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 #include "include/resource.h" 29 30 /** 31 * aa_simple_write_to_buffer - common routine for getting policy from user 32 * @op: operation doing the user buffer copy 33 * @userbuf: user buffer to copy data from (NOT NULL) 34 * @alloc_size: size of user buffer (REQUIRES: @alloc_size >= @copy_size) 35 * @copy_size: size of data to copy from user buffer 36 * @pos: position write is at in the file (NOT NULL) 37 * 38 * Returns: kernel buffer containing copy of user buffer data or an 39 * ERR_PTR on failure. 40 */ 41 static char *aa_simple_write_to_buffer(int op, const char __user *userbuf, 42 size_t alloc_size, size_t copy_size, 43 loff_t *pos) 44 { 45 char *data; 46 47 BUG_ON(copy_size > alloc_size); 48 49 if (*pos != 0) 50 /* only writes from pos 0, that is complete writes */ 51 return ERR_PTR(-ESPIPE); 52 53 /* 54 * Don't allow profile load/replace/remove from profiles that don't 55 * have CAP_MAC_ADMIN 56 */ 57 if (!aa_may_manage_policy(op)) 58 return ERR_PTR(-EACCES); 59 60 /* freed by caller to simple_write_to_buffer */ 61 data = kvmalloc(alloc_size); 62 if (data == NULL) 63 return ERR_PTR(-ENOMEM); 64 65 if (copy_from_user(data, userbuf, copy_size)) { 66 kvfree(data); 67 return ERR_PTR(-EFAULT); 68 } 69 70 return data; 71 } 72 73 74 /* .load file hook fn to load policy */ 75 static ssize_t profile_load(struct file *f, const char __user *buf, size_t size, 76 loff_t *pos) 77 { 78 char *data; 79 ssize_t error; 80 81 data = aa_simple_write_to_buffer(OP_PROF_LOAD, buf, size, size, pos); 82 83 error = PTR_ERR(data); 84 if (!IS_ERR(data)) { 85 error = aa_replace_profiles(data, size, PROF_ADD); 86 kvfree(data); 87 } 88 89 return error; 90 } 91 92 static const struct file_operations aa_fs_profile_load = { 93 .write = profile_load, 94 .llseek = default_llseek, 95 }; 96 97 /* .replace file hook fn to load and/or replace policy */ 98 static ssize_t profile_replace(struct file *f, const char __user *buf, 99 size_t size, loff_t *pos) 100 { 101 char *data; 102 ssize_t error; 103 104 data = aa_simple_write_to_buffer(OP_PROF_REPL, buf, size, size, pos); 105 error = PTR_ERR(data); 106 if (!IS_ERR(data)) { 107 error = aa_replace_profiles(data, size, PROF_REPLACE); 108 kvfree(data); 109 } 110 111 return error; 112 } 113 114 static const struct file_operations aa_fs_profile_replace = { 115 .write = profile_replace, 116 .llseek = default_llseek, 117 }; 118 119 /* .remove file hook fn to remove loaded policy */ 120 static ssize_t profile_remove(struct file *f, const char __user *buf, 121 size_t size, loff_t *pos) 122 { 123 char *data; 124 ssize_t error; 125 126 /* 127 * aa_remove_profile needs a null terminated string so 1 extra 128 * byte is allocated and the copied data is null terminated. 129 */ 130 data = aa_simple_write_to_buffer(OP_PROF_RM, buf, size + 1, size, pos); 131 132 error = PTR_ERR(data); 133 if (!IS_ERR(data)) { 134 data[size] = 0; 135 error = aa_remove_profiles(data, size); 136 kvfree(data); 137 } 138 139 return error; 140 } 141 142 static const struct file_operations aa_fs_profile_remove = { 143 .write = profile_remove, 144 .llseek = default_llseek, 145 }; 146 147 static int aa_fs_seq_show(struct seq_file *seq, void *v) 148 { 149 struct aa_fs_entry *fs_file = seq->private; 150 151 if (!fs_file) 152 return 0; 153 154 switch (fs_file->v_type) { 155 case AA_FS_TYPE_BOOLEAN: 156 seq_printf(seq, "%s\n", fs_file->v.boolean ? "yes" : "no"); 157 break; 158 case AA_FS_TYPE_STRING: 159 seq_printf(seq, "%s\n", fs_file->v.string); 160 break; 161 case AA_FS_TYPE_U64: 162 seq_printf(seq, "%#08lx\n", fs_file->v.u64); 163 break; 164 default: 165 /* Ignore unpritable entry types. */ 166 break; 167 } 168 169 return 0; 170 } 171 172 static int aa_fs_seq_open(struct inode *inode, struct file *file) 173 { 174 return single_open(file, aa_fs_seq_show, inode->i_private); 175 } 176 177 const struct file_operations aa_fs_seq_file_ops = { 178 .owner = THIS_MODULE, 179 .open = aa_fs_seq_open, 180 .read = seq_read, 181 .llseek = seq_lseek, 182 .release = single_release, 183 }; 184 185 /** Base file system setup **/ 186 187 static struct aa_fs_entry aa_fs_entry_file[] = { 188 AA_FS_FILE_STRING("mask", "create read write exec append mmap_exec " \ 189 "link lock"), 190 { } 191 }; 192 193 static struct aa_fs_entry aa_fs_entry_domain[] = { 194 AA_FS_FILE_BOOLEAN("change_hat", 1), 195 AA_FS_FILE_BOOLEAN("change_hatv", 1), 196 AA_FS_FILE_BOOLEAN("change_onexec", 1), 197 AA_FS_FILE_BOOLEAN("change_profile", 1), 198 { } 199 }; 200 201 static struct aa_fs_entry aa_fs_entry_features[] = { 202 AA_FS_DIR("domain", aa_fs_entry_domain), 203 AA_FS_DIR("file", aa_fs_entry_file), 204 AA_FS_FILE_U64("capability", VFS_CAP_FLAGS_MASK), 205 AA_FS_DIR("rlimit", aa_fs_entry_rlimit), 206 { } 207 }; 208 209 static struct aa_fs_entry aa_fs_entry_apparmor[] = { 210 AA_FS_FILE_FOPS(".load", 0640, &aa_fs_profile_load), 211 AA_FS_FILE_FOPS(".replace", 0640, &aa_fs_profile_replace), 212 AA_FS_FILE_FOPS(".remove", 0640, &aa_fs_profile_remove), 213 AA_FS_DIR("features", aa_fs_entry_features), 214 { } 215 }; 216 217 static struct aa_fs_entry aa_fs_entry = 218 AA_FS_DIR("apparmor", aa_fs_entry_apparmor); 219 220 /** 221 * aafs_create_file - create a file entry in the apparmor securityfs 222 * @fs_file: aa_fs_entry to build an entry for (NOT NULL) 223 * @parent: the parent dentry in the securityfs 224 * 225 * Use aafs_remove_file to remove entries created with this fn. 226 */ 227 static int __init aafs_create_file(struct aa_fs_entry *fs_file, 228 struct dentry *parent) 229 { 230 int error = 0; 231 232 fs_file->dentry = securityfs_create_file(fs_file->name, 233 S_IFREG | fs_file->mode, 234 parent, fs_file, 235 fs_file->file_ops); 236 if (IS_ERR(fs_file->dentry)) { 237 error = PTR_ERR(fs_file->dentry); 238 fs_file->dentry = NULL; 239 } 240 return error; 241 } 242 243 /** 244 * aafs_create_dir - recursively create a directory entry in the securityfs 245 * @fs_dir: aa_fs_entry (and all child entries) to build (NOT NULL) 246 * @parent: the parent dentry in the securityfs 247 * 248 * Use aafs_remove_dir to remove entries created with this fn. 249 */ 250 static int __init aafs_create_dir(struct aa_fs_entry *fs_dir, 251 struct dentry *parent) 252 { 253 int error; 254 struct aa_fs_entry *fs_file; 255 256 fs_dir->dentry = securityfs_create_dir(fs_dir->name, parent); 257 if (IS_ERR(fs_dir->dentry)) { 258 error = PTR_ERR(fs_dir->dentry); 259 fs_dir->dentry = NULL; 260 goto failed; 261 } 262 263 for (fs_file = fs_dir->v.files; fs_file->name; ++fs_file) { 264 if (fs_file->v_type == AA_FS_TYPE_DIR) 265 error = aafs_create_dir(fs_file, fs_dir->dentry); 266 else 267 error = aafs_create_file(fs_file, fs_dir->dentry); 268 if (error) 269 goto failed; 270 } 271 272 return 0; 273 274 failed: 275 return error; 276 } 277 278 /** 279 * aafs_remove_file - drop a single file entry in the apparmor securityfs 280 * @fs_file: aa_fs_entry to detach from the securityfs (NOT NULL) 281 */ 282 static void __init aafs_remove_file(struct aa_fs_entry *fs_file) 283 { 284 if (!fs_file->dentry) 285 return; 286 287 securityfs_remove(fs_file->dentry); 288 fs_file->dentry = NULL; 289 } 290 291 /** 292 * aafs_remove_dir - recursively drop a directory entry from the securityfs 293 * @fs_dir: aa_fs_entry (and all child entries) to detach (NOT NULL) 294 */ 295 static void __init aafs_remove_dir(struct aa_fs_entry *fs_dir) 296 { 297 struct aa_fs_entry *fs_file; 298 299 for (fs_file = fs_dir->v.files; fs_file->name; ++fs_file) { 300 if (fs_file->v_type == AA_FS_TYPE_DIR) 301 aafs_remove_dir(fs_file); 302 else 303 aafs_remove_file(fs_file); 304 } 305 306 aafs_remove_file(fs_dir); 307 } 308 309 /** 310 * aa_destroy_aafs - cleanup and free aafs 311 * 312 * releases dentries allocated by aa_create_aafs 313 */ 314 void __init aa_destroy_aafs(void) 315 { 316 aafs_remove_dir(&aa_fs_entry); 317 } 318 319 /** 320 * aa_create_aafs - create the apparmor security filesystem 321 * 322 * dentries created here are released by aa_destroy_aafs 323 * 324 * Returns: error on failure 325 */ 326 static int __init aa_create_aafs(void) 327 { 328 int error; 329 330 if (!apparmor_initialized) 331 return 0; 332 333 if (aa_fs_entry.dentry) { 334 AA_ERROR("%s: AppArmor securityfs already exists\n", __func__); 335 return -EEXIST; 336 } 337 338 /* Populate fs tree. */ 339 error = aafs_create_dir(&aa_fs_entry, NULL); 340 if (error) 341 goto error; 342 343 /* TODO: add support for apparmorfs_null and apparmorfs_mnt */ 344 345 /* Report that AppArmor fs is enabled */ 346 aa_info_message("AppArmor Filesystem Enabled"); 347 return 0; 348 349 error: 350 aa_destroy_aafs(); 351 AA_ERROR("Error creating AppArmor securityfs\n"); 352 return error; 353 } 354 355 fs_initcall(aa_create_aafs); 356