| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 2 | /* |
| 3 | * User-space I/O driver support for HID subsystem |
| 4 | * Copyright (c) 2012 David Herrmann |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | */ |
| 9 | |
| 10 | #include <linux/atomic.h> |
| 11 | #include <linux/compat.h> |
| 12 | #include <linux/cred.h> |
| 13 | #include <linux/device.h> |
| 14 | #include <linux/fs.h> |
| 15 | #include <linux/hid.h> |
| 16 | #include <linux/input.h> |
| 17 | #include <linux/miscdevice.h> |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/mutex.h> |
| 20 | #include <linux/poll.h> |
| 21 | #include <linux/sched.h> |
| 22 | #include <linux/spinlock.h> |
| 23 | #include <linux/uhid.h> |
| 24 | #include <linux/wait.h> |
| 25 | |
| 26 | #define UHID_NAME "uhid" |
| 27 | #define UHID_BUFSIZE 32 |
| 28 | |
| 29 | struct uhid_device { |
| 30 | struct mutex devlock; |
| 31 | |
| 32 | /* This flag tracks whether the HID device is usable for commands from |
| 33 | * userspace. The flag is already set before hid_add_device(), which |
| 34 | * runs in workqueue context, to allow hid_add_device() to communicate |
| 35 | * with userspace. |
| 36 | * However, if hid_add_device() fails, the flag is cleared without |
| 37 | * holding devlock. |
| 38 | * We guarantee that if @running changes from true to false while you're |
| 39 | * holding @devlock, it's still fine to access @hid. |
| 40 | */ |
| 41 | bool running; |
| 42 | |
| 43 | __u8 *rd_data; |
| 44 | uint rd_size; |
| 45 | |
| 46 | /* When this is NULL, userspace may use UHID_CREATE/UHID_CREATE2. */ |
| 47 | struct hid_device *hid; |
| 48 | struct uhid_event input_buf; |
| 49 | |
| 50 | wait_queue_head_t waitq; |
| 51 | spinlock_t qlock; |
| 52 | __u8 head; |
| 53 | __u8 tail; |
| 54 | struct uhid_event *outq[UHID_BUFSIZE]; |
| 55 | |
| 56 | /* blocking GET_REPORT support; state changes protected by qlock */ |
| 57 | struct mutex report_lock; |
| 58 | wait_queue_head_t report_wait; |
| 59 | bool report_running; |
| 60 | u32 report_id; |
| 61 | u32 report_type; |
| 62 | struct uhid_event report_buf; |
| 63 | struct work_struct worker; |
| 64 | }; |
| 65 | |
| 66 | static struct miscdevice uhid_misc; |
| 67 | |
| 68 | static void uhid_device_add_worker(struct work_struct *work) |
| 69 | { |
| 70 | struct uhid_device *uhid = container_of(work, struct uhid_device, worker); |
| 71 | int ret; |
| 72 | |
| 73 | ret = hid_add_device(uhid->hid); |
| 74 | if (ret) { |
| 75 | hid_err(uhid->hid, "Cannot register HID device: error %d\n", ret); |
| 76 | |
| 77 | /* We used to call hid_destroy_device() here, but that's really |
| 78 | * messy to get right because we have to coordinate with |
| 79 | * concurrent writes from userspace that might be in the middle |
| 80 | * of using uhid->hid. |
| 81 | * Just leave uhid->hid as-is for now, and clean it up when |
| 82 | * userspace tries to close or reinitialize the uhid instance. |
| 83 | * |
| 84 | * However, we do have to clear the ->running flag and do a |
| 85 | * wakeup to make sure userspace knows that the device is gone. |
| 86 | */ |
| 87 | WRITE_ONCE(uhid->running, false); |
| 88 | wake_up_interruptible(&uhid->report_wait); |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev) |
| 93 | { |
| 94 | __u8 newhead; |
| 95 | |
| 96 | newhead = (uhid->head + 1) % UHID_BUFSIZE; |
| 97 | |
| 98 | if (newhead != uhid->tail) { |
| 99 | uhid->outq[uhid->head] = ev; |
| 100 | uhid->head = newhead; |
| 101 | wake_up_interruptible(&uhid->waitq); |
| 102 | } else { |
| 103 | hid_warn(uhid->hid, "Output queue is full\n"); |
| 104 | kfree(ev); |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | static int uhid_queue_event(struct uhid_device *uhid, __u32 event) |
| 109 | { |
| 110 | unsigned long flags; |
| 111 | struct uhid_event *ev; |
| 112 | |
| 113 | ev = kzalloc(sizeof(*ev), GFP_KERNEL); |
| 114 | if (!ev) |
| 115 | return -ENOMEM; |
| 116 | |
| 117 | ev->type = event; |
| 118 | |
| 119 | spin_lock_irqsave(&uhid->qlock, flags); |
| 120 | uhid_queue(uhid, ev); |
| 121 | spin_unlock_irqrestore(&uhid->qlock, flags); |
| 122 | |
| 123 | return 0; |
| 124 | } |
| 125 | |
| 126 | static int uhid_hid_start(struct hid_device *hid) |
| 127 | { |
| 128 | struct uhid_device *uhid = hid->driver_data; |
| 129 | struct uhid_event *ev; |
| 130 | unsigned long flags; |
| 131 | |
| 132 | ev = kzalloc(sizeof(*ev), GFP_KERNEL); |
| 133 | if (!ev) |
| 134 | return -ENOMEM; |
| 135 | |
| 136 | ev->type = UHID_START; |
| 137 | |
| 138 | if (hid->report_enum[HID_FEATURE_REPORT].numbered) |
| 139 | ev->u.start.dev_flags |= UHID_DEV_NUMBERED_FEATURE_REPORTS; |
| 140 | if (hid->report_enum[HID_OUTPUT_REPORT].numbered) |
| 141 | ev->u.start.dev_flags |= UHID_DEV_NUMBERED_OUTPUT_REPORTS; |
| 142 | if (hid->report_enum[HID_INPUT_REPORT].numbered) |
| 143 | ev->u.start.dev_flags |= UHID_DEV_NUMBERED_INPUT_REPORTS; |
| 144 | |
| 145 | spin_lock_irqsave(&uhid->qlock, flags); |
| 146 | uhid_queue(uhid, ev); |
| 147 | spin_unlock_irqrestore(&uhid->qlock, flags); |
| 148 | |
| 149 | return 0; |
| 150 | } |
| 151 | |
| 152 | static void uhid_hid_stop(struct hid_device *hid) |
| 153 | { |
| 154 | struct uhid_device *uhid = hid->driver_data; |
| 155 | |
| 156 | hid->claimed = 0; |
| 157 | uhid_queue_event(uhid, UHID_STOP); |
| 158 | } |
| 159 | |
| 160 | static int uhid_hid_open(struct hid_device *hid) |
| 161 | { |
| 162 | struct uhid_device *uhid = hid->driver_data; |
| 163 | |
| 164 | return uhid_queue_event(uhid, UHID_OPEN); |
| 165 | } |
| 166 | |
| 167 | static void uhid_hid_close(struct hid_device *hid) |
| 168 | { |
| 169 | struct uhid_device *uhid = hid->driver_data; |
| 170 | |
| 171 | uhid_queue_event(uhid, UHID_CLOSE); |
| 172 | } |
| 173 | |
| 174 | static int uhid_hid_parse(struct hid_device *hid) |
| 175 | { |
| 176 | struct uhid_device *uhid = hid->driver_data; |
| 177 | |
| 178 | return hid_parse_report(hid, uhid->rd_data, uhid->rd_size); |
| 179 | } |
| 180 | |
| 181 | /* must be called with report_lock held */ |
| 182 | static int __uhid_report_queue_and_wait(struct uhid_device *uhid, |
| 183 | struct uhid_event *ev, |
| 184 | __u32 *report_id) |
| 185 | { |
| 186 | unsigned long flags; |
| 187 | int ret; |
| 188 | |
| 189 | spin_lock_irqsave(&uhid->qlock, flags); |
| 190 | *report_id = ++uhid->report_id; |
| 191 | uhid->report_type = ev->type + 1; |
| 192 | uhid->report_running = true; |
| 193 | uhid_queue(uhid, ev); |
| 194 | spin_unlock_irqrestore(&uhid->qlock, flags); |
| 195 | |
| 196 | ret = wait_event_interruptible_timeout(uhid->report_wait, |
| 197 | !uhid->report_running || !READ_ONCE(uhid->running), |
| 198 | 5 * HZ); |
| 199 | if (!ret || !READ_ONCE(uhid->running) || uhid->report_running) |
| 200 | ret = -EIO; |
| 201 | else if (ret < 0) |
| 202 | ret = -ERESTARTSYS; |
| 203 | else |
| 204 | ret = 0; |
| 205 | |
| 206 | uhid->report_running = false; |
| 207 | |
| 208 | return ret; |
| 209 | } |
| 210 | |
| 211 | static void uhid_report_wake_up(struct uhid_device *uhid, u32 id, |
| 212 | const struct uhid_event *ev) |
| 213 | { |
| 214 | unsigned long flags; |
| 215 | |
| 216 | spin_lock_irqsave(&uhid->qlock, flags); |
| 217 | |
| 218 | /* id for old report; drop it silently */ |
| 219 | if (uhid->report_type != ev->type || uhid->report_id != id) |
| 220 | goto unlock; |
| 221 | if (!uhid->report_running) |
| 222 | goto unlock; |
| 223 | |
| 224 | memcpy(&uhid->report_buf, ev, sizeof(*ev)); |
| 225 | uhid->report_running = false; |
| 226 | wake_up_interruptible(&uhid->report_wait); |
| 227 | |
| 228 | unlock: |
| 229 | spin_unlock_irqrestore(&uhid->qlock, flags); |
| 230 | } |
| 231 | |
| 232 | static int uhid_hid_get_report(struct hid_device *hid, unsigned char rnum, |
| 233 | u8 *buf, size_t count, u8 rtype) |
| 234 | { |
| 235 | struct uhid_device *uhid = hid->driver_data; |
| 236 | struct uhid_get_report_reply_req *req; |
| 237 | struct uhid_event *ev; |
| 238 | int ret; |
| 239 | |
| 240 | if (!READ_ONCE(uhid->running)) |
| 241 | return -EIO; |
| 242 | |
| 243 | ev = kzalloc(sizeof(*ev), GFP_KERNEL); |
| 244 | if (!ev) |
| 245 | return -ENOMEM; |
| 246 | |
| 247 | ev->type = UHID_GET_REPORT; |
| 248 | ev->u.get_report.rnum = rnum; |
| 249 | ev->u.get_report.rtype = rtype; |
| 250 | |
| 251 | ret = mutex_lock_interruptible(&uhid->report_lock); |
| 252 | if (ret) { |
| 253 | kfree(ev); |
| 254 | return ret; |
| 255 | } |
| 256 | |
| 257 | /* this _always_ takes ownership of @ev */ |
| 258 | ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.get_report.id); |
| 259 | if (ret) |
| 260 | goto unlock; |
| 261 | |
| 262 | req = &uhid->report_buf.u.get_report_reply; |
| 263 | if (req->err) { |
| 264 | ret = -EIO; |
| 265 | } else { |
| 266 | ret = min3(count, (size_t)req->size, (size_t)UHID_DATA_MAX); |
| 267 | memcpy(buf, req->data, ret); |
| 268 | } |
| 269 | |
| 270 | unlock: |
| 271 | mutex_unlock(&uhid->report_lock); |
| 272 | return ret; |
| 273 | } |
| 274 | |
| 275 | static int uhid_hid_set_report(struct hid_device *hid, unsigned char rnum, |
| 276 | const u8 *buf, size_t count, u8 rtype) |
| 277 | { |
| 278 | struct uhid_device *uhid = hid->driver_data; |
| 279 | struct uhid_event *ev; |
| 280 | int ret; |
| 281 | |
| 282 | if (!READ_ONCE(uhid->running) || count > UHID_DATA_MAX) |
| 283 | return -EIO; |
| 284 | |
| 285 | ev = kzalloc(sizeof(*ev), GFP_KERNEL); |
| 286 | if (!ev) |
| 287 | return -ENOMEM; |
| 288 | |
| 289 | ev->type = UHID_SET_REPORT; |
| 290 | ev->u.set_report.rnum = rnum; |
| 291 | ev->u.set_report.rtype = rtype; |
| 292 | ev->u.set_report.size = count; |
| 293 | memcpy(ev->u.set_report.data, buf, count); |
| 294 | |
| 295 | ret = mutex_lock_interruptible(&uhid->report_lock); |
| 296 | if (ret) { |
| 297 | kfree(ev); |
| 298 | return ret; |
| 299 | } |
| 300 | |
| 301 | /* this _always_ takes ownership of @ev */ |
| 302 | ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.set_report.id); |
| 303 | if (ret) |
| 304 | goto unlock; |
| 305 | |
| 306 | if (uhid->report_buf.u.set_report_reply.err) |
| 307 | ret = -EIO; |
| 308 | else |
| 309 | ret = count; |
| 310 | |
| 311 | unlock: |
| 312 | mutex_unlock(&uhid->report_lock); |
| 313 | return ret; |
| 314 | } |
| 315 | |
| 316 | static int uhid_hid_raw_request(struct hid_device *hid, unsigned char reportnum, |
| 317 | __u8 *buf, size_t len, unsigned char rtype, |
| 318 | int reqtype) |
| 319 | { |
| 320 | u8 u_rtype; |
| 321 | |
| 322 | switch (rtype) { |
| 323 | case HID_FEATURE_REPORT: |
| 324 | u_rtype = UHID_FEATURE_REPORT; |
| 325 | break; |
| 326 | case HID_OUTPUT_REPORT: |
| 327 | u_rtype = UHID_OUTPUT_REPORT; |
| 328 | break; |
| 329 | case HID_INPUT_REPORT: |
| 330 | u_rtype = UHID_INPUT_REPORT; |
| 331 | break; |
| 332 | default: |
| 333 | return -EINVAL; |
| 334 | } |
| 335 | |
| 336 | switch (reqtype) { |
| 337 | case HID_REQ_GET_REPORT: |
| 338 | return uhid_hid_get_report(hid, reportnum, buf, len, u_rtype); |
| 339 | case HID_REQ_SET_REPORT: |
| 340 | return uhid_hid_set_report(hid, reportnum, buf, len, u_rtype); |
| 341 | default: |
| 342 | return -EIO; |
| 343 | } |
| 344 | } |
| 345 | |
| 346 | static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count, |
| 347 | unsigned char report_type) |
| 348 | { |
| 349 | struct uhid_device *uhid = hid->driver_data; |
| 350 | __u8 rtype; |
| 351 | unsigned long flags; |
| 352 | struct uhid_event *ev; |
| 353 | |
| 354 | switch (report_type) { |
| 355 | case HID_FEATURE_REPORT: |
| 356 | rtype = UHID_FEATURE_REPORT; |
| 357 | break; |
| 358 | case HID_OUTPUT_REPORT: |
| 359 | rtype = UHID_OUTPUT_REPORT; |
| 360 | break; |
| 361 | default: |
| 362 | return -EINVAL; |
| 363 | } |
| 364 | |
| 365 | if (count < 1 || count > UHID_DATA_MAX) |
| 366 | return -EINVAL; |
| 367 | |
| 368 | ev = kzalloc(sizeof(*ev), GFP_KERNEL); |
| 369 | if (!ev) |
| 370 | return -ENOMEM; |
| 371 | |
| 372 | ev->type = UHID_OUTPUT; |
| 373 | ev->u.output.size = count; |
| 374 | ev->u.output.rtype = rtype; |
| 375 | memcpy(ev->u.output.data, buf, count); |
| 376 | |
| 377 | spin_lock_irqsave(&uhid->qlock, flags); |
| 378 | uhid_queue(uhid, ev); |
| 379 | spin_unlock_irqrestore(&uhid->qlock, flags); |
| 380 | |
| 381 | return count; |
| 382 | } |
| 383 | |
| 384 | static int uhid_hid_output_report(struct hid_device *hid, __u8 *buf, |
| 385 | size_t count) |
| 386 | { |
| 387 | return uhid_hid_output_raw(hid, buf, count, HID_OUTPUT_REPORT); |
| 388 | } |
| 389 | |
| 390 | static const struct hid_ll_driver uhid_hid_driver = { |
| 391 | .start = uhid_hid_start, |
| 392 | .stop = uhid_hid_stop, |
| 393 | .open = uhid_hid_open, |
| 394 | .close = uhid_hid_close, |
| 395 | .parse = uhid_hid_parse, |
| 396 | .raw_request = uhid_hid_raw_request, |
| 397 | .output_report = uhid_hid_output_report, |
| 398 | .max_buffer_size = UHID_DATA_MAX, |
| 399 | }; |
| 400 | |
| 401 | #ifdef CONFIG_COMPAT |
| 402 | |
| 403 | /* Apparently we haven't stepped on these rakes enough times yet. */ |
| 404 | struct uhid_create_req_compat { |
| 405 | __u8 name[128]; |
| 406 | __u8 phys[64]; |
| 407 | __u8 uniq[64]; |
| 408 | |
| 409 | compat_uptr_t rd_data; |
| 410 | __u16 rd_size; |
| 411 | |
| 412 | __u16 bus; |
| 413 | __u32 vendor; |
| 414 | __u32 product; |
| 415 | __u32 version; |
| 416 | __u32 country; |
| 417 | } __attribute__((__packed__)); |
| 418 | |
| 419 | static int uhid_event_from_user(const char __user *buffer, size_t len, |
| 420 | struct uhid_event *event) |
| 421 | { |
| 422 | if (in_compat_syscall()) { |
| 423 | u32 type; |
| 424 | |
| 425 | if (get_user(type, buffer)) |
| 426 | return -EFAULT; |
| 427 | |
| 428 | if (type == UHID_CREATE) { |
| 429 | /* |
| 430 | * This is our messed up request with compat pointer. |
| 431 | * It is largish (more than 256 bytes) so we better |
| 432 | * allocate it from the heap. |
| 433 | */ |
| 434 | struct uhid_create_req_compat *compat; |
| 435 | |
| 436 | compat = kzalloc(sizeof(*compat), GFP_KERNEL); |
| 437 | if (!compat) |
| 438 | return -ENOMEM; |
| 439 | |
| 440 | buffer += sizeof(type); |
| 441 | len -= sizeof(type); |
| 442 | if (copy_from_user(compat, buffer, |
| 443 | min(len, sizeof(*compat)))) { |
| 444 | kfree(compat); |
| 445 | return -EFAULT; |
| 446 | } |
| 447 | |
| 448 | /* Shuffle the data over to proper structure */ |
| 449 | event->type = type; |
| 450 | |
| 451 | memcpy(event->u.create.name, compat->name, |
| 452 | sizeof(compat->name)); |
| 453 | memcpy(event->u.create.phys, compat->phys, |
| 454 | sizeof(compat->phys)); |
| 455 | memcpy(event->u.create.uniq, compat->uniq, |
| 456 | sizeof(compat->uniq)); |
| 457 | |
| 458 | event->u.create.rd_data = compat_ptr(compat->rd_data); |
| 459 | event->u.create.rd_size = compat->rd_size; |
| 460 | |
| 461 | event->u.create.bus = compat->bus; |
| 462 | event->u.create.vendor = compat->vendor; |
| 463 | event->u.create.product = compat->product; |
| 464 | event->u.create.version = compat->version; |
| 465 | event->u.create.country = compat->country; |
| 466 | |
| 467 | kfree(compat); |
| 468 | return 0; |
| 469 | } |
| 470 | /* All others can be copied directly */ |
| 471 | } |
| 472 | |
| 473 | if (copy_from_user(event, buffer, min(len, sizeof(*event)))) |
| 474 | return -EFAULT; |
| 475 | |
| 476 | return 0; |
| 477 | } |
| 478 | #else |
| 479 | static int uhid_event_from_user(const char __user *buffer, size_t len, |
| 480 | struct uhid_event *event) |
| 481 | { |
| 482 | if (copy_from_user(event, buffer, min(len, sizeof(*event)))) |
| 483 | return -EFAULT; |
| 484 | |
| 485 | return 0; |
| 486 | } |
| 487 | #endif |
| 488 | |
| 489 | static int uhid_dev_create2(struct uhid_device *uhid, |
| 490 | const struct uhid_event *ev) |
| 491 | { |
| 492 | struct hid_device *hid; |
| 493 | size_t rd_size; |
| 494 | void *rd_data; |
| 495 | int ret; |
| 496 | |
| 497 | if (uhid->hid) |
| 498 | return -EALREADY; |
| 499 | |
| 500 | rd_size = ev->u.create2.rd_size; |
| 501 | if (rd_size <= 0 || rd_size > HID_MAX_DESCRIPTOR_SIZE) |
| 502 | return -EINVAL; |
| 503 | |
| 504 | rd_data = kmemdup(ev->u.create2.rd_data, rd_size, GFP_KERNEL); |
| 505 | if (!rd_data) |
| 506 | return -ENOMEM; |
| 507 | |
| 508 | uhid->rd_size = rd_size; |
| 509 | uhid->rd_data = rd_data; |
| 510 | |
| 511 | hid = hid_allocate_device(); |
| 512 | if (IS_ERR(hid)) { |
| 513 | ret = PTR_ERR(hid); |
| 514 | goto err_free; |
| 515 | } |
| 516 | |
| 517 | BUILD_BUG_ON(sizeof(hid->name) != sizeof(ev->u.create2.name)); |
| 518 | strscpy(hid->name, ev->u.create2.name, sizeof(hid->name)); |
| 519 | BUILD_BUG_ON(sizeof(hid->phys) != sizeof(ev->u.create2.phys)); |
| 520 | strscpy(hid->phys, ev->u.create2.phys, sizeof(hid->phys)); |
| 521 | BUILD_BUG_ON(sizeof(hid->uniq) != sizeof(ev->u.create2.uniq)); |
| 522 | strscpy(hid->uniq, ev->u.create2.uniq, sizeof(hid->uniq)); |
| 523 | |
| 524 | hid->ll_driver = &uhid_hid_driver; |
| 525 | hid->bus = ev->u.create2.bus; |
| 526 | hid->vendor = ev->u.create2.vendor; |
| 527 | hid->product = ev->u.create2.product; |
| 528 | hid->version = ev->u.create2.version; |
| 529 | hid->country = ev->u.create2.country; |
| 530 | hid->driver_data = uhid; |
| 531 | hid->dev.parent = uhid_misc.this_device; |
| 532 | |
| 533 | uhid->hid = hid; |
| 534 | uhid->running = true; |
| 535 | |
| 536 | /* Adding of a HID device is done through a worker, to allow HID drivers |
| 537 | * which use feature requests during .probe to work, without they would |
| 538 | * be blocked on devlock, which is held by uhid_char_write. |
| 539 | */ |
| 540 | schedule_work(&uhid->worker); |
| 541 | |
| 542 | return 0; |
| 543 | |
| 544 | err_free: |
| 545 | kfree(uhid->rd_data); |
| 546 | uhid->rd_data = NULL; |
| 547 | uhid->rd_size = 0; |
| 548 | return ret; |
| 549 | } |
| 550 | |
| 551 | static int uhid_dev_create(struct uhid_device *uhid, |
| 552 | struct uhid_event *ev) |
| 553 | { |
| 554 | struct uhid_create_req orig; |
| 555 | |
| 556 | orig = ev->u.create; |
| 557 | |
| 558 | if (orig.rd_size <= 0 || orig.rd_size > HID_MAX_DESCRIPTOR_SIZE) |
| 559 | return -EINVAL; |
| 560 | if (copy_from_user(&ev->u.create2.rd_data, orig.rd_data, orig.rd_size)) |
| 561 | return -EFAULT; |
| 562 | |
| 563 | memcpy(ev->u.create2.name, orig.name, sizeof(orig.name)); |
| 564 | memcpy(ev->u.create2.phys, orig.phys, sizeof(orig.phys)); |
| 565 | memcpy(ev->u.create2.uniq, orig.uniq, sizeof(orig.uniq)); |
| 566 | ev->u.create2.rd_size = orig.rd_size; |
| 567 | ev->u.create2.bus = orig.bus; |
| 568 | ev->u.create2.vendor = orig.vendor; |
| 569 | ev->u.create2.product = orig.product; |
| 570 | ev->u.create2.version = orig.version; |
| 571 | ev->u.create2.country = orig.country; |
| 572 | |
| 573 | return uhid_dev_create2(uhid, ev); |
| 574 | } |
| 575 | |
| 576 | static int uhid_dev_destroy(struct uhid_device *uhid) |
| 577 | { |
| 578 | if (!uhid->hid) |
| 579 | return -EINVAL; |
| 580 | |
| 581 | WRITE_ONCE(uhid->running, false); |
| 582 | wake_up_interruptible(&uhid->report_wait); |
| 583 | |
| 584 | cancel_work_sync(&uhid->worker); |
| 585 | |
| 586 | hid_destroy_device(uhid->hid); |
| 587 | uhid->hid = NULL; |
| 588 | kfree(uhid->rd_data); |
| 589 | |
| 590 | return 0; |
| 591 | } |
| 592 | |
| 593 | static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev) |
| 594 | { |
| 595 | if (!READ_ONCE(uhid->running)) |
| 596 | return -EINVAL; |
| 597 | |
| 598 | hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data, |
| 599 | min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0); |
| 600 | |
| 601 | return 0; |
| 602 | } |
| 603 | |
| 604 | static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev) |
| 605 | { |
| 606 | if (!READ_ONCE(uhid->running)) |
| 607 | return -EINVAL; |
| 608 | |
| 609 | hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data, |
| 610 | min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0); |
| 611 | |
| 612 | return 0; |
| 613 | } |
| 614 | |
| 615 | static int uhid_dev_get_report_reply(struct uhid_device *uhid, |
| 616 | struct uhid_event *ev) |
| 617 | { |
| 618 | if (!READ_ONCE(uhid->running)) |
| 619 | return -EINVAL; |
| 620 | |
| 621 | uhid_report_wake_up(uhid, ev->u.get_report_reply.id, ev); |
| 622 | return 0; |
| 623 | } |
| 624 | |
| 625 | static int uhid_dev_set_report_reply(struct uhid_device *uhid, |
| 626 | struct uhid_event *ev) |
| 627 | { |
| 628 | if (!READ_ONCE(uhid->running)) |
| 629 | return -EINVAL; |
| 630 | |
| 631 | uhid_report_wake_up(uhid, ev->u.set_report_reply.id, ev); |
| 632 | return 0; |
| 633 | } |
| 634 | |
| 635 | static int uhid_char_open(struct inode *inode, struct file *file) |
| 636 | { |
| 637 | struct uhid_device *uhid; |
| 638 | |
| 639 | uhid = kzalloc(sizeof(*uhid), GFP_KERNEL); |
| 640 | if (!uhid) |
| 641 | return -ENOMEM; |
| 642 | |
| 643 | mutex_init(&uhid->devlock); |
| 644 | mutex_init(&uhid->report_lock); |
| 645 | spin_lock_init(&uhid->qlock); |
| 646 | init_waitqueue_head(&uhid->waitq); |
| 647 | init_waitqueue_head(&uhid->report_wait); |
| 648 | uhid->running = false; |
| 649 | INIT_WORK(&uhid->worker, uhid_device_add_worker); |
| 650 | |
| 651 | file->private_data = uhid; |
| 652 | stream_open(inode, file); |
| 653 | |
| 654 | return 0; |
| 655 | } |
| 656 | |
| 657 | static int uhid_char_release(struct inode *inode, struct file *file) |
| 658 | { |
| 659 | struct uhid_device *uhid = file->private_data; |
| 660 | unsigned int i; |
| 661 | |
| 662 | uhid_dev_destroy(uhid); |
| 663 | |
| 664 | for (i = 0; i < UHID_BUFSIZE; ++i) |
| 665 | kfree(uhid->outq[i]); |
| 666 | |
| 667 | kfree(uhid); |
| 668 | |
| 669 | return 0; |
| 670 | } |
| 671 | |
| 672 | static ssize_t uhid_char_read(struct file *file, char __user *buffer, |
| 673 | size_t count, loff_t *ppos) |
| 674 | { |
| 675 | struct uhid_device *uhid = file->private_data; |
| 676 | int ret; |
| 677 | unsigned long flags; |
| 678 | size_t len; |
| 679 | |
| 680 | /* they need at least the "type" member of uhid_event */ |
| 681 | if (count < sizeof(__u32)) |
| 682 | return -EINVAL; |
| 683 | |
| 684 | try_again: |
| 685 | if (file->f_flags & O_NONBLOCK) { |
| 686 | if (uhid->head == uhid->tail) |
| 687 | return -EAGAIN; |
| 688 | } else { |
| 689 | ret = wait_event_interruptible(uhid->waitq, |
| 690 | uhid->head != uhid->tail); |
| 691 | if (ret) |
| 692 | return ret; |
| 693 | } |
| 694 | |
| 695 | ret = mutex_lock_interruptible(&uhid->devlock); |
| 696 | if (ret) |
| 697 | return ret; |
| 698 | |
| 699 | if (uhid->head == uhid->tail) { |
| 700 | mutex_unlock(&uhid->devlock); |
| 701 | goto try_again; |
| 702 | } else { |
| 703 | len = min(count, sizeof(**uhid->outq)); |
| 704 | if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) { |
| 705 | ret = -EFAULT; |
| 706 | } else { |
| 707 | kfree(uhid->outq[uhid->tail]); |
| 708 | uhid->outq[uhid->tail] = NULL; |
| 709 | |
| 710 | spin_lock_irqsave(&uhid->qlock, flags); |
| 711 | uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE; |
| 712 | spin_unlock_irqrestore(&uhid->qlock, flags); |
| 713 | } |
| 714 | } |
| 715 | |
| 716 | mutex_unlock(&uhid->devlock); |
| 717 | return ret ? ret : len; |
| 718 | } |
| 719 | |
| 720 | static ssize_t uhid_char_write(struct file *file, const char __user *buffer, |
| 721 | size_t count, loff_t *ppos) |
| 722 | { |
| 723 | struct uhid_device *uhid = file->private_data; |
| 724 | int ret; |
| 725 | size_t len; |
| 726 | |
| 727 | /* we need at least the "type" member of uhid_event */ |
| 728 | if (count < sizeof(__u32)) |
| 729 | return -EINVAL; |
| 730 | |
| 731 | ret = mutex_lock_interruptible(&uhid->devlock); |
| 732 | if (ret) |
| 733 | return ret; |
| 734 | |
| 735 | memset(&uhid->input_buf, 0, sizeof(uhid->input_buf)); |
| 736 | len = min(count, sizeof(uhid->input_buf)); |
| 737 | |
| 738 | ret = uhid_event_from_user(buffer, len, &uhid->input_buf); |
| 739 | if (ret) |
| 740 | goto unlock; |
| 741 | |
| 742 | switch (uhid->input_buf.type) { |
| 743 | case UHID_CREATE: |
| 744 | /* |
| 745 | * 'struct uhid_create_req' contains a __user pointer which is |
| 746 | * copied from, so it's unsafe to allow this with elevated |
| 747 | * privileges (e.g. from a setuid binary) or via kernel_write(). |
| 748 | */ |
| 749 | if (file->f_cred != current_cred()) { |
| 750 | pr_err_once("UHID_CREATE from different security context by process %d (%s), this is not allowed.\n", |
| 751 | task_tgid_vnr(current), current->comm); |
| 752 | ret = -EACCES; |
| 753 | goto unlock; |
| 754 | } |
| 755 | ret = uhid_dev_create(uhid, &uhid->input_buf); |
| 756 | break; |
| 757 | case UHID_CREATE2: |
| 758 | ret = uhid_dev_create2(uhid, &uhid->input_buf); |
| 759 | break; |
| 760 | case UHID_DESTROY: |
| 761 | ret = uhid_dev_destroy(uhid); |
| 762 | break; |
| 763 | case UHID_INPUT: |
| 764 | ret = uhid_dev_input(uhid, &uhid->input_buf); |
| 765 | break; |
| 766 | case UHID_INPUT2: |
| 767 | ret = uhid_dev_input2(uhid, &uhid->input_buf); |
| 768 | break; |
| 769 | case UHID_GET_REPORT_REPLY: |
| 770 | ret = uhid_dev_get_report_reply(uhid, &uhid->input_buf); |
| 771 | break; |
| 772 | case UHID_SET_REPORT_REPLY: |
| 773 | ret = uhid_dev_set_report_reply(uhid, &uhid->input_buf); |
| 774 | break; |
| 775 | default: |
| 776 | ret = -EOPNOTSUPP; |
| 777 | } |
| 778 | |
| 779 | unlock: |
| 780 | mutex_unlock(&uhid->devlock); |
| 781 | |
| 782 | /* return "count" not "len" to not confuse the caller */ |
| 783 | return ret ? ret : count; |
| 784 | } |
| 785 | |
| 786 | static __poll_t uhid_char_poll(struct file *file, poll_table *wait) |
| 787 | { |
| 788 | struct uhid_device *uhid = file->private_data; |
| 789 | __poll_t mask = EPOLLOUT | EPOLLWRNORM; /* uhid is always writable */ |
| 790 | |
| 791 | poll_wait(file, &uhid->waitq, wait); |
| 792 | |
| 793 | if (uhid->head != uhid->tail) |
| 794 | mask |= EPOLLIN | EPOLLRDNORM; |
| 795 | |
| 796 | return mask; |
| 797 | } |
| 798 | |
| 799 | static const struct file_operations uhid_fops = { |
| 800 | .owner = THIS_MODULE, |
| 801 | .open = uhid_char_open, |
| 802 | .release = uhid_char_release, |
| 803 | .read = uhid_char_read, |
| 804 | .write = uhid_char_write, |
| 805 | .poll = uhid_char_poll, |
| 806 | .llseek = no_llseek, |
| 807 | }; |
| 808 | |
| 809 | static struct miscdevice uhid_misc = { |
| 810 | .fops = &uhid_fops, |
| 811 | .minor = UHID_MINOR, |
| 812 | .name = UHID_NAME, |
| 813 | }; |
| 814 | module_misc_device(uhid_misc); |
| 815 | |
| 816 | MODULE_LICENSE("GPL"); |
| 817 | MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>"); |
| 818 | MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem"); |
| 819 | MODULE_ALIAS_MISCDEV(UHID_MINOR); |
| 820 | MODULE_ALIAS("devname:" UHID_NAME); |