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