projects/linux·blob uaccess-cleanups · refs

1453 lines · 32.6 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Event char devices, giving access to raw input device events.
4 *
5 * Copyright (c) 1999-2002 Vojtech Pavlik
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#define EVDEV_MINOR_BASE 64
11#define EVDEV_MINORS 32
12#define EVDEV_MIN_BUFFER_SIZE 64U
13#define EVDEV_BUF_PACKETS 8
14
15#include <linux/poll.h>
16#include <linux/sched.h>
17#include <linux/slab.h>
18#include <linux/vmalloc.h>
19#include <linux/mm.h>
20#include <linux/module.h>
21#include <linux/init.h>
22#include <linux/input/mt.h>
23#include <linux/major.h>
24#include <linux/nospec.h>
25#include <linux/device.h>
26#include <linux/cdev.h>
27#include "input-compat.h"
28
29struct evdev {
30 int open;
31 struct input_handle handle;
32 struct evdev_client __rcu *grab;
33 struct list_head client_list;
34 spinlock_t client_lock; /* protects client_list */
35 struct mutex mutex;
36 struct device dev;
37 struct cdev cdev;
38 bool exist;
39};
40
41struct evdev_client {
42 unsigned int head;
43 unsigned int tail;
44 unsigned int packet_head; /* [future] position of the first element of next packet */
45 spinlock_t buffer_lock; /* protects access to buffer, head and tail */
46 wait_queue_head_t wait;
47 struct fasync_struct *fasync;
48 struct evdev *evdev;
49 struct list_head node;
50 enum input_clock_type clk_type;
51 bool revoked;
52 unsigned long *evmasks[EV_CNT];
53 unsigned int bufsize;
54 struct input_event buffer[] __counted_by(bufsize);
55};
56
57static size_t evdev_get_mask_cnt(unsigned int type)
58{
59 static const size_t counts[EV_CNT] = {
60 /* EV_SYN==0 is EV_CNT, _not_ SYN_CNT, see EVIOCGBIT */
61 [EV_SYN] = EV_CNT,
62 [EV_KEY] = KEY_CNT,
63 [EV_REL] = REL_CNT,
64 [EV_ABS] = ABS_CNT,
65 [EV_MSC] = MSC_CNT,
66 [EV_SW] = SW_CNT,
67 [EV_LED] = LED_CNT,
68 [EV_SND] = SND_CNT,
69 [EV_FF] = FF_CNT,
70 };
71 unsigned long mask = array_index_mask_nospec(type, EV_CNT);
72
73 /* Returns 0 for out-of-bounds types, including speculatively */
74 return counts[type & mask] & mask;
75}
76
77/* requires the buffer lock to be held */
78static bool __evdev_is_filtered(struct evdev_client *client,
79 unsigned int type,
80 unsigned int code)
81{
82 unsigned long *mask;
83 size_t cnt;
84
85 /* EV_SYN and unknown codes are never filtered */
86 if (type == EV_SYN || type >= EV_CNT)
87 return false;
88
89 /* first test whether the type is filtered */
90 mask = client->evmasks[0];
91 if (mask && !test_bit(type, mask))
92 return true;
93
94 /* unknown values are never filtered */
95 cnt = evdev_get_mask_cnt(type);
96 if (!cnt || code >= cnt)
97 return false;
98
99 mask = client->evmasks[type];
100 return mask && !test_bit(code, mask);
101}
102
103/* flush queued events of type @type, caller must hold client->buffer_lock */
104static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
105{
106 unsigned int i, head, num;
107 unsigned int mask = client->bufsize - 1;
108 bool is_report;
109 struct input_event *ev;
110
111 BUG_ON(type == EV_SYN);
112
113 head = client->tail;
114 client->packet_head = client->tail;
115
116 /* init to 1 so a leading SYN_REPORT will not be dropped */
117 num = 1;
118
119 for (i = client->tail; i != client->head; i = (i + 1) & mask) {
120 ev = &client->buffer[i];
121 is_report = ev->type == EV_SYN && ev->code == SYN_REPORT;
122
123 if (ev->type == type) {
124 /* drop matched entry */
125 continue;
126 } else if (is_report && !num) {
127 /* drop empty SYN_REPORT groups */
128 continue;
129 } else if (head != i) {
130 /* move entry to fill the gap */
131 client->buffer[head] = *ev;
132 }
133
134 num++;
135 head = (head + 1) & mask;
136
137 if (is_report) {
138 num = 0;
139 client->packet_head = head;
140 }
141 }
142
143 client->head = head;
144}
145
146static void __evdev_queue_syn_dropped(struct evdev_client *client)
147{
148 ktime_t *ev_time = input_get_timestamp(client->evdev->handle.dev);
149 struct timespec64 ts = ktime_to_timespec64(ev_time[client->clk_type]);
150 struct input_event ev;
151
152 memset(&ev, 0, sizeof(ev));
153 ev.input_event_sec = ts.tv_sec;
154 ev.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
155 ev.type = EV_SYN;
156 ev.code = SYN_DROPPED;
157
158 client->buffer[client->head++] = ev;
159 client->head &= client->bufsize - 1;
160
161 if (unlikely(client->head == client->tail)) {
162 /* drop queue but keep our SYN_DROPPED event */
163 client->tail = (client->head - 1) & (client->bufsize - 1);
164 client->packet_head = client->tail;
165 }
166}
167
168static void evdev_queue_syn_dropped(struct evdev_client *client)
169{
170 unsigned long flags;
171
172 spin_lock_irqsave(&client->buffer_lock, flags);
173 __evdev_queue_syn_dropped(client);
174 spin_unlock_irqrestore(&client->buffer_lock, flags);
175}
176
177static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid)
178{
179 unsigned long flags;
180 enum input_clock_type clk_type;
181
182 switch (clkid) {
183
184 case CLOCK_REALTIME:
185 clk_type = INPUT_CLK_REAL;
186 break;
187 case CLOCK_MONOTONIC:
188 clk_type = INPUT_CLK_MONO;
189 break;
190 case CLOCK_BOOTTIME:
191 clk_type = INPUT_CLK_BOOT;
192 break;
193 default:
194 return -EINVAL;
195 }
196
197 if (client->clk_type != clk_type) {
198 client->clk_type = clk_type;
199
200 /*
201 * Flush pending events and queue SYN_DROPPED event,
202 * but only if the queue is not empty.
203 */
204 spin_lock_irqsave(&client->buffer_lock, flags);
205
206 if (client->head != client->tail) {
207 client->packet_head = client->head = client->tail;
208 __evdev_queue_syn_dropped(client);
209 }
210
211 spin_unlock_irqrestore(&client->buffer_lock, flags);
212 }
213
214 return 0;
215}
216
217static void __pass_event(struct evdev_client *client,
218 const struct input_event *event)
219{
220 client->buffer[client->head++] = *event;
221 client->head &= client->bufsize - 1;
222
223 if (unlikely(client->head == client->tail)) {
224 struct input_event ev;
225
226 memset(&ev, 0, sizeof(ev));
227 ev.input_event_sec = event->input_event_sec;
228 ev.input_event_usec = event->input_event_usec;
229 ev.type = EV_SYN;
230 ev.code = SYN_DROPPED;
231
232 /*
233 * This effectively "drops" all unconsumed events, leaving
234 * EV_SYN/SYN_DROPPED plus the newest event in the queue.
235 */
236 client->tail = (client->head - 2) & (client->bufsize - 1);
237 client->buffer[client->tail] = ev;
238 client->packet_head = client->tail;
239 }
240
241 if (event->type == EV_SYN && event->code == SYN_REPORT) {
242 client->packet_head = client->head;
243 kill_fasync(&client->fasync, SIGIO, POLL_IN);
244 }
245}
246
247static void evdev_pass_values(struct evdev_client *client,
248 const struct input_value *vals, unsigned int count,
249 ktime_t *ev_time)
250{
251 const struct input_value *v;
252 struct input_event event;
253 struct timespec64 ts;
254 bool wakeup = false;
255
256 if (client->revoked)
257 return;
258
259 memset(&event, 0, sizeof(event));
260
261 ts = ktime_to_timespec64(ev_time[client->clk_type]);
262 event.input_event_sec = ts.tv_sec;
263 event.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
264
265 /* Interrupts are disabled, just acquire the lock. */
266 spin_lock(&client->buffer_lock);
267
268 for (v = vals; v != vals + count; v++) {
269 if (__evdev_is_filtered(client, v->type, v->code))
270 continue;
271
272 if (v->type == EV_SYN && v->code == SYN_REPORT) {
273 /* drop empty SYN_REPORT */
274 if (client->packet_head == client->head)
275 continue;
276
277 wakeup = true;
278 }
279
280 event.type = v->type;
281 event.code = v->code;
282 event.value = v->value;
283 __pass_event(client, &event);
284 }
285
286 spin_unlock(&client->buffer_lock);
287
288 if (wakeup)
289 wake_up_interruptible_poll(&client->wait,
290 EPOLLIN | EPOLLOUT | EPOLLRDNORM | EPOLLWRNORM);
291}
292
293/*
294 * Pass incoming events to all connected clients.
295 */
296static unsigned int evdev_events(struct input_handle *handle,
297 struct input_value *vals, unsigned int count)
298{
299 struct evdev *evdev = handle->private;
300 struct evdev_client *client;
301 ktime_t *ev_time = input_get_timestamp(handle->dev);
302
303 rcu_read_lock();
304
305 client = rcu_dereference(evdev->grab);
306
307 if (client)
308 evdev_pass_values(client, vals, count, ev_time);
309 else
310 list_for_each_entry_rcu(client, &evdev->client_list, node)
311 evdev_pass_values(client, vals, count, ev_time);
312
313 rcu_read_unlock();
314
315 return count;
316}
317
318static int evdev_fasync(int fd, struct file *file, int on)
319{
320 struct evdev_client *client = file->private_data;
321
322 return fasync_helper(fd, file, on, &client->fasync);
323}
324
325static void evdev_free(struct device *dev)
326{
327 struct evdev *evdev = container_of(dev, struct evdev, dev);
328
329 input_put_device(evdev->handle.dev);
330 kfree(evdev);
331}
332
333/*
334 * Grabs an event device (along with underlying input device).
335 * This function is called with evdev->mutex taken.
336 */
337static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
338{
339 int error;
340
341 if (evdev->grab)
342 return -EBUSY;
343
344 error = input_grab_device(&evdev->handle);
345 if (error)
346 return error;
347
348 rcu_assign_pointer(evdev->grab, client);
349
350 return 0;
351}
352
353static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
354{
355 struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
356 lockdep_is_held(&evdev->mutex));
357
358 if (grab != client)
359 return -EINVAL;
360
361 rcu_assign_pointer(evdev->grab, NULL);
362 synchronize_rcu();
363 input_release_device(&evdev->handle);
364
365 return 0;
366}
367
368static void evdev_attach_client(struct evdev *evdev,
369 struct evdev_client *client)
370{
371 spin_lock(&evdev->client_lock);
372 list_add_tail_rcu(&client->node, &evdev->client_list);
373 spin_unlock(&evdev->client_lock);
374}
375
376static void evdev_detach_client(struct evdev *evdev,
377 struct evdev_client *client)
378{
379 spin_lock(&evdev->client_lock);
380 list_del_rcu(&client->node);
381 spin_unlock(&evdev->client_lock);
382 synchronize_rcu();
383}
384
385static int evdev_open_device(struct evdev *evdev)
386{
387 int retval;
388
389 retval = mutex_lock_interruptible(&evdev->mutex);
390 if (retval)
391 return retval;
392
393 if (!evdev->exist)
394 retval = -ENODEV;
395 else if (!evdev->open++) {
396 retval = input_open_device(&evdev->handle);
397 if (retval)
398 evdev->open--;
399 }
400
401 mutex_unlock(&evdev->mutex);
402 return retval;
403}
404
405static void evdev_close_device(struct evdev *evdev)
406{
407 mutex_lock(&evdev->mutex);
408
409 if (evdev->exist && !--evdev->open)
410 input_close_device(&evdev->handle);
411
412 mutex_unlock(&evdev->mutex);
413}
414
415/*
416 * Wake up users waiting for IO so they can disconnect from
417 * dead device.
418 */
419static void evdev_hangup(struct evdev *evdev)
420{
421 struct evdev_client *client;
422
423 spin_lock(&evdev->client_lock);
424 list_for_each_entry(client, &evdev->client_list, node) {
425 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
426 wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR);
427 }
428 spin_unlock(&evdev->client_lock);
429}
430
431static int evdev_release(struct inode *inode, struct file *file)
432{
433 struct evdev_client *client = file->private_data;
434 struct evdev *evdev = client->evdev;
435 unsigned int i;
436
437 mutex_lock(&evdev->mutex);
438
439 if (evdev->exist && !client->revoked)
440 input_flush_device(&evdev->handle, file);
441
442 evdev_ungrab(evdev, client);
443 mutex_unlock(&evdev->mutex);
444
445 evdev_detach_client(evdev, client);
446
447 for (i = 0; i < EV_CNT; ++i)
448 bitmap_free(client->evmasks[i]);
449
450 kvfree(client);
451
452 evdev_close_device(evdev);
453
454 return 0;
455}
456
457static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
458{
459 unsigned int n_events =
460 max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
461 EVDEV_MIN_BUFFER_SIZE);
462
463 return roundup_pow_of_two(n_events);
464}
465
466static int evdev_open(struct inode *inode, struct file *file)
467{
468 struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
469 unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
470 struct evdev_client *client;
471 int error;
472
473 client = kvzalloc_flex(*client, buffer, bufsize);
474 if (!client)
475 return -ENOMEM;
476
477 init_waitqueue_head(&client->wait);
478 client->bufsize = bufsize;
479 spin_lock_init(&client->buffer_lock);
480 client->evdev = evdev;
481 evdev_attach_client(evdev, client);
482
483 error = evdev_open_device(evdev);
484 if (error)
485 goto err_free_client;
486
487 file->private_data = client;
488 stream_open(inode, file);
489
490 return 0;
491
492 err_free_client:
493 evdev_detach_client(evdev, client);
494 kvfree(client);
495 return error;
496}
497
498static ssize_t evdev_write(struct file *file, const char __user *buffer,
499 size_t count, loff_t *ppos)
500{
501 struct evdev_client *client = file->private_data;
502 struct evdev *evdev = client->evdev;
503 struct input_event event;
504 int retval = 0;
505
506 /*
507 * Limit amount of data we inject into the input subsystem so that
508 * we do not hold evdev->mutex for too long. 4096 bytes corresponds
509 * to 170 input events.
510 */
511 count = min(count, 4096);
512
513 if (count != 0 && count < input_event_size())
514 return -EINVAL;
515
516 retval = mutex_lock_interruptible(&evdev->mutex);
517 if (retval)
518 return retval;
519
520 if (!evdev->exist || client->revoked) {
521 retval = -ENODEV;
522 goto out;
523 }
524
525 while (retval + input_event_size() <= count) {
526
527 if (input_event_from_user(buffer + retval, &event)) {
528 retval = -EFAULT;
529 goto out;
530 }
531 retval += input_event_size();
532
533 input_inject_event(&evdev->handle,
534 event.type, event.code, event.value);
535 cond_resched();
536 }
537
538 out:
539 mutex_unlock(&evdev->mutex);
540 return retval;
541}
542
543static int evdev_fetch_next_event(struct evdev_client *client,
544 struct input_event *event)
545{
546 int have_event;
547
548 spin_lock_irq(&client->buffer_lock);
549
550 have_event = client->packet_head != client->tail;
551 if (have_event) {
552 *event = client->buffer[client->tail++];
553 client->tail &= client->bufsize - 1;
554 }
555
556 spin_unlock_irq(&client->buffer_lock);
557
558 return have_event;
559}
560
561static ssize_t evdev_read(struct file *file, char __user *buffer,
562 size_t count, loff_t *ppos)
563{
564 struct evdev_client *client = file->private_data;
565 struct evdev *evdev = client->evdev;
566 struct input_event event;
567 size_t read = 0;
568 int error;
569
570 if (count != 0 && count < input_event_size())
571 return -EINVAL;
572
573 for (;;) {
574 if (!evdev->exist || client->revoked)
575 return -ENODEV;
576
577 if (client->packet_head == client->tail &&
578 (file->f_flags & O_NONBLOCK))
579 return -EAGAIN;
580
581 /*
582 * count == 0 is special - no IO is done but we check
583 * for error conditions (see above).
584 */
585 if (count == 0)
586 break;
587
588 while (read + input_event_size() <= count &&
589 evdev_fetch_next_event(client, &event)) {
590
591 if (input_event_to_user(buffer + read, &event))
592 return -EFAULT;
593
594 read += input_event_size();
595 }
596
597 if (read)
598 break;
599
600 if (!(file->f_flags & O_NONBLOCK)) {
601 error = wait_event_interruptible(client->wait,
602 client->packet_head != client->tail ||
603 !evdev->exist || client->revoked);
604 if (error)
605 return error;
606 }
607 }
608
609 return read;
610}
611
612/* No kernel lock - fine */
613static __poll_t evdev_poll(struct file *file, poll_table *wait)
614{
615 struct evdev_client *client = file->private_data;
616 struct evdev *evdev = client->evdev;
617 __poll_t mask;
618
619 poll_wait(file, &client->wait, wait);
620
621 if (evdev->exist && !client->revoked)
622 mask = EPOLLOUT | EPOLLWRNORM;
623 else
624 mask = EPOLLHUP | EPOLLERR;
625
626 if (client->packet_head != client->tail)
627 mask |= EPOLLIN | EPOLLRDNORM;
628
629 return mask;
630}
631
632#ifdef CONFIG_COMPAT
633
634#define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
635#define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
636
637#ifdef __BIG_ENDIAN
638static int bits_to_user(unsigned long *bits, unsigned int maxbit,
639 unsigned int maxlen, void __user *p, int compat)
640{
641 int len, i;
642
643 if (compat) {
644 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
645 if (len > maxlen)
646 len = maxlen;
647
648 for (i = 0; i < len / sizeof(compat_long_t); i++)
649 if (copy_to_user((compat_long_t __user *) p + i,
650 (compat_long_t *) bits +
651 i + 1 - ((i % 2) << 1),
652 sizeof(compat_long_t)))
653 return -EFAULT;
654 } else {
655 len = BITS_TO_LONGS(maxbit) * sizeof(long);
656 if (len > maxlen)
657 len = maxlen;
658
659 if (copy_to_user(p, bits, len))
660 return -EFAULT;
661 }
662
663 return len;
664}
665
666static int bits_from_user(unsigned long *bits, unsigned int maxbit,
667 unsigned int maxlen, const void __user *p, int compat)
668{
669 int len, i;
670
671 if (compat) {
672 if (maxlen % sizeof(compat_long_t))
673 return -EINVAL;
674
675 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
676 if (len > maxlen)
677 len = maxlen;
678
679 for (i = 0; i < len / sizeof(compat_long_t); i++)
680 if (copy_from_user((compat_long_t *) bits +
681 i + 1 - ((i % 2) << 1),
682 (compat_long_t __user *) p + i,
683 sizeof(compat_long_t)))
684 return -EFAULT;
685 if (i % 2)
686 *((compat_long_t *) bits + i - 1) = 0;
687
688 } else {
689 if (maxlen % sizeof(long))
690 return -EINVAL;
691
692 len = BITS_TO_LONGS(maxbit) * sizeof(long);
693 if (len > maxlen)
694 len = maxlen;
695
696 if (copy_from_user(bits, p, len))
697 return -EFAULT;
698 }
699
700 return len;
701}
702
703#else
704
705static int bits_to_user(unsigned long *bits, unsigned int maxbit,
706 unsigned int maxlen, void __user *p, int compat)
707{
708 int len = compat ?
709 BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
710 BITS_TO_LONGS(maxbit) * sizeof(long);
711
712 if (len > maxlen)
713 len = maxlen;
714
715 return copy_to_user(p, bits, len) ? -EFAULT : len;
716}
717
718static int bits_from_user(unsigned long *bits, unsigned int maxbit,
719 unsigned int maxlen, const void __user *p, int compat)
720{
721 size_t chunk_size = compat ? sizeof(compat_long_t) : sizeof(long);
722 int len;
723
724 if (maxlen % chunk_size)
725 return -EINVAL;
726
727 len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit);
728 len *= chunk_size;
729 if (len > maxlen)
730 len = maxlen;
731
732 return copy_from_user(bits, p, len) ? -EFAULT : len;
733}
734
735#endif /* __BIG_ENDIAN */
736
737#else
738
739static int bits_to_user(unsigned long *bits, unsigned int maxbit,
740 unsigned int maxlen, void __user *p, int compat)
741{
742 int len = BITS_TO_LONGS(maxbit) * sizeof(long);
743
744 if (len > maxlen)
745 len = maxlen;
746
747 return copy_to_user(p, bits, len) ? -EFAULT : len;
748}
749
750static int bits_from_user(unsigned long *bits, unsigned int maxbit,
751 unsigned int maxlen, const void __user *p, int compat)
752{
753 int len;
754
755 if (maxlen % sizeof(long))
756 return -EINVAL;
757
758 len = BITS_TO_LONGS(maxbit) * sizeof(long);
759 if (len > maxlen)
760 len = maxlen;
761
762 return copy_from_user(bits, p, len) ? -EFAULT : len;
763}
764
765#endif /* CONFIG_COMPAT */
766
767static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
768{
769 int len;
770
771 if (!str)
772 return -ENOENT;
773
774 len = strlen(str) + 1;
775 if (len > maxlen)
776 len = maxlen;
777
778 return copy_to_user(p, str, len) ? -EFAULT : len;
779}
780
781static int handle_eviocgbit(struct input_dev *dev,
782 unsigned int type, unsigned int size,
783 void __user *p, int compat_mode)
784{
785 unsigned long *bits;
786 int len;
787
788 switch (type) {
789
790 case 0: bits = dev->evbit; len = EV_MAX; break;
791 case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
792 case EV_REL: bits = dev->relbit; len = REL_MAX; break;
793 case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
794 case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
795 case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
796 case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
797 case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
798 case EV_SW: bits = dev->swbit; len = SW_MAX; break;
799 default: return -EINVAL;
800 }
801
802 return bits_to_user(bits, len, size, p, compat_mode);
803}
804
805static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
806{
807 struct input_keymap_entry ke = {
808 .len = sizeof(unsigned int),
809 .flags = 0,
810 };
811 int __user *ip = (int __user *)p;
812 int error;
813
814 /* legacy case */
815 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
816 return -EFAULT;
817
818 error = input_get_keycode(dev, &ke);
819 if (error)
820 return error;
821
822 if (put_user(ke.keycode, ip + 1))
823 return -EFAULT;
824
825 return 0;
826}
827
828static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
829{
830 struct input_keymap_entry ke;
831 int error;
832
833 if (copy_from_user(&ke, p, sizeof(ke)))
834 return -EFAULT;
835
836 error = input_get_keycode(dev, &ke);
837 if (error)
838 return error;
839
840 if (copy_to_user(p, &ke, sizeof(ke)))
841 return -EFAULT;
842
843 return 0;
844}
845
846static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
847{
848 struct input_keymap_entry ke = {
849 .len = sizeof(unsigned int),
850 .flags = 0,
851 };
852 int __user *ip = (int __user *)p;
853
854 if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
855 return -EFAULT;
856
857 if (get_user(ke.keycode, ip + 1))
858 return -EFAULT;
859
860 return input_set_keycode(dev, &ke);
861}
862
863static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
864{
865 struct input_keymap_entry ke;
866
867 if (copy_from_user(&ke, p, sizeof(ke)))
868 return -EFAULT;
869
870 if (ke.len > sizeof(ke.scancode))
871 return -EINVAL;
872
873 return input_set_keycode(dev, &ke);
874}
875
876/*
877 * If we transfer state to the user, we should flush all pending events
878 * of the same type from the client's queue. Otherwise, they might end up
879 * with duplicate events, which can screw up client's state tracking.
880 * If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
881 * event so user-space will notice missing events.
882 *
883 * LOCKING:
884 * We need to take event_lock before buffer_lock to avoid dead-locks. But we
885 * need the even_lock only to guarantee consistent state. We can safely release
886 * it while flushing the queue. This allows input-core to handle filters while
887 * we flush the queue.
888 */
889static int evdev_handle_get_val(struct evdev_client *client,
890 struct input_dev *dev, unsigned int type,
891 unsigned long *bits, unsigned int maxbit,
892 unsigned int maxlen, void __user *p,
893 int compat)
894{
895 int ret;
896 unsigned long *mem;
897
898 mem = bitmap_alloc(maxbit, GFP_KERNEL);
899 if (!mem)
900 return -ENOMEM;
901
902 spin_lock_irq(&dev->event_lock);
903 spin_lock(&client->buffer_lock);
904
905 bitmap_copy(mem, bits, maxbit);
906
907 spin_unlock(&dev->event_lock);
908
909 __evdev_flush_queue(client, type);
910
911 spin_unlock_irq(&client->buffer_lock);
912
913 ret = bits_to_user(mem, maxbit, maxlen, p, compat);
914 if (ret < 0)
915 evdev_queue_syn_dropped(client);
916
917 bitmap_free(mem);
918
919 return ret;
920}
921
922static int evdev_handle_mt_request(struct input_dev *dev,
923 unsigned int size,
924 int __user *ip)
925{
926 const struct input_mt *mt = dev->mt;
927 unsigned int code;
928 int max_slots;
929 int i;
930
931 if (get_user(code, &ip[0]))
932 return -EFAULT;
933 if (!mt || !input_is_mt_value(code))
934 return -EINVAL;
935
936 max_slots = (size - sizeof(__u32)) / sizeof(__s32);
937 for (i = 0; i < mt->num_slots && i < max_slots; i++) {
938 int value = input_mt_get_value(&mt->slots[i], code);
939 if (put_user(value, &ip[1 + i]))
940 return -EFAULT;
941 }
942
943 return 0;
944}
945
946static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
947 struct file *file)
948{
949 client->revoked = true;
950 evdev_ungrab(evdev, client);
951 input_flush_device(&evdev->handle, file);
952 wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR);
953
954 return 0;
955}
956
957/* must be called with evdev-mutex held */
958static int evdev_set_mask(struct evdev_client *client,
959 unsigned int type,
960 const void __user *codes,
961 u32 codes_size,
962 int compat)
963{
964 unsigned long flags, *mask, *oldmask;
965 size_t cnt;
966 int error;
967
968 /* we allow unknown types and 'codes_size > size' for forward-compat */
969 cnt = evdev_get_mask_cnt(type);
970 if (!cnt)
971 return 0;
972
973 mask = bitmap_zalloc(cnt, GFP_KERNEL);
974 if (!mask)
975 return -ENOMEM;
976
977 error = bits_from_user(mask, cnt - 1, codes_size, codes, compat);
978 if (error < 0) {
979 bitmap_free(mask);
980 return error;
981 }
982
983 spin_lock_irqsave(&client->buffer_lock, flags);
984 oldmask = client->evmasks[type];
985 client->evmasks[type] = mask;
986 spin_unlock_irqrestore(&client->buffer_lock, flags);
987
988 bitmap_free(oldmask);
989
990 return 0;
991}
992
993/* must be called with evdev-mutex held */
994static int evdev_get_mask(struct evdev_client *client,
995 unsigned int type,
996 void __user *codes,
997 u32 codes_size,
998 int compat)
999{
1000 unsigned long *mask;
1001 size_t cnt, size, xfer_size;
1002 int i;
1003 int error;
1004
1005 /* we allow unknown types and 'codes_size > size' for forward-compat */
1006 cnt = evdev_get_mask_cnt(type);
1007 size = sizeof(unsigned long) * BITS_TO_LONGS(cnt);
1008 xfer_size = min_t(size_t, codes_size, size);
1009
1010 if (cnt > 0) {
1011 mask = client->evmasks[type];
1012 if (mask) {
1013 error = bits_to_user(mask, cnt - 1,
1014 xfer_size, codes, compat);
1015 if (error < 0)
1016 return error;
1017 } else {
1018 /* fake mask with all bits set */
1019 for (i = 0; i < xfer_size; i++)
1020 if (put_user(0xffU, (u8 __user *)codes + i))
1021 return -EFAULT;
1022 }
1023 }
1024
1025 if (xfer_size < codes_size)
1026 if (clear_user(codes + xfer_size, codes_size - xfer_size))
1027 return -EFAULT;
1028
1029 return 0;
1030}
1031
1032static long evdev_do_ioctl(struct file *file, unsigned int cmd,
1033 void __user *p, int compat_mode)
1034{
1035 struct evdev_client *client = file->private_data;
1036 struct evdev *evdev = client->evdev;
1037 struct input_dev *dev = evdev->handle.dev;
1038 struct input_absinfo abs;
1039 struct input_mask mask;
1040 struct ff_effect effect;
1041 int __user *ip = (int __user *)p;
1042 unsigned int i, t, u, v;
1043 unsigned int size;
1044 int error;
1045
1046 /* First we check for fixed-length commands */
1047 switch (cmd) {
1048
1049 case EVIOCGVERSION:
1050 return put_user(EV_VERSION, ip);
1051
1052 case EVIOCGID:
1053 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
1054 return -EFAULT;
1055 return 0;
1056
1057 case EVIOCGREP:
1058 if (!test_bit(EV_REP, dev->evbit))
1059 return -ENOSYS;
1060 if (put_user(dev->rep[REP_DELAY], ip))
1061 return -EFAULT;
1062 if (put_user(dev->rep[REP_PERIOD], ip + 1))
1063 return -EFAULT;
1064 return 0;
1065
1066 case EVIOCSREP:
1067 if (!test_bit(EV_REP, dev->evbit))
1068 return -ENOSYS;
1069 if (get_user(u, ip))
1070 return -EFAULT;
1071 if (get_user(v, ip + 1))
1072 return -EFAULT;
1073
1074 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
1075 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
1076
1077 return 0;
1078
1079 case EVIOCRMFF:
1080 return input_ff_erase(dev, (int)(unsigned long) p, file);
1081
1082 case EVIOCGEFFECTS:
1083 i = test_bit(EV_FF, dev->evbit) ?
1084 dev->ff->max_effects : 0;
1085 if (put_user(i, ip))
1086 return -EFAULT;
1087 return 0;
1088
1089 case EVIOCGRAB:
1090 if (p)
1091 return evdev_grab(evdev, client);
1092 else
1093 return evdev_ungrab(evdev, client);
1094
1095 case EVIOCREVOKE:
1096 if (p)
1097 return -EINVAL;
1098 else
1099 return evdev_revoke(evdev, client, file);
1100
1101 case EVIOCGMASK: {
1102 void __user *codes_ptr;
1103
1104 if (copy_from_user(&mask, p, sizeof(mask)))
1105 return -EFAULT;
1106
1107 codes_ptr = (void __user *)(unsigned long)mask.codes_ptr;
1108 return evdev_get_mask(client,
1109 mask.type, codes_ptr, mask.codes_size,
1110 compat_mode);
1111 }
1112
1113 case EVIOCSMASK: {
1114 const void __user *codes_ptr;
1115
1116 if (copy_from_user(&mask, p, sizeof(mask)))
1117 return -EFAULT;
1118
1119 codes_ptr = (const void __user *)(unsigned long)mask.codes_ptr;
1120 return evdev_set_mask(client,
1121 mask.type, codes_ptr, mask.codes_size,
1122 compat_mode);
1123 }
1124
1125 case EVIOCSCLOCKID:
1126 if (copy_from_user(&i, p, sizeof(unsigned int)))
1127 return -EFAULT;
1128
1129 return evdev_set_clk_type(client, i);
1130
1131 case EVIOCGKEYCODE:
1132 return evdev_handle_get_keycode(dev, p);
1133
1134 case EVIOCSKEYCODE:
1135 return evdev_handle_set_keycode(dev, p);
1136
1137 case EVIOCGKEYCODE_V2:
1138 return evdev_handle_get_keycode_v2(dev, p);
1139
1140 case EVIOCSKEYCODE_V2:
1141 return evdev_handle_set_keycode_v2(dev, p);
1142 }
1143
1144 size = _IOC_SIZE(cmd);
1145
1146 /* Now check variable-length commands */
1147#define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
1148 switch (EVIOC_MASK_SIZE(cmd)) {
1149
1150 case EVIOCGPROP(0):
1151 return bits_to_user(dev->propbit, INPUT_PROP_MAX,
1152 size, p, compat_mode);
1153
1154 case EVIOCGMTSLOTS(0):
1155 return evdev_handle_mt_request(dev, size, ip);
1156
1157 case EVIOCGKEY(0):
1158 return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
1159 KEY_MAX, size, p, compat_mode);
1160
1161 case EVIOCGLED(0):
1162 return evdev_handle_get_val(client, dev, EV_LED, dev->led,
1163 LED_MAX, size, p, compat_mode);
1164
1165 case EVIOCGSND(0):
1166 return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
1167 SND_MAX, size, p, compat_mode);
1168
1169 case EVIOCGSW(0):
1170 return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
1171 SW_MAX, size, p, compat_mode);
1172
1173 case EVIOCGNAME(0):
1174 return str_to_user(dev->name, size, p);
1175
1176 case EVIOCGPHYS(0):
1177 return str_to_user(dev->phys, size, p);
1178
1179 case EVIOCGUNIQ(0):
1180 return str_to_user(dev->uniq, size, p);
1181
1182 case EVIOC_MASK_SIZE(EVIOCSFF):
1183 if (input_ff_effect_from_user(p, size, &effect))
1184 return -EFAULT;
1185
1186 error = input_ff_upload(dev, &effect, file);
1187 if (error)
1188 return error;
1189
1190 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
1191 return -EFAULT;
1192
1193 return 0;
1194 }
1195
1196 /* Multi-number variable-length handlers */
1197 if (_IOC_TYPE(cmd) != 'E')
1198 return -EINVAL;
1199
1200 if (_IOC_DIR(cmd) == _IOC_READ) {
1201
1202 if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
1203 return handle_eviocgbit(dev,
1204 _IOC_NR(cmd) & EV_MAX, size,
1205 p, compat_mode);
1206
1207 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
1208
1209 if (!dev->absinfo)
1210 return -EINVAL;
1211
1212 t = _IOC_NR(cmd) & ABS_MAX;
1213 abs = dev->absinfo[t];
1214
1215 if (copy_to_user(p, &abs, min_t(size_t,
1216 size, sizeof(struct input_absinfo))))
1217 return -EFAULT;
1218
1219 return 0;
1220 }
1221 }
1222
1223 if (_IOC_DIR(cmd) == _IOC_WRITE) {
1224
1225 if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
1226
1227 if (!dev->absinfo)
1228 return -EINVAL;
1229
1230 t = _IOC_NR(cmd) & ABS_MAX;
1231
1232 memset(&abs, 0, sizeof(abs));
1233
1234 if (copy_from_user(&abs, p, min_t(size_t,
1235 size, sizeof(struct input_absinfo))))
1236 return -EFAULT;
1237
1238 if (size < sizeof(struct input_absinfo))
1239 abs.resolution = 0;
1240
1241 /* We can't change number of reserved MT slots */
1242 if (t == ABS_MT_SLOT)
1243 return -EINVAL;
1244
1245 /*
1246 * Take event lock to ensure that we are not
1247 * changing device parameters in the middle
1248 * of event.
1249 */
1250 spin_lock_irq(&dev->event_lock);
1251 dev->absinfo[t] = abs;
1252 spin_unlock_irq(&dev->event_lock);
1253
1254 return 0;
1255 }
1256 }
1257
1258 return -EINVAL;
1259}
1260
1261static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
1262 void __user *p, int compat_mode)
1263{
1264 struct evdev_client *client = file->private_data;
1265 struct evdev *evdev = client->evdev;
1266 int retval;
1267
1268 retval = mutex_lock_interruptible(&evdev->mutex);
1269 if (retval)
1270 return retval;
1271
1272 if (!evdev->exist || client->revoked) {
1273 retval = -ENODEV;
1274 goto out;
1275 }
1276
1277 retval = evdev_do_ioctl(file, cmd, p, compat_mode);
1278
1279 out:
1280 mutex_unlock(&evdev->mutex);
1281 return retval;
1282}
1283
1284static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1285{
1286 return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
1287}
1288
1289#ifdef CONFIG_COMPAT
1290static long evdev_ioctl_compat(struct file *file,
1291 unsigned int cmd, unsigned long arg)
1292{
1293 return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
1294}
1295#endif
1296
1297static const struct file_operations evdev_fops = {
1298 .owner = THIS_MODULE,
1299 .read = evdev_read,
1300 .write = evdev_write,
1301 .poll = evdev_poll,
1302 .open = evdev_open,
1303 .release = evdev_release,
1304 .unlocked_ioctl = evdev_ioctl,
1305#ifdef CONFIG_COMPAT
1306 .compat_ioctl = evdev_ioctl_compat,
1307#endif
1308 .fasync = evdev_fasync,
1309};
1310
1311/*
1312 * Mark device non-existent. This disables writes, ioctls and
1313 * prevents new users from opening the device. Already posted
1314 * blocking reads will stay, however new ones will fail.
1315 */
1316static void evdev_mark_dead(struct evdev *evdev)
1317{
1318 mutex_lock(&evdev->mutex);
1319 evdev->exist = false;
1320 mutex_unlock(&evdev->mutex);
1321}
1322
1323static void evdev_cleanup(struct evdev *evdev)
1324{
1325 struct input_handle *handle = &evdev->handle;
1326
1327 evdev_mark_dead(evdev);
1328 evdev_hangup(evdev);
1329
1330 /* evdev is marked dead so no one else accesses evdev->open */
1331 if (evdev->open) {
1332 input_flush_device(handle, NULL);
1333 input_close_device(handle);
1334 }
1335}
1336
1337/*
1338 * Create new evdev device. Note that input core serializes calls
1339 * to connect and disconnect.
1340 */
1341static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
1342 const struct input_device_id *id)
1343{
1344 struct evdev *evdev;
1345 int minor;
1346 int dev_no;
1347 int error;
1348
1349 minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
1350 if (minor < 0) {
1351 error = minor;
1352 pr_err("failed to reserve new minor: %d\n", error);
1353 return error;
1354 }
1355
1356 evdev = kzalloc_obj(struct evdev);
1357 if (!evdev) {
1358 error = -ENOMEM;
1359 goto err_free_minor;
1360 }
1361
1362 INIT_LIST_HEAD(&evdev->client_list);
1363 spin_lock_init(&evdev->client_lock);
1364 mutex_init(&evdev->mutex);
1365 evdev->exist = true;
1366
1367 dev_no = minor;
1368 /* Normalize device number if it falls into legacy range */
1369 if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
1370 dev_no -= EVDEV_MINOR_BASE;
1371 dev_set_name(&evdev->dev, "event%d", dev_no);
1372
1373 evdev->handle.dev = input_get_device(dev);
1374 evdev->handle.name = dev_name(&evdev->dev);
1375 evdev->handle.handler = handler;
1376 evdev->handle.private = evdev;
1377
1378 evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
1379 evdev->dev.class = &input_class;
1380 evdev->dev.parent = &dev->dev;
1381 evdev->dev.release = evdev_free;
1382 device_initialize(&evdev->dev);
1383
1384 error = input_register_handle(&evdev->handle);
1385 if (error)
1386 goto err_free_evdev;
1387
1388 cdev_init(&evdev->cdev, &evdev_fops);
1389
1390 error = cdev_device_add(&evdev->cdev, &evdev->dev);
1391 if (error)
1392 goto err_cleanup_evdev;
1393
1394 return 0;
1395
1396 err_cleanup_evdev:
1397 evdev_cleanup(evdev);
1398 input_unregister_handle(&evdev->handle);
1399 err_free_evdev:
1400 put_device(&evdev->dev);
1401 err_free_minor:
1402 input_free_minor(minor);
1403 return error;
1404}
1405
1406static void evdev_disconnect(struct input_handle *handle)
1407{
1408 struct evdev *evdev = handle->private;
1409
1410 cdev_device_del(&evdev->cdev, &evdev->dev);
1411 evdev_cleanup(evdev);
1412 input_free_minor(MINOR(evdev->dev.devt));
1413 input_unregister_handle(handle);
1414 put_device(&evdev->dev);
1415}
1416
1417static const struct input_device_id evdev_ids[] = {
1418 {
1419 /* Matches all devices */
1420 .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
1421 .evbit = { BIT_MASK(EV_SYN) },
1422 },
1423 { } /* Terminating zero entry */
1424};
1425
1426MODULE_DEVICE_TABLE(input, evdev_ids);
1427
1428static struct input_handler evdev_handler = {
1429 .events = evdev_events,
1430 .connect = evdev_connect,
1431 .disconnect = evdev_disconnect,
1432 .legacy_minors = true,
1433 .minor = EVDEV_MINOR_BASE,
1434 .name = "evdev",
1435 .id_table = evdev_ids,
1436};
1437
1438static int __init evdev_init(void)
1439{
1440 return input_register_handler(&evdev_handler);
1441}
1442
1443static void __exit evdev_exit(void)
1444{
1445 input_unregister_handler(&evdev_handler);
1446}
1447
1448module_init(evdev_init);
1449module_exit(evdev_exit);
1450
1451MODULE_AUTHOR("Vojtech Pavlik <[email protected]>");
1452MODULE_DESCRIPTION("Input driver event char devices");
1453MODULE_LICENSE("GPL");