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
 409         sub_info = kzalloc(sizeof(struct subprocess_info), GFP_KERNEL);
 410         if (!sub_info)
 411                 return NULL;
 412
 413         INIT_WORK(&sub_info->work, call_usermodehelper_exec_work);
 414         sub_info->path = "none";
 415         sub_info->file = file;
 416         sub_info->init = init;
 417         sub_info->cleanup = cleanup;
 418         sub_info->data = data;
 419         return sub_info;
 420 }
 421
 422 static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
 423 {
 424         struct umh_info *umh_info = info->data;
 425         struct file *from_umh[2];
 426         struct file *to_umh[2];
 427         int err;
 428
 429         /* create pipe to send data to umh */
 430         err = create_pipe_files(to_umh, 0);
 431         if (err)
 432                 return err;
 433         err = replace_fd(0, to_umh[0], 0);
 434         fput(to_umh[0]);
 435         if (err < 0) {
 436                 fput(to_umh[1]);
 437                 return err;
 438         }
 439
 440         /* create pipe to receive data from umh */
 441         err = create_pipe_files(from_umh, 0);
 442         if (err) {
 443                 fput(to_umh[1]);
 444                 replace_fd(0, NULL, 0);
 445                 return err;
 446         }
 447         err = replace_fd(1, from_umh[1], 0);
 448         fput(from_umh[1]);
 449         if (err < 0) {
 450                 fput(to_umh[1]);
 451                 replace_fd(0, NULL, 0);
 452                 fput(from_umh[0]);
 453                 return err;
 454         }
 455
 456         umh_info->pipe_to_umh = to_umh[1];
 457         umh_info->pipe_from_umh = from_umh[0];
 458         return 0;
 459 }
 460
 461 static void umh_save_pid(struct subprocess_info *info)
 462 {
 463         struct umh_info *umh_info = info->data;
 464
 465         umh_info->pid = info->pid;
 466 }
 467
 468 /**
 469  * fork_usermode_blob - fork a blob of bytes as a usermode process
 470  * @data: a blob of bytes that can be do_execv-ed as a file
 471  * @len: length of the blob
 472  * @info: information about usermode process (shouldn't be NULL)
 473  *
 474  * Returns either negative error or zero which indicates success
 475  * in executing a blob of bytes as a usermode process. In such
 476  * case 'struct umh_info *info' is populated with two pipes
 477  * and a pid of the process. The caller is responsible for health
 478  * check of the user process, killing it via pid, and closing the
 479  * pipes when user process is no longer needed.
 480  */
 481 int fork_usermode_blob(void *data, size_t len, struct umh_info *info)
 482 {
 483         struct subprocess_info *sub_info;
 484         struct file *file;
 485         ssize_t written;
 486         loff_t pos = 0;
 487         int err;
 488
 489         file = shmem_kernel_file_setup("", len, 0);
 490         if (IS_ERR(file))
 491                 return PTR_ERR(file);
 492
 493         written = kernel_write(file, data, len, &pos);
 494         if (written != len) {
 495                 err = written;
 496                 if (err >= 0)
 497                         err = -ENOMEM;
 498                 goto out;
 499         }
 500
 501         err = -ENOMEM;
 502         sub_info = call_usermodehelper_setup_file(file, umh_pipe_setup,
 503                                                   umh_save_pid, info);
 504         if (!sub_info)
 505                 goto out;
 506
 507         err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
 508 out:
 509         fput(file);
 510         return err;
 511 }
 512 EXPORT_SYMBOL_GPL(fork_usermode_blob);
 513
 514 /**
 515  * call_usermodehelper_exec - start a usermode application
 516  * @sub_info: information about the subprocessa
 517  * @wait: wait for the application to finish and return status.
 518  *        when UMH_NO_WAIT don't wait at all, but you get no useful error back
 519  *        when the program couldn't be exec'ed. This makes it safe to call
 520  *        from interrupt context.
 521  *
 522  * Runs a user-space application.  The application is started
 523  * asynchronously if wait is not set, and runs as a child of system workqueues.
 524  * (ie. it runs with full root capabilities and optimized affinity).
 525  */
 526 int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
 527 {
 528         DECLARE_COMPLETION_ONSTACK(done);
 529         int retval = 0;
 530
 531         if (!sub_info->path) {
 532                 call_usermodehelper_freeinfo(sub_info);
 533                 return -EINVAL;
 534         }
 535         helper_lock();
 536         if (usermodehelper_disabled) {
 537                 retval = -EBUSY;
 538                 goto out;
 539         }
 540
 541         /*
 542          * If there is no binary for us to call, then just return and get out of
 543          * here.  This allows us to set STATIC_USERMODEHELPER_PATH to "" and
 544          * disable all call_usermodehelper() calls.
 545          */
 546         if (strlen(sub_info->path) == 0)
 547                 goto out;
 548
 549         /*
 550          * Set the completion pointer only if there is a waiter.
 551          * This makes it possible to use umh_complete to free
 552          * the data structure in case of UMH_NO_WAIT.
 553          */
 554         sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done;
 555         sub_info->wait = wait;
 556
 557         queue_work(system_unbound_wq, &sub_info->work);
 558         if (wait == UMH_NO_WAIT)        /* task has freed sub_info */
 559                 goto unlock;
 560
 561         if (wait & UMH_KILLABLE) {
 562                 retval = wait_for_completion_killable(&done);
 563                 if (!retval)
 564                         goto wait_done;
 565
 566                 /* umh_complete() will see NULL and free sub_info */
 567                 if (xchg(&sub_info->complete, NULL))
 568                         goto unlock;
 569                 /* fallthrough, umh_complete() was already called */
 570         }
 571
 572         wait_for_completion(&done);
 573 wait_done:
 574         retval = sub_info->retval;
 575 out:
 576         call_usermodehelper_freeinfo(sub_info);
 577 unlock:
 578         helper_unlock();
 579         return retval;
 580 }
 581 EXPORT_SYMBOL(call_usermodehelper_exec);
 582
 583 /**
 584  * call_usermodehelper() - prepare and start a usermode application
 585  * @path: path to usermode executable
 586  * @argv: arg vector for process
 587  * @envp: environment for process
 588  * @wait: wait for the application to finish and return status.
 589  *        when UMH_NO_WAIT don't wait at all, but you get no useful error back
 590  *        when the program couldn't be exec'ed. This makes it safe to call
 591  *        from interrupt context.
 592  *
 593  * This function is the equivalent to use call_usermodehelper_setup() and
 594  * call_usermodehelper_exec().
 595  */
 596 int call_usermodehelper(const char *path, char **argv, char **envp, int wait)
 597 {
 598         struct subprocess_info *info;
 599         gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
 600
 601         info = call_usermodehelper_setup(path, argv, envp, gfp_mask,
 602                                          NULL, NULL, NULL);
 603         if (info == NULL)
 604                 return -ENOMEM;
 605
 606         return call_usermodehelper_exec(info, wait);
 607 }
 608 EXPORT_SYMBOL(call_usermodehelper);
 609
 610 static int proc_cap_handler(struct ctl_table *table, int write,
 611                          void __user *buffer, size_t *lenp, loff_t *ppos)
 612 {
 613         struct ctl_table t;
 614         unsigned long cap_array[_KERNEL_CAPABILITY_U32S];
 615         kernel_cap_t new_cap;
 616         int err, i;
 617
 618         if (write && (!capable(CAP_SETPCAP) ||
 619                       !capable(CAP_SYS_MODULE)))
 620                 return -EPERM;
 621
 622         /*
 623          * convert from the global kernel_cap_t to the ulong array to print to
 624          * userspace if this is a read.
 625          */
 626         spin_lock(&umh_sysctl_lock);
 627         for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++)  {
 628                 if (table->data == CAP_BSET)
 629                         cap_array[i] = usermodehelper_bset.cap[i];
 630                 else if (table->data == CAP_PI)
 631                         cap_array[i] = usermodehelper_inheritable.cap[i];
 632                 else
 633                         BUG();
 634         }
 635         spin_unlock(&umh_sysctl_lock);
 636
 637         t = *table;
 638         t.data = &cap_array;
 639
 640         /*
 641          * actually read or write and array of ulongs from userspace.  Remember
 642          * these are least significant 32 bits first
 643          */
 644         err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
 645         if (err < 0)
 646                 return err;
 647
 648         /*
 649          * convert from the sysctl array of ulongs to the kernel_cap_t
 650          * internal representation
 651          */
 652         for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++)
 653                 new_cap.cap[i] = cap_array[i];
 654
 655         /*
 656          * Drop everything not in the new_cap (but don't add things)
 657          */
 658         if (write) {
 659                 spin_lock(&umh_sysctl_lock);
 660                 if (table->data == CAP_BSET)
 661                         usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap);
 662                 if (table->data == CAP_PI)
 663                         usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap);
 664                 spin_unlock(&umh_sysctl_lock);
 665         }
 666
 667         return 0;
 668 }
 669
 670 struct ctl_table usermodehelper_table[] = {
 671         {
 672                 .procname       = "bset",
 673                 .data           = CAP_BSET,
 674                 .maxlen         = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long),
 675                 .mode           = 0600,
 676                 .proc_handler   = proc_cap_handler,
 677         },
 678         {
 679                 .procname       = "inheritable",
 680                 .data           = CAP_PI,
 681                 .maxlen         = _KERNEL_CAPABILITY_U32S * sizeof(unsigned long),
 682                 .mode           = 0600,
 683                 .proc_handler   = proc_cap_handler,
 684         },
 685         { }
 686 };