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 return s; 258 } 259 260 static char *check_special_flags(char *sfs, Node *e) 261 { 262 char *p = sfs; 263 int cont = 1; 264 265 /* special flags */ 266 while (cont) { 267 switch (*p) { 268 case 'P': 269 pr_debug("register: flag: P (preserve argv0)\n"); 270 p++; 271 e->flags |= MISC_FMT_PRESERVE_ARGV0; 272 break; 273 case 'O': 274 pr_debug("register: flag: O (open binary)\n"); 275 p++; 276 e->flags |= MISC_FMT_OPEN_BINARY; 277 break; 278 case 'C': 279 pr_debug("register: flag: C (preserve creds)\n"); 280 p++; 281 /* this flags also implies the 282 open-binary flag */ 283 e->flags |= (MISC_FMT_CREDENTIALS | 284 MISC_FMT_OPEN_BINARY); 285 break; 286 default: 287 cont = 0; 288 } 289 } 290 291 return p; 292 } 293 294 /* 295 * This registers a new binary format, it recognises the syntax 296 * ':name:type:offset:magic:mask:interpreter:flags' 297 * where the ':' is the IFS, that can be chosen with the first char 298 */ 299 static Node *create_entry(const char __user *buffer, size_t count) 300 { 301 Node *e; 302 int memsize, err; 303 char *buf, *p; 304 char del; 305 306 pr_debug("register: received %zu bytes\n", count); 307 308 /* some sanity checks */ 309 err = -EINVAL; 310 if ((count < 11) || (count > MAX_REGISTER_LENGTH)) 311 goto out; 312 313 err = -ENOMEM; 314 memsize = sizeof(Node) + count + 8; 315 e = kmalloc(memsize, GFP_KERNEL); 316 if (!e) 317 goto out; 318 319 p = buf = (char *)e + sizeof(Node); 320 321 memset(e, 0, sizeof(Node)); 322 if (copy_from_user(buf, buffer, count)) 323 goto efault; 324 325 del = *p++; /* delimeter */ 326 327 pr_debug("register: delim: %#x {%c}\n", del, del); 328 329 /* Pad the buffer with the delim to simplify parsing below. */ 330 memset(buf + count, del, 8); 331 332 /* Parse the 'name' field. */ 333 e->name = p; 334 p = strchr(p, del); 335 if (!p) 336 goto einval; 337 *p++ = '\0'; 338 if (!e->name[0] || 339 !strcmp(e->name, ".") || 340 !strcmp(e->name, "..") || 341 strchr(e->name, '/')) 342 goto einval; 343 344 pr_debug("register: name: {%s}\n", e->name); 345 346 /* Parse the 'type' field. */ 347 switch (*p++) { 348 case 'E': 349 pr_debug("register: type: E (extension)\n"); 350 e->flags = 1 << Enabled; 351 break; 352 case 'M': 353 pr_debug("register: type: M (magic)\n"); 354 e->flags = (1 << Enabled) | (1 << Magic); 355 break; 356 default: 357 goto einval; 358 } 359 if (*p++ != del) 360 goto einval; 361 362 if (test_bit(Magic, &e->flags)) { 363 /* Handle the 'M' (magic) format. */ 364 char *s; 365 366 /* Parse the 'offset' field. */ 367 s = strchr(p, del); 368 if (!s) 369 goto einval; 370 *s++ = '\0'; 371 e->offset = simple_strtoul(p, &p, 10); 372 if (*p++) 373 goto einval; 374 pr_debug("register: offset: %#x\n", e->offset); 375 376 /* Parse the 'magic' field. */ 377 e->magic = p; 378 p = scanarg(p, del); 379 if (!p) 380 goto einval; 381 p[-1] = '\0'; 382 if (p == e->magic) 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 p[-1] = '\0'; 395 if (p == e->mask) { 396 e->mask = NULL; 397 pr_debug("register: mask[raw]: none\n"); 398 } else if (USE_DEBUG) 399 print_hex_dump_bytes( 400 KBUILD_MODNAME ": register: mask[raw]: ", 401 DUMP_PREFIX_NONE, e->mask, p - e->mask); 402 403 /* 404 * Decode the magic & mask fields. 405 * Note: while we might have accepted embedded NUL bytes from 406 * above, the unescape helpers here will stop at the first one 407 * it encounters. 408 */ 409 e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX); 410 if (e->mask && 411 string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size) 412 goto einval; 413 if (e->size + e->offset > BINPRM_BUF_SIZE) 414 goto einval; 415 pr_debug("register: magic/mask length: %i\n", e->size); 416 if (USE_DEBUG) { 417 print_hex_dump_bytes( 418 KBUILD_MODNAME ": register: magic[decoded]: ", 419 DUMP_PREFIX_NONE, e->magic, e->size); 420 421 if (e->mask) { 422 int i; 423 char *masked = kmalloc(e->size, GFP_KERNEL); 424 425 print_hex_dump_bytes( 426 KBUILD_MODNAME ": register: mask[decoded]: ", 427 DUMP_PREFIX_NONE, e->mask, e->size); 428 429 if (masked) { 430 for (i = 0; i < e->size; ++i) 431 masked[i] = e->magic[i] & e->mask[i]; 432 print_hex_dump_bytes( 433 KBUILD_MODNAME ": register: magic[masked]: ", 434 DUMP_PREFIX_NONE, masked, e->size); 435 436 kfree(masked); 437 } 438 } 439 } 440 } else { 441 /* Handle the 'E' (extension) format. */ 442 443 /* Skip the 'offset' field. */ 444 p = strchr(p, del); 445 if (!p) 446 goto einval; 447 *p++ = '\0'; 448 449 /* Parse the 'magic' field. */ 450 e->magic = p; 451 p = strchr(p, del); 452 if (!p) 453 goto einval; 454 *p++ = '\0'; 455 if (!e->magic[0] || strchr(e->magic, '/')) 456 goto einval; 457 pr_debug("register: extension: {%s}\n", e->magic); 458 459 /* Skip the 'mask' field. */ 460 p = strchr(p, del); 461 if (!p) 462 goto einval; 463 *p++ = '\0'; 464 } 465 466 /* Parse the 'interpreter' field. */ 467 e->interpreter = p; 468 p = strchr(p, del); 469 if (!p) 470 goto einval; 471 *p++ = '\0'; 472 if (!e->interpreter[0]) 473 goto einval; 474 pr_debug("register: interpreter: {%s}\n", e->interpreter); 475 476 /* Parse the 'flags' field. */ 477 p = check_special_flags(p, e); 478 if (*p == '\n') 479 p++; 480 if (p != buf + count) 481 goto einval; 482 483 return e; 484 485 out: 486 return ERR_PTR(err); 487 488 efault: 489 kfree(e); 490 return ERR_PTR(-EFAULT); 491 einval: 492 kfree(e); 493 return ERR_PTR(-EINVAL); 494 } 495 496 /* 497 * Set status of entry/binfmt_misc: 498 * '1' enables, '0' disables and '-1' clears entry/binfmt_misc 499 */ 500 static int parse_command(const char __user *buffer, size_t count) 501 { 502 char s[4]; 503 504 if (count > 3) 505 return -EINVAL; 506 if (copy_from_user(s, buffer, count)) 507 return -EFAULT; 508 if (!count) 509 return 0; 510 if (s[count - 1] == '\n') 511 count--; 512 if (count == 1 && s[0] == '0') 513 return 1; 514 if (count == 1 && s[0] == '1') 515 return 2; 516 if (count == 2 && s[0] == '-' && s[1] == '1') 517 return 3; 518 return -EINVAL; 519 } 520 521 /* generic stuff */ 522 523 static void entry_status(Node *e, char *page) 524 { 525 char *dp; 526 char *status = "disabled"; 527 const char *flags = "flags: "; 528 529 if (test_bit(Enabled, &e->flags)) 530 status = "enabled"; 531 532 if (!VERBOSE_STATUS) { 533 sprintf(page, "%s\n", status); 534 return; 535 } 536 537 sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter); 538 dp = page + strlen(page); 539 540 /* print the special flags */ 541 sprintf(dp, "%s", flags); 542 dp += strlen(flags); 543 if (e->flags & MISC_FMT_PRESERVE_ARGV0) 544 *dp++ = 'P'; 545 if (e->flags & MISC_FMT_OPEN_BINARY) 546 *dp++ = 'O'; 547 if (e->flags & MISC_FMT_CREDENTIALS) 548 *dp++ = 'C'; 549 *dp++ = '\n'; 550 551 if (!test_bit(Magic, &e->flags)) { 552 sprintf(dp, "extension .%s\n", e->magic); 553 } else { 554 int i; 555 556 sprintf(dp, "offset %i\nmagic ", e->offset); 557 dp = page + strlen(page); 558 for (i = 0; i < e->size; i++) { 559 sprintf(dp, "%02x", 0xff & (int) (e->magic[i])); 560 dp += 2; 561 } 562 if (e->mask) { 563 sprintf(dp, "\nmask "); 564 dp += 6; 565 for (i = 0; i < e->size; i++) { 566 sprintf(dp, "%02x", 0xff & (int) (e->mask[i])); 567 dp += 2; 568 } 569 } 570 *dp++ = '\n'; 571 *dp = '\0'; 572 } 573 } 574 575 static struct inode *bm_get_inode(struct super_block *sb, int mode) 576 { 577 struct inode *inode = new_inode(sb); 578 579 if (inode) { 580 inode->i_ino = get_next_ino(); 581 inode->i_mode = mode; 582 inode->i_atime = inode->i_mtime = inode->i_ctime = 583 current_fs_time(inode->i_sb); 584 } 585 return inode; 586 } 587 588 static void bm_evict_inode(struct inode *inode) 589 { 590 clear_inode(inode); 591 kfree(inode->i_private); 592 } 593 594 static void kill_node(Node *e) 595 { 596 struct dentry *dentry; 597 598 write_lock(&entries_lock); 599 dentry = e->dentry; 600 if (dentry) { 601 list_del_init(&e->list); 602 e->dentry = NULL; 603 } 604 write_unlock(&entries_lock); 605 606 if (dentry) { 607 drop_nlink(dentry->d_inode); 608 d_drop(dentry); 609 dput(dentry); 610 simple_release_fs(&bm_mnt, &entry_count); 611 } 612 } 613 614 /* /<entry> */ 615 616 static ssize_t 617 bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) 618 { 619 Node *e = file_inode(file)->i_private; 620 ssize_t res; 621 char *page; 622 623 page = (char *) __get_free_page(GFP_KERNEL); 624 if (!page) 625 return -ENOMEM; 626 627 entry_status(e, page); 628 629 res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); 630 631 free_page((unsigned long) page); 632 return res; 633 } 634 635 static ssize_t bm_entry_write(struct file *file, const char __user *buffer, 636 size_t count, loff_t *ppos) 637 { 638 struct dentry *root; 639 Node *e = file_inode(file)->i_private; 640 int res = parse_command(buffer, count); 641 642 switch (res) { 643 case 1: 644 /* Disable this handler. */ 645 clear_bit(Enabled, &e->flags); 646 break; 647 case 2: 648 /* Enable this handler. */ 649 set_bit(Enabled, &e->flags); 650 break; 651 case 3: 652 /* Delete this handler. */ 653 root = dget(file->f_path.dentry->d_sb->s_root); 654 mutex_lock(&root->d_inode->i_mutex); 655 656 kill_node(e); 657 658 mutex_unlock(&root->d_inode->i_mutex); 659 dput(root); 660 break; 661 default: 662 return res; 663 } 664 665 return count; 666 } 667 668 static const struct file_operations bm_entry_operations = { 669 .read = bm_entry_read, 670 .write = bm_entry_write, 671 .llseek = default_llseek, 672 }; 673 674 /* /register */ 675 676 static ssize_t bm_register_write(struct file *file, const char __user *buffer, 677 size_t count, loff_t *ppos) 678 { 679 Node *e; 680 struct inode *inode; 681 struct dentry *root, *dentry; 682 struct super_block *sb = file->f_path.dentry->d_sb; 683 int err = 0; 684 685 e = create_entry(buffer, count); 686 687 if (IS_ERR(e)) 688 return PTR_ERR(e); 689 690 root = dget(sb->s_root); 691 mutex_lock(&root->d_inode->i_mutex); 692 dentry = lookup_one_len(e->name, root, strlen(e->name)); 693 err = PTR_ERR(dentry); 694 if (IS_ERR(dentry)) 695 goto out; 696 697 err = -EEXIST; 698 if (dentry->d_inode) 699 goto out2; 700 701 inode = bm_get_inode(sb, S_IFREG | 0644); 702 703 err = -ENOMEM; 704 if (!inode) 705 goto out2; 706 707 err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); 708 if (err) { 709 iput(inode); 710 inode = NULL; 711 goto out2; 712 } 713 714 e->dentry = dget(dentry); 715 inode->i_private = e; 716 inode->i_fop = &bm_entry_operations; 717 718 d_instantiate(dentry, inode); 719 write_lock(&entries_lock); 720 list_add(&e->list, &entries); 721 write_unlock(&entries_lock); 722 723 err = 0; 724 out2: 725 dput(dentry); 726 out: 727 mutex_unlock(&root->d_inode->i_mutex); 728 dput(root); 729 730 if (err) { 731 kfree(e); 732 return -EINVAL; 733 } 734 return count; 735 } 736 737 static const struct file_operations bm_register_operations = { 738 .write = bm_register_write, 739 .llseek = noop_llseek, 740 }; 741 742 /* /status */ 743 744 static ssize_t 745 bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) 746 { 747 char *s = enabled ? "enabled\n" : "disabled\n"; 748 749 return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); 750 } 751 752 static ssize_t bm_status_write(struct file *file, const char __user *buffer, 753 size_t count, loff_t *ppos) 754 { 755 int res = parse_command(buffer, count); 756 struct dentry *root; 757 758 switch (res) { 759 case 1: 760 /* Disable all handlers. */ 761 enabled = 0; 762 break; 763 case 2: 764 /* Enable all handlers. */ 765 enabled = 1; 766 break; 767 case 3: 768 /* Delete all handlers. */ 769 root = dget(file->f_path.dentry->d_sb->s_root); 770 mutex_lock(&root->d_inode->i_mutex); 771 772 while (!list_empty(&entries)) 773 kill_node(list_entry(entries.next, Node, list)); 774 775 mutex_unlock(&root->d_inode->i_mutex); 776 dput(root); 777 break; 778 default: 779 return res; 780 } 781 782 return count; 783 } 784 785 static const struct file_operations bm_status_operations = { 786 .read = bm_status_read, 787 .write = bm_status_write, 788 .llseek = default_llseek, 789 }; 790 791 /* Superblock handling */ 792 793 static const struct super_operations s_ops = { 794 .statfs = simple_statfs, 795 .evict_inode = bm_evict_inode, 796 }; 797 798 static int bm_fill_super(struct super_block *sb, void *data, int silent) 799 { 800 int err; 801 static struct tree_descr bm_files[] = { 802 [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, 803 [3] = {"register", &bm_register_operations, S_IWUSR}, 804 /* last one */ {""} 805 }; 806 807 err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); 808 if (!err) 809 sb->s_op = &s_ops; 810 return err; 811 } 812 813 static struct dentry *bm_mount(struct file_system_type *fs_type, 814 int flags, const char *dev_name, void *data) 815 { 816 return mount_single(fs_type, flags, data, bm_fill_super); 817 } 818 819 static struct linux_binfmt misc_format = { 820 .module = THIS_MODULE, 821 .load_binary = load_misc_binary, 822 }; 823 824 static struct file_system_type bm_fs_type = { 825 .owner = THIS_MODULE, 826 .name = "binfmt_misc", 827 .mount = bm_mount, 828 .kill_sb = kill_litter_super, 829 }; 830 MODULE_ALIAS_FS("binfmt_misc"); 831 832 static int __init init_misc_binfmt(void) 833 { 834 int err = register_filesystem(&bm_fs_type); 835 if (!err) 836 insert_binfmt(&misc_format); 837 return err; 838 } 839 840 static void __exit exit_misc_binfmt(void) 841 { 842 unregister_binfmt(&misc_format); 843 unregister_filesystem(&bm_fs_type); 844 } 845 846 core_initcall(init_misc_binfmt); 847 module_exit(exit_misc_binfmt); 848 MODULE_LICENSE("GPL"); 849