kernel/security/tomoyo/tomoyo.c

   1 /*
   2  * security/tomoyo/tomoyo.c
   3  *
   4  * Copyright (C) 2005-2011  NTT DATA CORPORATION
   5  */
   6
   7 #include <linux/security.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         int rc;
  76
  77         rc = cap_bprm_set_creds(bprm);
  78         if (rc)
  79                 return rc;
  80
  81         /*
  82          * Do only if this function is called for the first time of an execve
  83          * operation.
  84          */
  85         if (bprm->cred_prepared)
  86                 return 0;
  87 #ifndef CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
  88         /*
  89          * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
  90          * for the first time.
  91          */
  92         if (!tomoyo_policy_loaded)
  93                 tomoyo_load_policy(bprm->filename);
  94 #endif
  95         /*
  96          * Release reference to "struct tomoyo_domain_info" stored inside
  97          * "bprm->cred->security". New reference to "struct tomoyo_domain_info"
  98          * stored inside "bprm->cred->security" will be acquired later inside
  99          * tomoyo_find_next_domain().
 100          */
 101         atomic_dec(&((struct tomoyo_domain_info *)
 102                      bprm->cred->security)->users);
 103         /*
 104          * Tell tomoyo_bprm_check_security() is called for the first time of an
 105          * execve operation.
 106          */
 107         bprm->cred->security = NULL;
 108         return 0;
 109 }
 110
 111 /**
 112  * tomoyo_bprm_check_security - Target for security_bprm_check().
 113  *
 114  * @bprm: Pointer to "struct linux_binprm".
 115  *
 116  * Returns 0 on success, negative value otherwise.
 117  */
 118 static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
 119 {
 120         struct tomoyo_domain_info *domain = bprm->cred->security;
 121
 122         /*
 123          * Execute permission is checked against pathname passed to do_execve()
 124          * using current domain.
 125          */
 126         if (!domain) {
 127                 const int idx = tomoyo_read_lock();
 128                 const int err = tomoyo_find_next_domain(bprm);
 129                 tomoyo_read_unlock(idx);
 130                 return err;
 131         }
 132         /*
 133          * Read permission is checked against interpreters using next domain.
 134          */
 135         return tomoyo_check_open_permission(domain, &bprm->file->f_path,
 136                                             O_RDONLY);
 137 }
 138
 139 /**
 140  * tomoyo_inode_getattr - Target for security_inode_getattr().
 141  *
 142  * @mnt:    Pointer to "struct vfsmount".
 143  * @dentry: Pointer to "struct dentry".
 144  *
 145  * Returns 0 on success, negative value otherwise.
 146  */
 147 static int tomoyo_inode_getattr(const struct path *path)
 148 {
 149         return tomoyo_path_perm(TOMOYO_TYPE_GETATTR, path, NULL);
 150 }
 151
 152 /**
 153  * tomoyo_path_truncate - Target for security_path_truncate().
 154  *
 155  * @path: Pointer to "struct path".
 156  *
 157  * Returns 0 on success, negative value otherwise.
 158  */
 159 static int tomoyo_path_truncate(struct path *path)
 160 {
 161         return tomoyo_path_perm(TOMOYO_TYPE_TRUNCATE, path, NULL);
 162 }
 163
 164 /**
 165  * tomoyo_path_unlink - Target for security_path_unlink().
 166  *
 167  * @parent: Pointer to "struct path".
 168  * @dentry: Pointer to "struct dentry".
 169  *
 170  * Returns 0 on success, negative value otherwise.
 171  */
 172 static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
 173 {
 174         struct path path = { parent->mnt, dentry };
 175         return tomoyo_path_perm(TOMOYO_TYPE_UNLINK, &path, NULL);
 176 }
 177
 178 /**
 179  * tomoyo_path_mkdir - Target for security_path_mkdir().
 180  *
 181  * @parent: Pointer to "struct path".
 182  * @dentry: Pointer to "struct dentry".
 183  * @mode:   DAC permission mode.
 184  *
 185  * Returns 0 on success, negative value otherwise.
 186  */
 187 static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
 188                              umode_t mode)
 189 {
 190         struct path path = { parent->mnt, dentry };
 191         return tomoyo_path_number_perm(TOMOYO_TYPE_MKDIR, &path,
 192                                        mode & S_IALLUGO);
 193 }
 194
 195 /**
 196  * tomoyo_path_rmdir - Target for security_path_rmdir().
 197  *
 198  * @parent: Pointer to "struct path".
 199  * @dentry: Pointer to "struct dentry".
 200  *
 201  * Returns 0 on success, negative value otherwise.
 202  */
 203 static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
 204 {
 205         struct path path = { parent->mnt, dentry };
 206         return tomoyo_path_perm(TOMOYO_TYPE_RMDIR, &path, NULL);
 207 }
 208
 209 /**
 210  * tomoyo_path_symlink - Target for security_path_symlink().
 211  *
 212  * @parent:   Pointer to "struct path".
 213  * @dentry:   Pointer to "struct dentry".
 214  * @old_name: Symlink's content.
 215  *
 216  * Returns 0 on success, negative value otherwise.
 217  */
 218 static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
 219                                const char *old_name)
 220 {
 221         struct path path = { parent->mnt, dentry };
 222         return tomoyo_path_perm(TOMOYO_TYPE_SYMLINK, &path, old_name);
 223 }
 224
 225 /**
 226  * tomoyo_path_mknod - Target for security_path_mknod().
 227  *
 228  * @parent: Pointer to "struct path".
 229  * @dentry: Pointer to "struct dentry".
 230  * @mode:   DAC permission mode.
 231  * @dev:    Device attributes.
 232  *
 233  * Returns 0 on success, negative value otherwise.
 234  */
 235 static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
 236                              umode_t mode, unsigned int dev)
 237 {
 238         struct path path = { parent->mnt, dentry };
 239         int type = TOMOYO_TYPE_CREATE;
 240         const unsigned int perm = mode & S_IALLUGO;
 241
 242         switch (mode & S_IFMT) {
 243         case S_IFCHR:
 244                 type = TOMOYO_TYPE_MKCHAR;
 245                 break;
 246         case S_IFBLK:
 247                 type = TOMOYO_TYPE_MKBLOCK;
 248                 break;
 249         default:
 250                 goto no_dev;
 251         }
 252         return tomoyo_mkdev_perm(type, &path, perm, dev);
 253  no_dev:
 254         switch (mode & S_IFMT) {
 255         case S_IFIFO:
 256                 type = TOMOYO_TYPE_MKFIFO;
 257                 break;
 258         case S_IFSOCK:
 259                 type = TOMOYO_TYPE_MKSOCK;
 260                 break;
 261         }
 262         return tomoyo_path_number_perm(type, &path, perm);
 263 }
 264
 265 /**
 266  * tomoyo_path_link - Target for security_path_link().
 267  *
 268  * @old_dentry: Pointer to "struct dentry".
 269  * @new_dir:    Pointer to "struct path".
 270  * @new_dentry: Pointer to "struct dentry".
 271  *
 272  * Returns 0 on success, negative value otherwise.
 273  */
 274 static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
 275                             struct dentry *new_dentry)
 276 {
 277         struct path path1 = { new_dir->mnt, old_dentry };
 278         struct path path2 = { new_dir->mnt, new_dentry };
 279         return tomoyo_path2_perm(TOMOYO_TYPE_LINK, &path1, &path2);
 280 }
 281
 282 /**
 283  * tomoyo_path_rename - Target for security_path_rename().
 284  *
 285  * @old_parent: Pointer to "struct path".
 286  * @old_dentry: Pointer to "struct dentry".
 287  * @new_parent: Pointer to "struct path".
 288  * @new_dentry: Pointer to "struct dentry".
 289  *
 290  * Returns 0 on success, negative value otherwise.
 291  */
 292 static int tomoyo_path_rename(struct path *old_parent,
 293                               struct dentry *old_dentry,
 294                               struct path *new_parent,
 295                               struct dentry *new_dentry)
 296 {
 297         struct path path1 = { old_parent->mnt, old_dentry };
 298         struct path path2 = { new_parent->mnt, new_dentry };
 299         return tomoyo_path2_perm(TOMOYO_TYPE_RENAME, &path1, &path2);
 300 }
 301
 302 /**
 303  * tomoyo_file_fcntl - Target for security_file_fcntl().
 304  *
 305  * @file: Pointer to "struct file".
 306  * @cmd:  Command for fcntl().
 307  * @arg:  Argument for @cmd.
 308  *
 309  * Returns 0 on success, negative value otherwise.
 310  */
 311 static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
 312                              unsigned long arg)
 313 {
 314         if (!(cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND)))
 315                 return 0;
 316         return tomoyo_check_open_permission(tomoyo_domain(), &file->f_path,
 317                                             O_WRONLY | (arg & O_APPEND));
 318 }
 319
 320 /**
 321  * tomoyo_file_open - Target for security_file_open().
 322  *
 323  * @f:    Pointer to "struct file".
 324  * @cred: Pointer to "struct cred".
 325  *
 326  * Returns 0 on success, negative value otherwise.
 327  */
 328 static int tomoyo_file_open(struct file *f, const struct cred *cred)
 329 {
 330         int flags = f->f_flags;
 331         /* Don't check read permission here if called from do_execve(). */
 332         if (current->in_execve)
 333                 return 0;
 334         return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
 335 }
 336
 337 /**
 338  * tomoyo_file_ioctl - Target for security_file_ioctl().
 339  *
 340  * @file: Pointer to "struct file".
 341  * @cmd:  Command for ioctl().
 342  * @arg:  Argument for @cmd.
 343  *
 344  * Returns 0 on success, negative value otherwise.
 345  */
 346 static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
 347                              unsigned long arg)
 348 {
 349         return tomoyo_path_number_perm(TOMOYO_TYPE_IOCTL, &file->f_path, cmd);
 350 }
 351
 352 /**
 353  * tomoyo_path_chmod - Target for security_path_chmod().
 354  *
 355  * @path: Pointer to "struct path".
 356  * @mode: DAC permission mode.
 357  *
 358  * Returns 0 on success, negative value otherwise.
 359  */
 360 static int tomoyo_path_chmod(struct path *path, umode_t mode)
 361 {
 362         return tomoyo_path_number_perm(TOMOYO_TYPE_CHMOD, path,
 363                                        mode & S_IALLUGO);
 364 }
 365
 366 /**
 367  * tomoyo_path_chown - Target for security_path_chown().
 368  *
 369  * @path: Pointer to "struct path".
 370  * @uid:  Owner ID.
 371  * @gid:  Group ID.
 372  *
 373  * Returns 0 on success, negative value otherwise.
 374  */
 375 static int tomoyo_path_chown(struct path *path, kuid_t uid, kgid_t gid)
 376 {
 377         int error = 0;
 378         if (uid_valid(uid))
 379                 error = tomoyo_path_number_perm(TOMOYO_TYPE_CHOWN, path,
 380                                                 from_kuid(&init_user_ns, uid));
 381         if (!error && gid_valid(gid))
 382                 error = tomoyo_path_number_perm(TOMOYO_TYPE_CHGRP, path,
 383                                                 from_kgid(&init_user_ns, gid));
 384         return error;
 385 }
 386
 387 /**
 388  * tomoyo_path_chroot - Target for security_path_chroot().
 389  *
 390  * @path: Pointer to "struct path".
 391  *
 392  * Returns 0 on success, negative value otherwise.
 393  */
 394 static int tomoyo_path_chroot(struct path *path)
 395 {
 396         return tomoyo_path_perm(TOMOYO_TYPE_CHROOT, path, NULL);
 397 }
 398
 399 /**
 400  * tomoyo_sb_mount - Target for security_sb_mount().
 401  *
 402  * @dev_name: Name of device file. Maybe NULL.
 403  * @path:     Pointer to "struct path".
 404  * @type:     Name of filesystem type. Maybe NULL.
 405  * @flags:    Mount options.
 406  * @data:     Optional data. Maybe NULL.
 407  *
 408  * Returns 0 on success, negative value otherwise.
 409  */
 410 static int tomoyo_sb_mount(const char *dev_name, struct path *path,
 411                            const char *type, unsigned long flags, void *data)
 412 {
 413         return tomoyo_mount_permission(dev_name, path, type, flags, data);
 414 }
 415
 416 /**
 417  * tomoyo_sb_umount - Target for security_sb_umount().
 418  *
 419  * @mnt:   Pointer to "struct vfsmount".
 420  * @flags: Unmount options.
 421  *
 422  * Returns 0 on success, negative value otherwise.
 423  */
 424 static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
 425 {
 426         struct path path = { mnt, mnt->mnt_root };
 427         return tomoyo_path_perm(TOMOYO_TYPE_UMOUNT, &path, NULL);
 428 }
 429
 430 /**
 431  * tomoyo_sb_pivotroot - Target for security_sb_pivotroot().
 432  *
 433  * @old_path: Pointer to "struct path".
 434  * @new_path: Pointer to "struct path".
 435  *
 436  * Returns 0 on success, negative value otherwise.
 437  */
 438 static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
 439 {
 440         return tomoyo_path2_perm(TOMOYO_TYPE_PIVOT_ROOT, new_path, old_path);
 441 }
 442
 443 /**
 444  * tomoyo_socket_listen - Check permission for listen().
 445  *
 446  * @sock:    Pointer to "struct socket".
 447  * @backlog: Backlog parameter.
 448  *
 449  * Returns 0 on success, negative value otherwise.
 450  */
 451 static int tomoyo_socket_listen(struct socket *sock, int backlog)
 452 {
 453         return tomoyo_socket_listen_permission(sock);
 454 }
 455
 456 /**
 457  * tomoyo_socket_connect - Check permission for connect().
 458  *
 459  * @sock:     Pointer to "struct socket".
 460  * @addr:     Pointer to "struct sockaddr".
 461  * @addr_len: Size of @addr.
 462  *
 463  * Returns 0 on success, negative value otherwise.
 464  */
 465 static int tomoyo_socket_connect(struct socket *sock, struct sockaddr *addr,
 466                                  int addr_len)
 467 {
 468         return tomoyo_socket_connect_permission(sock, addr, addr_len);
 469 }
 470
 471 /**
 472  * tomoyo_socket_bind - Check permission for bind().
 473  *
 474  * @sock:     Pointer to "struct socket".
 475  * @addr:     Pointer to "struct sockaddr".
 476  * @addr_len: Size of @addr.
 477  *
 478  * Returns 0 on success, negative value otherwise.
 479  */
 480 static int tomoyo_socket_bind(struct socket *sock, struct sockaddr *addr,
 481                               int addr_len)
 482 {
 483         return tomoyo_socket_bind_permission(sock, addr, addr_len);
 484 }
 485
 486 /**
 487  * tomoyo_socket_sendmsg - Check permission for sendmsg().
 488  *
 489  * @sock: Pointer to "struct socket".
 490  * @msg:  Pointer to "struct msghdr".
 491  * @size: Size of message.
 492  *
 493  * Returns 0 on success, negative value otherwise.
 494  */
 495 static int tomoyo_socket_sendmsg(struct socket *sock, struct msghdr *msg,
 496                                  int size)
 497 {
 498         return tomoyo_socket_sendmsg_permission(sock, msg, size);
 499 }
 500
 501 /*
 502  * tomoyo_security_ops is a "struct security_operations" which is used for
 503  * registering TOMOYO.
 504  */
 505 static struct security_operations tomoyo_security_ops = {
 506         .name                = "tomoyo",
 507         .cred_alloc_blank    = tomoyo_cred_alloc_blank,
 508         .cred_prepare        = tomoyo_cred_prepare,
 509         .cred_transfer       = tomoyo_cred_transfer,
 510         .cred_free           = tomoyo_cred_free,
 511         .bprm_set_creds      = tomoyo_bprm_set_creds,
 512         .bprm_check_security = tomoyo_bprm_check_security,
 513         .file_fcntl          = tomoyo_file_fcntl,
 514         .file_open           = tomoyo_file_open,
 515         .path_truncate       = tomoyo_path_truncate,
 516         .path_unlink         = tomoyo_path_unlink,
 517         .path_mkdir          = tomoyo_path_mkdir,
 518         .path_rmdir          = tomoyo_path_rmdir,
 519         .path_symlink        = tomoyo_path_symlink,
 520         .path_mknod          = tomoyo_path_mknod,
 521         .path_link           = tomoyo_path_link,
 522         .path_rename         = tomoyo_path_rename,
 523         .inode_getattr       = tomoyo_inode_getattr,
 524         .file_ioctl          = tomoyo_file_ioctl,
 525         .path_chmod          = tomoyo_path_chmod,
 526         .path_chown          = tomoyo_path_chown,
 527         .path_chroot         = tomoyo_path_chroot,
 528         .sb_mount            = tomoyo_sb_mount,
 529         .sb_umount           = tomoyo_sb_umount,
 530         .sb_pivotroot        = tomoyo_sb_pivotroot,
 531         .socket_bind         = tomoyo_socket_bind,
 532         .socket_connect      = tomoyo_socket_connect,
 533         .socket_listen       = tomoyo_socket_listen,
 534         .socket_sendmsg      = tomoyo_socket_sendmsg,
 535 };
 536
 537 /* Lock for GC. */
 538 DEFINE_SRCU(tomoyo_ss);
 539
 540 /**
 541  * tomoyo_init - Register TOMOYO Linux as a LSM module.
 542  *
 543  * Returns 0.
 544  */
 545 static int __init tomoyo_init(void)
 546 {
 547         struct cred *cred = (struct cred *) current_cred();
 548
 549         if (!security_module_enable(&tomoyo_security_ops))
 550                 return 0;
 551         /* register ourselves with the security framework */
 552         if (register_security(&tomoyo_security_ops))
 553                 panic("Failure registering TOMOYO Linux");
 554         printk(KERN_INFO "TOMOYO Linux initialized\n");
 555         cred->security = &tomoyo_kernel_domain;
 556         tomoyo_mm_init();
 557         return 0;
 558 }
 559
 560 security_initcall(tomoyo_init);