drivers/usb/core/config.c

   1 #include <linux/usb.h>
   2 #include <linux/module.h>
   3 #include <linux/init.h>
   4 #include <linux/slab.h>
   5 #include <linux/device.h>
   6 #include <asm/byteorder.h>
   7 #include "usb.h"
   8 #include "hcd.h"
   9
  10 #define USB_MAXALTSETTING               128     /* Hard limit */
  11 #define USB_MAXENDPOINTS                30      /* Hard limit */
  12
  13 #define USB_MAXCONFIG                   8       /* Arbitrary limit */
  14
  15
  16 static inline const char *plural(int n)
  17 {
  18         return (n == 1 ? "" : "s");
  19 }
  20
  21 static int find_next_descriptor(unsigned char *buffer, int size,
  22     int dt1, int dt2, int *num_skipped)
  23 {
  24         struct usb_descriptor_header *h;
  25         int n = 0;
  26         unsigned char *buffer0 = buffer;
  27
  28         /* Find the next descriptor of type dt1 or dt2 */
  29         while (size > 0) {
  30                 h = (struct usb_descriptor_header *) buffer;
  31                 if (h->bDescriptorType == dt1 || h->bDescriptorType == dt2)
  32                         break;
  33                 buffer += h->bLength;
  34                 size -= h->bLength;
  35                 ++n;
  36         }
  37
  38         /* Store the number of descriptors skipped and return the
  39          * number of bytes skipped */
  40         if (num_skipped)
  41                 *num_skipped = n;
  42         return buffer - buffer0;
  43 }
  44
  45 static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
  46     int asnum, struct usb_host_interface *ifp, int num_ep,
  47     unsigned char *buffer, int size)
  48 {
  49         unsigned char *buffer0 = buffer;
  50         struct usb_endpoint_descriptor *d;
  51         struct usb_host_endpoint *endpoint;
  52         int n, i;
  53
  54         d = (struct usb_endpoint_descriptor *) buffer;
  55         buffer += d->bLength;
  56         size -= d->bLength;
  57
  58         if (d->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE)
  59                 n = USB_DT_ENDPOINT_AUDIO_SIZE;
  60         else if (d->bLength >= USB_DT_ENDPOINT_SIZE)
  61                 n = USB_DT_ENDPOINT_SIZE;
  62         else {
  63                 dev_warn(ddev, "config %d interface %d altsetting %d has an "
  64                     "invalid endpoint descriptor of length %d, skipping\n",
  65                     cfgno, inum, asnum, d->bLength);
  66                 goto skip_to_next_endpoint_or_interface_descriptor;
  67         }
  68
  69         i = d->bEndpointAddress & ~USB_ENDPOINT_DIR_MASK;
  70         if (i >= 16 || i == 0) {
  71                 dev_warn(ddev, "config %d interface %d altsetting %d has an "
  72                     "invalid endpoint with address 0x%X, skipping\n",
  73                     cfgno, inum, asnum, d->bEndpointAddress);
  74                 goto skip_to_next_endpoint_or_interface_descriptor;
  75         }
  76
  77         /* Only store as many endpoints as we have room for */
  78         if (ifp->desc.bNumEndpoints >= num_ep)
  79                 goto skip_to_next_endpoint_or_interface_descriptor;
  80
  81         endpoint = &ifp->endpoint[ifp->desc.bNumEndpoints];
  82         ++ifp->desc.bNumEndpoints;
  83
  84         memcpy(&endpoint->desc, d, n);
  85         INIT_LIST_HEAD(&endpoint->urb_list);
  86
  87         /* Skip over any Class Specific or Vendor Specific descriptors;
  88          * find the next endpoint or interface descriptor */
  89         endpoint->extra = buffer;
  90         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
  91             USB_DT_INTERFACE, &n);
  92         endpoint->extralen = i;
  93         if (n > 0)
  94                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
  95                     n, plural(n), "endpoint");
  96         return buffer - buffer0 + i;
  97
  98 skip_to_next_endpoint_or_interface_descriptor:
  99         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 100             USB_DT_INTERFACE, NULL);
 101         return buffer - buffer0 + i;
 102 }
 103
 104 void usb_release_interface_cache(struct kref *ref)
 105 {
 106         struct usb_interface_cache *intfc = ref_to_usb_interface_cache(ref);
 107         int j;
 108
 109         for (j = 0; j < intfc->num_altsetting; j++) {
 110                 struct usb_host_interface *alt = &intfc->altsetting[j];
 111
 112                 kfree(alt->endpoint);
 113                 kfree(alt->string);
 114         }
 115         kfree(intfc);
 116 }
 117
 118 static int usb_parse_interface(struct device *ddev, int cfgno,
 119     struct usb_host_config *config, unsigned char *buffer, int size,
 120     u8 inums[], u8 nalts[])
 121 {
 122         unsigned char *buffer0 = buffer;
 123         struct usb_interface_descriptor *d;
 124         int inum, asnum;
 125         struct usb_interface_cache *intfc;
 126         struct usb_host_interface *alt;
 127         int i, n;
 128         int len, retval;
 129         int num_ep, num_ep_orig;
 130
 131         d = (struct usb_interface_descriptor *) buffer;
 132         buffer += d->bLength;
 133         size -= d->bLength;
 134
 135         if (d->bLength < USB_DT_INTERFACE_SIZE)
 136                 goto skip_to_next_interface_descriptor;
 137
 138         /* Which interface entry is this? */
 139         intfc = NULL;
 140         inum = d->bInterfaceNumber;
 141         for (i = 0; i < config->desc.bNumInterfaces; ++i) {
 142                 if (inums[i] == inum) {
 143                         intfc = config->intf_cache[i];
 144                         break;
 145                 }
 146         }
 147         if (!intfc || intfc->num_altsetting >= nalts[i])
 148                 goto skip_to_next_interface_descriptor;
 149
 150         /* Check for duplicate altsetting entries */
 151         asnum = d->bAlternateSetting;
 152         for ((i = 0, alt = &intfc->altsetting[0]);
 153               i < intfc->num_altsetting;
 154              (++i, ++alt)) {
 155                 if (alt->desc.bAlternateSetting == asnum) {
 156                         dev_warn(ddev, "Duplicate descriptor for config %d "
 157                             "interface %d altsetting %d, skipping\n",
 158                             cfgno, inum, asnum);
 159                         goto skip_to_next_interface_descriptor;
 160                 }
 161         }
 162
 163         ++intfc->num_altsetting;
 164         memcpy(&alt->desc, d, USB_DT_INTERFACE_SIZE);
 165
 166         /* Skip over any Class Specific or Vendor Specific descriptors;
 167          * find the first endpoint or interface descriptor */
 168         alt->extra = buffer;
 169         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 170             USB_DT_INTERFACE, &n);
 171         alt->extralen = i;
 172         if (n > 0)
 173                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 174                     n, plural(n), "interface");
 175         buffer += i;
 176         size -= i;
 177
 178         /* Allocate space for the right(?) number of endpoints */
 179         num_ep = num_ep_orig = alt->desc.bNumEndpoints;
 180         alt->desc.bNumEndpoints = 0;            // Use as a counter
 181         if (num_ep > USB_MAXENDPOINTS) {
 182                 dev_warn(ddev, "too many endpoints for config %d interface %d "
 183                     "altsetting %d: %d, using maximum allowed: %d\n",
 184                     cfgno, inum, asnum, num_ep, USB_MAXENDPOINTS);
 185                 num_ep = USB_MAXENDPOINTS;
 186         }
 187
 188         len = sizeof(struct usb_host_endpoint) * num_ep;
 189         alt->endpoint = kzalloc(len, GFP_KERNEL);
 190         if (!alt->endpoint)
 191                 return -ENOMEM;
 192
 193         /* Parse all the endpoint descriptors */
 194         n = 0;
 195         while (size > 0) {
 196                 if (((struct usb_descriptor_header *) buffer)->bDescriptorType
 197                      == USB_DT_INTERFACE)
 198                         break;
 199                 retval = usb_parse_endpoint(ddev, cfgno, inum, asnum, alt,
 200                     num_ep, buffer, size);
 201                 if (retval < 0)
 202                         return retval;
 203                 ++n;
 204
 205                 buffer += retval;
 206                 size -= retval;
 207         }
 208
 209         if (n != num_ep_orig)
 210                 dev_warn(ddev, "config %d interface %d altsetting %d has %d "
 211                     "endpoint descriptor%s, different from the interface "
 212                     "descriptor's value: %d\n",
 213                     cfgno, inum, asnum, n, plural(n), num_ep_orig);
 214         return buffer - buffer0;
 215
 216 skip_to_next_interface_descriptor:
 217         i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
 218             USB_DT_INTERFACE, NULL);
 219         return buffer - buffer0 + i;
 220 }
 221
 222 static int usb_parse_configuration(struct device *ddev, int cfgidx,
 223     struct usb_host_config *config, unsigned char *buffer, int size)
 224 {
 225         unsigned char *buffer0 = buffer;
 226         int cfgno;
 227         int nintf, nintf_orig;
 228         int i, j, n;
 229         struct usb_interface_cache *intfc;
 230         unsigned char *buffer2;
 231         int size2;
 232         struct usb_descriptor_header *header;
 233         int len, retval;
 234         u8 inums[USB_MAXINTERFACES], nalts[USB_MAXINTERFACES];
 235
 236         memcpy(&config->desc, buffer, USB_DT_CONFIG_SIZE);
 237         if (config->desc.bDescriptorType != USB_DT_CONFIG ||
 238             config->desc.bLength < USB_DT_CONFIG_SIZE) {
 239                 dev_err(ddev, "invalid descriptor for config index %d: "
 240                     "type = 0x%X, length = %d\n", cfgidx,
 241                     config->desc.bDescriptorType, config->desc.bLength);
 242                 return -EINVAL;
 243         }
 244         cfgno = config->desc.bConfigurationValue;
 245
 246         buffer += config->desc.bLength;
 247         size -= config->desc.bLength;
 248
 249         nintf = nintf_orig = config->desc.bNumInterfaces;
 250         if (nintf > USB_MAXINTERFACES) {
 251                 dev_warn(ddev, "config %d has too many interfaces: %d, "
 252                     "using maximum allowed: %d\n",
 253                     cfgno, nintf, USB_MAXINTERFACES);
 254                 nintf = USB_MAXINTERFACES;
 255         }
 256
 257         /* Go through the descriptors, checking their length and counting the
 258          * number of altsettings for each interface */
 259         n = 0;
 260         for ((buffer2 = buffer, size2 = size);
 261               size2 > 0;
 262              (buffer2 += header->bLength, size2 -= header->bLength)) {
 263
 264                 if (size2 < sizeof(struct usb_descriptor_header)) {
 265                         dev_warn(ddev, "config %d descriptor has %d excess "
 266                             "byte%s, ignoring\n",
 267                             cfgno, size2, plural(size2));
 268                         break;
 269                 }
 270
 271                 header = (struct usb_descriptor_header *) buffer2;
 272                 if ((header->bLength > size2) || (header->bLength < 2)) {
 273                         dev_warn(ddev, "config %d has an invalid descriptor "
 274                             "of length %d, skipping remainder of the config\n",
 275                             cfgno, header->bLength);
 276                         break;
 277                 }
 278
 279                 if (header->bDescriptorType == USB_DT_INTERFACE) {
 280                         struct usb_interface_descriptor *d;
 281                         int inum;
 282
 283                         d = (struct usb_interface_descriptor *) header;
 284                         if (d->bLength < USB_DT_INTERFACE_SIZE) {
 285                                 dev_warn(ddev, "config %d has an invalid "
 286                                     "interface descriptor of length %d, "
 287                                     "skipping\n", cfgno, d->bLength);
 288                                 continue;
 289                         }
 290
 291                         inum = d->bInterfaceNumber;
 292                         if (inum >= nintf_orig)
 293                                 dev_warn(ddev, "config %d has an invalid "
 294                                     "interface number: %d but max is %d\n",
 295                                     cfgno, inum, nintf_orig - 1);
 296
 297                         /* Have we already encountered this interface?
 298                          * Count its altsettings */
 299                         for (i = 0; i < n; ++i) {
 300                                 if (inums[i] == inum)
 301                                         break;
 302                         }
 303                         if (i < n) {
 304                                 if (nalts[i] < 255)
 305                                         ++nalts[i];
 306                         } else if (n < USB_MAXINTERFACES) {
 307                                 inums[n] = inum;
 308                                 nalts[n] = 1;
 309                                 ++n;
 310                         }
 311
 312                 } else if (header->bDescriptorType == USB_DT_DEVICE ||
 313                             header->bDescriptorType == USB_DT_CONFIG)
 314                         dev_warn(ddev, "config %d contains an unexpected "
 315                             "descriptor of type 0x%X, skipping\n",
 316                             cfgno, header->bDescriptorType);
 317
 318         }       /* for ((buffer2 = buffer, size2 = size); ...) */
 319         size = buffer2 - buffer;
 320         config->desc.wTotalLength = cpu_to_le16(buffer2 - buffer0);
 321
 322         if (n != nintf)
 323                 dev_warn(ddev, "config %d has %d interface%s, different from "
 324                     "the descriptor's value: %d\n",
 325                     cfgno, n, plural(n), nintf_orig);
 326         else if (n == 0)
 327                 dev_warn(ddev, "config %d has no interfaces?\n", cfgno);
 328         config->desc.bNumInterfaces = nintf = n;
 329
 330         /* Check for missing interface numbers */
 331         for (i = 0; i < nintf; ++i) {
 332                 for (j = 0; j < nintf; ++j) {
 333                         if (inums[j] == i)
 334                                 break;
 335                 }
 336                 if (j >= nintf)
 337                         dev_warn(ddev, "config %d has no interface number "
 338                             "%d\n", cfgno, i);
 339         }
 340
 341         /* Allocate the usb_interface_caches and altsetting arrays */
 342         for (i = 0; i < nintf; ++i) {
 343                 j = nalts[i];
 344                 if (j > USB_MAXALTSETTING) {
 345                         dev_warn(ddev, "too many alternate settings for "
 346                             "config %d interface %d: %d, "
 347                             "using maximum allowed: %d\n",
 348                             cfgno, inums[i], j, USB_MAXALTSETTING);
 349                         nalts[i] = j = USB_MAXALTSETTING;
 350                 }
 351
 352                 len = sizeof(*intfc) + sizeof(struct usb_host_interface) * j;
 353                 config->intf_cache[i] = intfc = kzalloc(len, GFP_KERNEL);
 354                 if (!intfc)
 355                         return -ENOMEM;
 356                 kref_init(&intfc->ref);
 357         }
 358
 359         /* Skip over any Class Specific or Vendor Specific descriptors;
 360          * find the first interface descriptor */
 361         config->extra = buffer;
 362         i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
 363             USB_DT_INTERFACE, &n);
 364         config->extralen = i;
 365         if (n > 0)
 366                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 367                     n, plural(n), "configuration");
 368         buffer += i;
 369         size -= i;
 370
 371         /* Parse all the interface/altsetting descriptors */
 372         while (size > 0) {
 373                 retval = usb_parse_interface(ddev, cfgno, config,
 374                     buffer, size, inums, nalts);
 375                 if (retval < 0)
 376                         return retval;
 377
 378                 buffer += retval;
 379                 size -= retval;
 380         }
 381
 382         /* Check for missing altsettings */
 383         for (i = 0; i < nintf; ++i) {
 384                 intfc = config->intf_cache[i];
 385                 for (j = 0; j < intfc->num_altsetting; ++j) {
 386                         for (n = 0; n < intfc->num_altsetting; ++n) {
 387                                 if (intfc->altsetting[n].desc.
 388                                     bAlternateSetting == j)
 389                                         break;
 390                         }
 391                         if (n >= intfc->num_altsetting)
 392                                 dev_warn(ddev, "config %d interface %d has no "
 393                                     "altsetting %d\n", cfgno, inums[i], j);
 394                 }
 395         }
 396
 397         return 0;
 398 }
 399
 400 // hub-only!! ... and only exported for reset/reinit path.
 401 // otherwise used internally on disconnect/destroy path
 402 void usb_destroy_configuration(struct usb_device *dev)
 403 {
 404         int c, i;
 405
 406         if (!dev->config)
 407                 return;
 408
 409         if (dev->rawdescriptors) {
 410                 for (i = 0; i < dev->descriptor.bNumConfigurations; i++)
 411                         kfree(dev->rawdescriptors[i]);
 412
 413                 kfree(dev->rawdescriptors);
 414                 dev->rawdescriptors = NULL;
 415         }
 416
 417         for (c = 0; c < dev->descriptor.bNumConfigurations; c++) {
 418                 struct usb_host_config *cf = &dev->config[c];
 419
 420                 kfree(cf->string);
 421                 for (i = 0; i < cf->desc.bNumInterfaces; i++) {
 422                         if (cf->intf_cache[i])
 423                                 kref_put(&cf->intf_cache[i]->ref,
 424                                           usb_release_interface_cache);
 425                 }
 426         }
 427         kfree(dev->config);
 428         dev->config = NULL;
 429 }
 430
 431
 432 // hub-only!! ... and only in reset path, or usb_new_device()
 433 // (used by real hubs and virtual root hubs)
 434 int usb_get_configuration(struct usb_device *dev)
 435 {
 436         struct device *ddev = &dev->dev;
 437         int ncfg = dev->descriptor.bNumConfigurations;
 438         int result = -ENOMEM;
 439         unsigned int cfgno, length;
 440         unsigned char *buffer;
 441         unsigned char *bigbuffer;
 442         struct usb_config_descriptor *desc;
 443
 444         if (ncfg > USB_MAXCONFIG) {
 445                 dev_warn(ddev, "too many configurations: %d, "
 446                     "using maximum allowed: %d\n", ncfg, USB_MAXCONFIG);
 447                 dev->descriptor.bNumConfigurations = ncfg = USB_MAXCONFIG;
 448         }
 449
 450         if (ncfg < 1) {
 451                 dev_err(ddev, "no configurations\n");
 452                 return -EINVAL;
 453         }
 454
 455         length = ncfg * sizeof(struct usb_host_config);
 456         dev->config = kzalloc(length, GFP_KERNEL);
 457         if (!dev->config)
 458                 goto err2;
 459
 460         length = ncfg * sizeof(char *);
 461         dev->rawdescriptors = kzalloc(length, GFP_KERNEL);
 462         if (!dev->rawdescriptors)
 463                 goto err2;
 464
 465         buffer = kmalloc(USB_DT_CONFIG_SIZE, GFP_KERNEL);
 466         if (!buffer)
 467                 goto err2;
 468         desc = (struct usb_config_descriptor *)buffer;
 469
 470         for (cfgno = 0; cfgno < ncfg; cfgno++) {
 471                 /* We grab just the first descriptor so we know how long
 472                  * the whole configuration is */
 473                 result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
 474                     buffer, USB_DT_CONFIG_SIZE);
 475                 if (result < 0) {
 476                         dev_err(ddev, "unable to read config index %d "
 477                             "descriptor/%s\n", cfgno, "start");
 478                         dev_err(ddev, "chopping to %d config(s)\n", cfgno);
 479                         dev->descriptor.bNumConfigurations = cfgno;
 480                         break;
 481                 } else if (result < 4) {
 482                         dev_err(ddev, "config index %d descriptor too short "
 483                             "(expected %i, got %i)\n", cfgno,
 484                             USB_DT_CONFIG_SIZE, result);
 485                         result = -EINVAL;
 486                         goto err;
 487                 }
 488                 length = max((int) le16_to_cpu(desc->wTotalLength),
 489                     USB_DT_CONFIG_SIZE);
 490
 491                 /* Now that we know the length, get the whole thing */
 492                 bigbuffer = kmalloc(length, GFP_KERNEL);
 493                 if (!bigbuffer) {
 494                         result = -ENOMEM;
 495                         goto err;
 496                 }
 497                 result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
 498                     bigbuffer, length);
 499                 if (result < 0) {
 500                         dev_err(ddev, "unable to read config index %d "
 501                             "descriptor/%s\n", cfgno, "all");
 502                         kfree(bigbuffer);
 503                         goto err;
 504                 }
 505                 if (result < length) {
 506                         dev_warn(ddev, "config index %d descriptor too short "
 507                             "(expected %i, got %i)\n", cfgno, length, result);
 508                         length = result;
 509                 }
 510
 511                 dev->rawdescriptors[cfgno] = bigbuffer;
 512
 513                 result = usb_parse_configuration(&dev->dev, cfgno,
 514                     &dev->config[cfgno], bigbuffer, length);
 515                 if (result < 0) {
 516                         ++cfgno;
 517                         goto err;
 518                 }
 519         }
 520         result = 0;
 521
 522 err:
 523         kfree(buffer);
 524         dev->descriptor.bNumConfigurations = cfgno;
 525 err2:
 526         if (result == -ENOMEM)
 527                 dev_err(ddev, "out of memory\n");
 528         return result;
 529 }