copy from user buffer 35 * @pos: position write is at in the file (NOT NULL) 36 * 37 * Returns: kernel buffer containing copy of user buffer data or an 38 * ERR_PTR on failure. 39 */ 40 static char *aa_simple_write_to_buffer(int op, const char __user *userbuf, 41 size_t alloc_size, size_t copy_size, 42 loff_t *pos) 43 { 44 char *data; 45 46 BUG_ON(copy_size > alloc_size); 47 48 if (*pos != 0) 49 /* only writes from pos 0, that is complete writes */ 50 return ERR_PTR(-ESPIPE); 51 52 /* 53 * Don't allow profile load/replace/remove from profiles that don't 54 * have CAP_MAC_ADMIN 55 */ 56 if (!aa_may_manage_policy(op)) 57 return ERR_PTR(-EACCES); 58 59 /* freed by caller to simple_write_to_buffer */ 60 data = kvmalloc(alloc_size); 61 if (data == NULL) 62 return ERR_PTR(-ENOMEM); 63 64 if (copy_from_user(data, userbuf, copy_size)) { 65 kvfree(data); 66 return ERR_PTR(-EFAULT); 67 } 68 69 return data; 70 } 71 72 73 /* .load file hook fn to load policy */ 74 static ssize_t profile_load(struct file *f, const char __user *buf, size_t size, 75 loff_t *pos) 76 { 77 char *data; 78 ssize_t error; 79 80 data = aa_simple_write_to_buffer(OP_PROF_LOAD, buf, size, size, pos); 81 82 error = PTR_ERR(data); 83 if (!IS_ERR(data)) { 84 error = aa_replace_profiles(data, size, PROF_ADD); 85 kvfree(data); 86 } 87 88 return error; 89 } 90 91 static const struct file_operations aa_fs_profile_load = { 92 .write = profile_load, 93 .llseek = default_llseek, 94 }; 95 96 /* .replace file hook fn to load and/or replace policy */ 97 static ssize_t profile_replace(struct file *f, const char __user *buf, 98 size_t size, loff_t *pos) 99 { 100 char *data; 101 ssize_t error; 102 103 data = aa_simple_write_to_buffer(OP_PROF_REPL, buf, size, size, pos); 104 error = PTR_ERR(data); 105 if (!IS_ERR(data)) { 106 error = aa_replace_profiles(data, size, PROF_REPLACE); 107 kvfree(data); 108 } 109 110 return error; 111 } 112 113 static const struct file_operations aa_fs_profile_replace = { 114 .write = profile_replace, 115 .llseek = default_llseek, 116 }; 117 118 /* .remove file hook fn to remove loaded policy */ 119 static ssize_t profile_remove(struct file *f, const char __user *buf, 120 size_t size, loff_t *pos) 121 { 122 char *data; 123 ssize_t error; 124 125 /* 126 * aa_remove_profile needs a null terminated string so 1 extra 127 * byte is allocated and the copied data is null terminated. 128 */ 129 data = aa_simple_write_to_buffer(OP_PROF_RM, buf, size + 1, size, pos); 130 131 error = PTR_ERR(data); 132 if (!IS_ERR(data)) { 133 data[size] = 0; 134 error = aa_remove_profiles(data, size); 135 kvfree(data); 136 } 137 138 return error; 139 } 140 141 static const struct file_operations aa_fs_profile_remove = { 142 .write = profile_remove, 143 .llseek = default_llseek, 144 }; 145 146 static int aa_fs_seq_show(struct seq_file *seq, void *v) 147 { 148 struct aa_fs_entry *fs_file = seq->private; 149 150 if (!fs_file) 151 return 0; 152 153 switch (fs_file->v_type) { 154 case AA_FS_TYPE_BOOLEAN: 155 seq_printf(seq, "%s\n", fs_file->v.boolean ? "yes" : "no"); 156 break; 157 case AA_FS_TYPE_STRING: 158 seq_printf(seq, "%s\n", fs_file->v.string); 159 break; 160 case AA_FS_TYPE_U64: 161 seq_printf(seq, "%#08lx\n", fs_file->v.u64); 162 break; 163 default: 164 /* Ignore unpritable entry types. */ 165 break; 166 } 167 168 return 0; 169 } 170 171 static int aa_fs_seq_open(struct inode *inode, struct file *file) 172 { 173 return single_open(file, aa_fs_seq_show, inode->i_private); 174 } 175 176 const struct file_operations aa_fs_seq_file_ops = { 177 .owner = THIS_MODULE, 178 .open = aa_fs_seq_open, 179 .read = seq_read, 180 .llseek = seq_lseek, 181 .release = single_release, 182 }; 183 184 /** Base file system setup **/ 185 186 static struct aa_fs_entry aa_fs_entry_file[] = { 187 AA_FS_FILE_STRING("mask", "create read write exec append mmap_exec " \ 188 "link lock"), 189 { } 190 }; 191 192 static struct aa_fs_entry aa_fs_entry_domain[] = { 193 AA_FS_FILE_BOOLEAN("change_hat", 1), 194 AA_FS_FILE_BOOLEAN("change_hatv", 1), 195 AA_FS_FILE_BOOLEAN("change_onexec", 1), 196 AA_FS_FILE_BOOLEAN("change_profile", 1), 197 { } 198 }; 199 200 static struct aa_fs_entry aa_fs_entry_features[] = { 201 AA_FS_DIR("domain", aa_fs_entry_domain), 202 AA_FS_DIR("file", aa_fs_entry_file), 203 AA_FS_FILE_U64("capability", VFS_CAP_FLAGS_MASK), 204 { } 205 }; 206 207 static struct aa_fs_entry aa_fs_entry_apparmor[] = { 208 AA_FS_FILE_FOPS(".load", 0640, &aa_fs_profile_load), 209 AA_FS_FILE_FOPS(".replace", 0640, &aa_fs_profile_replace), 210 AA_FS_FILE_FOPS(".remove", 0640, &aa_fs_profile_remove), 211 AA_FS_DIR("features", aa_fs_entry_features), 212 { } 213 }; 214 215 static struct aa_fs_entry aa_fs_entry = 216 AA_FS_DIR("apparmor", aa_fs_entry_apparmor); 217 218 /** 219 * aafs_create_file - create a file entry in the apparmor securityfs 220 * @fs_file: aa_fs_entry to build an entry for (NOT NULL) 221 * @parent: the parent dentry in the securityfs 222 * 223 * Use aafs_remove_file to remove entries created with this fn. 224 */ 225 static int __init aafs_create_file(struct aa_fs_entry *fs_file, 226 struct dentry *parent) 227 { 228 int error = 0; 229 230 fs_file->dentry = securityfs_create_file(fs_file->name, 231 S_IFREG | fs_file->mode, 232 parent, fs_file, 233 fs_file->file_ops); 234 if (IS_ERR(fs_file->dentry)) { 235 error = PTR_ERR(fs_file->dentry); 236 fs_file->dentry = NULL; 237 } 238 return error; 239 } 240 241 /** 242 * aafs_create_dir - recursively create a directory entry in the securityfs 243 * @fs_dir: aa_fs_entry (and all child entries) to build (NOT NULL) 244 * @parent: the parent dentry in the securityfs 245 * 246 * Use aafs_remove_dir to remove entries created with this fn. 247 */ 248 static int __init aafs_create_dir(struct aa_fs_entry *fs_dir, 249 struct dentry *parent) 250 { 251 int error; 252 struct aa_fs_entry *fs_file; 253 254 fs_dir->dentry = securityfs_create_dir(fs_dir->name, parent); 255 if (IS_ERR(fs_dir->dentry)) { 256 error = PTR_ERR(fs_dir->dentry); 257 fs_dir->dentry = NULL; 258 goto failed; 259 } 260 261 for (fs_file = fs_dir->v.files; fs_file->name; ++fs_file) { 262 if (fs_file->v_type == AA_FS_TYPE_DIR) 263 error = aafs_create_dir(fs_file, fs_dir->dentry); 264 else 265 error = aafs_create_file(fs_file, fs_dir->dentry); 266 if (error) 267 goto failed; 268 } 269 270 return 0; 271 272 failed: 273 return error; 274 } 275 276 /** 277 * aafs_remove_file - drop a single file entry in the apparmor securityfs 278 * @fs_file: aa_fs_entry to detach from the securityfs (NOT NULL) 279 */ 280 static void __init aafs_remove_file(struct aa_fs_entry *fs_file) 281 { 282 if (!fs_file->dentry) 283 return; 284 285 securityfs_remove(fs_file->dentry); 286 fs_file->dentry = NULL; 287 } 288 289 /** 290 * aafs_remove_dir - recursively drop a directory entry from the securityfs 291 * @fs_dir: aa_fs_entry (and all child entries) to detach (NOT NULL) 292 */ 293 static void __init aafs_remove_dir(struct aa_fs_entry *fs_dir) 294 { 295 struct aa_fs_entry *fs_file; 296 297 for (fs_file = fs_dir->v.files; fs_file->name; ++fs_file) { 298 if (fs_file->v_type == AA_FS_TYPE_DIR) 299 aafs_remove_dir(fs_file); 300 else 301 aafs_remove_file(fs_file); 302 } 303 304 aafs_remove_file(fs_dir); 305 } 306 307 /** 308 * aa_destroy_aafs - cleanup and free aafs 309 * 310 * releases dentries allocated by aa_create_aafs 311 */ 312 void __init aa_destroy_aafs(void) 313 { 314 aafs_remove_dir(&aa_fs_entry); 315 } 316 317 /** 318 * aa_create_aafs - create the apparmor security filesystem 319 * 320 * dentries created here are released by aa_destroy_aafs 321 * 322 * Returns: error on failure 323 */ 324 static int __init aa_create_aafs(void) 325 { 326 int error; 327 328 if (!apparmor_initialized) 329 return 0; 330 331 if (aa_fs_entry.dentry) { 332 AA_ERROR("%s: AppArmor securityfs already exists\n", __func__); 333 return -EEXIST; 334 } 335 336 /* Populate fs tree. */ 337 error = aafs_create_dir(&aa_fs_entry, NULL); 338 if (error) 339 goto error; 340 341 /* TODO: add support for apparmorfs_null and apparmorfs_mnt */ 342 343 /* Report that AppArmor fs is enabled */ 344 aa_info_message("AppArmor Filesystem Enabled"); 345 return 0; 346 347 error: 348 aa_destroy_aafs(); 349 AA_ERROR("Error creating AppArmor securityfs\n"); 350 return error; 351 } 352 353 fs_initcall(aa_create_aafs); 354