security/tomoyo/tomoyo.c

   1 /*
   2  * security/tomoyo/tomoyo.c
   3  *
   4  * Copyright (C) 2005-2011  NTT DATA CORPORATION
   5  */
   6
   7 #include <linux/lsm_hooks.h>
   8 #include "common.h"
   9
  10 /**
  11  * tomoyo_cred_alloc_blank - Target for security_cred_alloc_blank().
  12  *
  13  * @new: Pointer to "struct cred".
  14  * @gfp: Memory allocation flags.
  15  *
  16  * Returns 0.
  17  */
  18 static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
  19 {
  20         new->security = NULL;
  21         return 0;
  22 }
  23
  24 /**
  25  * tomoyo_cred_prepare - Target for security_prepare_creds().
  26  *
  27  * @new: Pointer to "struct cred".
  28  * @old: Pointer to "struct cred".
  29  * @gfp: Memory allocation flags.
  30  *
  31  * Returns 0.
  32  */
  33 static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
  34                                gfp_t gfp)
  35 {
  36         struct tomoyo_domain_info *domain = old->security;
  37         new->security = domain;
  38         if (domain)
  39                 atomic_inc(&domain->users);
  40         return 0;
  41 }
  42
  43 /**
  44  * tomoyo_cred_transfer - Target for security_transfer_creds().
  45  *
  46  * @new: Pointer to "struct cred".
  47  * @old: Pointer to "struct cred".
  48  */
  49 static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
  50 {
  51         tomoyo_cred_prepare(new, old, 0);
  52 }
  53
  54 /**
  55  * tomoyo_cred_free - Target for security_cred_free().
  56  *
  57  * @cred: Pointer to "struct cred".
  58  */
  59 static void tomoyo_cred_free(struct cred *cred)
  60 {
  61         struct tomoyo_domain_info *domain = cred->security;
  62         if (domain)
  63                 atomic_dec(&domain->users);
  64 }
  65
  66 /**
  67  * tomoyo_bprm_set_creds - Target for security_bprm_set_creds().
  68  *
  69  * @bprm: Pointer to "struct linux_binprm".
  70  *
  71  * Returns 0 on success, negative value otherwise.
  72  */
  73 static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
  74 {
  75         /*
  76          * Do only if this function is called for the first time of an execve
  77          * operation.
  78          */
  79         if (bprm->cred_prepared)
  80                 return 0;
  81 #ifndef CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
  82         /*
  83          * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
  84          * for the first time.
  85          */
  86         if (!tomoyo_policy_loaded)
  87                 tomoyo_load_policy(bprm->filename);
  88 #endif
  89         /*
  90          * Release reference to "struct tomoyo_domain_info" stored inside
  91          * "bprm->cred->security". New reference to "struct tomoyo_domain_info"
  92          * stored inside "bprm->cred->security" will be acquired later inside
  93          * tomoyo_find_next_domain().
  94          */
  95         atomic_dec(&((struct tomoyo_domain_info *)
  96                      bprm->cred->security)->users);
  97         /*
  98          * Tell tomoyo_bprm_check_security() is called for the first time of an
  99          * execve operation.
 100          */
 101         bprm->cred->security = NULL;
 102         return 0;
 103 }
 104
 105 /**
 106  * tomoyo_bprm_check_security - Target for security_bprm_check().
 107  *
 108  * @bprm: Pointer to "struct linux_binprm".
 109  *
 110  * Returns 0 on success, negative value otherwise.
 111  */
 112 static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
 113 {
 114         struct tomoyo_domain_info *domain = bprm->cred->security;
 115
 116         /*
 117          * Execute permission is checked against pathname passed to do_execve()
 118          * using current domain.
 119          */
 120         if (!domain) {
 121                 const int idx = tomoyo_read_lock();
 122                 const int err = tomoyo_find_next_domain(bprm);
 123                 tomoyo_read_unlock(idx);
 124                 return err;
 125         }
 126         /*
 127          * Read permission is checked against interpreters using next domain.
 128          */
 129         return tomoyo_check_open_permission(domain, &bprm->file->f_path,
 130                                             O_RDONLY);
 131 }
 132
 133 /**
 134  * tomoyo_inode_getattr - Target for security_inode_getattr().
 135  *
 136  * @mnt:    Pointer to "struct vfsmount".
 137  * @dentry: Pointer to "struct dentry".
 138  *
 139  * Returns 0 on success, negative value otherwise.
 140  */
 141 static int tomoyo_inode_getattr(const struct path *path)
 142 {
 143         return tomoyo_path_perm(TOMOYO_TYPE_GETATTR, path, NULL);
 144 }
 145
 146 /**
 147  * tomoyo_path_truncate - Target for security_path_truncate().
 148  *
 149  * @path: Pointer to "struct path".
 150  *
 151  * Returns 0 on success, negative value otherwise.
 152  */
 153 static int tomoyo_path_truncate(struct path *path)
 154 {
 155         return tomoyo_path_perm(TOMOYO_TYPE_TRUNCATE, path, NULL);
 156 }
 157
 158 /**
 159  * tomoyo_path_unlink - Target for security_path_unlink().
 160  *
 161  * @parent: Pointer to "struct path".
 162  * @dentry: Pointer to "struct dentry".
 163  *
 164  * Returns 0 on success, negative value otherwise.
 165  */
 166 static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
 167 {
 168         struct path path = { parent->mnt, dentry };
 169         return tomoyo_path_perm(TOMOYO_TYPE_UNLINK, &path, NULL);
 170 }
 171
 172 /**
 173  * tomoyo_path_mkdir - Target for security_path_mkdir().
 174  *
 175  * @parent: Pointer to "struct path".
 176  * @dentry: Pointer to "struct dentry".
 177  * @mode:   DAC permission mode.
 178  *
 179  * Returns 0 on success, negative value otherwise.
 180  */
 181 static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
 182                              umode_t mode)
 183 {
 184         struct path path = { parent->mnt, dentry };
 185         return tomoyo_path_number_perm(TOMOYO_TYPE_MKDIR, &path,
 186                                        mode & S_IALLUGO);
 187 }
 188
 189 /**
 190  * tomoyo_path_rmdir - Target for security_path_rmdir().
 191  *
 192  * @parent: Pointer to "struct path".
 193  * @dentry: Pointer to "struct dentry".
 194  *
 195  * Returns 0 on success, negative value otherwise.
 196  */
 197 static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
 198 {
 199         struct path path = { parent->mnt, dentry };
 200         return tomoyo_path_perm(TOMOYO_TYPE_RMDIR, &path, NULL);
 201 }
 202
 203 /**
 204  * tomoyo_path_symlink - Target for security_path_symlink().
 205  *
 206  * @parent:   Pointer to "struct path".
 207  * @dentry:   Pointer to "struct dentry".
 208  * @old_name: Symlink's content.
 209  *
 210  * Returns 0 on success, negative value otherwise.
 211  */
 212 static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
 213                                const char *old_name)
 214 {
 215         struct path path = { parent->mnt, dentry };
 216         return tomoyo_path_perm(TOMOYO_TYPE_SYMLINK, &path, old_name);
 217 }
 218
 219 /**
 220  * tomoyo_path_mknod - Target for security_path_mknod().
 221  *
 222  * @parent: Pointer to "struct path".
 223  * @dentry: Pointer to "struct dentry".
 224  * @mode:   DAC permission mode.
 225  * @dev:    Device attributes.
 226  *
 227  * Returns 0 on success, negative value otherwise.
 228  */
 229 static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
 230                              umode_t mode, unsigned int dev)
 231 {
 232         struct path path = { parent->mnt, dentry };
 233         int type = TOMOYO_TYPE_CREATE;
 234         const unsigned int perm = mode & S_IALLUGO;
 235
 236         switch (mode & S_IFMT) {
 237         case S_IFCHR:
 238                 type = TOMOYO_TYPE_MKCHAR;
 239                 break;
 240         case S_IFBLK:
 241                 type = TOMOYO_TYPE_MKBLOCK;
 242                 break;
 243         default:
 244                 goto no_dev;
 245         }
 246         return tomoyo_mkdev_perm(type, &path, perm, dev);
 247  no_dev:
 248         switch (mode & S_IFMT) {
 249         case S_IFIFO:
 250                 type = TOMOYO_TYPE_MKFIFO;
 251                 break;
 252         case S_IFSOCK:
 253                 type = TOMOYO_TYPE_MKSOCK;
 254                 break;
 255         }
 256         return tomoyo_path_number_perm(type, &path, perm);
 257 }
 258
 259 /**
 260  * tomoyo_path_link - Target for security_path_link().
 261  *
 262  * @old_dentry: Pointer to "struct dentry".
 263  * @new_dir:    Pointer to "struct path".
 264  * @new_dentry: Pointer to "struct dentry".
 265  *
 266  * Returns 0 on success, negative value otherwise.
 267  */
 268 static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
 269                             struct dentry *new_dentry)
 270 {
 271         struct path path1 = { new_dir->mnt, old_dentry };
 272         struct path path2 = { new_dir->mnt, new_dentry };
 273         return tomoyo_path2_perm(TOMOYO_TYPE_LINK, &path1, &path2);
 274 }
 275
 276 /**
 277  * tomoyo_path_rename - Target for security_path_rename().
 278  *
 279  * @old_parent: Pointer to "struct path".
 280  * @old_dentry: Pointer to "struct dentry".
 281  * @new_parent: Pointer to "struct path".
 282  * @new_dentry: Pointer to "struct dentry".
 283  *
 284  * Returns 0 on success, negative value otherwise.
 285  */
 286 static int tomoyo_path_rename(struct path *old_parent,
 287                               struct dentry *old_dentry,
 288                               struct path *new_parent,
 289                               struct dentry *new_dentry)
 290 {
 291         struct path path1 = { old_parent->mnt, old_dentry };
 292         struct path path2 = { new_parent->mnt, new_dentry };
 293         return tomoyo_path2_perm(TOMOYO_TYPE_RENAME, &path1, &path2);
 294 }
 295
 296 /**
 297  * tomoyo_file_fcntl - Target for security_file_fcntl().
 298  *
 299  * @file: Pointer to "struct file".
 300  * @cmd:  Command for fcntl().
 301  * @arg:  Argument for @cmd.
 302  *
 303  * Returns 0 on success, negative value otherwise.
 304  */
 305 static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
 306                              unsigned long arg)
 307 {
 308         if (!(cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND)))
 309                 return 0;
 310         return tomoyo_check_open_permission(tomoyo_domain(), &file->f_path,
 311                                             O_WRONLY | (arg & O_APPEND));
 312 }
 313
 314 /**
 315  * tomoyo_file_open - Target for security_file_open().
 316  *
 317  * @f:    Pointer to "struct file".
 318  * @cred: Pointer to "struct cred".
 319  *
 320  * Returns 0 on success, negative value otherwise.
 321  */
 322 static int tomoyo_file_open(struct file *f, const struct cred *cred)
 323 {
 324         int flags = f->f_flags;
 325         /* Don't check read permission here if called from do_execve(). */
 326         if (current->in_execve)
 327                 return 0;
 328         return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
 329 }
 330
 331 /**
 332  * tomoyo_file_ioctl - Target for security_file_ioctl().
 333  *
 334  * @file: Pointer to "struct file".
 335  * @cmd:  Command for ioctl().
 336  * @arg:  Argument for @cmd.
 337  *
 338  * Returns 0 on success, negative value otherwise.
 339  */
 340 static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
 341                              unsigned long arg)
 342 {
 343         return tomoyo_path_number_perm(TOMOYO_TYPE_IOCTL, &file->f_path, cmd);
 344 }
 345
 346 /**
 347  * tomoyo_path_chmod - Target for security_path_chmod().
 348  *
 349  * @path: Pointer to "struct path".
 350  * @mode: DAC permission mode.
 351  *
 352  * Returns 0 on success, negative value otherwise.
 353  */
 354 static int tomoyo_path_chmod(struct path *path, umode_t mode)
 355 {
 356         return tomoyo_path_number_perm(TOMOYO_TYPE_CHMOD, path,
 357                                        mode & S_IALLUGO);
 358 }
 359
 360 /**
 361  * tomoyo_path_chown - Target for security_path_chown().
 362  *
 363  * @path: Pointer to "struct path".
 364  * @uid:  Owner ID.
 365  * @gid:  Group ID.
 366  *
 367  * Returns 0 on success, negative value otherwise.
 368  */
 369 static int tomoyo_path_chown(struct path *path, kuid_t uid, kgid_t gid)
 370 {
 371         int error = 0;
 372         if (uid_valid(uid))
 373                 error = tomoyo_path_number_perm(TOMOYO_TYPE_CHOWN, path,
 374                                                 from_kuid(&init_user_ns, uid));
 375         if (!error && gid_valid(gid))
 376                 error = tomoyo_path_number_perm(TOMOYO_TYPE_CHGRP, path,
 377                                                 from_kgid(&init_user_ns, gid));
 378         return error;
 379 }
 380
 381 /**
 382  * tomoyo_path_chroot - Target for security_path_chroot().
 383  *
 384  * @path: Pointer to "struct path".
 385  *
 386  * Returns 0 on success, negative value otherwise.
 387  */
 388 static int tomoyo_path_chroot(struct path *path)
 389 {
 390         return tomoyo_path_perm(TOMOYO_TYPE_CHROOT, path, NULL);
 391 }
 392
 393 /**
 394  * tomoyo_sb_mount - Target for security_sb_mount().
 395  *
 396  * @dev_name: Name of device file. Maybe NULL.
 397  * @path:     Pointer to "struct path".
 398  * @type:     Name of filesystem type. Maybe NULL.
 399  * @flags:    Mount options.
 400  * @data:     Optional data. Maybe NULL.
 401  *
 402  * Returns 0 on success, negative value otherwise.
 403  */
 404 static int tomoyo_sb_mount(const char *dev_name, struct path *path,
 405                            const char *type, unsigned long flags, void *data)
 406 {
 407         return tomoyo_mount_permission(dev_name, path, type, flags, data);
 408 }
 409
 410 /**
 411  * tomoyo_sb_umount - Target for security_sb_umount().
 412  *
 413  * @mnt:   Pointer to "struct vfsmount".
 414  * @flags: Unmount options.
 415  *
 416  * Returns 0 on success, negative value otherwise.
 417  */
 418 static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
 419 {
 420         struct path path = { mnt, mnt->mnt_root };
 421         return tomoyo_path_perm(TOMOYO_TYPE_UMOUNT, &path, NULL);
 422 }
 423
 424 /**
 425  * tomoyo_sb_pivotroot - Target for security_sb_pivotroot().
 426  *
 427  * @old_path: Pointer to "struct path".
 428  * @new_path: Pointer to "struct path".
 429  *
 430  * Returns 0 on success, negative value otherwise.
 431  */
 432 static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
 433 {
 434         return tomoyo_path2_perm(TOMOYO_TYPE_PIVOT_ROOT, new_path, old_path);
 435 }
 436
 437 /**
 438  * tomoyo_socket_listen - Check permission for listen().
 439  *
 440  * @sock:    Pointer to "struct socket".
 441  * @backlog: Backlog parameter.
 442  *
 443  * Returns 0 on success, negative value otherwise.
 444  */
 445 static int tomoyo_socket_listen(struct socket *sock, int backlog)
 446 {
 447         return tomoyo_socket_listen_permission(sock);
 448 }
 449
 450 /**
 451  * tomoyo_socket_connect - Check permission for connect().
 452  *
 453  * @sock:     Pointer to "struct socket".
 454  * @addr:     Pointer to "struct sockaddr".
 455  * @addr_len: Size of @addr.
 456  *
 457  * Returns 0 on success, negative value otherwise.
 458  */
 459 static int tomoyo_socket_connect(struct socket *sock, struct sockaddr *addr,
 460                                  int addr_len)
 461 {
 462         return tomoyo_socket_connect_permission(sock, addr, addr_len);
 463 }
 464
 465 /**
 466  * tomoyo_socket_bind - Check permission for bind().
 467  *
 468  * @sock:     Pointer to "struct socket".
 469  * @addr:     Pointer to "struct sockaddr".
 470  * @addr_len: Size of @addr.
 471  *
 472  * Returns 0 on success, negative value otherwise.
 473  */
 474 static int tomoyo_socket_bind(struct socket *sock, struct sockaddr *addr,
 475                               int addr_len)
 476 {
 477         return tomoyo_socket_bind_permission(sock, addr, addr_len);
 478 }
 479
 480 /**
 481  * tomoyo_socket_sendmsg - Check permission for sendmsg().
 482  *
 483  * @sock: Pointer to "struct socket".
 484  * @msg:  Pointer to "struct msghdr".
 485  * @size: Size of message.
 486  *
 487  * Returns 0 on success, negative value otherwise.
 488  */
 489 static int tomoyo_socket_sendmsg(struct socket *sock, struct msghdr *msg,
 490                                  int size)
 491 {
 492         return tomoyo_socket_sendmsg_permission(sock, msg, size);
 493 }
 494
 495 /*
 496  * tomoyo_security_ops is a "struct security_operations" which is used for
 497  * registering TOMOYO.
 498  */
 499 static struct security_hook_list tomoyo_hooks[] = {
 500         LSM_HOOK_INIT(cred_alloc_blank, tomoyo_cred_alloc_blank),
 501         LSM_HOOK_INIT(cred_prepare, tomoyo_cred_prepare),
 502         LSM_HOOK_INIT(cred_transfer, tomoyo_cred_transfer),
 503         LSM_HOOK_INIT(cred_free, tomoyo_cred_free),
 504         LSM_HOOK_INIT(bprm_set_creds, tomoyo_bprm_set_creds),
 505         LSM_HOOK_INIT(bprm_check_security, tomoyo_bprm_check_security),
 506         LSM_HOOK_INIT(file_fcntl, tomoyo_file_fcntl),
 507         LSM_HOOK_INIT(file_open, tomoyo_file_open),
 508         LSM_HOOK_INIT(path_truncate, tomoyo_path_truncate),
 509         LSM_HOOK_INIT(path_unlink, tomoyo_path_unlink),
 510         LSM_HOOK_INIT(path_mkdir, tomoyo_path_mkdir),
 511         LSM_HOOK_INIT(path_rmdir, tomoyo_path_rmdir),
 512         LSM_HOOK_INIT(path_symlink, tomoyo_path_symlink),
 513         LSM_HOOK_INIT(path_mknod, tomoyo_path_mknod),
 514         LSM_HOOK_INIT(path_link, tomoyo_path_link),
 515         LSM_HOOK_INIT(path_rename, tomoyo_path_rename),
 516         LSM_HOOK_INIT(inode_getattr, tomoyo_inode_getattr),
 517         LSM_HOOK_INIT(file_ioctl, tomoyo_file_ioctl),
 518         LSM_HOOK_INIT(path_chmod, tomoyo_path_chmod),
 519         LSM_HOOK_INIT(path_chown, tomoyo_path_chown),
 520         LSM_HOOK_INIT(path_chroot, tomoyo_path_chroot),
 521         LSM_HOOK_INIT(sb_mount, tomoyo_sb_mount),
 522         LSM_HOOK_INIT(sb_umount, tomoyo_sb_umount),
 523         LSM_HOOK_INIT(sb_pivotroot, tomoyo_sb_pivotroot),
 524         LSM_HOOK_INIT(socket_bind, tomoyo_socket_bind),
 525         LSM_HOOK_INIT(socket_connect, tomoyo_socket_connect),
 526         LSM_HOOK_INIT(socket_listen, tomoyo_socket_listen),
 527         LSM_HOOK_INIT(socket_sendmsg, tomoyo_socket_sendmsg),
 528 };
 529
 530 /* Lock for GC. */
 531 DEFINE_SRCU(tomoyo_ss);
 532
 533 /**
 534  * tomoyo_init - Register TOMOYO Linux as a LSM module.
 535  *
 536  * Returns 0.
 537  */
 538 static int __init tomoyo_init(void)
 539 {
 540         struct cred *cred = (struct cred *) current_cred();
 541
 542         if (!security_module_enable("tomoyo"))
 543                 return 0;
 544         /* register ourselves with the security framework */
 545         security_add_hooks(tomoyo_hooks, ARRAY_SIZE(tomoyo_hooks));
 546         printk(KERN_INFO "TOMOYO Linux initialized\n");
 547         cred->security = &tomoyo_kernel_domain;
 548         tomoyo_mm_init();
 549         return 0;
 550 }
 551
 552 security_initcall(tomoyo_init);