fs/binfmt_misc.c

   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. This should obsolete binfmt_java, binfmt_em86 and
   8  *  binfmt_mz.
   9  *
  10  *  1997-04-25 first version
  11  *  [...]
  12  *  1997-05-19 cleanup
  13  *  1997-06-26 hpa: pass the real filename rather than argv[0]
  14  *  1997-06-30 minor cleanup
  15  *  1997-08-09 removed extension stripping, locking cleanup
  16  *  2001-02-28 AV: rewritten into something that resembles C. Original didn't.
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21
  22 #include <linux/binfmts.h>
  23 #include <linux/slab.h>
  24 #include <linux/ctype.h>
  25 #include <linux/file.h>
  26 #include <linux/pagemap.h>
  27 #include <linux/namei.h>
  28 #include <linux/mount.h>
  29 #include <linux/syscalls.h>
  30
  31 #include <asm/uaccess.h>
  32
  33 enum {
  34         VERBOSE_STATUS = 1 /* make it zero to save 400 bytes kernel memory */
  35 };
  36
  37 static LIST_HEAD(entries);
  38 static int enabled = 1;
  39
  40 enum {Enabled, Magic};
  41 #define MISC_FMT_PRESERVE_ARGV0 (1<<31)
  42 #define MISC_FMT_OPEN_BINARY (1<<30)
  43 #define MISC_FMT_CREDENTIALS (1<<29)
  44
  45 typedef struct {
  46         struct list_head list;
  47         unsigned long flags;            /* type, status, etc. */
  48         int offset;                     /* offset of magic */
  49         int size;                       /* size of magic/mask */
  50         char *magic;                    /* magic or filename extension */
  51         char *mask;                     /* mask, NULL for exact match */
  52         char *interpreter;              /* filename of interpreter */
  53         char *name;
  54         struct dentry *dentry;
  55 } Node;
  56
  57 static DEFINE_RWLOCK(entries_lock);
  58 static struct vfsmount *bm_mnt;
  59 static int entry_count;
  60
  61 /*
  62  * Check if we support the binfmt
  63  * if we do, return the node, else NULL
  64  * locking is done in load_misc_binary
  65  */
  66 static Node *check_file(struct linux_binprm *bprm)
  67 {
  68         char *p = strrchr(bprm->interp, '.');
  69         struct list_head *l;
  70
  71         list_for_each(l, &entries) {
  72                 Node *e = list_entry(l, Node, list);
  73                 char *s;
  74                 int j;
  75
  76                 if (!test_bit(Enabled, &e->flags))
  77                         continue;
  78
  79                 if (!test_bit(Magic, &e->flags)) {
  80                         if (p && !strcmp(e->magic, p + 1))
  81                                 return e;
  82                         continue;
  83                 }
  84
  85                 s = bprm->buf + e->offset;
  86                 if (e->mask) {
  87                         for (j = 0; j < e->size; j++)
  88                                 if ((*s++ ^ e->magic[j]) & e->mask[j])
  89                                         break;
  90                 } else {
  91                         for (j = 0; j < e->size; j++)
  92                                 if ((*s++ ^ e->magic[j]))
  93                                         break;
  94                 }
  95                 if (j == e->size)
  96                         return e;
  97         }
  98         return NULL;
  99 }
 100
 101 /*
 102  * the loader itself
 103  */
 104 static int load_misc_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 105 {
 106         Node *fmt;
 107         struct file * interp_file = NULL;
 108         char iname[BINPRM_BUF_SIZE];
 109         char *iname_addr = iname;
 110         int retval;
 111         int fd_binary = -1;
 112         struct files_struct *files = NULL;
 113
 114         retval = -ENOEXEC;
 115         if (!enabled)
 116                 goto _ret;
 117
 118         /* to keep locking time low, we copy the interpreter string */
 119         read_lock(&entries_lock);
 120         fmt = check_file(bprm);
 121         if (fmt)
 122                 strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE);
 123         read_unlock(&entries_lock);
 124         if (!fmt)
 125                 goto _ret;
 126
 127         if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) {
 128                 remove_arg_zero(bprm);
 129         }
 130
 131         if (fmt->flags & MISC_FMT_OPEN_BINARY) {
 132
 133                 files = current->files;
 134                 retval = unshare_files();
 135                 if (retval < 0)
 136                         goto _ret;
 137                 if (files == current->files) {
 138                         put_files_struct(files);
 139                         files = NULL;
 140                 }
 141                 /* if the binary should be opened on behalf of the
 142                  * interpreter than keep it open and assign descriptor
 143                  * to it */
 144                 fd_binary = get_unused_fd();
 145                 if (fd_binary < 0) {
 146                         retval = fd_binary;
 147                         goto _unshare;
 148                 }
 149                 fd_install(fd_binary, bprm->file);
 150
 151                 /* if the binary is not readable than enforce mm->dumpable=0
 152                    regardless of the interpreter's permissions */
 153                 if (file_permission(bprm->file, MAY_READ))
 154                         bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
 155
 156                 allow_write_access(bprm->file);
 157                 bprm->file = NULL;
 158
 159                 /* mark the bprm that fd should be passed to interp */
 160                 bprm->interp_flags |= BINPRM_FLAGS_EXECFD;
 161                 bprm->interp_data = fd_binary;
 162
 163         } else {
 164                 allow_write_access(bprm->file);
 165                 fput(bprm->file);
 166                 bprm->file = NULL;
 167         }
 168         /* make argv[1] be the path to the binary */
 169         retval = copy_strings_kernel (1, &bprm->interp, bprm);
 170         if (retval < 0)
 171                 goto _error;
 172         bprm->argc++;
 173
 174         /* add the interp as argv[0] */
 175         retval = copy_strings_kernel (1, &iname_addr, bprm);
 176         if (retval < 0)
 177                 goto _error;
 178         bprm->argc ++;
 179
 180         bprm->interp = iname;   /* for binfmt_script */
 181
 182         interp_file = open_exec (iname);
 183         retval = PTR_ERR (interp_file);
 184         if (IS_ERR (interp_file))
 185                 goto _error;
 186
 187         bprm->file = interp_file;
 188         if (fmt->flags & MISC_FMT_CREDENTIALS) {
 189                 /*
 190                  * No need to call prepare_binprm(), it's already been
 191                  * done.  bprm->buf is stale, update from interp_file.
 192                  */
 193                 memset(bprm->buf, 0, BINPRM_BUF_SIZE);
 194                 retval = kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE);
 195         } else
 196                 retval = prepare_binprm (bprm);
 197
 198         if (retval < 0)
 199                 goto _error;
 200
 201         retval = search_binary_handler (bprm, regs);
 202         if (retval < 0)
 203                 goto _error;
 204
 205         if (files) {
 206                 put_files_struct(files);
 207                 files = NULL;
 208         }
 209 _ret:
 210         return retval;
 211 _error:
 212         if (fd_binary > 0)
 213                 sys_close(fd_binary);
 214         bprm->interp_flags = 0;
 215         bprm->interp_data = 0;
 216 _unshare:
 217         if (files) {
 218                 put_files_struct(current->files);
 219                 current->files = files;
 220         }
 221         goto _ret;
 222 }
 223
 224 /* Command parsers */
 225
 226 /*
 227  * parses and copies one argument enclosed in del from *sp to *dp,
 228  * recognising the \x special.
 229  * returns pointer to the copied argument or NULL in case of an
 230  * error (and sets err) or null argument length.
 231  */
 232 static char *scanarg(char *s, char del)
 233 {
 234         char c;
 235
 236         while ((c = *s++) != del) {
 237                 if (c == '\\' && *s == 'x') {
 238                         s++;
 239                         if (!isxdigit(*s++))
 240                                 return NULL;
 241                         if (!isxdigit(*s++))
 242                                 return NULL;
 243                 }
 244         }
 245         return s;
 246 }
 247
 248 static int unquote(char *from)
 249 {
 250         char c = 0, *s = from, *p = from;
 251
 252         while ((c = *s++) != '\0') {
 253                 if (c == '\\' && *s == 'x') {
 254                         s++;
 255                         c = toupper(*s++);
 256                         *p = (c - (isdigit(c) ? '0' : 'A' - 10)) << 4;
 257                         c = toupper(*s++);
 258                         *p++ |= c - (isdigit(c) ? '0' : 'A' - 10);
 259                         continue;
 260                 }
 261                 *p++ = c;
 262         }
 263         return p - from;
 264 }
 265
 266 static char * check_special_flags (char * sfs, Node * e)
 267 {
 268         char * p = sfs;
 269         int cont = 1;
 270
 271         /* special flags */
 272         while (cont) {
 273                 switch (*p) {
 274                         case 'P':
 275                                 p++;
 276                                 e->flags |= MISC_FMT_PRESERVE_ARGV0;
 277                                 break;
 278                         case 'O':
 279                                 p++;
 280                                 e->flags |= MISC_FMT_OPEN_BINARY;
 281                                 break;
 282                         case 'C':
 283                                 p++;
 284                                 /* this flags also implies the
 285                                    open-binary flag */
 286                                 e->flags |= (MISC_FMT_CREDENTIALS |
 287                                                 MISC_FMT_OPEN_BINARY);
 288                                 break;
 289                         default:
 290                                 cont = 0;
 291                 }
 292         }
 293
 294         return p;
 295 }
 296 /*
 297  * This registers a new binary format, it recognises the syntax
 298  * ':name:type:offset:magic:mask:interpreter:flags'
 299  * where the ':' is the IFS, that can be chosen with the first char
 300  */
 301 static Node *create_entry(const char __user *buffer, size_t count)
 302 {
 303         Node *e;
 304         int memsize, err;
 305         char *buf, *p;
 306         char del;
 307
 308         /* some sanity checks */
 309         err = -EINVAL;
 310         if ((count < 11) || (count > 256))
 311                 goto out;
 312
 313         err = -ENOMEM;
 314         memsize = sizeof(Node) + count + 8;
 315         e = (Node *) kmalloc(memsize, GFP_USER);
 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         memset(buf+count, del, 8);
 328
 329         e->name = p;
 330         p = strchr(p, del);
 331         if (!p)
 332                 goto Einval;
 333         *p++ = '\0';
 334         if (!e->name[0] ||
 335             !strcmp(e->name, ".") ||
 336             !strcmp(e->name, "..") ||
 337             strchr(e->name, '/'))
 338                 goto Einval;
 339         switch (*p++) {
 340                 case 'E': e->flags = 1<<Enabled; break;
 341                 case 'M': e->flags = (1<<Enabled) | (1<<Magic); break;
 342                 default: goto Einval;
 343         }
 344         if (*p++ != del)
 345                 goto Einval;
 346         if (test_bit(Magic, &e->flags)) {
 347                 char *s = strchr(p, del);
 348                 if (!s)
 349                         goto Einval;
 350                 *s++ = '\0';
 351                 e->offset = simple_strtoul(p, &p, 10);
 352                 if (*p++)
 353                         goto Einval;
 354                 e->magic = p;
 355                 p = scanarg(p, del);
 356                 if (!p)
 357                         goto Einval;
 358                 p[-1] = '\0';
 359                 if (!e->magic[0])
 360                         goto Einval;
 361                 e->mask = p;
 362                 p = scanarg(p, del);
 363                 if (!p)
 364                         goto Einval;
 365                 p[-1] = '\0';
 366                 if (!e->mask[0])
 367                         e->mask = NULL;
 368                 e->size = unquote(e->magic);
 369                 if (e->mask && unquote(e->mask) != e->size)
 370                         goto Einval;
 371                 if (e->size + e->offset > BINPRM_BUF_SIZE)
 372                         goto Einval;
 373         } else {
 374                 p = strchr(p, del);
 375                 if (!p)
 376                         goto Einval;
 377                 *p++ = '\0';
 378                 e->magic = p;
 379                 p = strchr(p, del);
 380                 if (!p)
 381                         goto Einval;
 382                 *p++ = '\0';
 383                 if (!e->magic[0] || strchr(e->magic, '/'))
 384                         goto Einval;
 385                 p = strchr(p, del);
 386                 if (!p)
 387                         goto Einval;
 388                 *p++ = '\0';
 389         }
 390         e->interpreter = p;
 391         p = strchr(p, del);
 392         if (!p)
 393                 goto Einval;
 394         *p++ = '\0';
 395         if (!e->interpreter[0])
 396                 goto Einval;
 397
 398
 399         p = check_special_flags (p, e);
 400
 401         if (*p == '\n')
 402                 p++;
 403         if (p != buf + count)
 404                 goto Einval;
 405         return e;
 406
 407 out:
 408         return ERR_PTR(err);
 409
 410 Efault:
 411         kfree(e);
 412         return ERR_PTR(-EFAULT);
 413 Einval:
 414         kfree(e);
 415         return ERR_PTR(-EINVAL);
 416 }
 417
 418 /*
 419  * Set status of entry/binfmt_misc:
 420  * '1' enables, '0' disables and '-1' clears entry/binfmt_misc
 421  */
 422 static int parse_command(const char __user *buffer, size_t count)
 423 {
 424         char s[4];
 425
 426         if (!count)
 427                 return 0;
 428         if (count > 3)
 429                 return -EINVAL;
 430         if (copy_from_user(s, buffer, count))
 431                 return -EFAULT;
 432         if (s[count-1] == '\n')
 433                 count--;
 434         if (count == 1 && s[0] == '0')
 435                 return 1;
 436         if (count == 1 && s[0] == '1')
 437                 return 2;
 438         if (count == 2 && s[0] == '-' && s[1] == '1')
 439                 return 3;
 440         return -EINVAL;
 441 }
 442
 443 /* generic stuff */
 444
 445 static void entry_status(Node *e, char *page)
 446 {
 447         char *dp;
 448         char *status = "disabled";
 449         const char * flags = "flags: ";
 450
 451         if (test_bit(Enabled, &e->flags))
 452                 status = "enabled";
 453
 454         if (!VERBOSE_STATUS) {
 455                 sprintf(page, "%s\n", status);
 456                 return;
 457         }
 458
 459         sprintf(page, "%s\ninterpreter %s\n", status, e->interpreter);
 460         dp = page + strlen(page);
 461
 462         /* print the special flags */
 463         sprintf (dp, "%s", flags);
 464         dp += strlen (flags);
 465         if (e->flags & MISC_FMT_PRESERVE_ARGV0) {
 466                 *dp ++ = 'P';
 467         }
 468         if (e->flags & MISC_FMT_OPEN_BINARY) {
 469                 *dp ++ = 'O';
 470         }
 471         if (e->flags & MISC_FMT_CREDENTIALS) {
 472                 *dp ++ = 'C';
 473         }
 474         *dp ++ = '\n';
 475
 476
 477         if (!test_bit(Magic, &e->flags)) {
 478                 sprintf(dp, "extension .%s\n", e->magic);
 479         } else {
 480                 int i;
 481
 482                 sprintf(dp, "offset %i\nmagic ", e->offset);
 483                 dp = page + strlen(page);
 484                 for (i = 0; i < e->size; i++) {
 485                         sprintf(dp, "%02x", 0xff & (int) (e->magic[i]));
 486                         dp += 2;
 487                 }
 488                 if (e->mask) {
 489                         sprintf(dp, "\nmask ");
 490                         dp += 6;
 491                         for (i = 0; i < e->size; i++) {
 492                                 sprintf(dp, "%02x", 0xff & (int) (e->mask[i]));
 493                                 dp += 2;
 494                         }
 495                 }
 496                 *dp++ = '\n';
 497                 *dp = '\0';
 498         }
 499 }
 500
 501 static struct inode *bm_get_inode(struct super_block *sb, int mode)
 502 {
 503         struct inode * inode = new_inode(sb);
 504
 505         if (inode) {
 506                 inode->i_mode = mode;
 507                 inode->i_uid = 0;
 508                 inode->i_gid = 0;
 509                 inode->i_blksize = PAGE_CACHE_SIZE;
 510                 inode->i_blocks = 0;
 511                 inode->i_atime = inode->i_mtime = inode->i_ctime =
 512                         current_fs_time(inode->i_sb);
 513         }
 514         return inode;
 515 }
 516
 517 static void bm_clear_inode(struct inode *inode)
 518 {
 519         kfree(inode->u.generic_ip);
 520 }
 521
 522 static void kill_node(Node *e)
 523 {
 524         struct dentry *dentry;
 525
 526         write_lock(&entries_lock);
 527         dentry = e->dentry;
 528         if (dentry) {
 529                 list_del_init(&e->list);
 530                 e->dentry = NULL;
 531         }
 532         write_unlock(&entries_lock);
 533
 534         if (dentry) {
 535                 dentry->d_inode->i_nlink--;
 536                 d_drop(dentry);
 537                 dput(dentry);
 538                 simple_release_fs(&bm_mnt, &entry_count);
 539         }
 540 }
 541
 542 /* /<entry> */
 543
 544 static ssize_t
 545 bm_entry_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos)
 546 {
 547         Node *e = file->f_dentry->d_inode->u.generic_ip;
 548         loff_t pos = *ppos;
 549         ssize_t res;
 550         char *page;
 551         int len;
 552
 553         if (!(page = (char*) __get_free_page(GFP_KERNEL)))
 554                 return -ENOMEM;
 555
 556         entry_status(e, page);
 557         len = strlen(page);
 558
 559         res = -EINVAL;
 560         if (pos < 0)
 561                 goto out;
 562         res = 0;
 563         if (pos >= len)
 564                 goto out;
 565         if (len < pos + nbytes)
 566                 nbytes = len - pos;
 567         res = -EFAULT;
 568         if (copy_to_user(buf, page + pos, nbytes))
 569                 goto out;
 570         *ppos = pos + nbytes;
 571         res = nbytes;
 572 out:
 573         free_page((unsigned long) page);
 574         return res;
 575 }
 576
 577 static ssize_t bm_entry_write(struct file *file, const char __user *buffer,
 578                                 size_t count, loff_t *ppos)
 579 {
 580         struct dentry *root;
 581         Node *e = file->f_dentry->d_inode->u.generic_ip;
 582         int res = parse_command(buffer, count);
 583
 584         switch (res) {
 585                 case 1: clear_bit(Enabled, &e->flags);
 586                         break;
 587                 case 2: set_bit(Enabled, &e->flags);
 588                         break;
 589                 case 3: root = dget(file->f_vfsmnt->mnt_sb->s_root);
 590                         mutex_lock(&root->d_inode->i_mutex);
 591
 592                         kill_node(e);
 593
 594                         mutex_unlock(&root->d_inode->i_mutex);
 595                         dput(root);
 596                         break;
 597                 default: return res;
 598         }
 599         return count;
 600 }
 601
 602 static const struct file_operations bm_entry_operations = {
 603         .read           = bm_entry_read,
 604         .write          = bm_entry_write,
 605 };
 606
 607 /* /register */
 608
 609 static ssize_t bm_register_write(struct file *file, const char __user *buffer,
 610                                size_t count, loff_t *ppos)
 611 {
 612         Node *e;
 613         struct inode *inode;
 614         struct dentry *root, *dentry;
 615         struct super_block *sb = file->f_vfsmnt->mnt_sb;
 616         int err = 0;
 617
 618         e = create_entry(buffer, count);
 619
 620         if (IS_ERR(e))
 621                 return PTR_ERR(e);
 622
 623         root = dget(sb->s_root);
 624         mutex_lock(&root->d_inode->i_mutex);
 625         dentry = lookup_one_len(e->name, root, strlen(e->name));
 626         err = PTR_ERR(dentry);
 627         if (IS_ERR(dentry))
 628                 goto out;
 629
 630         err = -EEXIST;
 631         if (dentry->d_inode)
 632                 goto out2;
 633
 634         inode = bm_get_inode(sb, S_IFREG | 0644);
 635
 636         err = -ENOMEM;
 637         if (!inode)
 638                 goto out2;
 639
 640         err = simple_pin_fs("binfmt_misc", &bm_mnt, &entry_count);
 641         if (err) {
 642                 iput(inode);
 643                 inode = NULL;
 644                 goto out2;
 645         }
 646
 647         e->dentry = dget(dentry);
 648         inode->u.generic_ip = e;
 649         inode->i_fop = &bm_entry_operations;
 650
 651         d_instantiate(dentry, inode);
 652         write_lock(&entries_lock);
 653         list_add(&e->list, &entries);
 654         write_unlock(&entries_lock);
 655
 656         err = 0;
 657 out2:
 658         dput(dentry);
 659 out:
 660         mutex_unlock(&root->d_inode->i_mutex);
 661         dput(root);
 662
 663         if (err) {
 664                 kfree(e);
 665                 return -EINVAL;
 666         }
 667         return count;
 668 }
 669
 670 static const struct file_operations bm_register_operations = {
 671         .write          = bm_register_write,
 672 };
 673
 674 /* /status */
 675
 676 static ssize_t
 677 bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
 678 {
 679         char *s = enabled ? "enabled" : "disabled";
 680         int len = strlen(s);
 681         loff_t pos = *ppos;
 682
 683         if (pos < 0)
 684                 return -EINVAL;
 685         if (pos >= len)
 686                 return 0;
 687         if (len < pos + nbytes)
 688                 nbytes = len - pos;
 689         if (copy_to_user(buf, s + pos, nbytes))
 690                 return -EFAULT;
 691         *ppos = pos + nbytes;
 692         return nbytes;
 693 }
 694
 695 static ssize_t bm_status_write(struct file * file, const char __user * buffer,
 696                 size_t count, loff_t *ppos)
 697 {
 698         int res = parse_command(buffer, count);
 699         struct dentry *root;
 700
 701         switch (res) {
 702                 case 1: enabled = 0; break;
 703                 case 2: enabled = 1; break;
 704                 case 3: root = dget(file->f_vfsmnt->mnt_sb->s_root);
 705                         mutex_lock(&root->d_inode->i_mutex);
 706
 707                         while (!list_empty(&entries))
 708                                 kill_node(list_entry(entries.next, Node, list));
 709
 710                         mutex_unlock(&root->d_inode->i_mutex);
 711                         dput(root);
 712                 default: return res;
 713         }
 714         return count;
 715 }
 716
 717 static const struct file_operations bm_status_operations = {
 718         .read           = bm_status_read,
 719         .write          = bm_status_write,
 720 };
 721
 722 /* Superblock handling */
 723
 724 static struct super_operations s_ops = {
 725         .statfs         = simple_statfs,
 726         .clear_inode    = bm_clear_inode,
 727 };
 728
 729 static int bm_fill_super(struct super_block * sb, void * data, int silent)
 730 {
 731         static struct tree_descr bm_files[] = {
 732                 [1] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO},
 733                 [2] = {"register", &bm_register_operations, S_IWUSR},
 734                 /* last one */ {""}
 735         };
 736         int err = simple_fill_super(sb, 0x42494e4d, bm_files);
 737         if (!err)
 738                 sb->s_op = &s_ops;
 739         return err;
 740 }
 741
 742 static struct super_block *bm_get_sb(struct file_system_type *fs_type,
 743         int flags, const char *dev_name, void *data)
 744 {
 745         return get_sb_single(fs_type, flags, data, bm_fill_super);
 746 }
 747
 748 static struct linux_binfmt misc_format = {
 749         .module = THIS_MODULE,
 750         .load_binary = load_misc_binary,
 751 };
 752
 753 static struct file_system_type bm_fs_type = {
 754         .owner          = THIS_MODULE,
 755         .name           = "binfmt_misc",
 756         .get_sb         = bm_get_sb,
 757         .kill_sb        = kill_litter_super,
 758 };
 759
 760 static int __init init_misc_binfmt(void)
 761 {
 762         int err = register_filesystem(&bm_fs_type);
 763         if (!err) {
 764                 err = register_binfmt(&misc_format);
 765                 if (err)
 766                         unregister_filesystem(&bm_fs_type);
 767         }
 768         return err;
 769 }
 770
 771 static void __exit exit_misc_binfmt(void)
 772 {
 773         unregister_binfmt(&misc_format);
 774         unregister_filesystem(&bm_fs_type);
 775 }
 776
 777 core_initcall(init_misc_binfmt);
 778 module_exit(exit_misc_binfmt);
 779 MODULE_LICENSE("GPL");