drivers/hid/hidraw.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * HID raw devices, giving access to raw HID events.
   4  *
   5  * In comparison to hiddev, this device does not process the
   6  * hid events at all (no parsing, no lookups). This lets applications
   7  * to work on raw hid events as they want to, and avoids a need to
   8  * use a transport-specific userspace libhid/libusb libraries.
   9  *
  10  *  Copyright (c) 2007-2014 Jiri Kosina
  11  */
  12
  13
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/fs.h>
  17 #include <linux/module.h>
  18 #include <linux/errno.h>
  19 #include <linux/kernel.h>
  20 #include <linux/init.h>
  21 #include <linux/cdev.h>
  22 #include <linux/poll.h>
  23 #include <linux/device.h>
  24 #include <linux/major.h>
  25 #include <linux/slab.h>
  26 #include <linux/hid.h>
  27 #include <linux/mutex.h>
  28 #include <linux/sched/signal.h>
  29 #include <linux/string.h>
  30
  31 #include <linux/hidraw.h>
  32
  33 static int hidraw_major;
  34 static struct cdev hidraw_cdev;
  35 static struct class *hidraw_class;
  36 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
  37 static DECLARE_RWSEM(minors_rwsem);
  38
  39 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
  40 {
  41         struct hidraw_list *list = file->private_data;
  42         int ret = 0, len;
  43         DECLARE_WAITQUEUE(wait, current);
  44
  45         mutex_lock(&list->read_mutex);
  46
  47         while (ret == 0) {
  48                 if (list->head == list->tail) {
  49                         add_wait_queue(&list->hidraw->wait, &wait);
  50                         set_current_state(TASK_INTERRUPTIBLE);
  51
  52                         while (list->head == list->tail) {
  53                                 if (signal_pending(current)) {
  54                                         ret = -ERESTARTSYS;
  55                                         break;
  56                                 }
  57                                 if (!list->hidraw->exist) {
  58                                         ret = -EIO;
  59                                         break;
  60                                 }
  61                                 if (file->f_flags & O_NONBLOCK) {
  62                                         ret = -EAGAIN;
  63                                         break;
  64                                 }
  65
  66                                 /* allow O_NONBLOCK to work well from other threads */
  67                                 mutex_unlock(&list->read_mutex);
  68                                 schedule();
  69                                 mutex_lock(&list->read_mutex);
  70                                 set_current_state(TASK_INTERRUPTIBLE);
  71                         }
  72
  73                         set_current_state(TASK_RUNNING);
  74                         remove_wait_queue(&list->hidraw->wait, &wait);
  75                 }
  76
  77                 if (ret)
  78                         goto out;
  79
  80                 len = list->buffer[list->tail].len > count ?
  81                         count : list->buffer[list->tail].len;
  82
  83                 if (list->buffer[list->tail].value) {
  84                         if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
  85                                 ret = -EFAULT;
  86                                 goto out;
  87                         }
  88                         ret = len;
  89                 }
  90
  91                 kfree(list->buffer[list->tail].value);
  92                 list->buffer[list->tail].value = NULL;
  93                 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
  94         }
  95 out:
  96         mutex_unlock(&list->read_mutex);
  97         return ret;
  98 }
  99
 100 /*
 101  * The first byte of the report buffer is expected to be a report number.
 102  */
 103 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
 104 {
 105         unsigned int minor = iminor(file_inode(file));
 106         struct hid_device *dev;
 107         __u8 *buf;
 108         int ret = 0;
 109
 110         lockdep_assert_held(&minors_rwsem);
 111
 112         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 113                 ret = -ENODEV;
 114                 goto out;
 115         }
 116
 117         dev = hidraw_table[minor]->hid;
 118
 119         if (count > HID_MAX_BUFFER_SIZE) {
 120                 hid_warn(dev, "pid %d passed too large report\n",
 121                          task_pid_nr(current));
 122                 ret = -EINVAL;
 123                 goto out;
 124         }
 125
 126         if (count < 2) {
 127                 hid_warn(dev, "pid %d passed too short report\n",
 128                          task_pid_nr(current));
 129                 ret = -EINVAL;
 130                 goto out;
 131         }
 132
 133         buf = memdup_user(buffer, count);
 134         if (IS_ERR(buf)) {
 135                 ret = PTR_ERR(buf);
 136                 goto out;
 137         }
 138
 139         if ((report_type == HID_OUTPUT_REPORT) &&
 140             !(dev->quirks & HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP)) {
 141                 ret = hid_hw_output_report(dev, buf, count);
 142                 /*
 143                  * compatibility with old implementation of USB-HID and I2C-HID:
 144                  * if the device does not support receiving output reports,
 145                  * on an interrupt endpoint, fallback to SET_REPORT HID command.
 146                  */
 147                 if (ret != -ENOSYS)
 148                         goto out_free;
 149         }
 150
 151         ret = hid_hw_raw_request(dev, buf[0], buf, count, report_type,
 152                                 HID_REQ_SET_REPORT);
 153
 154 out_free:
 155         kfree(buf);
 156 out:
 157         return ret;
 158 }
 159
 160 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 161 {
 162         ssize_t ret;
 163         down_read(&minors_rwsem);
 164         ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
 165         up_read(&minors_rwsem);
 166         return ret;
 167 }
 168
 169
 170 /*
 171  * This function performs a Get_Report transfer over the control endpoint
 172  * per section 7.2.1 of the HID specification, version 1.1.  The first byte
 173  * of buffer is the report number to request, or 0x0 if the device does not
 174  * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
 175  * or HID_INPUT_REPORT.
 176  */
 177 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
 178 {
 179         unsigned int minor = iminor(file_inode(file));
 180         struct hid_device *dev;
 181         __u8 *buf;
 182         int ret = 0, len;
 183         unsigned char report_number;
 184
 185         lockdep_assert_held(&minors_rwsem);
 186
 187         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 188                 ret = -ENODEV;
 189                 goto out;
 190         }
 191
 192         dev = hidraw_table[minor]->hid;
 193
 194         if (!dev->ll_driver->raw_request) {
 195                 ret = -ENODEV;
 196                 goto out;
 197         }
 198
 199         if (count > HID_MAX_BUFFER_SIZE) {
 200                 hid_warn(dev, "pid %d passed too large report\n",
 201                         task_pid_nr(current));
 202                 ret = -EINVAL;
 203                 goto out;
 204         }
 205
 206         if (count < 2) {
 207                 hid_warn(dev, "pid %d passed too short report\n",
 208                         task_pid_nr(current));
 209                 ret = -EINVAL;
 210                 goto out;
 211         }
 212
 213         buf = kmalloc(count, GFP_KERNEL);
 214         if (!buf) {
 215                 ret = -ENOMEM;
 216                 goto out;
 217         }
 218
 219         /*
 220          * Read the first byte from the user. This is the report number,
 221          * which is passed to hid_hw_raw_request().
 222          */
 223         if (copy_from_user(&report_number, buffer, 1)) {
 224                 ret = -EFAULT;
 225                 goto out_free;
 226         }
 227
 228         ret = hid_hw_raw_request(dev, report_number, buf, count, report_type,
 229                                  HID_REQ_GET_REPORT);
 230
 231         if (ret < 0)
 232                 goto out_free;
 233
 234         len = (ret < count) ? ret : count;
 235
 236         if (copy_to_user(buffer, buf, len)) {
 237                 ret = -EFAULT;
 238                 goto out_free;
 239         }
 240
 241         ret = len;
 242
 243 out_free:
 244         kfree(buf);
 245 out:
 246         return ret;
 247 }
 248
 249 static __poll_t hidraw_poll(struct file *file, poll_table *wait)
 250 {
 251         struct hidraw_list *list = file->private_data;
 252         __poll_t mask = EPOLLOUT | EPOLLWRNORM; /* hidraw is always writable */
 253
 254         poll_wait(file, &list->hidraw->wait, wait);
 255         if (list->head != list->tail)
 256                 mask |= EPOLLIN | EPOLLRDNORM;
 257         if (!list->hidraw->exist)
 258                 mask |= EPOLLERR | EPOLLHUP;
 259         return mask;
 260 }
 261
 262 static int hidraw_open(struct inode *inode, struct file *file)
 263 {
 264         unsigned int minor = iminor(inode);
 265         struct hidraw *dev;
 266         struct hidraw_list *list;
 267         unsigned long flags;
 268         int err = 0;
 269
 270         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 271                 err = -ENOMEM;
 272                 goto out;
 273         }
 274
 275         /*
 276          * Technically not writing to the hidraw_table but a write lock is
 277          * required to protect the device refcount. This is symmetrical to
 278          * hidraw_release().
 279          */
 280         down_write(&minors_rwsem);
 281         if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
 282                 err = -ENODEV;
 283                 goto out_unlock;
 284         }
 285
 286         dev = hidraw_table[minor];
 287         if (!dev->open++) {
 288                 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
 289                 if (err < 0) {
 290                         dev->open--;
 291                         goto out_unlock;
 292                 }
 293
 294                 err = hid_hw_open(dev->hid);
 295                 if (err < 0) {
 296                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 297                         dev->open--;
 298                         goto out_unlock;
 299                 }
 300         }
 301
 302         list->hidraw = hidraw_table[minor];
 303         mutex_init(&list->read_mutex);
 304         spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
 305         list_add_tail(&list->node, &hidraw_table[minor]->list);
 306         spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
 307         file->private_data = list;
 308 out_unlock:
 309         up_write(&minors_rwsem);
 310 out:
 311         if (err < 0)
 312                 kfree(list);
 313         return err;
 314
 315 }
 316
 317 static int hidraw_fasync(int fd, struct file *file, int on)
 318 {
 319         struct hidraw_list *list = file->private_data;
 320
 321         return fasync_helper(fd, file, on, &list->fasync);
 322 }
 323
 324 static void drop_ref(struct hidraw *hidraw, int exists_bit)
 325 {
 326         if (exists_bit) {
 327                 hidraw->exist = 0;
 328                 if (hidraw->open) {
 329                         hid_hw_close(hidraw->hid);
 330                         wake_up_interruptible(&hidraw->wait);
 331                 }
 332                 device_destroy(hidraw_class,
 333                                MKDEV(hidraw_major, hidraw->minor));
 334         } else {
 335                 --hidraw->open;
 336         }
 337         if (!hidraw->open) {
 338                 if (!hidraw->exist) {
 339                         hidraw_table[hidraw->minor] = NULL;
 340                         kfree(hidraw);
 341                 } else {
 342                         /* close device for last reader */
 343                         hid_hw_close(hidraw->hid);
 344                         hid_hw_power(hidraw->hid, PM_HINT_NORMAL);
 345                 }
 346         }
 347 }
 348
 349 static int hidraw_release(struct inode * inode, struct file * file)
 350 {
 351         unsigned int minor = iminor(inode);
 352         struct hidraw_list *list = file->private_data;
 353         unsigned long flags;
 354
 355         down_write(&minors_rwsem);
 356
 357         spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
 358         for (int i = list->tail; i < list->head; i++)
 359                 kfree(list->buffer[i].value);
 360         list_del(&list->node);
 361         spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
 362         kfree(list);
 363
 364         drop_ref(hidraw_table[minor], 0);
 365
 366         up_write(&minors_rwsem);
 367         return 0;
 368 }
 369
 370 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 371                                                         unsigned long arg)
 372 {
 373         struct inode *inode = file_inode(file);
 374         unsigned int minor = iminor(inode);
 375         long ret = 0;
 376         struct hidraw *dev;
 377         void __user *user_arg = (void __user*) arg;
 378
 379         down_read(&minors_rwsem);
 380         dev = hidraw_table[minor];
 381         if (!dev || !dev->exist) {
 382                 ret = -ENODEV;
 383                 goto out;
 384         }
 385
 386         switch (cmd) {
 387                 case HIDIOCGRDESCSIZE:
 388                         if (put_user(dev->hid->rsize, (int __user *)arg))
 389                                 ret = -EFAULT;
 390                         break;
 391
 392                 case HIDIOCGRDESC:
 393                         {
 394                                 __u32 len;
 395
 396                                 if (get_user(len, (int __user *)arg))
 397                                         ret = -EFAULT;
 398                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 399                                         ret = -EINVAL;
 400                                 else if (copy_to_user(user_arg + offsetof(
 401                                         struct hidraw_report_descriptor,
 402                                         value[0]),
 403                                         dev->hid->rdesc,
 404                                         min(dev->hid->rsize, len)))
 405                                         ret = -EFAULT;
 406                                 break;
 407                         }
 408                 case HIDIOCGRAWINFO:
 409                         {
 410                                 struct hidraw_devinfo dinfo;
 411
 412                                 dinfo.bustype = dev->hid->bus;
 413                                 dinfo.vendor = dev->hid->vendor;
 414                                 dinfo.product = dev->hid->product;
 415                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 416                                         ret = -EFAULT;
 417                                 break;
 418                         }
 419                 default:
 420                         {
 421                                 struct hid_device *hid = dev->hid;
 422                                 if (_IOC_TYPE(cmd) != 'H') {
 423                                         ret = -EINVAL;
 424                                         break;
 425                                 }
 426
 427                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
 428                                         int len = _IOC_SIZE(cmd);
 429                                         ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
 430                                         break;
 431                                 }
 432                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
 433                                         int len = _IOC_SIZE(cmd);
 434                                         ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
 435                                         break;
 436                                 }
 437
 438                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSINPUT(0))) {
 439                                         int len = _IOC_SIZE(cmd);
 440                                         ret = hidraw_send_report(file, user_arg, len, HID_INPUT_REPORT);
 441                                         break;
 442                                 }
 443                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGINPUT(0))) {
 444                                         int len = _IOC_SIZE(cmd);
 445                                         ret = hidraw_get_report(file, user_arg, len, HID_INPUT_REPORT);
 446                                         break;
 447                                 }
 448
 449                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSOUTPUT(0))) {
 450                                         int len = _IOC_SIZE(cmd);
 451                                         ret = hidraw_send_report(file, user_arg, len, HID_OUTPUT_REPORT);
 452                                         break;
 453                                 }
 454                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGOUTPUT(0))) {
 455                                         int len = _IOC_SIZE(cmd);
 456                                         ret = hidraw_get_report(file, user_arg, len, HID_OUTPUT_REPORT);
 457                                         break;
 458                                 }
 459
 460                                 /* Begin Read-only ioctls. */
 461                                 if (_IOC_DIR(cmd) != _IOC_READ) {
 462                                         ret = -EINVAL;
 463                                         break;
 464                                 }
 465
 466                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 467                                         int len = strlen(hid->name) + 1;
 468                                         if (len > _IOC_SIZE(cmd))
 469                                                 len = _IOC_SIZE(cmd);
 470                                         ret = copy_to_user(user_arg, hid->name, len) ?
 471                                                 -EFAULT : len;
 472                                         break;
 473                                 }
 474
 475                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 476                                         int len = strlen(hid->phys) + 1;
 477                                         if (len > _IOC_SIZE(cmd))
 478                                                 len = _IOC_SIZE(cmd);
 479                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 480                                                 -EFAULT : len;
 481                                         break;
 482                                 }
 483
 484                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWUNIQ(0))) {
 485                                         int len = strlen(hid->uniq) + 1;
 486                                         if (len > _IOC_SIZE(cmd))
 487                                                 len = _IOC_SIZE(cmd);
 488                                         ret = copy_to_user(user_arg, hid->uniq, len) ?
 489                                                 -EFAULT : len;
 490                                         break;
 491                                 }
 492                         }
 493
 494                 ret = -ENOTTY;
 495         }
 496 out:
 497         up_read(&minors_rwsem);
 498         return ret;
 499 }
 500
 501 static const struct file_operations hidraw_ops = {
 502         .owner =        THIS_MODULE,
 503         .read =         hidraw_read,
 504         .write =        hidraw_write,
 505         .poll =         hidraw_poll,
 506         .open =         hidraw_open,
 507         .release =      hidraw_release,
 508         .unlocked_ioctl = hidraw_ioctl,
 509         .fasync =       hidraw_fasync,
 510         .compat_ioctl   = compat_ptr_ioctl,
 511         .llseek =       noop_llseek,
 512 };
 513
 514 int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 515 {
 516         struct hidraw *dev = hid->hidraw;
 517         struct hidraw_list *list;
 518         int ret = 0;
 519         unsigned long flags;
 520
 521         spin_lock_irqsave(&dev->list_lock, flags);
 522         list_for_each_entry(list, &dev->list, node) {
 523                 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 524
 525                 if (new_head == list->tail)
 526                         continue;
 527
 528                 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
 529                         ret = -ENOMEM;
 530                         break;
 531                 }
 532                 list->buffer[list->head].len = len;
 533                 list->head = new_head;
 534                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 535         }
 536         spin_unlock_irqrestore(&dev->list_lock, flags);
 537
 538         wake_up_interruptible(&dev->wait);
 539         return ret;
 540 }
 541 EXPORT_SYMBOL_GPL(hidraw_report_event);
 542
 543 int hidraw_connect(struct hid_device *hid)
 544 {
 545         int minor, result;
 546         struct hidraw *dev;
 547
 548         /* we accept any HID device, all applications */
 549
 550         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 551         if (!dev)
 552                 return -ENOMEM;
 553
 554         result = -EINVAL;
 555
 556         down_write(&minors_rwsem);
 557
 558         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 559                 if (hidraw_table[minor])
 560                         continue;
 561                 hidraw_table[minor] = dev;
 562                 result = 0;
 563                 break;
 564         }
 565
 566         if (result) {
 567                 up_write(&minors_rwsem);
 568                 kfree(dev);
 569                 goto out;
 570         }
 571
 572         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 573                                  NULL, "%s%d", "hidraw", minor);
 574
 575         if (IS_ERR(dev->dev)) {
 576                 hidraw_table[minor] = NULL;
 577                 up_write(&minors_rwsem);
 578                 result = PTR_ERR(dev->dev);
 579                 kfree(dev);
 580                 goto out;
 581         }
 582
 583         init_waitqueue_head(&dev->wait);
 584         spin_lock_init(&dev->list_lock);
 585         INIT_LIST_HEAD(&dev->list);
 586
 587         dev->hid = hid;
 588         dev->minor = minor;
 589
 590         dev->exist = 1;
 591         hid->hidraw = dev;
 592
 593         up_write(&minors_rwsem);
 594 out:
 595         return result;
 596
 597 }
 598 EXPORT_SYMBOL_GPL(hidraw_connect);
 599
 600 void hidraw_disconnect(struct hid_device *hid)
 601 {
 602         struct hidraw *hidraw = hid->hidraw;
 603
 604         down_write(&minors_rwsem);
 605
 606         drop_ref(hidraw, 1);
 607
 608         up_write(&minors_rwsem);
 609 }
 610 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 611
 612 int __init hidraw_init(void)
 613 {
 614         int result;
 615         dev_t dev_id;
 616
 617         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 618                         HIDRAW_MAX_DEVICES, "hidraw");
 619         if (result < 0) {
 620                 pr_warn("can't get major number\n");
 621                 goto out;
 622         }
 623
 624         hidraw_major = MAJOR(dev_id);
 625
 626         hidraw_class = class_create("hidraw");
 627         if (IS_ERR(hidraw_class)) {
 628                 result = PTR_ERR(hidraw_class);
 629                 goto error_cdev;
 630         }
 631
 632         cdev_init(&hidraw_cdev, &hidraw_ops);
 633         result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 634         if (result < 0)
 635                 goto error_class;
 636
 637         pr_info("raw HID events driver (C) Jiri Kosina\n");
 638 out:
 639         return result;
 640
 641 error_class:
 642         class_destroy(hidraw_class);
 643 error_cdev:
 644         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 645         goto out;
 646 }
 647
 648 void hidraw_exit(void)
 649 {
 650         dev_t dev_id = MKDEV(hidraw_major, 0);
 651
 652         cdev_del(&hidraw_cdev);
 653         class_destroy(hidraw_class);
 654         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 655
 656 }