1 /* 2 * binfmt_misc.c 3 * 4 * Copyright (C) 1997 Richard Günther 5 * 6 * binfmt_misc detects binaries via a magic or filename extension and invokes 7 * a specified wrapper. See Documentation/binfmt_misc.txt for more details. 8 */ 9 10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 11 12 #include <linux/module.h> 13 #include <linux/init.h> 14 #include <linux/sched.h> 15 #include <linux/magic.h> 16 #include <linux/binfmts.h> 17 #include <linux/slab.h> 18 #include <linux/ctype.h> 19 #include <linux/string_helpers.h> 20 #include <linux/file.h> 21 #include <linux/pagemap.h> 22 #include <linux/namei.h> 23 #include <linux/mount.h> 24 #include <linux/syscalls.h> 25 #include <linux/fs.h> 26 #include <linux/uaccess.h> 27 28 #ifdef DEBUG 29 # define USE_DEBUG 1 30 #else 31 # define USE_DEBUG 0 32 #endif 33 34 enum { 35 VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */ 36 }; 37 38 static LIST_HEAD(entries); 39 static int enabled = 1; 40 41 enum {Enabled, Magic}; 42 #define MISC_FMT_PRESERVE_ARGV0 (1 << 31) 43 #define MISC_FMT_OPEN_BINARY (1 << 30) 44 #define MISC_FMT_CREDENTIALS (1 << 29) 45 46 typedef struct { 47 struct list_head list; 48 unsigned long flags; /* type, status, etc. */ 49 int offset; /* offset of magic */ 50 int size; /* size of magic/mask */ 51 char *magic; /* magic or filename extension */ 52 char *mask; /* mask, NULL for exact match */ 53 char *interpreter; /* filename of interpreter */ 54 char *name; 55 struct dentry *dentry; 56 } Node; 57 58 static DEFINE_RWLOCK(entries_lock); 59 static struct file_system_type bm_fs_type; 60 static struct vfsmount *bm_mnt; 61 static int entry_count; 62 63 /* 64 * Max length of the register string. Determined by: 65 * - 7 delimiters 66 * - name: ~50 bytes 67 * - type: 1 byte 68 * - offset: 3 bytes (has to be smaller than BINPRM_BUF_SIZE) 69 * - magic: 128 bytes (512 in escaped form) 70 * - mask: 128 bytes (512 in escaped form) 71 * - interp: ~50 bytes 72 * - flags: 5 bytes 73 * Round that up a bit, and then back off to hold the internal data 74 * (like struct Node). 75 */ 76 #define MAX_REGISTER_LENGTH 1920 77 78 /* 79 * Check if we support the binfmt 80 * if we do, return the node, else NULL 81 * locking is done in load_misc_binary 82 */ 83 static Node *check_file(struct linux_binprm *bprm) 84 { 85 char *p = strrchr(bprm->interp, '.'); 86 struct list_head *l; 87 88 /* Walk all the registered handlers. */ 89 list_for_each(l, &entries) { 90 Node *e = list_entry(l, Node, list); 91 char *s; 92 int j; 93 94 /* Make sure this one is currently enabled. */ 95 if (!test_bit(Enabled, &e->flags)) 96 continue; 97 98 /* Do matching based on extension if applicable. */ 99 if (!test_bit(Magic, &e->flags)) { 100 if (p && !strcmp(e->magic, p + 1)) 101 return e; 102 continue; 103 } 104 105 /* Do matching based on magic & mask. */ 106 s = bprm->buf + e->offset; 107 if (e->mask) { 108 for (j = 0; j < e->size; j++) 109 if ((*s++ ^ e->magic[j]) & e->mask[j]) 110 break; 111 } else { 112 for (j = 0; j < e->size; j++) 113 if ((*s++ ^ e->magic[j])) 114 break; 115 } 116 if (j == e->size) 117 return e; 118 } 119 return NULL; 120 } 121 122 /* 123 * the loader itself 124 */ 125 static int load_misc_binary(struct linux_binprm *bprm) 126 { 127 Node *fmt; 128 struct file *interp_file = NULL; 129 char iname[BINPRM_BUF_SIZE]; 130 const char *iname_addr = iname; 131 int retval; 132 int fd_binary = -1; 133 134 retval = -ENOEXEC; 135 if (!enabled) 136 goto ret; 137 138 /* to keep locking time low, we copy the interpreter string */ 139 read_lock(&entries_lock); 140 fmt = check_file(bprm); 141 if (fmt) 142 strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE); 143 read_unlock(&entries_lock); 144 if (!fmt) 145 goto ret; 146 147 /* Need to be able to load the file after exec */ 148 if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) 149 return -ENOENT; 150 151 if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { 152 retval = remove_arg_zero(bprm); 153 if (retval) 154 goto ret; 155 } 156 157 if (fmt->flags & MISC_FMT_OPEN_BINARY) { 158 159 /* if the binary should be opened on behalf of the 160 * interpreter than keep it open and assign descriptor 161 * to it 162 */ 163 fd_binary = get_unused_fd_flags(0); 164 if (fd_binary < 0) { 165 retval = fd_binary; 166 goto ret; 167 } 168 fd_install(fd_binary, bprm->file); 169 170 /* if the binary is not readable than enforce mm->dumpable=0 171 regardless of the interpreter's permissions */ 172 would_dump(bprm, bprm->file); 173 174 allow_write_access(bprm->file); 175 bprm->file = NULL; 176 177 /* mark the bprm that fd should be passed to interp */ 178 bprm->interp_flags |= BINPRM_FLAGS_EXECFD; 179 bprm->interp_data = fd_binary; 180 181 } else { 182 allow_write_access(bprm->file); 183 fput(bprm->file); 184 bprm->file = NULL; 185 } 186 /* make argv[1] be the path to the binary */ 187 retval = copy_strings_kernel(1, &bprm->interp, bprm); 188 if (retval < 0) 189 goto error; 190 bprm->argc++; 191 192 /* add the interp as argv[0] */ 193 retval = copy_strings_kernel(1, &iname_addr, bprm); 194 if (retval < 0) 195 goto error; 196 bprm->argc++; 197 198 /* Update interp in case binfmt_script needs it. */ 199 retval = bprm_change_interp(iname, bprm); 200 if (retval < 0) 201 goto error; 202 203 interp_file = open_exec(iname); 204 retval = PTR_ERR(interp_file); 205 if (IS_ERR(interp_file)) 206 goto error; 207 208 bprm->file = interp_file; 209 if (fmt->flags & MISC_FMT_CREDENTIALS) { 210 /* 211 * No need to call prepare_binprm(), it's already been 212 * done. bprm->buf is stale, update from interp_file. 213 */ 214 memset(bprm->buf, 0, BINPRM_BUF_SIZE); 215 retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); 216 } else 217 retval = prepare_binprm(bprm); 218 219 if (retval < 0) 220 goto error; 221 222 retval = search_binary_handler(bprm); 223 if (retval < 0) 224 goto error; 225 226 ret: 227 return retval; 228 error: 229 if (fd_binary > 0) 230 sys_close(fd_binary); 231 bprm->interp_flags = 0; 232 bprm->interp_data = 0; 233 goto ret; 234 } 235 236 /* Command parsers */ 237 238 /* 239 * parses and copies one argument enclosed in del from *sp to *dp, 240 * recognising the \x special. 241 * returns pointer to the copied argument or NULL in case of an 242 * error (and sets err) or null argument length. 243 */ 244 static char *scanarg(char *s, char del) 245 { 246 char c; 247 248 while ((c = *s++) != del) { 249 if (c == '\\' && *s == 'x') { 250 s++; 251 if (!isxdigit(*s++)) 252 return NULL; 253 if (!isxdigit(*s++)) 254 return NULL; 255 } 256 } 257 s[-1] ='\0'; 258 return s; 259 } 260 261 static char *check_special_flags(char *sfs, Node *e) 262 { 263 char *p = sfs; 264 int cont = 1; 265 266 /* special flags */ 267 while (cont) { 268 switch (*p) { 269 case 'P': 270 pr_debug("register: flag: P (preserve argv0)\n"); 271 p++; 272 e->flags |= MISC_FMT_PRESERVE_ARGV0; 273 break; 274 case 'O': 275 pr_debug("register: flag: O (open binary)\n"); 276 p++; 277 e->flags |= MISC_FMT_OPEN_BINARY; 278 break; 279 case 'C': 280 pr_debug("register: flag: C (preserve creds)\n"); 281 p++; 282 /* this flags also implies the 283 open-binary flag */ 284 e->flags |= (MISC_FMT_CREDENTIALS | 285 MISC_FMT_OPEN_BINARY); 286 break; 287 default: 288 cont = 0; 289 } 290 } 291 292 return p; 293 } 294 295 /* 296 * This registers a new binary format, it recognises the syntax 297 * ':name:type:offset:magic:mask:interpreter:flags' 298 * where the ':' is the IFS, that can be chosen with the first char 299 */ 300 static Node *create_entry(const char __user *buffer, size_t count) 301 { 302 Node *e; 303 int memsize, err; 304 char *buf, *p; 305 char del; 306 307 pr_debug("register: received %zu bytes\n", count); 308 309 /* some sanity checks */ 310 err = -EINVAL; 311 if ((count < 11) || (count > MAX_REGISTER_LENGTH)) 312 goto out; 313 314 err = -ENOMEM; 315 memsize = sizeof(Node) + count + 8; 316 e = kmalloc(memsize, GFP_KERNEL); 317 if (!e) 318 goto out; 319 320 p = buf = (char *)e + sizeof(Node); 321 322 memset(e, 0, sizeof(Node)); 323 if (copy_from_user(buf, buffer, count)) 324 goto efault; 325 326 del = *p++; /* delimeter */ 327 328 pr_debug("register: delim: %#x {%c}\n", del, del); 329 330 /* Pad the buffer with the delim to simplify parsing below. */ 331 memset(buf + count, del, 8); 332 333 /* Parse the 'name' field. */ 334 e->name = p; 335 p = strchr(p, del); 336 if (!p) 337 goto einval; 338 *p++ = '\0'; 339 if (!e->name[0] || 340 !strcmp(e->name, ".") || 341 !strcmp(e->name, "..") || 342 strchr(e->name, '/')) 343 goto einval; 344 345 pr_debug("register: name: {%s}\n", e->name); 346 347 /* Parse the 'type' field. */ 348 switch (*p++) { 349 case 'E': 350 pr_debug("register: type: E (extension)\n"); 351 e->flags = 1 << Enabled; 352 break; 353 case 'M': 354 pr_debug("register: type: M (magic)\n"); 355 e->flags = (1 << Enabled) | (1 << Magic); 356 break; 357 default: 358 goto einval; 359 } 360 if (*p++ != del) 361 goto einval; 362 363 if (test_bit(Magic, &e->flags)) { 364 /* Handle the 'M' (magic) format. */ 365 char *s; 366 367 /* Parse the 'offset' field. */ 368 s = strchr(p, del); 369 if (!s) 370 goto einval; 371 *s++ = '\0'; 372 e->offset = simple_strtoul(p, &p, 10); 373 if (*p++) 374 goto einval; 375 pr_debug("register: offset: %#x\n", e->offset); 376 377 /* Parse the 'magic' field. */ 378 e->magic = p; 379 p = scanarg(p, del); 380 if (!p) 381 goto einval; 382 if (!e->magic[0]) 383 goto einval; 384 if (USE_DEBUG) 385 print_hex_dump_bytes( 386 KBUILD_MODNAME ": register: magic[raw]: ", 387 DUMP_PREFIX_NONE, e->magic, p - e->magic); 388 389 /* Parse the 'mask' field. */ 390 e->mask = p; 391 p = scanarg(p, del); 392 if (!p) 393 goto einval; 394 if (!e->mask[0]) { 395 e->mask = NULL; 396 pr_debug("register: mask[raw]: none\n"); 397 } else if (USE_DEBUG) 398 print_hex_dump_bytes( 399 KBUILD_MODNAME ": register: mask[raw]: ", 400 DUMP_PREFIX_NONE, e->mask, p - e->mask); 401 402 /* 403 * Decode the magic & mask fields. 404 * Note: while we might have accepted embedded NUL bytes from 405 * above, the unescape helpers here will stop at the first one 406 * it encounters. 407 */ 408 e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX); 409 if (e->mask && 410 string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size) 411 goto einval; 412 if (e->size + e->offset > BINPRM_BUF_SIZE) 413 goto einval; 414 pr_debug("register: magic/mask length: %i\n", e->size); 415 if (USE_DEBUG) { 416 print_hex_dump_bytes( 417 KBUILD_MODNAME ": register: magic[decoded]: ", 418 DUMP_PREFIX_NONE, e->magic, e->size); 419 420 if (e->mask) { 421 int i; 422 char *masked = kmalloc(e->size, GFP_KERNEL); 423 424 print_hex_dump_bytes( 425 KBUILD_MODNAME ": register: mask[decoded]: ", 426 DUMP_PREFIX_NONE, e->mask, e->size); 427 428 if (masked) { 429 for (i = 0; i < e->size; ++i) 430 masked[i] = e->magic[i] & e->mask[i]; 431 print_hex_dump_bytes( 432 KBUILD_MODNAME ": register: magic[masked]: ", 433 DUMP_PREFIX_NONE, masked, e->size); 434 435 kfree(masked); 436 } 437 } 438 } 439 } else { 440 /* Handle the 'E' (extension) format. */ 441 442 /* Skip the 'offset' field. */ 443 p = strchr(p, del); 444 if (!p) 445 goto einval; 446 *p++ = '\0'; 447 448 /* Parse the 'magic' field. */ 449 e->magic = p; 450 p = strchr(p, del); 451 if (!p) 452 goto einval; 453 *p++ = '\0'; 454 if (!e->magic[0] || strchr(e->magic, '/')) 455 goto einval; 456 pr_debug("register: extension: {%s}\n", e->magic); 457 458 /* Skip the 'mask' field. */ 459 p = strchr(p, del); 460 if (!p) 461 goto einval; 462 *p++ = '\0'; 463 } 464 465 /* Parse the 'interpreter' field. */ 466 e->interpreter = p; 467 p = strchr(p, del); 468 if (!p) 469 goto einval; 470 *p++ = '\0'; 471 if (!e->interpreter[0]) 472 goto einval; 473 pr_debug("register: interpreter: {%s}\n", e->interpreter); 474 475 /* Parse the 'flags' field. */ 476 p = check_special_flags(p, e); 477 if (*p == '\n') 478 p++; 479 if (p != buf + count) 480 goto einval; 481 482 return e; 483 484 out: 485 return ERR_PTR(err); 486 487 efault: 488 kfree(e); 489 return ERR_PTR(-EFAULT); 490 einval: 491 kfree(e); 492 return ERR_PTR(-EINVAL); 493 } 494 495 /* 496 * Set status of entry/binfmt_misc: 497 * '1' enables, '0' disables and '-1' clears entry/binfmt_misc 498 */ 499 static int parse_command(const char __user *buffer, size_t count) 500 { 501 char s[4]; 502 503 if (count > 3) 504 return -EINVAL; 505 if (copy_from_user(s, buffer, count)) 506 return -EFAULT; 507 if (!count) 508 return 0; 509 if (s[count - 1] == '\n') 510 count--; 511 if (count == 1 && s[0] == '0') 512 return 1; 513 if (count == 1 && s[0] == '1') 514 return 2; 515 if (count == 2 && s[0] == '-' && s[1] == '1') 516 return 3; 517 return -EINVAL; 518 } 519 520 /* generic stuff */ 521 522 static void entry_status(Node *e, char *page) 523 { 524 char *dp; 525 char *status = "disabled"; 526 const char *flags = "flags: "; 527 528 if (test_bit(Enabled, &e->flags)) 529 status = "enabled"; 530 531 if (!VERBOSE_STATUS) { 532 sprintf(page, "%s\n", status); 533 return; 534 } 535 536 sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter); 537 dp = page + strlen(page); 538 539 /* print the special flags */ 540 sprintf(dp, "%s", flags); 541 dp += strlen(flags); 542 if (e->flags & MISC_FMT_PRESERVE_ARGV0) 543 *dp++ = 'P'; 544 if (e->flags & MISC_FMT_OPEN_BINARY) 545 *dp++ = 'O'; 546 if (e->flags & MISC_FMT_CREDENTIALS) 547 *dp++ = 'C'; 548 *dp++ = '\n'; 549 550 if (!test_bit(Magic, &e->flags)) { 551 sprintf(dp, "extension .%s\n", e->magic); 552 } else { 553 int i; 554 555 sprintf(dp, "offset %i\nmagic ", e->offset); 556 dp = page + strlen(page); 557 for (i = 0; i < e->size; i++) { 558 sprintf(dp, "%02x", 0xff & (int) (e->magic[i])); 559 dp += 2; 560 } 561 if (e->mask) { 562 sprintf(dp, "\nmask "); 563 dp += 6; 564 for (i = 0; i < e->size; i++) { 565 sprintf(dp, "%02x", 0xff & (int) (e->mask[i])); 566 dp += 2; 567 } 568 } 569 *dp++ = '\n'; 570 *dp = '\0'; 571 } 572 } 573 574 static struct inode *bm_get_inode(struct super_block *sb, int mode) 575 { 576 struct inode *inode = new_inode(sb); 577 578 if (inode) { 579 inode->i_ino = get_next_ino(); 580 inode->i_mode = mode; 581 inode->i_atime = inode->i_mtime = inode->i_ctime = 582 current_fs_time(inode->i_sb); 583 } 584 return inode; 585 } 586 587 static void bm_evict_inode(struct inode *inode) 588 { 589 clear_inode(inode); 590 kfree(inode->i_private); 591 } 592 593 static void kill_node(Node *e) 594 { 595 struct dentry *dentry; 596 597 write_lock(&entries_lock); 598 dentry = e->dentry; 599 if (dentry) { 600 list_del_init(&e->list); 601 e->dentry = NULL; 602 } 603 write_unlock(&entries_lock); 604 605 if (dentry) { 606 drop_nlink(dentry->d_inode); 607 d_drop(dentry); 608 dput(dentry); 609 simple_release_fs(&bm_mnt, &entry_count); 610 } 611 } 612 613 /* /<entry> */ 614 615 static ssize_t 616 bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) 617 { 618 Node *e = file_inode(file)->i_private; 619 ssize_t res; 620 char *page; 621 622 page = (char *) __get_free_page(GFP_KERNEL); 623 if (!page) 624 return -ENOMEM; 625 626 entry_status(e, page); 627 628 res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); 629 630 free_page((unsigned long) page); 631 return res; 632 } 633 634 static ssize_t bm_entry_write(struct file *file, const char __user *buffer, 635 size_t count, loff_t *ppos) 636 { 637 struct dentry *root; 638 Node *e = file_inode(file)->i_private; 639 int res = parse_command(buffer, count); 640 641 switch (res) { 642 case 1: 643 /* Disable this handler. */ 644 clear_bit(Enabled, &e->flags); 645 break; 646 case 2: 647 /* Enable this handler. */ 648 set_bit(Enabled, &e->flags); 649 break; 650 case 3: 651 /* Delete this handler. */ 652 root = dget(file->f_path.dentry->d_sb->s_root); 653 mutex_lock(&root->d_inode->i_mutex); 654 655 kill_node(e); 656 657 mutex_unlock(&root->d_inode->i_mutex); 658 dput(root); 659 break; 660 default: 661 return res; 662 } 663 664 return count; 665 } 666 667 static const struct file_operations bm_entry_operations = { 668 .read = bm_entry_read, 669 .write = bm_entry_write, 670 .llseek = default_llseek, 671 }; 672 673 /* /register */ 674 675 static ssize_t bm_register_write(struct file *file, const char __user *buffer, 676 size_t count, loff_t *ppos) 677 { 678 Node *e; 679 struct inode *inode; 680 struct dentry *root, *dentry; 681 struct super_block *sb = file->f_path.dentry->d_sb; 682 int err = 0; 683 684 e = create_entry(buffer, count); 685 686 if (IS_ERR(e)) 687 return PTR_ERR(e); 688 689 root = dget(sb->s_root); 690 mutex_lock(&root->d_inode->i_mutex); 691 dentry = lookup_one_len(e->name, root, strlen(e->name)); 692 err = PTR_ERR(dentry); 693 if (IS_ERR(dentry)) 694 goto out; 695 696 err = -EEXIST; 697 if (dentry->d_inode) 698 goto out2; 699 700 inode = bm_get_inode(sb, S_IFREG | 0644); 701 702 err = -ENOMEM; 703 if (!inode) 704 goto out2; 705 706 err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); 707 if (err) { 708 iput(inode); 709 inode = NULL; 710 goto out2; 711 } 712 713 e->dentry = dget(dentry); 714 inode->i_private = e; 715 inode->i_fop = &bm_entry_operations; 716 717 d_instantiate(dentry, inode); 718 write_lock(&entries_lock); 719 list_add(&e->list, &entries); 720 write_unlock(&entries_lock); 721 722 err = 0; 723 out2: 724 dput(dentry); 725 out: 726 mutex_unlock(&root->d_inode->i_mutex); 727 dput(root); 728 729 if (err) { 730 kfree(e); 731 return -EINVAL; 732 } 733 return count; 734 } 735 736 static const struct file_operations bm_register_operations = { 737 .write = bm_register_write, 738 .llseek = noop_llseek, 739 }; 740 741 /* /status */ 742 743 static ssize_t 744 bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) 745 { 746 char *s = enabled ? "enabled\n" : "disabled\n"; 747 748 return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); 749 } 750 751 static ssize_t bm_status_write(struct file *file, const char __user *buffer, 752 size_t count, loff_t *ppos) 753 { 754 int res = parse_command(buffer, count); 755 struct dentry *root; 756 757 switch (res) { 758 case 1: 759 /* Disable all handlers. */ 760 enabled = 0; 761 break; 762 case 2: 763 /* Enable all handlers. */ 764 enabled = 1; 765 break; 766 case 3: 767 /* Delete all handlers. */ 768 root = dget(file->f_path.dentry->d_sb->s_root); 769 mutex_lock(&root->d_inode->i_mutex); 770 771 while (!list_empty(&entries)) 772 kill_node(list_entry(entries.next, Node, list)); 773 774 mutex_unlock(&root->d_inode->i_mutex); 775 dput(root); 776 break; 777 default: 778 return res; 779 } 780 781 return count; 782 } 783 784 static const struct file_operations bm_status_operations = { 785 .read = bm_status_read, 786 .write = bm_status_write, 787 .llseek = default_llseek, 788 }; 789 790 /* Superblock handling */ 791 792 static const struct super_operations s_ops = { 793 .statfs = simple_statfs, 794 .evict_inode = bm_evict_inode, 795 }; 796 797 static int bm_fill_super(struct super_block *sb, void *data, int silent) 798 { 799 int err; 800 static struct tree_descr bm_files[] = { 801 [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, 802 [3] = {"register", &bm_register_operations, S_IWUSR}, 803 /* last one */ {""} 804 }; 805 806 err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); 807 if (!err) 808 sb->s_op = &s_ops; 809 return err; 810 } 811 812 static struct dentry *bm_mount(struct file_system_type *fs_type, 813 int flags, const char *dev_name, void *data) 814 { 815 return mount_single(fs_type, flags, data, bm_fill_super); 816 } 817 818 static struct linux_binfmt misc_format = { 819 .module = THIS_MODULE, 820 .load_binary = load_misc_binary, 821 }; 822 823 static struct file_system_type bm_fs_type = { 824 .owner = THIS_MODULE, 825 .name = "binfmt_misc", 826 .mount = bm_mount, 827 .kill_sb = kill_litter_super, 828 }; 829 MODULE_ALIAS_FS("binfmt_misc"); 830 831 static int __init init_misc_binfmt(void) 832 { 833 int err = register_filesystem(&bm_fs_type); 834 if (!err) 835 insert_binfmt(&misc_format); 836 return err; 837 } 838 839 static void __exit exit_misc_binfmt(void) 840 { 841 unregister_binfmt(&misc_format); 842 unregister_filesystem(&bm_fs_type); 843 } 844 845 core_initcall(init_misc_binfmt); 846 module_exit(exit_misc_binfmt); 847 MODULE_LICENSE("GPL"); 848