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/kernel.h> 13 #include <linux/module.h> 14 #include <linux/init.h> 15 #include <linux/sched.h> 16 #include <linux/magic.h> 17 #include <linux/binfmts.h> 18 #include <linux/slab.h> 19 #include <linux/ctype.h> 20 #include <linux/string_helpers.h> 21 #include <linux/file.h> 22 #include <linux/pagemap.h> 23 #include <linux/namei.h> 24 #include <linux/mount.h> 25 #include <linux/syscalls.h> 26 #include <linux/fs.h> 27 #include <linux/uaccess.h> 28 29 #include "internal.h" 30 31 #ifdef DEBUG 32 # define USE_DEBUG 1 33 #else 34 # define USE_DEBUG 0 35 #endif 36 37 enum { 38 VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */ 39 }; 40 41 static LIST_HEAD(entries); 42 static int enabled = 1; 43 44 enum {Enabled, Magic}; 45 #define MISC_FMT_PRESERVE_ARGV0 (1 << 31) 46 #define MISC_FMT_OPEN_BINARY (1 << 30) 47 #define MISC_FMT_CREDENTIALS (1 << 29) 48 #define MISC_FMT_OPEN_FILE (1 << 28) 49 50 typedef struct { 51 struct list_head list; 52 unsigned long flags; /* type, status, etc. */ 53 int offset; /* offset of magic */ 54 int size; /* size of magic/mask */ 55 char *magic; /* magic or filename extension */ 56 char *mask; /* mask, NULL for exact match */ 57 char *interpreter; /* filename of interpreter */ 58 char *name; 59 struct dentry *dentry; 60 struct file *interp_file; 61 } Node; 62 63 static DEFINE_RWLOCK(entries_lock); 64 static struct file_system_type bm_fs_type; 65 static struct vfsmount *bm_mnt; 66 static int entry_count; 67 68 /* 69 * Max length of the register string. Determined by: 70 * - 7 delimiters 71 * - name: ~50 bytes 72 * - type: 1 byte 73 * - offset: 3 bytes (has to be smaller than BINPRM_BUF_SIZE) 74 * - magic: 128 bytes (512 in escaped form) 75 * - mask: 128 bytes (512 in escaped form) 76 * - interp: ~50 bytes 77 * - flags: 5 bytes 78 * Round that up a bit, and then back off to hold the internal data 79 * (like struct Node). 80 */ 81 #define MAX_REGISTER_LENGTH 1920 82 83 /* 84 * Check if we support the binfmt 85 * if we do, return the node, else NULL 86 * locking is done in load_misc_binary 87 */ 88 static Node *check_file(struct linux_binprm *bprm) 89 { 90 char *p = strrchr(bprm->interp, '.'); 91 struct list_head *l; 92 93 /* Walk all the registered handlers. */ 94 list_for_each(l, &entries) { 95 Node *e = list_entry(l, Node, list); 96 char *s; 97 int j; 98 99 /* Make sure this one is currently enabled. */ 100 if (!test_bit(Enabled, &e->flags)) 101 continue; 102 103 /* Do matching based on extension if applicable. */ 104 if (!test_bit(Magic, &e->flags)) { 105 if (p && !strcmp(e->magic, p + 1)) 106 return e; 107 continue; 108 } 109 110 /* Do matching based on magic & mask. */ 111 s = bprm->buf + e->offset; 112 if (e->mask) { 113 for (j = 0; j < e->size; j++) 114 if ((*s++ ^ e->magic[j]) & e->mask[j]) 115 break; 116 } else { 117 for (j = 0; j < e->size; j++) 118 if ((*s++ ^ e->magic[j])) 119 break; 120 } 121 if (j == e->size) 122 return e; 123 } 124 return NULL; 125 } 126 127 /* 128 * the loader itself 129 */ 130 static int load_misc_binary(struct linux_binprm *bprm) 131 { 132 Node *fmt; 133 struct file *interp_file = NULL; 134 char iname[BINPRM_BUF_SIZE]; 135 const char *iname_addr = iname; 136 int retval; 137 int fd_binary = -1; 138 139 retval = -ENOEXEC; 140 if (!enabled) 141 goto ret; 142 143 /* to keep locking time low, we copy the interpreter string */ 144 read_lock(&entries_lock); 145 fmt = check_file(bprm); 146 if (fmt) 147 strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE); 148 read_unlock(&entries_lock); 149 if (!fmt) 150 goto ret; 151 152 /* Need to be able to load the file after exec */ 153 if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) 154 return -ENOENT; 155 156 if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { 157 retval = remove_arg_zero(bprm); 158 if (retval) 159 goto ret; 160 } 161 162 if (fmt->flags & MISC_FMT_OPEN_BINARY) { 163 164 /* if the binary should be opened on behalf of the 165 * interpreter than keep it open and assign descriptor 166 * to it 167 */ 168 fd_binary = get_unused_fd_flags(0); 169 if (fd_binary < 0) { 170 retval = fd_binary; 171 goto ret; 172 } 173 fd_install(fd_binary, bprm->file); 174 175 /* if the binary is not readable than enforce mm->dumpable=0 176 regardless of the interpreter's permissions */ 177 would_dump(bprm, bprm->file); 178 179 allow_write_access(bprm->file); 180 bprm->file = NULL; 181 182 /* mark the bprm that fd should be passed to interp */ 183 bprm->interp_flags |= BINPRM_FLAGS_EXECFD; 184 bprm->interp_data = fd_binary; 185 186 } else { 187 allow_write_access(bprm->file); 188 fput(bprm->file); 189 bprm->file = NULL; 190 } 191 /* make argv[1] be the path to the binary */ 192 retval = copy_strings_kernel(1, &bprm->interp, bprm); 193 if (retval < 0) 194 goto error; 195 bprm->argc++; 196 197 /* add the interp as argv[0] */ 198 retval = copy_strings_kernel(1, &iname_addr, bprm); 199 if (retval < 0) 200 goto error; 201 bprm->argc++; 202 203 /* Update interp in case binfmt_script needs it. */ 204 retval = bprm_change_interp(iname, bprm); 205 if (retval < 0) 206 goto error; 207 208 if (fmt->flags & MISC_FMT_OPEN_FILE && fmt->interp_file) { 209 interp_file = filp_clone_open(fmt->interp_file); 210 if (!IS_ERR(interp_file)) 211 deny_write_access(interp_file); 212 } else { 213 interp_file = open_exec(iname); 214 } 215 retval = PTR_ERR(interp_file); 216 if (IS_ERR(interp_file)) 217 goto error; 218 219 bprm->file = interp_file; 220 if (fmt->flags & MISC_FMT_CREDENTIALS) { 221 /* 222 * No need to call prepare_binprm(), it's already been 223 * done. bprm->buf is stale, update from interp_file. 224 */ 225 memset(bprm->buf, 0, BINPRM_BUF_SIZE); 226 retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); 227 } else 228 retval = prepare_binprm(bprm); 229 230 if (retval < 0) 231 goto error; 232 233 retval = search_binary_handler(bprm); 234 if (retval < 0) 235 goto error; 236 237 ret: 238 return retval; 239 error: 240 if (fd_binary > 0) 241 sys_close(fd_binary); 242 bprm->interp_flags = 0; 243 bprm->interp_data = 0; 244 goto ret; 245 } 246 247 /* Command parsers */ 248 249 /* 250 * parses and copies one argument enclosed in del from *sp to *dp, 251 * recognising the \x special. 252 * returns pointer to the copied argument or NULL in case of an 253 * error (and sets err) or null argument length. 254 */ 255 static char *scanarg(char *s, char del) 256 { 257 char c; 258 259 while ((c = *s++) != del) { 260 if (c == '\\' && *s == 'x') { 261 s++; 262 if (!isxdigit(*s++)) 263 return NULL; 264 if (!isxdigit(*s++)) 265 return NULL; 266 } 267 } 268 s[-1] ='\0'; 269 return s; 270 } 271 272 static char *check_special_flags(char *sfs, Node *e) 273 { 274 char *p = sfs; 275 int cont = 1; 276 277 /* special flags */ 278 while (cont) { 279 switch (*p) { 280 case 'P': 281 pr_debug("register: flag: P (preserve argv0)\n"); 282 p++; 283 e->flags |= MISC_FMT_PRESERVE_ARGV0; 284 break; 285 case 'O': 286 pr_debug("register: flag: O (open binary)\n"); 287 p++; 288 e->flags |= MISC_FMT_OPEN_BINARY; 289 break; 290 case 'C': 291 pr_debug("register: flag: C (preserve creds)\n"); 292 p++; 293 /* this flags also implies the 294 open-binary flag */ 295 e->flags |= (MISC_FMT_CREDENTIALS | 296 MISC_FMT_OPEN_BINARY); 297 break; 298 case 'F': 299 pr_debug("register: flag: F: open interpreter file now\n"); 300 p++; 301 e->flags |= MISC_FMT_OPEN_FILE; 302 break; 303 default: 304 cont = 0; 305 } 306 } 307 308 return p; 309 } 310 311 /* 312 * This registers a new binary format, it recognises the syntax 313 * ':name:type:offset:magic:mask:interpreter:flags' 314 * where the ':' is the IFS, that can be chosen with the first char 315 */ 316 static Node *create_entry(const char __user *buffer, size_t count) 317 { 318 Node *e; 319 int memsize, err; 320 char *buf, *p; 321 char del; 322 323 pr_debug("register: received %zu bytes\n", count); 324 325 /* some sanity checks */ 326 err = -EINVAL; 327 if ((count < 11) || (count > MAX_REGISTER_LENGTH)) 328 goto out; 329 330 err = -ENOMEM; 331 memsize = sizeof(Node) + count + 8; 332 e = kmalloc(memsize, GFP_KERNEL); 333 if (!e) 334 goto out; 335 336 p = buf = (char *)e + sizeof(Node); 337 338 memset(e, 0, sizeof(Node)); 339 if (copy_from_user(buf, buffer, count)) 340 goto efault; 341 342 del = *p++; /* delimeter */ 343 344 pr_debug("register: delim: %#x {%c}\n", del, del); 345 346 /* Pad the buffer with the delim to simplify parsing below. */ 347 memset(buf + count, del, 8); 348 349 /* Parse the 'name' field. */ 350 e->name = p; 351 p = strchr(p, del); 352 if (!p) 353 goto einval; 354 *p++ = '\0'; 355 if (!e->name[0] || 356 !strcmp(e->name, ".") || 357 !strcmp(e->name, "..") || 358 strchr(e->name, '/')) 359 goto einval; 360 361 pr_debug("register: name: {%s}\n", e->name); 362 363 /* Parse the 'type' field. */ 364 switch (*p++) { 365 case 'E': 366 pr_debug("register: type: E (extension)\n"); 367 e->flags = 1 << Enabled; 368 break; 369 case 'M': 370 pr_debug("register: type: M (magic)\n"); 371 e->flags = (1 << Enabled) | (1 << Magic); 372 break; 373 default: 374 goto einval; 375 } 376 if (*p++ != del) 377 goto einval; 378 379 if (test_bit(Magic, &e->flags)) { 380 /* Handle the 'M' (magic) format. */ 381 char *s; 382 383 /* Parse the 'offset' field. */ 384 s = strchr(p, del); 385 if (!s) 386 goto einval; 387 *s++ = '\0'; 388 e->offset = simple_strtoul(p, &p, 10); 389 if (*p++) 390 goto einval; 391 pr_debug("register: offset: %#x\n", e->offset); 392 393 /* Parse the 'magic' field. */ 394 e->magic = p; 395 p = scanarg(p, del); 396 if (!p) 397 goto einval; 398 if (!e->magic[0]) 399 goto einval; 400 if (USE_DEBUG) 401 print_hex_dump_bytes( 402 KBUILD_MODNAME ": register: magic[raw]: ", 403 DUMP_PREFIX_NONE, e->magic, p - e->magic); 404 405 /* Parse the 'mask' field. */ 406 e->mask = p; 407 p = scanarg(p, del); 408 if (!p) 409 goto einval; 410 if (!e->mask[0]) { 411 e->mask = NULL; 412 pr_debug("register: mask[raw]: none\n"); 413 } else if (USE_DEBUG) 414 print_hex_dump_bytes( 415 KBUILD_MODNAME ": register: mask[raw]: ", 416 DUMP_PREFIX_NONE, e->mask, p - e->mask); 417 418 /* 419 * Decode the magic & mask fields. 420 * Note: while we might have accepted embedded NUL bytes from 421 * above, the unescape helpers here will stop at the first one 422 * it encounters. 423 */ 424 e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX); 425 if (e->mask && 426 string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size) 427 goto einval; 428 if (e->size + e->offset > BINPRM_BUF_SIZE) 429 goto einval; 430 pr_debug("register: magic/mask length: %i\n", e->size); 431 if (USE_DEBUG) { 432 print_hex_dump_bytes( 433 KBUILD_MODNAME ": register: magic[decoded]: ", 434 DUMP_PREFIX_NONE, e->magic, e->size); 435 436 if (e->mask) { 437 int i; 438 char *masked = kmalloc(e->size, GFP_KERNEL); 439 440 print_hex_dump_bytes( 441 KBUILD_MODNAME ": register: mask[decoded]: ", 442 DUMP_PREFIX_NONE, e->mask, e->size); 443 444 if (masked) { 445 for (i = 0; i < e->size; ++i) 446 masked[i] = e->magic[i] & e->mask[i]; 447 print_hex_dump_bytes( 448 KBUILD_MODNAME ": register: magic[masked]: ", 449 DUMP_PREFIX_NONE, masked, e->size); 450 451 kfree(masked); 452 } 453 } 454 } 455 } else { 456 /* Handle the 'E' (extension) format. */ 457 458 /* Skip the 'offset' field. */ 459 p = strchr(p, del); 460 if (!p) 461 goto einval; 462 *p++ = '\0'; 463 464 /* Parse the 'magic' field. */ 465 e->magic = p; 466 p = strchr(p, del); 467 if (!p) 468 goto einval; 469 *p++ = '\0'; 470 if (!e->magic[0] || strchr(e->magic, '/')) 471 goto einval; 472 pr_debug("register: extension: {%s}\n", e->magic); 473 474 /* Skip the 'mask' field. */ 475 p = strchr(p, del); 476 if (!p) 477 goto einval; 478 *p++ = '\0'; 479 } 480 481 /* Parse the 'interpreter' field. */ 482 e->interpreter = p; 483 p = strchr(p, del); 484 if (!p) 485 goto einval; 486 *p++ = '\0'; 487 if (!e->interpreter[0]) 488 goto einval; 489 pr_debug("register: interpreter: {%s}\n", e->interpreter); 490 491 /* Parse the 'flags' field. */ 492 p = check_special_flags(p, e); 493 if (*p == '\n') 494 p++; 495 if (p != buf + count) 496 goto einval; 497 498 return e; 499 500 out: 501 return ERR_PTR(err); 502 503 efault: 504 kfree(e); 505 return ERR_PTR(-EFAULT); 506 einval: 507 kfree(e); 508 return ERR_PTR(-EINVAL); 509 } 510 511 /* 512 * Set status of entry/binfmt_misc: 513 * '1' enables, '0' disables and '-1' clears entry/binfmt_misc 514 */ 515 static int parse_command(const char __user *buffer, size_t count) 516 { 517 char s[4]; 518 519 if (count > 3) 520 return -EINVAL; 521 if (copy_from_user(s, buffer, count)) 522 return -EFAULT; 523 if (!count) 524 return 0; 525 if (s[count - 1] == '\n') 526 count--; 527 if (count == 1 && s[0] == '0') 528 return 1; 529 if (count == 1 && s[0] == '1') 530 return 2; 531 if (count == 2 && s[0] == '-' && s[1] == '1') 532 return 3; 533 return -EINVAL; 534 } 535 536 /* generic stuff */ 537 538 static void entry_status(Node *e, char *page) 539 { 540 char *dp = page; 541 const char *status = "disabled"; 542 543 if (test_bit(Enabled, &e->flags)) 544 status = "enabled"; 545 546 if (!VERBOSE_STATUS) { 547 sprintf(page, "%s\n", status); 548 return; 549 } 550 551 dp += sprintf(dp, "%s\ninterpreter %s\n", status, e->interpreter); 552 553 /* print the special flags */ 554 dp += sprintf(dp, "flags: "); 555 if (e->flags & MISC_FMT_PRESERVE_ARGV0) 556 *dp++ = 'P'; 557 if (e->flags & MISC_FMT_OPEN_BINARY) 558 *dp++ = 'O'; 559 if (e->flags & MISC_FMT_CREDENTIALS) 560 *dp++ = 'C'; 561 if (e->flags & MISC_FMT_OPEN_FILE) 562 *dp++ = 'F'; 563 *dp++ = '\n'; 564 565 if (!test_bit(Magic, &e->flags)) { 566 sprintf(dp, "extension .%s\n", e->magic); 567 } else { 568 dp += sprintf(dp, "offset %i\nmagic ", e->offset); 569 dp = bin2hex(dp, e->magic, e->size); 570 if (e->mask) { 571 dp += sprintf(dp, "\nmask "); 572 dp = bin2hex(dp, e->mask, e->size); 573 } 574 *dp++ = '\n'; 575 *dp = '\0'; 576 } 577 } 578 579 static struct inode *bm_get_inode(struct super_block *sb, int mode) 580 { 581 struct inode *inode = new_inode(sb); 582 583 if (inode) { 584 inode->i_ino = get_next_ino(); 585 inode->i_mode = mode; 586 inode->i_atime = inode->i_mtime = inode->i_ctime = 587 current_time(inode); 588 } 589 return inode; 590 } 591 592 static void bm_evict_inode(struct inode *inode) 593 { 594 clear_inode(inode); 595 kfree(inode->i_private); 596 } 597 598 static void kill_node(Node *e) 599 { 600 struct dentry *dentry; 601 602 write_lock(&entries_lock); 603 dentry = e->dentry; 604 if (dentry) { 605 list_del_init(&e->list); 606 e->dentry = NULL; 607 } 608 write_unlock(&entries_lock); 609 610 if ((e->flags & MISC_FMT_OPEN_FILE) && e->interp_file) { 611 filp_close(e->interp_file, NULL); 612 e->interp_file = NULL; 613 } 614 615 if (dentry) { 616 drop_nlink(d_inode(dentry)); 617 d_drop(dentry); 618 dput(dentry); 619 simple_release_fs(&bm_mnt, &entry_count); 620 } 621 } 622 623 /* /<entry> */ 624 625 static ssize_t 626 bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) 627 { 628 Node *e = file_inode(file)->i_private; 629 ssize_t res; 630 char *page; 631 632 page = (char *) __get_free_page(GFP_KERNEL); 633 if (!page) 634 return -ENOMEM; 635 636 entry_status(e, page); 637 638 res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); 639 640 free_page((unsigned long) page); 641 return res; 642 } 643 644 static ssize_t bm_entry_write(struct file *file, const char __user *buffer, 645 size_t count, loff_t *ppos) 646 { 647 struct dentry *root; 648 Node *e = file_inode(file)->i_private; 649 int res = parse_command(buffer, count); 650 651 switch (res) { 652 case 1: 653 /* Disable this handler. */ 654 clear_bit(Enabled, &e->flags); 655 break; 656 case 2: 657 /* Enable this handler. */ 658 set_bit(Enabled, &e->flags); 659 break; 660 case 3: 661 /* Delete this handler. */ 662 root = file_inode(file)->i_sb->s_root; 663 inode_lock(d_inode(root)); 664 665 kill_node(e); 666 667 inode_unlock(d_inode(root)); 668 break; 669 default: 670 return res; 671 } 672 673 return count; 674 } 675 676 static const struct file_operations bm_entry_operations = { 677 .read = bm_entry_read, 678 .write = bm_entry_write, 679 .llseek = default_llseek, 680 }; 681 682 /* /register */ 683 684 static ssize_t bm_register_write(struct file *file, const char __user *buffer, 685 size_t count, loff_t *ppos) 686 { 687 Node *e; 688 struct inode *inode; 689 struct super_block *sb = file_inode(file)->i_sb; 690 struct dentry *root = sb->s_root, *dentry; 691 int err = 0; 692 693 e = create_entry(buffer, count); 694 695 if (IS_ERR(e)) 696 return PTR_ERR(e); 697 698 inode_lock(d_inode(root)); 699 dentry = lookup_one_len(e->name, root, strlen(e->name)); 700 err = PTR_ERR(dentry); 701 if (IS_ERR(dentry)) 702 goto out; 703 704 err = -EEXIST; 705 if (d_really_is_positive(dentry)) 706 goto out2; 707 708 inode = bm_get_inode(sb, S_IFREG | 0644); 709 710 err = -ENOMEM; 711 if (!inode) 712 goto out2; 713 714 err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); 715 if (err) { 716 iput(inode); 717 inode = NULL; 718 goto out2; 719 } 720 721 if (e->flags & MISC_FMT_OPEN_FILE) { 722 struct file *f; 723 724 f = open_exec(e->interpreter); 725 if (IS_ERR(f)) { 726 err = PTR_ERR(f); 727 pr_notice("register: failed to install interpreter file %s\n", e->interpreter); 728 simple_release_fs(&bm_mnt, &entry_count); 729 iput(inode); 730 inode = NULL; 731 goto out2; 732 } 733 e->interp_file = f; 734 } 735 736 e->dentry = dget(dentry); 737 inode->i_private = e; 738 inode->i_fop = &bm_entry_operations; 739 740 d_instantiate(dentry, inode); 741 write_lock(&entries_lock); 742 list_add(&e->list, &entries); 743 write_unlock(&entries_lock); 744 745 err = 0; 746 out2: 747 dput(dentry); 748 out: 749 inode_unlock(d_inode(root)); 750 751 if (err) { 752 kfree(e); 753 return err; 754 } 755 return count; 756 } 757 758 static const struct file_operations bm_register_operations = { 759 .write = bm_register_write, 760 .llseek = noop_llseek, 761 }; 762 763 /* /status */ 764 765 static ssize_t 766 bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) 767 { 768 char *s = enabled ? "enabled\n" : "disabled\n"; 769 770 return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); 771 } 772 773 static ssize_t bm_status_write(struct file *file, const char __user *buffer, 774 size_t count, loff_t *ppos) 775 { 776 int res = parse_command(buffer, count); 777 struct dentry *root; 778 779 switch (res) { 780 case 1: 781 /* Disable all handlers. */ 782 enabled = 0; 783 break; 784 case 2: 785 /* Enable all handlers. */ 786 enabled = 1; 787 break; 788 case 3: 789 /* Delete all handlers. */ 790 root = file_inode(file)->i_sb->s_root; 791 inode_lock(d_inode(root)); 792 793 while (!list_empty(&entries)) 794 kill_node(list_entry(entries.next, Node, list)); 795 796 inode_unlock(d_inode(root)); 797 break; 798 default: 799 return res; 800 } 801 802 return count; 803 } 804 805 static const struct file_operations bm_status_operations = { 806 .read = bm_status_read, 807 .write = bm_status_write, 808 .llseek = default_llseek, 809 }; 810 811 /* Superblock handling */ 812 813 static const struct super_operations s_ops = { 814 .statfs = simple_statfs, 815 .evict_inode = bm_evict_inode, 816 }; 817 818 static int bm_fill_super(struct super_block *sb, void *data, int silent) 819 { 820 int err; 821 static struct tree_descr bm_files[] = { 822 [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, 823 [3] = {"register", &bm_register_operations, S_IWUSR}, 824 /* last one */ {""} 825 }; 826 827 err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); 828 if (!err) 829 sb->s_op = &s_ops; 830 return err; 831 } 832 833 static struct dentry *bm_mount(struct file_system_type *fs_type, 834 int flags, const char *dev_name, void *data) 835 { 836 return mount_single(fs_type, flags, data, bm_fill_super); 837 } 838 839 static struct linux_binfmt misc_format = { 840 .module = THIS_MODULE, 841 .load_binary = load_misc_binary, 842 }; 843 844 static struct file_system_type bm_fs_type = { 845 .owner = THIS_MODULE, 846 .name = "binfmt_misc", 847 .mount = bm_mount, 848 .kill_sb = kill_litter_super, 849 }; 850 MODULE_ALIAS_FS("binfmt_misc"); 851 852 static int __init init_misc_binfmt(void) 853 { 854 int err = register_filesystem(&bm_fs_type); 855 if (!err) 856 insert_binfmt(&misc_format); 857 return err; 858 } 859 860 static void __exit exit_misc_binfmt(void) 861 { 862 unregister_binfmt(&misc_format); 863 unregister_filesystem(&bm_fs_type); 864 } 865 866 core_initcall(init_misc_binfmt); 867 module_exit(exit_misc_binfmt); 868 MODULE_LICENSE("GPL"); 869