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/admin-guide/binfmt-misc.rst 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/mm.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 const 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 int retval; 135 int fd_binary = -1; 136 137 retval = -ENOEXEC; 138 if (!enabled) 139 return retval; 140 141 /* to keep locking time low, we copy the interpreter string */ 142 read_lock(&entries_lock); 143 fmt = check_file(bprm); 144 if (fmt) 145 dget(fmt->dentry); 146 read_unlock(&entries_lock); 147 if (!fmt) 148 return retval; 149 150 /* Need to be able to load the file after exec */ 151 retval = -ENOENT; 152 if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) 153 goto ret; 154 155 if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { 156 retval = remove_arg_zero(bprm); 157 if (retval) 158 goto ret; 159 } 160 161 if (fmt->flags & MISC_FMT_OPEN_BINARY) { 162 163 /* if the binary should be opened on behalf of the 164 * interpreter than keep it open and assign descriptor 165 * to it 166 */ 167 fd_binary = get_unused_fd_flags(0); 168 if (fd_binary < 0) { 169 retval = fd_binary; 170 goto ret; 171 } 172 fd_install(fd_binary, bprm->file); 173 174 /* if the binary is not readable than enforce mm->dumpable=0 175 regardless of the interpreter's permissions */ 176 would_dump(bprm, bprm->file); 177 178 allow_write_access(bprm->file); 179 bprm->file = NULL; 180 181 /* mark the bprm that fd should be passed to interp */ 182 bprm->interp_flags |= BINPRM_FLAGS_EXECFD; 183 bprm->interp_data = fd_binary; 184 185 } else { 186 allow_write_access(bprm->file); 187 fput(bprm->file); 188 bprm->file = NULL; 189 } 190 /* make argv[1] be the path to the binary */ 191 retval = copy_strings_kernel(1, &bprm->interp, bprm); 192 if (retval < 0) 193 goto error; 194 bprm->argc++; 195 196 /* add the interp as argv[0] */ 197 retval = copy_strings_kernel(1, &fmt->interpreter, bprm); 198 if (retval < 0) 199 goto error; 200 bprm->argc++; 201 202 /* Update interp in case binfmt_script needs it. */ 203 retval = bprm_change_interp(fmt->interpreter, bprm); 204 if (retval < 0) 205 goto error; 206 207 if (fmt->flags & MISC_FMT_OPEN_FILE) { 208 interp_file = file_clone_open(fmt->interp_file); 209 if (!IS_ERR(interp_file)) 210 deny_write_access(interp_file); 211 } else { 212 interp_file = open_exec(fmt->interpreter); 213 } 214 retval = PTR_ERR(interp_file); 215 if (IS_ERR(interp_file)) 216 goto error; 217 218 bprm->file = interp_file; 219 if (fmt->flags & MISC_FMT_CREDENTIALS) { 220 loff_t pos = 0; 221 222 /* 223 * No need to call prepare_binprm(), it's already been 224 * done. bprm->buf is stale, update from interp_file. 225 */ 226 memset(bprm->buf, 0, BINPRM_BUF_SIZE); 227 retval = kernel_read(bprm->file, bprm->buf, BINPRM_BUF_SIZE, 228 &pos); 229 } else 230 retval = prepare_binprm(bprm); 231 232 if (retval < 0) 233 goto error; 234 235 retval = search_binary_handler(bprm); 236 if (retval < 0) 237 goto error; 238 239 ret: 240 dput(fmt->dentry); 241 return retval; 242 error: 243 if (fd_binary > 0) 244 ksys_close(fd_binary); 245 bprm->interp_flags = 0; 246 bprm->interp_data = 0; 247 goto ret; 248 } 249 250 /* Command parsers */ 251 252 /* 253 * parses and copies one argument enclosed in del from *sp to *dp, 254 * recognising the \x special. 255 * returns pointer to the copied argument or NULL in case of an 256 * error (and sets err) or null argument length. 257 */ 258 static char *scanarg(char *s, char del) 259 { 260 char c; 261 262 while ((c = *s++) != del) { 263 if (c == '\\' && *s == 'x') { 264 s++; 265 if (!isxdigit(*s++)) 266 return NULL; 267 if (!isxdigit(*s++)) 268 return NULL; 269 } 270 } 271 s[-1] ='\0'; 272 return s; 273 } 274 275 static char *check_special_flags(char *sfs, Node *e) 276 { 277 char *p = sfs; 278 int cont = 1; 279 280 /* special flags */ 281 while (cont) { 282 switch (*p) { 283 case 'P': 284 pr_debug("register: flag: P (preserve argv0)\n"); 285 p++; 286 e->flags |= MISC_FMT_PRESERVE_ARGV0; 287 break; 288 case 'O': 289 pr_debug("register: flag: O (open binary)\n"); 290 p++; 291 e->flags |= MISC_FMT_OPEN_BINARY; 292 break; 293 case 'C': 294 pr_debug("register: flag: C (preserve creds)\n"); 295 p++; 296 /* this flags also implies the 297 open-binary flag */ 298 e->flags |= (MISC_FMT_CREDENTIALS | 299 MISC_FMT_OPEN_BINARY); 300 break; 301 case 'F': 302 pr_debug("register: flag: F: open interpreter file now\n"); 303 p++; 304 e->flags |= MISC_FMT_OPEN_FILE; 305 break; 306 default: 307 cont = 0; 308 } 309 } 310 311 return p; 312 } 313 314 /* 315 * This registers a new binary format, it recognises the syntax 316 * ':name:type:offset:magic:mask:interpreter:flags' 317 * where the ':' is the IFS, that can be chosen with the first char 318 */ 319 static Node *create_entry(const char __user *buffer, size_t count) 320 { 321 Node *e; 322 int memsize, err; 323 char *buf, *p; 324 char del; 325 326 pr_debug("register: received %zu bytes\n", count); 327 328 /* some sanity checks */ 329 err = -EINVAL; 330 if ((count < 11) || (count > MAX_REGISTER_LENGTH)) 331 goto out; 332 333 err = -ENOMEM; 334 memsize = sizeof(Node) + count + 8; 335 e = kmalloc(memsize, GFP_KERNEL); 336 if (!e) 337 goto out; 338 339 p = buf = (char *)e + sizeof(Node); 340 341 memset(e, 0, sizeof(Node)); 342 if (copy_from_user(buf, buffer, count)) 343 goto efault; 344 345 del = *p++; /* delimeter */ 346 347 pr_debug("register: delim: %#x {%c}\n", del, del); 348 349 /* Pad the buffer with the delim to simplify parsing below. */ 350 memset(buf + count, del, 8); 351 352 /* Parse the 'name' field. */ 353 e->name = p; 354 p = strchr(p, del); 355 if (!p) 356 goto einval; 357 *p++ = '\0'; 358 if (!e->name[0] || 359 !strcmp(e->name, ".") || 360 !strcmp(e->name, "..") || 361 strchr(e->name, '/')) 362 goto einval; 363 364 pr_debug("register: name: {%s}\n", e->name); 365 366 /* Parse the 'type' field. */ 367 switch (*p++) { 368 case 'E': 369 pr_debug("register: type: E (extension)\n"); 370 e->flags = 1 << Enabled; 371 break; 372 case 'M': 373 pr_debug("register: type: M (magic)\n"); 374 e->flags = (1 << Enabled) | (1 << Magic); 375 break; 376 default: 377 goto einval; 378 } 379 if (*p++ != del) 380 goto einval; 381 382 if (test_bit(Magic, &e->flags)) { 383 /* Handle the 'M' (magic) format. */ 384 char *s; 385 386 /* Parse the 'offset' field. */ 387 s = strchr(p, del); 388 if (!s) 389 goto einval; 390 *s = '\0'; 391 if (p != s) { 392 int r = kstrtoint(p, 10, &e->offset); 393 if (r != 0 || e->offset < 0) 394 goto einval; 395 } 396 p = s; 397 if (*p++) 398 goto einval; 399 pr_debug("register: offset: %#x\n", e->offset); 400 401 /* Parse the 'magic' field. */ 402 e->magic = p; 403 p = scanarg(p, del); 404 if (!p) 405 goto einval; 406 if (!e->magic[0]) 407 goto einval; 408 if (USE_DEBUG) 409 print_hex_dump_bytes( 410 KBUILD_MODNAME ": register: magic[raw]: ", 411 DUMP_PREFIX_NONE, e->magic, p - e->magic); 412 413 /* Parse the 'mask' field. */ 414 e->mask = p; 415 p = scanarg(p, del); 416 if (!p) 417 goto einval; 418 if (!e->mask[0]) { 419 e->mask = NULL; 420 pr_debug("register: mask[raw]: none\n"); 421 } else if (USE_DEBUG) 422 print_hex_dump_bytes( 423 KBUILD_MODNAME ": register: mask[raw]: ", 424 DUMP_PREFIX_NONE, e->mask, p - e->mask); 425 426 /* 427 * Decode the magic & mask fields. 428 * Note: while we might have accepted embedded NUL bytes from 429 * above, the unescape helpers here will stop at the first one 430 * it encounters. 431 */ 432 e->size = string_unescape_inplace(e->magic, UNESCAPE_HEX); 433 if (e->mask && 434 string_unescape_inplace(e->mask, UNESCAPE_HEX) != e->size) 435 goto einval; 436 if (e->size > BINPRM_BUF_SIZE || 437 BINPRM_BUF_SIZE - e->size < e->offset) 438 goto einval; 439 pr_debug("register: magic/mask length: %i\n", e->size); 440 if (USE_DEBUG) { 441 print_hex_dump_bytes( 442 KBUILD_MODNAME ": register: magic[decoded]: ", 443 DUMP_PREFIX_NONE, e->magic, e->size); 444 445 if (e->mask) { 446 int i; 447 char *masked = kmalloc(e->size, GFP_KERNEL); 448 449 print_hex_dump_bytes( 450 KBUILD_MODNAME ": register: mask[decoded]: ", 451 DUMP_PREFIX_NONE, e->mask, e->size); 452 453 if (masked) { 454 for (i = 0; i < e->size; ++i) 455 masked[i] = e->magic[i] & e->mask[i]; 456 print_hex_dump_bytes( 457 KBUILD_MODNAME ": register: magic[masked]: ", 458 DUMP_PREFIX_NONE, masked, e->size); 459 460 kfree(masked); 461 } 462 } 463 } 464 } else { 465 /* Handle the 'E' (extension) format. */ 466 467 /* Skip the 'offset' field. */ 468 p = strchr(p, del); 469 if (!p) 470 goto einval; 471 *p++ = '\0'; 472 473 /* Parse the 'magic' field. */ 474 e->magic = p; 475 p = strchr(p, del); 476 if (!p) 477 goto einval; 478 *p++ = '\0'; 479 if (!e->magic[0] || strchr(e->magic, '/')) 480 goto einval; 481 pr_debug("register: extension: {%s}\n", e->magic); 482 483 /* Skip the 'mask' field. */ 484 p = strchr(p, del); 485 if (!p) 486 goto einval; 487 *p++ = '\0'; 488 } 489 490 /* Parse the 'interpreter' field. */ 491 e->interpreter = p; 492 p = strchr(p, del); 493 if (!p) 494 goto einval; 495 *p++ = '\0'; 496 if (!e->interpreter[0]) 497 goto einval; 498 pr_debug("register: interpreter: {%s}\n", e->interpreter); 499 500 /* Parse the 'flags' field. */ 501 p = check_special_flags(p, e); 502 if (*p == '\n') 503 p++; 504 if (p != buf + count) 505 goto einval; 506 507 return e; 508 509 out: 510 return ERR_PTR(err); 511 512 efault: 513 kfree(e); 514 return ERR_PTR(-EFAULT); 515 einval: 516 kfree(e); 517 return ERR_PTR(-EINVAL); 518 } 519 520 /* 521 * Set status of entry/binfmt_misc: 522 * '1' enables, '0' disables and '-1' clears entry/binfmt_misc 523 */ 524 static int parse_command(const char __user *buffer, size_t count) 525 { 526 char s[4]; 527 528 if (count > 3) 529 return -EINVAL; 530 if (copy_from_user(s, buffer, count)) 531 return -EFAULT; 532 if (!count) 533 return 0; 534 if (s[count - 1] == '\n') 535 count--; 536 if (count == 1 && s[0] == '0') 537 return 1; 538 if (count == 1 && s[0] == '1') 539 return 2; 540 if (count == 2 && s[0] == '-' && s[1] == '1') 541 return 3; 542 return -EINVAL; 543 } 544 545 /* generic stuff */ 546 547 static void entry_status(Node *e, char *page) 548 { 549 char *dp = page; 550 const char *status = "disabled"; 551 552 if (test_bit(Enabled, &e->flags)) 553 status = "enabled"; 554 555 if (!VERBOSE_STATUS) { 556 sprintf(page, "%s\n", status); 557 return; 558 } 559 560 dp += sprintf(dp, "%s\ninterpreter %s\n", status, e->interpreter); 561 562 /* print the special flags */ 563 dp += sprintf(dp, "flags: "); 564 if (e->flags & MISC_FMT_PRESERVE_ARGV0) 565 *dp++ = 'P'; 566 if (e->flags & MISC_FMT_OPEN_BINARY) 567 *dp++ = 'O'; 568 if (e->flags & MISC_FMT_CREDENTIALS) 569 *dp++ = 'C'; 570 if (e->flags & MISC_FMT_OPEN_FILE) 571 *dp++ = 'F'; 572 *dp++ = '\n'; 573 574 if (!test_bit(Magic, &e->flags)) { 575 sprintf(dp, "extension .%s\n", e->magic); 576 } else { 577 dp += sprintf(dp, "offset %i\nmagic ", e->offset); 578 dp = bin2hex(dp, e->magic, e->size); 579 if (e->mask) { 580 dp += sprintf(dp, "\nmask "); 581 dp = bin2hex(dp, e->mask, e->size); 582 } 583 *dp++ = '\n'; 584 *dp = '\0'; 585 } 586 } 587 588 static struct inode *bm_get_inode(struct super_block *sb, int mode) 589 { 590 struct inode *inode = new_inode(sb); 591 592 if (inode) { 593 inode->i_ino = get_next_ino(); 594 inode->i_mode = mode; 595 inode->i_atime = inode->i_mtime = inode->i_ctime = 596 current_time(inode); 597 } 598 return inode; 599 } 600 601 static void bm_evict_inode(struct inode *inode) 602 { 603 Node *e = inode->i_private; 604 605 if (e && e->flags & MISC_FMT_OPEN_FILE) 606 filp_close(e->interp_file, NULL); 607 608 clear_inode(inode); 609 kfree(e); 610 } 611 612 static void kill_node(Node *e) 613 { 614 struct dentry *dentry; 615 616 write_lock(&entries_lock); 617 list_del_init(&e->list); 618 write_unlock(&entries_lock); 619 620 dentry = e->dentry; 621 drop_nlink(d_inode(dentry)); 622 d_drop(dentry); 623 dput(dentry); 624 simple_release_fs(&bm_mnt, &entry_count); 625 } 626 627 /* /<entry> */ 628 629 static ssize_t 630 bm_entry_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) 631 { 632 Node *e = file_inode(file)->i_private; 633 ssize_t res; 634 char *page; 635 636 page = (char *) __get_free_page(GFP_KERNEL); 637 if (!page) 638 return -ENOMEM; 639 640 entry_status(e, page); 641 642 res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page)); 643 644 free_page((unsigned long) page); 645 return res; 646 } 647 648 static ssize_t bm_entry_write(struct file *file, const char __user *buffer, 649 size_t count, loff_t *ppos) 650 { 651 struct dentry *root; 652 Node *e = file_inode(file)->i_private; 653 int res = parse_command(buffer, count); 654 655 switch (res) { 656 case 1: 657 /* Disable this handler. */ 658 clear_bit(Enabled, &e->flags); 659 break; 660 case 2: 661 /* Enable this handler. */ 662 set_bit(Enabled, &e->flags); 663 break; 664 case 3: 665 /* Delete this handler. */ 666 root = file_inode(file)->i_sb->s_root; 667 inode_lock(d_inode(root)); 668 669 if (!list_empty(&e->list)) 670 kill_node(e); 671 672 inode_unlock(d_inode(root)); 673 break; 674 default: 675 return res; 676 } 677 678 return count; 679 } 680 681 static const struct file_operations bm_entry_operations = { 682 .read = bm_entry_read, 683 .write = bm_entry_write, 684 .llseek = default_llseek, 685 }; 686 687 /* /register */ 688 689 static ssize_t bm_register_write(struct file *file, const char __user *buffer, 690 size_t count, loff_t *ppos) 691 { 692 Node *e; 693 struct inode *inode; 694 struct super_block *sb = file_inode(file)->i_sb; 695 struct dentry *root = sb->s_root, *dentry; 696 int err = 0; 697 698 e = create_entry(buffer, count); 699 700 if (IS_ERR(e)) 701 return PTR_ERR(e); 702 703 inode_lock(d_inode(root)); 704 dentry = lookup_one_len(e->name, root, strlen(e->name)); 705 err = PTR_ERR(dentry); 706 if (IS_ERR(dentry)) 707 goto out; 708 709 err = -EEXIST; 710 if (d_really_is_positive(dentry)) 711 goto out2; 712 713 inode = bm_get_inode(sb, S_IFREG | 0644); 714 715 err = -ENOMEM; 716 if (!inode) 717 goto out2; 718 719 err = simple_pin_fs(&bm_fs_type, &bm_mnt, &entry_count); 720 if (err) { 721 iput(inode); 722 inode = NULL; 723 goto out2; 724 } 725 726 if (e->flags & MISC_FMT_OPEN_FILE) { 727 struct file *f; 728 729 f = open_exec(e->interpreter); 730 if (IS_ERR(f)) { 731 err = PTR_ERR(f); 732 pr_notice("register: failed to install interpreter file %s\n", e->interpreter); 733 simple_release_fs(&bm_mnt, &entry_count); 734 iput(inode); 735 inode = NULL; 736 goto out2; 737 } 738 e->interp_file = f; 739 } 740 741 e->dentry = dget(dentry); 742 inode->i_private = e; 743 inode->i_fop = &bm_entry_operations; 744 745 d_instantiate(dentry, inode); 746 write_lock(&entries_lock); 747 list_add(&e->list, &entries); 748 write_unlock(&entries_lock); 749 750 err = 0; 751 out2: 752 dput(dentry); 753 out: 754 inode_unlock(d_inode(root)); 755 756 if (err) { 757 kfree(e); 758 return err; 759 } 760 return count; 761 } 762 763 static const struct file_operations bm_register_operations = { 764 .write = bm_register_write, 765 .llseek = noop_llseek, 766 }; 767 768 /* /status */ 769 770 static ssize_t 771 bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) 772 { 773 char *s = enabled ? "enabled\n" : "disabled\n"; 774 775 return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); 776 } 777 778 static ssize_t bm_status_write(struct file *file, const char __user *buffer, 779 size_t count, loff_t *ppos) 780 { 781 int res = parse_command(buffer, count); 782 struct dentry *root; 783 784 switch (res) { 785 case 1: 786 /* Disable all handlers. */ 787 enabled = 0; 788 break; 789 case 2: 790 /* Enable all handlers. */ 791 enabled = 1; 792 break; 793 case 3: 794 /* Delete all handlers. */ 795 root = file_inode(file)->i_sb->s_root; 796 inode_lock(d_inode(root)); 797 798 while (!list_empty(&entries)) 799 kill_node(list_first_entry(&entries, Node, list)); 800 801 inode_unlock(d_inode(root)); 802 break; 803 default: 804 return res; 805 } 806 807 return count; 808 } 809 810 static const struct file_operations bm_status_operations = { 811 .read = bm_status_read, 812 .write = bm_status_write, 813 .llseek = default_llseek, 814 }; 815 816 /* Superblock handling */ 817 818 static const struct super_operations s_ops = { 819 .statfs = simple_statfs, 820 .evict_inode = bm_evict_inode, 821 }; 822 823 static int bm_fill_super(struct super_block *sb, void *data, int silent) 824 { 825 int err; 826 static const struct tree_descr bm_files[] = { 827 [2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO}, 828 [3] = {"register", &bm_register_operations, S_IWUSR}, 829 /* last one */ {""} 830 }; 831 832 err = simple_fill_super(sb, BINFMTFS_MAGIC, bm_files); 833 if (!err) 834 sb->s_op = &s_ops; 835 return err; 836 } 837 838 static struct dentry *bm_mount(struct file_system_type *fs_type, 839 int flags, const char *dev_name, void *data) 840 { 841 return mount_single(fs_type, flags, data, bm_fill_super); 842 } 843 844 static struct linux_binfmt misc_format = { 845 .module = THIS_MODULE, 846 .load_binary = load_misc_binary, 847 }; 848 849 static struct file_system_type bm_fs_type = { 850 .owner = THIS_MODULE, 851 .name = "binfmt_misc", 852 .mount = bm_mount, 853 .kill_sb = kill_litter_super, 854 }; 855 MODULE_ALIAS_FS("binfmt_misc"); 856 857 static int __init init_misc_binfmt(void) 858 { 859 int err = register_filesystem(&bm_fs_type); 860 if (!err) 861 insert_binfmt(&misc_format); 862 return err; 863 } 864 865 static void __exit exit_misc_binfmt(void) 866 { 867 unregister_binfmt(&misc_format); 868 unregister_filesystem(&bm_fs_type); 869 } 870 871 core_initcall(init_misc_binfmt); 872 module_exit(exit_misc_binfmt); 873 MODULE_LICENSE("GPL"); 874