kernel/umh.c

   1 /*
   2  * umh - the kernel usermode helper
   3  */
   4 #include <linux/module.h>
   5 #include <linux/sched.h>
   6 #include <linux/sched/task.h>
   7 #include <linux/binfmts.h>
   8 #include <linux/syscalls.h>
   9 #include <linux/unistd.h>
  10 #include <linux/kmod.h>
  11 #include <linux/slab.h>
  12 #include <linux/completion.h>
  13 #include <linux/cred.h>
  14 #include <linux/file.h>
  15 #include <linux/fdtable.h>
  16 #include <linux/workqueue.h>
  17 #include <linux/security.h>
  18 #include <linux/mount.h>
  19 #include <linux/kernel.h>
  20 #include <linux/init.h>
  21 #include <linux/resource.h>
  22 #include <linux/notifier.h>
  23 #include <linux/suspend.h>
  24 #include <linux/rwsem.h>
  25 #include <linux/ptrace.h>
  26 #include <linux/async.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/shmem_fs.h>
  29 #include <linux/pipe_fs_i.h>
  30
  31 #include <trace/events/module.h>
  32
  33 #define CAP_BSET        (void *)1
  34 #define CAP_PI          (void *)2
  35
  36 static kernel_cap_t usermodehelper_bset = CAP_FULL_SET;
  37 static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET;
  38 static DEFINE_SPINLOCK(umh_sysctl_lock);
  39 static DECLARE_RWSEM(umhelper_sem);
  40
  41 static void call_usermodehelper_freeinfo(struct subprocess_info *info)
  42 {
  43         if (info->cleanup)
  44                 (*info->cleanup)(info);
  45         kfree(info);
  46 }
  47
  48 static void umh_complete(struct subprocess_info *sub_info)
  49 {
  50         struct completion *comp = xchg(&sub_info->complete, NULL);
  51         /*
  52          * See call_usermodehelper_exec(). If xchg() returns NULL
  53          * we own sub_info, the UMH_KILLABLE caller has gone away
  54          * or the caller used UMH_NO_WAIT.
  55          */
  56         if (comp)
  57                 complete(comp);
  58         else
  59                 call_usermodehelper_freeinfo(sub_info);
  60 }
  61
  62 /*
  63  * This is the task which runs the usermode application
  64  */
  65 static int call_usermodehelper_exec_async(void *data)
  66 {
  67         struct subprocess_info *sub_info = data;
  68         struct cred *new;
  69         int retval;
  70
  71         spin_lock_irq(&current->sighand->siglock);
  72         flush_signal_handlers(current, 1);
  73         spin_unlock_irq(&current->sighand->siglock);
  74
  75         /*
  76          * Our parent (unbound workqueue) runs with elevated scheduling
  77          * priority. Avoid propagating that into the userspace child.
  78          */
  79         set_user_nice(current, 0);
  80
  81         retval = -ENOMEM;
  82         new = prepare_kernel_cred(current);
  83         if (!new)
  84                 goto out;
  85
  86         spin_lock(&umh_sysctl_lock);
  87         new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset);
  88         new->cap_inheritable = cap_intersect(usermodehelper_inheritable,
  89                                              new->cap_inheritable);
  90         spin_unlock(&umh_sysctl_lock);
  91
  92         if (sub_info->init) {
  93                 retval = sub_info->init(sub_info, new);
  94                 if (retval) {
  95                         abort_creds(new);
  96                         goto out;
  97                 }
  98         }
  99
 100         commit_creds(new);
 101
 102         sub_info->pid = task_pid_nr(current);
 103         if (sub_info->file)
 104                 retval = do_execve_file(sub_info->file,
 105                                         sub_info->argv, sub_info->envp);
 106         else
 107                 retval = do_execve(getname_kernel(sub_info->path),
 108                                    (const char __user *const __user *)sub_info->argv,
 109                                    (const char __user *const __user *)sub_info->envp);
 110 out:
 111         sub_info->retval = retval;
 112         /*
 113          * call_usermodehelper_exec_sync() will call umh_complete
 114          * if UHM_WAIT_PROC.
 115          */
 116         if (!(sub_info->wait & UMH_WAIT_PROC))
 117                 umh_complete(sub_info);
 118         if (!retval)
 119                 return 0;
 120         do_exit(0);
 121 }
 122
 123 /* Handles UMH_WAIT_PROC.  */
 124 static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info)
 125 {
 126         pid_t pid;
 127
 128         /* If SIGCLD is ignored kernel_wait4 won't populate the status. */
 129         kernel_sigaction(SIGCHLD, SIG_DFL);
 130         pid = kernel_thread(call_usermodehelper_exec_async, sub_info, SIGCHLD);
 131         if (pid < 0) {
 132                 sub_info->retval = pid;
 133         } else {
 134                 int ret = -ECHILD;
 135                 /*
 136                  * Normally it is bogus to call wait4() from in-kernel because
 137                  * wait4() wants to write the exit code to a userspace address.
 138                  * But call_usermodehelper_exec_sync() always runs as kernel
 139                  * thread (workqueue) and put_user() to a kernel address works
 140                  * OK for kernel threads, due to their having an mm_segment_t
 141                  * which spans the entire address space.
 142                  *
 143                  * Thus the __user pointer cast is valid here.
 144                  */
 145                 kernel_wait4(pid, (int __user *)&ret, 0, NULL);
 146
 147                 /*
 148                  * If ret is 0, either call_usermodehelper_exec_async failed and
 149                  * the real error code is already in sub_info->retval or
 150                  * sub_info->retval is 0 anyway, so don't mess with it then.
 151                  */
 152                 if (ret)
 153                         sub_info->retval = ret;
 154         }
 155
 156         /* Restore default kernel sig handler */
 157         kernel_sigaction(SIGCHLD, SIG_IGN);
 158
 159         umh_complete(sub_info);
 160 }
 161
 162 /*
 163  * We need to create the usermodehelper kernel thread from a task that is affine
 164  * to an optimized set of CPUs (or nohz housekeeping ones) such that they
 165  * inherit a widest affinity irrespective of call_usermodehelper() callers with
 166  * possibly reduced affinity (eg: per-cpu workqueues). We don't want
 167  * usermodehelper targets to contend a busy CPU.
 168  *
 169  * Unbound workqueues provide such wide affinity and allow to block on
 170  * UMH_WAIT_PROC requests without blocking pending request (up to some limit).
 171  *
 172  * Besides, workqueues provide the privilege level that caller might not have
 173  * to perform the usermodehelper request.
 174  *
 175  */
 176 static void call_usermodehelper_exec_work(struct work_struct *work)
 177 {
 178         struct subprocess_info *sub_info =
 179                 container_of(work, struct subprocess_info, work);
 180
 181         if (sub_info->wait & UMH_WAIT_PROC) {
 182                 call_usermodehelper_exec_sync(sub_info);
 183         } else {
 184                 pid_t pid;
 185                 /*
 186                  * Use CLONE_PARENT to reparent it to kthreadd; we do not
 187                  * want to pollute current->children, and we need a parent
 188                  * that always ignores SIGCHLD to ensure auto-reaping.
 189                  */
 190                 pid = kernel_thread(call_usermodehelper_exec_async, sub_info,
 191                                     CLONE_PARENT | SIGCHLD);
 192                 if (pid < 0) {
 193                         sub_info->retval = pid;
 194                         umh_complete(sub_info);
 195                 }
 196         }
 197 }
 198
 199 /*
 200  * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY
 201  * (used for preventing user land processes from being created after the user
 202  * land has been frozen during a system-wide hibernation or suspend operation).
 203  * Should always be manipulated under umhelper_sem acquired for write.
 204  */
 205 static enum umh_disable_depth usermodehelper_disabled = UMH_DISABLED;
 206
 207 /* Number of helpers running */
 208 static atomic_t running_helpers = ATOMIC_INIT(0);
 209
 210 /*
 211  * Wait queue head used by usermodehelper_disable() to wait for all running
 212  * helpers to finish.
 213  */
 214 static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq);
 215
 216 /*
 217  * Used by usermodehelper_read_lock_wait() to wait for usermodehelper_disabled
 218  * to become 'false'.
 219  */
 220 static DECLARE_WAIT_QUEUE_HEAD(usermodehelper_disabled_waitq);
 221
 222 /*
 223  * Time to wait for running_helpers to become zero before the setting of
 224  * usermodehelper_disabled in usermodehelper_disable() fails
 225  */
 226 #define RUNNING_HELPERS_TIMEOUT (5 * HZ)
 227
 228 int usermodehelper_read_trylock(void)
 229 {
 230         DEFINE_WAIT(wait);
 231         int ret = 0;
 232
 233         down_read(&umhelper_sem);
 234         for (;;) {
 235                 prepare_to_wait(&usermodehelper_disabled_waitq, &wait,
 236                                 TASK_INTERRUPTIBLE);
 237                 if (!usermodehelper_disabled)
 238                         break;
 239
 240                 if (usermodehelper_disabled == UMH_DISABLED)
 241                         ret = -EAGAIN;
 242
 243                 up_read(&umhelper_sem);
 244
 245                 if (ret)
 246                         break;
 247
 248                 schedule();
 249                 try_to_freeze();
 250
 251                 down_read(&umhelper_sem);
 252         }
 253         finish_wait(&usermodehelper_disabled_waitq, &wait);
 254         return ret;
 255 }
 256 EXPORT_SYMBOL_GPL(usermodehelper_read_trylock);
 257
 258 long usermodehelper_read_lock_wait(long timeout)
 259 {
 260         DEFINE_WAIT(wait);
 261
 262         if (timeout < 0)
 263                 return -EINVAL;
 264
 265         down_read(&umhelper_sem);
 266         for (;;) {
 267                 prepare_to_wait(&usermodehelper_disabled_waitq, &wait,
 268                                 TASK_UNINTERRUPTIBLE);
 269                 if (!usermodehelper_disabled)
 270                         break;
 271
 272                 up_read(&umhelper_sem);
 273
 274                 timeout = schedule_timeout(timeout);
 275                 if (!timeout)
 276                         break;
 277
 278                 down_read(&umhelper_sem);
 279         }
 280         finish_wait(&usermodehelper_disabled_waitq, &wait);
 281         return timeout;
 282 }
 283 EXPORT_SYMBOL_GPL(usermodehelper_read_lock_wait);
 284
 285 void usermodehelper_read_unlock(void)
 286 {
 287         up_read(&umhelper_sem);
 288 }
 289 EXPORT_SYMBOL_GPL(usermodehelper_read_unlock);
 290
 291 /**
 292  * __usermodehelper_set_disable_depth - Modify usermodehelper_disabled.
 293  * @depth: New value to assign to usermodehelper_disabled.
 294  *
 295  * Change the value of usermodehelper_disabled (under umhelper_sem locked for
 296  * writing) and wakeup tasks waiting for it to change.
 297  */
 298 void __usermodehelper_set_disable_depth(enum umh_disable_depth depth)
 299 {
 300         down_write(&umhelper_sem);
 301         usermodehelper_disabled = depth;
 302         wake_up(&usermodehelper_disabled_waitq);
 303         up_write(&umhelper_sem);
 304 }
 305
 306 /**
 307  * __usermodehelper_disable - Prevent new helpers from being started.
 308  * @depth: New value to assign to usermodehelper_disabled.
 309  *
 310  * Set usermodehelper_disabled to @depth and wait for running helpers to exit.
 311  */
 312 int __usermodehelper_disable(enum umh_disable_depth depth)
 313 {
 314         long retval;
 315
 316         if (!depth)
 317                 return -EINVAL;
 318
 319         down_write(&umhelper_sem);
 320         usermodehelper_disabled = depth;
 321         up_write(&umhelper_sem);
 322
 323         /*
 324          * From now on call_usermodehelper_exec() won't start any new
 325          * helpers, so it is sufficient if running_helpers turns out to
 326          * be zero at one point (it may be increased later, but that
 327          * doesn't matter).
 328          */
 329         retval = wait_event_timeout(running_helpers_waitq,
 330                                         atomic_read(&running_helpers) == 0,
 331                                         RUNNING_HELPERS_TIMEOUT);
 332         if (retval)
 333                 return 0;
 334
 335         __usermodehelper_set_disable_depth(UMH_ENABLED);
 336         return -EAGAIN;
 337 }
 338
 339 static void helper_lock(void)
 340 {
 341         atomic_inc(&running_helpers);
 342         smp_mb__after_atomic();
 343 }
 344
 345 static void helper_unlock(void)
 346 {
 347         if (atomic_dec_and_test(&running_helpers))
 348                 wake_up(&running_helpers_waitq);
 349 }
 350
 351 /**
 352  * call_usermodehelper_setup - prepare to call a usermode helper
 353  * @path: path to usermode executable
 354  * @argv: arg vector for process
 355  * @envp: environment for process
 356  * @gfp_mask: gfp mask for memory allocation
 357  * @cleanup: a cleanup function
 358  * @init: an init function
 359  * @data: arbitrary context sensitive data
 360  *
 361  * Returns either %NULL on allocation failure, or a subprocess_info
 362  * structure.  This should be passed to call_usermodehelper_exec to
 363  * exec the process and free the structure.
 364  *
 365  * The init function is used to customize the helper process prior to
 366  * exec.  A non-zero return code causes the process to error out, exit,
 367  * and return the failure to the calling process
 368  *
 369  * The cleanup function is just before ethe subprocess_info is about to
 370  * be freed.  This can be used for freeing the argv and envp.  The
 371  * Function must be runnable in either a process context or the
 372  * context in which call_usermodehelper_exec is called.
 373  */
 374 struct subprocess_info *call_usermodehelper_setup(const char *path, char **argv,
 375                 char **envp, gfp_t gfp_mask,
 376                 int (*init)(struct subprocess_info *info, struct cred *new),
 377                 void (*cleanup)(struct subprocess_info *info),
 378                 void *data)
 379 {
 380         struct subprocess_info *sub_info;
 381         sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask);
 382         if (!sub_info)
 383                 goto out;
 384
 385         INIT_WORK(&sub_info->work, call_usermodehelper_exec_work);
 386
 387 #ifdef CONFIG_STATIC_USERMODEHELPER
 388         sub_info->path = CONFIG_STATIC_USERMODEHELPER_PATH;
 389 #else
 390         sub_info->path = path;
 391 #endif
 392         sub_info->argv = argv;
 393         sub_info->envp = envp;
 394
 395         sub_info->cleanup = cleanup;
 396         sub_info->init = init;
 397         sub_info->data = data;
 398   out:
 399         return sub_info;
 400 }
 401 EXPORT_SYMBOL(call_usermodehelper_setup);
 402
 403 struct subprocess_info *call_usermodehelper_setup_file(struct file *file,
 404                 int (*init)(struct subprocess_info *info, struct cred *new),
 405                 void (*cleanup)(struct subprocess_info *info), void *data)
 406 {
 407         struct subprocess_info *sub_info;
 408         struct umh_info *info = data;
 409         const char *cmdline = (info->cmdline) ? info->cmdline : "usermodehelper";
 410
 411         sub_info = kzalloc(sizeof(struct subprocess_info), GFP_KERNEL);
 412         if (!sub_info)
 413                 return NULL;
 414
 415         sub_info->argv = argv_split(GFP_KERNEL, cmdline, NULL);
 416         if (!sub_info->argv) {
 417                 kfree(sub_info);
 418                 return NULL;
 419         }
 420
 421         INIT_WORK(&sub_info->work, call_usermodehelper_exec_work);
 422         sub_info->path = "none";
 423         sub_info->file = file;
 424         sub_info->init = init;
 425         sub_info->cleanup = cleanup;
 426         sub_info->data = data;
 427         return sub_info;
 428 }
 429
 430 static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
 431 {
 432         struct umh_info *umh_info = info->data;
 433         struct file *from_umh[2];
 434         struct file *to_umh[2];
 435         int err;
 436
 437         /* create pipe to send data to umh */
 438         err = create_pipe_files(to_umh, 0);
 439         if (err)
 440                 return err;
 441         err = replace_fd(0, to_umh[0], 0);
 442         fput(to_umh[0]);
 443         if (err < 0) {
 444                 fput(to_umh[1]);
 445                 return err;
 446         }
 447
 448         /* create pipe to receive data from umh */
 449         err = create_pipe_files(from_umh, 0);
 450         if (err) {
 451                 fput(to_umh[1]);
 452                 replace_fd(0, NULL, 0);
 453                 return err;
 454         }
 455         err = replace_fd(1, from_umh[1], 0);
 456         fput(from_umh[1]);
 457         if (err < 0) {
 458                 fput(to_umh[1]);
 459                 replace_fd(0, NULL, 0);
 460                 fput(from_umh[0]);
 461                 return err;
 462         }
 463
 464         umh_info->pipe_to_umh = to_umh[1];
 465         umh_info->pipe_from_umh = from_umh[0];
 466         return 0;
 467 }
 468
 469 static void umh_clean_and_save_pid(struct subprocess_info *info)
 470 {
 471         struct umh_info *umh_info = info->data;
 472
 473         argv_free(info->argv);
 474         umh_info->pid = info->pid;
 475 }
 476
 477 /**
 478  * fork_usermode_blob - fork a blob of bytes as a usermode process
 479  * @data: a blob of bytes that can be do_execv-ed as a file
 480  * @len: length of the blob
 481  * @info: information about usermode process (shouldn't be NULL)
 482  *
 483  * If info->cmdline is set it will be used as command line for the
 484  * user process, else "usermodehelper" is used.
 485  *
 486  * Returns either negative error or zero which indicates success
 487  * in executing a blob of bytes as a usermode process. In such
 488  * case 'struct umh_info *info' is populated with two pipes
 489  * and a pid of the process. The caller is responsible for health
 490  * check of the user process, killing it via pid, and closing the
 491  * pipes when user process is no longer needed.
 492  */
 493 int fork_usermode_blob(void *data, size_t len, struct umh_info *info)
 494 {
 495         struct subprocess_info *sub_info;
 496         struct file *file;
 497         ssize_t written;
 498         loff_t pos = 0;
 499         int err;
 500
 501         file = shmem_kernel_file_setup("", len, 0);
 502         if (IS_ERR(file))
 503                 return PTR_ERR(file);
 504
 505         written = kernel_write(file, data, len, &pos);
 506         if (written != len) {
 507                 err = written;
 508                 if (err >= 0)
 509                         err = -ENOMEM;
 510                 goto out;
 511         }
 512
 513         err = -ENOMEM;
 514         sub_info = call_usermodehelper_setup_file(file, umh_pipe_setup,
 515                                                   umh_clean_and_save_pid, info);
 516         if (!sub_info)
 517                 goto out;
 518
 519         err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
 520 out:
 521         fput(file);
 522         return err;
 523 }
 524 EXPORT_SYMBOL_GPL(fork_usermode_blob);
 525
 526 /**
 527  * call_usermodehelper_exec - start a usermode application
 528  * @sub_info: information about the subprocessa
 529  * @wait: wait for the application to finish and return status.
 530  *        when UMH_NO_WAIT don't wait at all, but you get no useful error back
 531  *        when the program couldn't be exec'ed. This makes it safe to call
 532  *        from interrupt context.
 533  *
 534  * Runs a user-space application.  The application is started
 535  * asynchronously if wait is not set, and runs as a child of system workqueues.
 536  * (ie. it runs with full root capabilities and optimized affinity).
 537  */
 538 int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
 539 {
 540         DECLARE_COMPLETION_ONSTACK(done);
 541         int retval = 0;
 542
 543         if (!sub_info->path) {
 544                 call_usermodehelper_freeinfo(sub_info);
 545                 return -EINVAL;
 546         }
 547         helper_lock();
 548         if (usermodehelper_disabled) {
 549                 retval = -EBUSY;
 550                 goto out;
 551         }
 552
 553         /*
 554          * If there is no binary for us to call, then just return and get out of
 555          * here.  This allows us to set STATIC_USERMODEHELPER_PATH to "" and
 556          * disable all call_usermodehelper() calls.
 557          */
 558         if (strlen(sub_info->path) == 0)
 559                 goto out;
 560
 561         /*
 562          * Set the completion pointer only if there is a waiter.
 563          * This makes it possible to use umh_complete to free
 564          * the data structure in case of UMH_NO_WAIT.
 565          */
 566         sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done;
 567         sub_info->wait = wait;
 568
 569         queue_work(system_unbound_wq, &sub_info->work);
 570         if (wait == UMH_NO_WAIT)        /* task has freed sub_info */
 571                 goto unlock;
 572
 573         if (wait & UMH_KILLABLE) {
 574                 retval = wait_for_completion_killable(&done);
 575                 if (!retval)
 576                         goto wait_done;
 577
 578                 /* umh_complete() will see NULL and free sub_info */
 579                 if (xchg(&sub_info->complete, NULL))
 580                         goto unlock;
 581                 /* fallthrough, umh_complete() was already called */
 582         }
 583
 584         wait_for_completion(&done);
 585 wait_done:
 586         retval = sub_info->retval;
 587 out:
 588         call_usermodehelper_freeinfo(sub_info);
 589 unlock:
 590         helper_unlock();
 591         return retval;
 592 }
 593 EXPORT_SYMBOL(call_usermodehelper_exec);
 594
 595 /**
 596  * call_usermodehelper() - prepare and start a usermode application
 597  * @path: path to usermode executable
 598  * @argv: arg vector for process
 599  * @envp: environment for process
 600  * @wait: wait for the application to finish and return status.
 601  *        when UMH_NO_WAIT don't wait at all, but you get no useful error back
 602  *        when the program couldn't be exec'ed. This makes it safe to call
 603  *        from interrupt context.
 604  *
 605  * This function is the equivalent to use call_usermodehelper_setup() and
 606  * call_usermodehelper_exec().
 607  */
 608 int call_usermodehelper(const char *path, char **argv, char **envp, int wait)
 609 {
 610         struct subprocess_info *info;
 611         gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
 612
 613         info = call_usermodehelper_setup(path, argv, envp, gfp_mask,
 614                                          NULL, NULL, NULL);
 615         if (info == NULL)
 616                 return -ENOMEM;
 617
 618         return call_usermodehelper_exec(info, wait);
 619 }
 620 EXPORT_SYMBOL(call_usermodehelper);
 621
 622 static int proc_cap_handler(struct ctl_table *table, int write,
 623                          void __user *buffer, size_t *lenp, loff_t *ppos)
 624 {
 625         struct ctl_table t;
 626         unsigned long cap_array[_KERNEL_CAPABILITY_U32S];
 627         kernel_cap_t new_cap;
 628         int err, i;
 629
 630         if (write && (!capable(CAP_SETPCAP) ||
 631                       !capable(CAP_SYS_MODULE)))
 632                 return -EPERM;
 633
 634         /*
 635          * convert from the global kernel_cap_t to the ulong array to print to
 636          * userspace if this is a read.
 637          */
 638         spin_lock(&umh_sysctl_lock);
 639         for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++)  {
 640                 if (table->data == CAP_BSET)
 641                         cap_array[i] = usermodehelper_bset.cap[i];
 642                 else if (table->data == CAP_PI)
 643                         cap_array[i] = usermodehelper_inheritable.cap[i];
 644                 else
 645                         BUG();
 646         }
 647         spin_unlock(&umh_sysctl_lock);
 648
 649         t = *table;
 650         t.data = &cap_array;
 651
 652         /*
 653          * actually read or write and array of ulongs from userspace.  Remember
 654          * these are least significant 32 bits first
 655          */
 656         err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
 657         if (err < 0)
 658                 return err;
 659
 660         /*
 661          * convert from the sysctl array of ulongs to the kernel_cap_t
 662          * internal representation
 663          */
 664         for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++)
 665                 new_cap.cap[i] = cap_array[i];
 666
 667         /*
 668          * Drop everything not in the new_cap (but don't add things)
 669          */
 670         if (write) {
 671                 spin_lock(&umh_sysctl_lock);
 672                 if (table->data == CAP_BSET)
 673                         usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap);
 674                 if (table->data == CAP_PI)
 675                         usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap);
 676                 spin_unlock(&umh_sysctl_lock);
 677         }
 678
 679         return 0;
 680 }
 681
 682 struct ctl_table usermodehelper_table[] = {
 683         {
 684                 .procname       = "bset",
 685                 .data           = CAP_BSET,
 686                 .maxlen         = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long),
 687                 .mode           = 0600,
 688                 .proc_handler   = proc_cap_handler,
 689         },
 690         {
 691                 .procname       = "inheritable",
 692                 .data           = CAP_PI,
 693                 .maxlen         = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long),
 694                 .mode           = 0600,
 695                 .proc_handler   = proc_cap_handler,
 696         },
 697         { }
 698 };