security/seclvl.c

   1 /**
   2  * BSD Secure Levels LSM
   3  *
   4  * Maintainers:
   5  *      Michael A. Halcrow <mike@halcrow.us>
   6  *      Serge Hallyn <hallyn@cs.wm.edu>
   7  *
   8  * Copyright (c) 2001 WireX Communications, Inc <chris@wirex.com>
   9  * Copyright (c) 2001 Greg Kroah-Hartman <greg@kroah.com>
  10  * Copyright (c) 2002 International Business Machines <robb@austin.ibm.com>
  11  * Copyright (c) 2006 Davi E. M. Arnaut <davi.arnaut@gmail.com>
  12  *
  13  *      This program is free software; you can redistribute it and/or modify
  14  *      it under the terms of the GNU General Public License as published by
  15  *      the Free Software Foundation; either version 2 of the License, or
  16  *      (at your option) any later version.
  17  */
  18
  19 #include <linux/config.h>
  20 #include <linux/module.h>
  21 #include <linux/moduleparam.h>
  22 #include <linux/kernel.h>
  23 #include <linux/init.h>
  24 #include <linux/security.h>
  25 #include <linux/netlink.h>
  26 #include <linux/fs.h>
  27 #include <linux/namei.h>
  28 #include <linux/mount.h>
  29 #include <linux/capability.h>
  30 #include <linux/time.h>
  31 #include <linux/proc_fs.h>
  32 #include <linux/kobject.h>
  33 #include <linux/crypto.h>
  34 #include <asm/scatterlist.h>
  35 #include <linux/scatterlist.h>
  36 #include <linux/gfp.h>
  37 #include <linux/sysfs.h>
  38
  39 #define SHA1_DIGEST_SIZE 20
  40
  41 /**
  42  * Module parameter that defines the initial secure level.
  43  *
  44  * When built as a module, it defaults to seclvl 1, which is the
  45  * behavior of BSD secure levels.  Note that this default behavior
  46  * wrecks havoc on a machine when the seclvl module is compiled into
  47  * the kernel.  In that case, we default to seclvl 0.
  48  */
  49 #ifdef CONFIG_SECURITY_SECLVL_MODULE
  50 static int initlvl = 1;
  51 #else
  52 static int initlvl;
  53 #endif
  54 module_param(initlvl, int, 0);
  55 MODULE_PARM_DESC(initlvl, "Initial secure level (defaults to 1)");
  56
  57 /* Module parameter that defines the verbosity level */
  58 static int verbosity;
  59 module_param(verbosity, int, 0);
  60 MODULE_PARM_DESC(verbosity, "Initial verbosity level (0 or 1; defaults to "
  61                  "0, which is Quiet)");
  62
  63 /**
  64  * Optional password which can be passed in to bring seclvl to 0
  65  * (i.e., for halt/reboot).  Defaults to NULL (the passwd attribute
  66  * file will not be registered in sysfs).
  67  *
  68  * This gets converted to its SHA1 hash when stored.  It's probably
  69  * not a good idea to use this parameter when loading seclvl from a
  70  * script; use sha1_passwd instead.
  71  */
  72
  73 #define MAX_PASSWD_SIZE 32
  74 static char passwd[MAX_PASSWD_SIZE];
  75 module_param_string(passwd, passwd, sizeof(passwd), 0);
  76 MODULE_PARM_DESC(passwd,
  77                  "Plaintext of password that sets seclvl=0 when written to "
  78                  "(sysfs mount point)/seclvl/passwd\n");
  79
  80 /**
  81  * SHA1 hashed version of the optional password which can be passed in
  82  * to bring seclvl to 0 (i.e., for halt/reboot).  Must be in
  83  * hexadecimal format (40 characters).  Defaults to NULL (the passwd
  84  * attribute file will not be registered in sysfs).
  85  *
  86  * Use the sha1sum utility to generate the SHA1 hash of a password:
  87  *
  88  * echo -n "secret" | sha1sum
  89  */
  90 #define MAX_SHA1_PASSWD 41
  91 static char sha1_passwd[MAX_SHA1_PASSWD];
  92 module_param_string(sha1_passwd, sha1_passwd, sizeof(sha1_passwd), 0);
  93 MODULE_PARM_DESC(sha1_passwd,
  94                  "SHA1 hash (40 hexadecimal characters) of password that "
  95                  "sets seclvl=0 when plaintext password is written to "
  96                  "(sysfs mount point)/seclvl/passwd\n");
  97
  98 static int hideHash = 1;
  99 module_param(hideHash, int, 0);
 100 MODULE_PARM_DESC(hideHash, "When set to 0, reading seclvl/passwd from sysfs "
 101                  "will return the SHA1-hashed value of the password that "
 102                  "lowers the secure level to 0.\n");
 103
 104 #define MY_NAME "seclvl"
 105
 106 /**
 107  * This time-limits log writes to one per second.
 108  */
 109 #define seclvl_printk(verb, type, fmt, arg...)                  \
 110         do {                                                    \
 111                 if (verbosity >= verb) {                        \
 112                         static unsigned long _prior;            \
 113                         unsigned long _now = jiffies;           \
 114                         if ((_now - _prior) > HZ) {             \
 115                                 printk(type "%s: %s: " fmt,     \
 116                                         MY_NAME, __FUNCTION__ , \
 117                                         ## arg);                \
 118                                 _prior = _now;                  \
 119                         }                                       \
 120                 }                                               \
 121         } while (0)
 122
 123 /**
 124  * The actual security level.  Ranges between -1 and 2 inclusive.
 125  */
 126 static int seclvl;
 127
 128 /**
 129  * flag to keep track of how we were registered
 130  */
 131 static int secondary;
 132
 133 /**
 134  * Verifies that the requested secure level is valid, given the current
 135  * secure level.
 136  */
 137 static int seclvl_sanity(int reqlvl)
 138 {
 139         if ((reqlvl < -1) || (reqlvl > 2)) {
 140                 seclvl_printk(1, KERN_WARNING, "Attempt to set seclvl out of "
 141                               "range: [%d]\n", reqlvl);
 142                 return -EINVAL;
 143         }
 144         if ((seclvl == 0) && (reqlvl == -1))
 145                 return 0;
 146         if (reqlvl < seclvl) {
 147                 seclvl_printk(1, KERN_WARNING, "Attempt to lower seclvl to "
 148                               "[%d]\n", reqlvl);
 149                 return -EPERM;
 150         }
 151         return 0;
 152 }
 153
 154 /**
 155  * security level advancement rules:
 156  *   Valid levels are -1 through 2, inclusive.
 157  *   From -1, stuck.  [ in case compiled into kernel ]
 158  *   From 0 or above, can only increment.
 159  */
 160 static void do_seclvl_advance(void *data, u64 val)
 161 {
 162         int ret;
 163         int newlvl = (int)val;
 164
 165         ret = seclvl_sanity(newlvl);
 166         if (ret)
 167                 return;
 168
 169         if (newlvl > 2) {
 170                 seclvl_printk(1, KERN_WARNING, "Cannot advance to seclvl "
 171                               "[%d]\n", newlvl);
 172                 return;
 173         }
 174         if (seclvl == -1) {
 175                 seclvl_printk(1, KERN_WARNING, "Not allowed to advance to "
 176                               "seclvl [%d]\n", seclvl);
 177                 return;
 178         }
 179         seclvl = newlvl;  /* would it be more "correct" to set *data? */
 180         return;
 181 }
 182
 183 static u64 seclvl_int_get(void *data)
 184 {
 185         return *(int *)data;
 186 }
 187
 188 DEFINE_SIMPLE_ATTRIBUTE(seclvl_file_ops, seclvl_int_get, do_seclvl_advance, "%lld\n");
 189
 190 static unsigned char hashedPassword[SHA1_DIGEST_SIZE];
 191
 192 /**
 193  * Converts a block of plaintext of into its SHA1 hashed value.
 194  *
 195  * It would be nice if crypto had a wrapper to do this for us linear
 196  * people...
 197  */
 198 static int
 199 plaintext_to_sha1(unsigned char *hash, const char *plaintext, unsigned int len)
 200 {
 201         struct crypto_tfm *tfm;
 202         struct scatterlist sg;
 203         if (len > PAGE_SIZE) {
 204                 seclvl_printk(0, KERN_ERR, "Plaintext password too large (%d "
 205                               "characters).  Largest possible is %lu "
 206                               "bytes.\n", len, PAGE_SIZE);
 207                 return -EINVAL;
 208         }
 209         tfm = crypto_alloc_tfm("sha1", CRYPTO_TFM_REQ_MAY_SLEEP);
 210         if (tfm == NULL) {
 211                 seclvl_printk(0, KERN_ERR,
 212                               "Failed to load transform for SHA1\n");
 213                 return -EINVAL;
 214         }
 215         sg_init_one(&sg, (u8 *)plaintext, len);
 216         crypto_digest_init(tfm);
 217         crypto_digest_update(tfm, &sg, 1);
 218         crypto_digest_final(tfm, hash);
 219         crypto_free_tfm(tfm);
 220         return 0;
 221 }
 222
 223 /**
 224  * Called whenever the user writes to the sysfs passwd handle to this kernel
 225  * object.  It hashes the password and compares the hashed results.
 226  */
 227 static ssize_t
 228 passwd_write_file(struct file * file, const char __user * buf,
 229                                 size_t count, loff_t *ppos)
 230 {
 231         char *p;
 232         int len;
 233         unsigned char tmp[SHA1_DIGEST_SIZE];
 234
 235         if (!*passwd && !*sha1_passwd) {
 236                 seclvl_printk(0, KERN_ERR, "Attempt to password-unlock the "
 237                               "seclvl module, but neither a plain text "
 238                               "password nor a SHA1 hashed password was "
 239                               "passed in as a module parameter!  This is a "
 240                               "bug, since it should not be possible to be in "
 241                               "this part of the module; please tell a "
 242                               "maintainer about this event.\n");
 243                 return -EINVAL;
 244         }
 245
 246         if (count >= PAGE_SIZE)
 247                 return -EINVAL;
 248         if (*ppos != 0)
 249                 return -EINVAL;
 250         p = kmalloc(count, GFP_KERNEL);
 251         if (!p)
 252                 return -ENOMEM;
 253         len = -EFAULT;
 254         if (copy_from_user(p, buf, count))
 255                 goto out;
 256
 257         len = count;
 258         /* ``echo "secret" > seclvl/passwd'' includes a newline */
 259         if (p[len - 1] == '\n')
 260                 len--;
 261         /* Hash the password, then compare the hashed values */
 262         if ((len = plaintext_to_sha1(tmp, p, len))) {
 263                 seclvl_printk(0, KERN_ERR, "Error hashing password: rc = "
 264                               "[%d]\n", len);
 265                 goto out;
 266         }
 267
 268         len = -EPERM;
 269         if (memcmp(hashedPassword, tmp, SHA1_DIGEST_SIZE))
 270                 goto out;
 271
 272         seclvl_printk(0, KERN_INFO,
 273                       "Password accepted; seclvl reduced to 0.\n");
 274         seclvl = 0;
 275         len = count;
 276
 277 out:
 278         kfree (p);
 279         return len;
 280 }
 281
 282 static struct file_operations passwd_file_ops = {
 283         .write = passwd_write_file,
 284 };
 285
 286 /**
 287  * Explicitely disallow ptrace'ing the init process.
 288  */
 289 static int seclvl_ptrace(struct task_struct *parent, struct task_struct *child)
 290 {
 291         if (seclvl >= 0 && child->pid == 1) {
 292                 seclvl_printk(1, KERN_WARNING, "Attempt to ptrace "
 293                               "the init process dissallowed in "
 294                               "secure level %d\n", seclvl);
 295                 return -EPERM;
 296         }
 297         return 0;
 298 }
 299
 300 /**
 301  * Capability checks for seclvl.  The majority of the policy
 302  * enforcement for seclvl takes place here.
 303  */
 304 static int seclvl_capable(struct task_struct *tsk, int cap)
 305 {
 306         int rc = 0;
 307
 308         /* init can do anything it wants */
 309         if (tsk->pid == 1)
 310                 return 0;
 311
 312         if (seclvl > 0) {
 313                 rc = -EPERM;
 314
 315                 if (cap == CAP_LINUX_IMMUTABLE)
 316                         seclvl_printk(1, KERN_WARNING, "Attempt to modify "
 317                                       "the IMMUTABLE and/or APPEND extended "
 318                                       "attribute on a file with the IMMUTABLE "
 319                                       "and/or APPEND extended attribute set "
 320                                       "denied in seclvl [%d]\n", seclvl);
 321                 else if (cap == CAP_SYS_RAWIO)
 322                         seclvl_printk(1, KERN_WARNING, "Attempt to perform "
 323                                       "raw I/O while in secure level [%d] "
 324                                       "denied\n", seclvl);
 325                 else if (cap == CAP_NET_ADMIN)
 326                         seclvl_printk(1, KERN_WARNING, "Attempt to perform "
 327                                       "network administrative task while "
 328                                       "in secure level [%d] denied\n", seclvl);
 329                 else if (cap == CAP_SETUID)
 330                         seclvl_printk(1, KERN_WARNING, "Attempt to setuid "
 331                                       "while in secure level [%d] denied\n",
 332                                       seclvl);
 333                 else if (cap == CAP_SETGID)
 334                         seclvl_printk(1, KERN_WARNING, "Attempt to setgid "
 335                                       "while in secure level [%d] denied\n",
 336                                       seclvl);
 337                 else if (cap == CAP_SYS_MODULE)
 338                         seclvl_printk(1, KERN_WARNING, "Attempt to perform "
 339                                       "a module operation while in secure "
 340                                       "level [%d] denied\n", seclvl);
 341                 else
 342                         rc = 0;
 343         }
 344
 345         if (!rc) {
 346                 if (!(cap_is_fs_cap(cap) ? tsk->fsuid == 0 : tsk->euid == 0))
 347                         rc = -EPERM;
 348         }
 349
 350         if (rc)
 351                 seclvl_printk(1, KERN_WARNING, "Capability denied\n");
 352
 353         return rc;
 354 }
 355
 356 /**
 357  * Disallow reversing the clock in seclvl > 1
 358  */
 359 static int seclvl_settime(struct timespec *tv, struct timezone *tz)
 360 {
 361         if (tv && seclvl > 1) {
 362                 struct timespec now;
 363                 now = current_kernel_time();
 364                 if (tv->tv_sec < now.tv_sec ||
 365                     (tv->tv_sec == now.tv_sec && tv->tv_nsec < now.tv_nsec)) {
 366                         seclvl_printk(1, KERN_WARNING, "Attempt to decrement "
 367                                       "time in secure level %d denied: "
 368                                       "current->pid = [%d], "
 369                                       "current->group_leader->pid = [%d]\n",
 370                                       seclvl, current->pid,
 371                                       current->group_leader->pid);
 372                         return -EPERM;
 373                 }               /* if attempt to decrement time */
 374         }                       /* if seclvl > 1 */
 375         return 0;
 376 }
 377
 378 /* claim the blockdev to exclude mounters, release on file close */
 379 static int seclvl_bd_claim(struct inode *inode)
 380 {
 381         int holder;
 382         struct block_device *bdev = NULL;
 383         dev_t dev = inode->i_rdev;
 384         bdev = open_by_devnum(dev, FMODE_WRITE);
 385         if (bdev) {
 386                 if (bd_claim(bdev, &holder)) {
 387                         blkdev_put(bdev);
 388                         return -EPERM;
 389                 }
 390                 /* claimed, mark it to release on close */
 391                 inode->i_security = current;
 392         }
 393         return 0;
 394 }
 395
 396 /* release the blockdev if you claimed it */
 397 static void seclvl_bd_release(struct inode *inode)
 398 {
 399         if (inode && S_ISBLK(inode->i_mode) && inode->i_security == current) {
 400                 struct block_device *bdev = inode->i_bdev;
 401                 if (bdev) {
 402                         bd_release(bdev);
 403                         blkdev_put(bdev);
 404                         inode->i_security = NULL;
 405                 }
 406         }
 407 }
 408
 409 /**
 410  * Security for writes to block devices is regulated by this seclvl
 411  * function.  Deny all writes to block devices in seclvl 2.  In
 412  * seclvl 1, we only deny writes to *mounted* block devices.
 413  */
 414 static int
 415 seclvl_inode_permission(struct inode *inode, int mask, struct nameidata *nd)
 416 {
 417         if (current->pid != 1 && S_ISBLK(inode->i_mode) && (mask & MAY_WRITE)) {
 418                 switch (seclvl) {
 419                 case 2:
 420                         seclvl_printk(1, KERN_WARNING, "Write to block device "
 421                                       "denied in secure level [%d]\n", seclvl);
 422                         return -EPERM;
 423                 case 1:
 424                         if (seclvl_bd_claim(inode)) {
 425                                 seclvl_printk(1, KERN_WARNING,
 426                                               "Write to mounted block device "
 427                                               "denied in secure level [%d]\n",
 428                                               seclvl);
 429                                 return -EPERM;
 430                         }
 431                 }
 432         }
 433         return 0;
 434 }
 435
 436 /**
 437  * The SUID and SGID bits cannot be set in seclvl >= 1
 438  */
 439 static int seclvl_inode_setattr(struct dentry *dentry, struct iattr *iattr)
 440 {
 441         if (seclvl > 0) {
 442                 if (iattr->ia_valid & ATTR_MODE)
 443                         if (iattr->ia_mode & S_ISUID ||
 444                             iattr->ia_mode & S_ISGID) {
 445                                 seclvl_printk(1, KERN_WARNING, "Attempt to "
 446                                               "modify SUID or SGID bit "
 447                                               "denied in seclvl [%d]\n",
 448                                               seclvl);
 449                                 return -EPERM;
 450                         }
 451         }
 452         return 0;
 453 }
 454
 455 /* release busied block devices */
 456 static void seclvl_file_free_security(struct file *filp)
 457 {
 458         struct dentry *dentry = filp->f_dentry;
 459
 460         if (dentry)
 461                 seclvl_bd_release(dentry->d_inode);
 462 }
 463
 464 /**
 465  * Cannot unmount in secure level 2
 466  */
 467 static int seclvl_umount(struct vfsmount *mnt, int flags)
 468 {
 469         if (current->pid != 1 && seclvl == 2) {
 470                 seclvl_printk(1, KERN_WARNING, "Attempt to unmount in secure "
 471                               "level %d\n", seclvl);
 472                 return -EPERM;
 473         }
 474         return 0;
 475 }
 476
 477 static struct security_operations seclvl_ops = {
 478         .ptrace = seclvl_ptrace,
 479         .capable = seclvl_capable,
 480         .inode_permission = seclvl_inode_permission,
 481         .inode_setattr = seclvl_inode_setattr,
 482         .file_free_security = seclvl_file_free_security,
 483         .settime = seclvl_settime,
 484         .sb_umount = seclvl_umount,
 485 };
 486
 487 /**
 488  * Process the password-related module parameters
 489  */
 490 static int processPassword(void)
 491 {
 492         int rc = 0;
 493         if (*passwd) {
 494                 char *p;
 495
 496                 if (*sha1_passwd) {
 497                         seclvl_printk(0, KERN_ERR, "Error: Both "
 498                                       "passwd and sha1_passwd "
 499                                       "were set, but they are mutually "
 500                                       "exclusive.\n");
 501                         return -EINVAL;
 502                 }
 503
 504                 p = kstrdup(passwd, GFP_KERNEL);
 505                 if (p == NULL)
 506                         return -ENOMEM;
 507
 508                 if ((rc = plaintext_to_sha1(hashedPassword, p, strlen(p))))
 509                         seclvl_printk(0, KERN_ERR, "Error: SHA1 support not "
 510                                       "in kernel\n");
 511
 512                 kfree (p);
 513                 /* All static data goes to the BSS, which zero's the
 514                  * plaintext password out for us. */
 515         } else if (*sha1_passwd) {      // Base 16
 516                 int i;
 517                 i = strlen(sha1_passwd);
 518                 if (i != (SHA1_DIGEST_SIZE * 2)) {
 519                         seclvl_printk(0, KERN_ERR, "Received [%d] bytes; "
 520                                       "expected [%d] for the hexadecimal "
 521                                       "representation of the SHA1 hash of "
 522                                       "the password.\n",
 523                                       i, (SHA1_DIGEST_SIZE * 2));
 524                         return -EINVAL;
 525                 }
 526                 while ((i -= 2) + 2) {
 527                         unsigned char tmp;
 528                         tmp = sha1_passwd[i + 2];
 529                         sha1_passwd[i + 2] = '\0';
 530                         hashedPassword[i / 2] = (unsigned char)
 531                             simple_strtol(&sha1_passwd[i], NULL, 16);
 532                         sha1_passwd[i + 2] = tmp;
 533                 }
 534         }
 535         return rc;
 536 }
 537
 538 /**
 539  * securityfs registrations
 540  */
 541 struct dentry *dir_ino, *seclvl_ino, *passwd_ino;
 542
 543 static int seclvlfs_register(void)
 544 {
 545         int rc = 0;
 546
 547         dir_ino = securityfs_create_dir("seclvl", NULL);
 548
 549         if (IS_ERR(dir_ino))
 550                 return PTR_ERR(dir_ino);
 551
 552         seclvl_ino = securityfs_create_file("seclvl", S_IRUGO | S_IWUSR,
 553                                 dir_ino, &seclvl, &seclvl_file_ops);
 554         if (IS_ERR(seclvl_ino)) {
 555                 rc = PTR_ERR(seclvl_ino);
 556                 goto out_deldir;
 557         }
 558         if (*passwd || *sha1_passwd) {
 559                 passwd_ino = securityfs_create_file("passwd", S_IRUGO | S_IWUSR,
 560                                 dir_ino, NULL, &passwd_file_ops);
 561                 if (IS_ERR(passwd_ino)) {
 562                         rc = PTR_ERR(passwd_ino);
 563                         goto out_delf;
 564                 }
 565         }
 566         return rc;
 567
 568 out_delf:
 569         securityfs_remove(seclvl_ino);
 570
 571 out_deldir:
 572         securityfs_remove(dir_ino);
 573
 574         return rc;
 575 }
 576
 577 static void seclvlfs_unregister(void)
 578 {
 579         securityfs_remove(seclvl_ino);
 580
 581         if (*passwd || *sha1_passwd)
 582                 securityfs_remove(passwd_ino);
 583
 584         securityfs_remove(dir_ino);
 585 }
 586
 587 /**
 588  * Initialize the seclvl module.
 589  */
 590 static int __init seclvl_init(void)
 591 {
 592         int rc = 0;
 593         static char once;
 594
 595         if (verbosity < 0 || verbosity > 1) {
 596                 printk(KERN_ERR "Error: bad verbosity [%d]; only 0 or 1 "
 597                        "are valid values\n", verbosity);
 598                 rc = -EINVAL;
 599                 goto exit;
 600         }
 601         if (initlvl < -1 || initlvl > 2) {
 602                 seclvl_printk(0, KERN_ERR, "Error: bad initial securelevel "
 603                               "[%d].\n", initlvl);
 604                 rc = -EINVAL;
 605                 goto exit;
 606         }
 607         seclvl = initlvl;
 608         if ((rc = processPassword())) {
 609                 seclvl_printk(0, KERN_ERR, "Error processing the password "
 610                               "module parameter(s): rc = [%d]\n", rc);
 611                 goto exit;
 612         }
 613
 614         if ((rc = seclvlfs_register())) {
 615                 seclvl_printk(0, KERN_ERR, "Error registering with sysfs\n");
 616                 goto exit;
 617         }
 618         /* register ourselves with the security framework */
 619         if (register_security(&seclvl_ops)) {
 620                 seclvl_printk(0, KERN_ERR,
 621                               "seclvl: Failure registering with the "
 622                               "kernel.\n");
 623                 /* try registering with primary module */
 624                 rc = mod_reg_security(MY_NAME, &seclvl_ops);
 625                 if (rc) {
 626                         seclvl_printk(0, KERN_ERR, "seclvl: Failure "
 627                                       "registering with primary security "
 628                                       "module.\n");
 629                         seclvlfs_unregister();
 630                         goto exit;
 631                 }               /* if primary module registered */
 632                 secondary = 1;
 633         }                       /* if we registered ourselves with the security framework */
 634
 635         seclvl_printk(0, KERN_INFO, "seclvl: Successfully initialized.\n");
 636
 637         if (once) {
 638                 once = 1;
 639                 seclvl_printk(0, KERN_INFO, "seclvl is going away. It has been "
 640                                 "buggy for ages. Also, be warned that "
 641                                 "Securelevels are useless.");
 642         }
 643  exit:
 644         if (rc)
 645                 printk(KERN_ERR "seclvl: Error during initialization: rc = "
 646                        "[%d]\n", rc);
 647         return rc;
 648 }
 649
 650 /**
 651  * Remove the seclvl module.
 652  */
 653 static void __exit seclvl_exit(void)
 654 {
 655         seclvlfs_unregister();
 656
 657         if (secondary)
 658                 mod_unreg_security(MY_NAME, &seclvl_ops);
 659         else if (unregister_security(&seclvl_ops))
 660                 seclvl_printk(0, KERN_INFO,
 661                               "seclvl: Failure unregistering with the "
 662                               "kernel\n");
 663 }
 664
 665 module_init(seclvl_init);
 666 module_exit(seclvl_exit);
 667
 668 MODULE_AUTHOR("Michael A. Halcrow <mike@halcrow.us>");
 669 MODULE_DESCRIPTION("LSM implementation of the BSD Secure Levels");
 670 MODULE_LICENSE("GPL");