drivers/usb/core/config.c

   1 #include <linux/config.h>
   2
   3 #ifdef CONFIG_USB_DEBUG
   4 #define DEBUG
   5 #endif
   6
   7 #include <linux/usb.h>
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/slab.h>
  11 #include <linux/device.h>
  12 #include <asm/byteorder.h>
  13 #include "usb.h"
  14 #include "hcd.h"
  15
  16 #define USB_MAXALTSETTING               128     /* Hard limit */
  17 #define USB_MAXENDPOINTS                30      /* Hard limit */
  18
  19 #define USB_MAXCONFIG                   8       /* Arbitrary limit */
  20
  21
  22 static inline const char *plural(int n)
  23 {
  24         return (n == 1 ? "" : "s");
  25 }
  26
  27 static int find_next_descriptor(unsigned char *buffer, int size,
  28     int dt1, int dt2, int *num_skipped)
  29 {
  30         struct usb_descriptor_header *h;
  31         int n = 0;
  32         unsigned char *buffer0 = buffer;
  33
  34         /* Find the next descriptor of type dt1 or dt2 */
  35         while (size > 0) {
  36                 h = (struct usb_descriptor_header *) buffer;
  37                 if (h->bDescriptorType == dt1 || h->bDescriptorType == dt2)
  38                         break;
  39                 buffer += h->bLength;
  40                 size -= h->bLength;
  41                 ++n;
  42         }
  43
  44         /* Store the number of descriptors skipped and return the
  45          * number of bytes skipped */
  46         if (num_skipped)
  47                 *num_skipped = n;
  48         return buffer - buffer0;
  49 }
  50
  51 static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
  52     int asnum, struct usb_host_interface *ifp, int num_ep,
  53     unsigned char *buffer, int size)
  54 {
  55         unsigned char *buffer0 = buffer;
  56         struct usb_endpoint_descriptor *d;
  57         struct usb_host_endpoint *endpoint;
  58         int n, i;
  59
  60         d = (struct usb_endpoint_descriptor *) buffer;
  61         buffer += d->bLength;
  62         size -= d->bLength;
  63
  64         if (d->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE)
  65                 n = USB_DT_ENDPOINT_AUDIO_SIZE;
  66         else if (d->bLength >= USB_DT_ENDPOINT_SIZE)
  67                 n = USB_DT_ENDPOINT_SIZE;
  68         else {
  69                 dev_warn(ddev, "config %d interface %d altsetting %d has an "
  70                     "invalid endpoint descriptor of length %d, skipping\n",
  71                     cfgno, inum, asnum, d->bLength);
  72                 goto skip_to_next_endpoint_or_interface_descriptor;
  73         }
  74
  75         i = d->bEndpointAddress & ~USB_ENDPOINT_DIR_MASK;
  76         if (i >= 16 || i == 0) {
  77                 dev_warn(ddev, "config %d interface %d altsetting %d has an "
  78                     "invalid endpoint with address 0x%X, skipping\n",
  79                     cfgno, inum, asnum, d->bEndpointAddress);
  80                 goto skip_to_next_endpoint_or_interface_descriptor;
  81         }
  82
  83         /* Only store as many endpoints as we have room for */
  84         if (ifp->desc.bNumEndpoints >= num_ep)
  85                 goto skip_to_next_endpoint_or_interface_descriptor;
  86
  87         endpoint = &ifp->endpoint[ifp->desc.bNumEndpoints];
  88         ++ifp->desc.bNumEndpoints;
  89
  90         memcpy(&endpoint->desc, d, n);
  91         INIT_LIST_HEAD(&endpoint->urb_list);
  92
  93         /* Skip over any Class Specific or Vendor Specific descriptors;
  94          * find the next endpoint or interface descriptor */
  95         endpoint->extra = buffer;
  96         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
  97             USB_DT_INTERFACE, &n);
  98         endpoint->extralen = i;
  99         if (n > 0)
 100                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 101                     n, plural(n), "endpoint");
 102         return buffer - buffer0 + i;
 103
 104 skip_to_next_endpoint_or_interface_descriptor:
 105         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 106             USB_DT_INTERFACE, NULL);
 107         return buffer - buffer0 + i;
 108 }
 109
 110 void usb_release_interface_cache(struct kref *ref)
 111 {
 112         struct usb_interface_cache *intfc = ref_to_usb_interface_cache(ref);
 113         int j;
 114
 115         for (j = 0; j < intfc->num_altsetting; j++) {
 116                 struct usb_host_interface *alt = &intfc->altsetting[j];
 117
 118                 kfree(alt->endpoint);
 119                 kfree(alt->string);
 120         }
 121         kfree(intfc);
 122 }
 123
 124 static int usb_parse_interface(struct device *ddev, int cfgno,
 125     struct usb_host_config *config, unsigned char *buffer, int size,
 126     u8 inums[], u8 nalts[])
 127 {
 128         unsigned char *buffer0 = buffer;
 129         struct usb_interface_descriptor *d;
 130         int inum, asnum;
 131         struct usb_interface_cache *intfc;
 132         struct usb_host_interface *alt;
 133         int i, n;
 134         int len, retval;
 135         int num_ep, num_ep_orig;
 136
 137         d = (struct usb_interface_descriptor *) buffer;
 138         buffer += d->bLength;
 139         size -= d->bLength;
 140
 141         if (d->bLength < USB_DT_INTERFACE_SIZE)
 142                 goto skip_to_next_interface_descriptor;
 143
 144         /* Which interface entry is this? */
 145         intfc = NULL;
 146         inum = d->bInterfaceNumber;
 147         for (i = 0; i < config->desc.bNumInterfaces; ++i) {
 148                 if (inums[i] == inum) {
 149                         intfc = config->intf_cache[i];
 150                         break;
 151                 }
 152         }
 153         if (!intfc || intfc->num_altsetting >= nalts[i])
 154                 goto skip_to_next_interface_descriptor;
 155
 156         /* Check for duplicate altsetting entries */
 157         asnum = d->bAlternateSetting;
 158         for ((i = 0, alt = &intfc->altsetting[0]);
 159               i < intfc->num_altsetting;
 160              (++i, ++alt)) {
 161                 if (alt->desc.bAlternateSetting == asnum) {
 162                         dev_warn(ddev, "Duplicate descriptor for config %d "
 163                             "interface %d altsetting %d, skipping\n",
 164                             cfgno, inum, asnum);
 165                         goto skip_to_next_interface_descriptor;
 166                 }
 167         }
 168
 169         ++intfc->num_altsetting;
 170         memcpy(&alt->desc, d, USB_DT_INTERFACE_SIZE);
 171
 172         /* Skip over any Class Specific or Vendor Specific descriptors;
 173          * find the first endpoint or interface descriptor */
 174         alt->extra = buffer;
 175         i = find_next_descriptor(buffer, size, USB_DT_ENDPOINT,
 176             USB_DT_INTERFACE, &n);
 177         alt->extralen = i;
 178         if (n > 0)
 179                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 180                     n, plural(n), "interface");
 181         buffer += i;
 182         size -= i;
 183
 184         /* Allocate space for the right(?) number of endpoints */
 185         num_ep = num_ep_orig = alt->desc.bNumEndpoints;
 186         alt->desc.bNumEndpoints = 0;            // Use as a counter
 187         if (num_ep > USB_MAXENDPOINTS) {
 188                 dev_warn(ddev, "too many endpoints for config %d interface %d "
 189                     "altsetting %d: %d, using maximum allowed: %d\n",
 190                     cfgno, inum, asnum, num_ep, USB_MAXENDPOINTS);
 191                 num_ep = USB_MAXENDPOINTS;
 192         }
 193
 194         len = sizeof(struct usb_host_endpoint) * num_ep;
 195         alt->endpoint = kzalloc(len, GFP_KERNEL);
 196         if (!alt->endpoint)
 197                 return -ENOMEM;
 198
 199         /* Parse all the endpoint descriptors */
 200         n = 0;
 201         while (size > 0) {
 202                 if (((struct usb_descriptor_header *) buffer)->bDescriptorType
 203                      == USB_DT_INTERFACE)
 204                         break;
 205                 retval = usb_parse_endpoint(ddev, cfgno, inum, asnum, alt,
 206                     num_ep, buffer, size);
 207                 if (retval < 0)
 208                         return retval;
 209                 ++n;
 210
 211                 buffer += retval;
 212                 size -= retval;
 213         }
 214
 215         if (n != num_ep_orig)
 216                 dev_warn(ddev, "config %d interface %d altsetting %d has %d "
 217                     "endpoint descriptor%s, different from the interface "
 218                     "descriptor's value: %d\n",
 219                     cfgno, inum, asnum, n, plural(n), num_ep_orig);
 220         return buffer - buffer0;
 221
 222 skip_to_next_interface_descriptor:
 223         i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
 224             USB_DT_INTERFACE, NULL);
 225         return buffer - buffer0 + i;
 226 }
 227
 228 static int usb_parse_configuration(struct device *ddev, int cfgidx,
 229     struct usb_host_config *config, unsigned char *buffer, int size)
 230 {
 231         unsigned char *buffer0 = buffer;
 232         int cfgno;
 233         int nintf, nintf_orig;
 234         int i, j, n;
 235         struct usb_interface_cache *intfc;
 236         unsigned char *buffer2;
 237         int size2;
 238         struct usb_descriptor_header *header;
 239         int len, retval;
 240         u8 inums[USB_MAXINTERFACES], nalts[USB_MAXINTERFACES];
 241
 242         memcpy(&config->desc, buffer, USB_DT_CONFIG_SIZE);
 243         if (config->desc.bDescriptorType != USB_DT_CONFIG ||
 244             config->desc.bLength < USB_DT_CONFIG_SIZE) {
 245                 dev_err(ddev, "invalid descriptor for config index %d: "
 246                     "type = 0x%X, length = %d\n", cfgidx,
 247                     config->desc.bDescriptorType, config->desc.bLength);
 248                 return -EINVAL;
 249         }
 250         cfgno = config->desc.bConfigurationValue;
 251
 252         buffer += config->desc.bLength;
 253         size -= config->desc.bLength;
 254
 255         nintf = nintf_orig = config->desc.bNumInterfaces;
 256         if (nintf > USB_MAXINTERFACES) {
 257                 dev_warn(ddev, "config %d has too many interfaces: %d, "
 258                     "using maximum allowed: %d\n",
 259                     cfgno, nintf, USB_MAXINTERFACES);
 260                 nintf = USB_MAXINTERFACES;
 261         }
 262
 263         /* Go through the descriptors, checking their length and counting the
 264          * number of altsettings for each interface */
 265         n = 0;
 266         for ((buffer2 = buffer, size2 = size);
 267               size2 > 0;
 268              (buffer2 += header->bLength, size2 -= header->bLength)) {
 269
 270                 if (size2 < sizeof(struct usb_descriptor_header)) {
 271                         dev_warn(ddev, "config %d descriptor has %d excess "
 272                             "byte%s, ignoring\n",
 273                             cfgno, size2, plural(size2));
 274                         break;
 275                 }
 276
 277                 header = (struct usb_descriptor_header *) buffer2;
 278                 if ((header->bLength > size2) || (header->bLength < 2)) {
 279                         dev_warn(ddev, "config %d has an invalid descriptor "
 280                             "of length %d, skipping remainder of the config\n",
 281                             cfgno, header->bLength);
 282                         break;
 283                 }
 284
 285                 if (header->bDescriptorType == USB_DT_INTERFACE) {
 286                         struct usb_interface_descriptor *d;
 287                         int inum;
 288
 289                         d = (struct usb_interface_descriptor *) header;
 290                         if (d->bLength < USB_DT_INTERFACE_SIZE) {
 291                                 dev_warn(ddev, "config %d has an invalid "
 292                                     "interface descriptor of length %d, "
 293                                     "skipping\n", cfgno, d->bLength);
 294                                 continue;
 295                         }
 296
 297                         inum = d->bInterfaceNumber;
 298                         if (inum >= nintf_orig)
 299                                 dev_warn(ddev, "config %d has an invalid "
 300                                     "interface number: %d but max is %d\n",
 301                                     cfgno, inum, nintf_orig - 1);
 302
 303                         /* Have we already encountered this interface?
 304                          * Count its altsettings */
 305                         for (i = 0; i < n; ++i) {
 306                                 if (inums[i] == inum)
 307                                         break;
 308                         }
 309                         if (i < n) {
 310                                 if (nalts[i] < 255)
 311                                         ++nalts[i];
 312                         } else if (n < USB_MAXINTERFACES) {
 313                                 inums[n] = inum;
 314                                 nalts[n] = 1;
 315                                 ++n;
 316                         }
 317
 318                 } else if (header->bDescriptorType == USB_DT_DEVICE ||
 319                             header->bDescriptorType == USB_DT_CONFIG)
 320                         dev_warn(ddev, "config %d contains an unexpected "
 321                             "descriptor of type 0x%X, skipping\n",
 322                             cfgno, header->bDescriptorType);
 323
 324         }       /* for ((buffer2 = buffer, size2 = size); ...) */
 325         size = buffer2 - buffer;
 326         config->desc.wTotalLength = cpu_to_le16(buffer2 - buffer0);
 327
 328         if (n != nintf)
 329                 dev_warn(ddev, "config %d has %d interface%s, different from "
 330                     "the descriptor's value: %d\n",
 331                     cfgno, n, plural(n), nintf_orig);
 332         else if (n == 0)
 333                 dev_warn(ddev, "config %d has no interfaces?\n", cfgno);
 334         config->desc.bNumInterfaces = nintf = n;
 335
 336         /* Check for missing interface numbers */
 337         for (i = 0; i < nintf; ++i) {
 338                 for (j = 0; j < nintf; ++j) {
 339                         if (inums[j] == i)
 340                                 break;
 341                 }
 342                 if (j >= nintf)
 343                         dev_warn(ddev, "config %d has no interface number "
 344                             "%d\n", cfgno, i);
 345         }
 346
 347         /* Allocate the usb_interface_caches and altsetting arrays */
 348         for (i = 0; i < nintf; ++i) {
 349                 j = nalts[i];
 350                 if (j > USB_MAXALTSETTING) {
 351                         dev_warn(ddev, "too many alternate settings for "
 352                             "config %d interface %d: %d, "
 353                             "using maximum allowed: %d\n",
 354                             cfgno, inums[i], j, USB_MAXALTSETTING);
 355                         nalts[i] = j = USB_MAXALTSETTING;
 356                 }
 357
 358                 len = sizeof(*intfc) + sizeof(struct usb_host_interface) * j;
 359                 config->intf_cache[i] = intfc = kzalloc(len, GFP_KERNEL);
 360                 if (!intfc)
 361                         return -ENOMEM;
 362                 kref_init(&intfc->ref);
 363         }
 364
 365         /* Skip over any Class Specific or Vendor Specific descriptors;
 366          * find the first interface descriptor */
 367         config->extra = buffer;
 368         i = find_next_descriptor(buffer, size, USB_DT_INTERFACE,
 369             USB_DT_INTERFACE, &n);
 370         config->extralen = i;
 371         if (n > 0)
 372                 dev_dbg(ddev, "skipped %d descriptor%s after %s\n",
 373                     n, plural(n), "configuration");
 374         buffer += i;
 375         size -= i;
 376
 377         /* Parse all the interface/altsetting descriptors */
 378         while (size > 0) {
 379                 retval = usb_parse_interface(ddev, cfgno, config,
 380                     buffer, size, inums, nalts);
 381                 if (retval < 0)
 382                         return retval;
 383
 384                 buffer += retval;
 385                 size -= retval;
 386         }
 387
 388         /* Check for missing altsettings */
 389         for (i = 0; i < nintf; ++i) {
 390                 intfc = config->intf_cache[i];
 391                 for (j = 0; j < intfc->num_altsetting; ++j) {
 392                         for (n = 0; n < intfc->num_altsetting; ++n) {
 393                                 if (intfc->altsetting[n].desc.
 394                                     bAlternateSetting == j)
 395                                         break;
 396                         }
 397                         if (n >= intfc->num_altsetting)
 398                                 dev_warn(ddev, "config %d interface %d has no "
 399                                     "altsetting %d\n", cfgno, inums[i], j);
 400                 }
 401         }
 402
 403         return 0;
 404 }
 405
 406 // hub-only!! ... and only exported for reset/reinit path.
 407 // otherwise used internally on disconnect/destroy path
 408 void usb_destroy_configuration(struct usb_device *dev)
 409 {
 410         int c, i;
 411
 412         if (!dev->config)
 413                 return;
 414
 415         if (dev->rawdescriptors) {
 416                 for (i = 0; i < dev->descriptor.bNumConfigurations; i++)
 417                         kfree(dev->rawdescriptors[i]);
 418
 419                 kfree(dev->rawdescriptors);
 420                 dev->rawdescriptors = NULL;
 421         }
 422
 423         for (c = 0; c < dev->descriptor.bNumConfigurations; c++) {
 424                 struct usb_host_config *cf = &dev->config[c];
 425
 426                 kfree(cf->string);
 427                 for (i = 0; i < cf->desc.bNumInterfaces; i++) {
 428                         if (cf->intf_cache[i])
 429                                 kref_put(&cf->intf_cache[i]->ref,
 430                                           usb_release_interface_cache);
 431                 }
 432         }
 433         kfree(dev->config);
 434         dev->config = NULL;
 435 }
 436
 437
 438 // hub-only!! ... and only in reset path, or usb_new_device()
 439 // (used by real hubs and virtual root hubs)
 440 int usb_get_configuration(struct usb_device *dev)
 441 {
 442         struct device *ddev = &dev->dev;
 443         int ncfg = dev->descriptor.bNumConfigurations;
 444         int result = -ENOMEM;
 445         unsigned int cfgno, length;
 446         unsigned char *buffer;
 447         unsigned char *bigbuffer;
 448         struct usb_config_descriptor *desc;
 449
 450         if (ncfg > USB_MAXCONFIG) {
 451                 dev_warn(ddev, "too many configurations: %d, "
 452                     "using maximum allowed: %d\n", ncfg, USB_MAXCONFIG);
 453                 dev->descriptor.bNumConfigurations = ncfg = USB_MAXCONFIG;
 454         }
 455
 456         if (ncfg < 1) {
 457                 dev_err(ddev, "no configurations\n");
 458                 return -EINVAL;
 459         }
 460
 461         length = ncfg * sizeof(struct usb_host_config);
 462         dev->config = kzalloc(length, GFP_KERNEL);
 463         if (!dev->config)
 464                 goto err2;
 465
 466         length = ncfg * sizeof(char *);
 467         dev->rawdescriptors = kzalloc(length, GFP_KERNEL);
 468         if (!dev->rawdescriptors)
 469                 goto err2;
 470
 471         buffer = kmalloc(USB_DT_CONFIG_SIZE, GFP_KERNEL);
 472         if (!buffer)
 473                 goto err2;
 474         desc = (struct usb_config_descriptor *)buffer;
 475
 476         for (cfgno = 0; cfgno < ncfg; cfgno++) {
 477                 /* We grab just the first descriptor so we know how long
 478                  * the whole configuration is */
 479                 result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
 480                     buffer, USB_DT_CONFIG_SIZE);
 481                 if (result < 0) {
 482                         dev_err(ddev, "unable to read config index %d "
 483                             "descriptor/%s\n", cfgno, "start");
 484                         goto err;
 485                 } else if (result < 4) {
 486                         dev_err(ddev, "config index %d descriptor too short "
 487                             "(expected %i, got %i)\n", cfgno,
 488                             USB_DT_CONFIG_SIZE, result);
 489                         result = -EINVAL;
 490                         goto err;
 491                 }
 492                 length = max((int) le16_to_cpu(desc->wTotalLength),
 493                     USB_DT_CONFIG_SIZE);
 494
 495                 /* Now that we know the length, get the whole thing */
 496                 bigbuffer = kmalloc(length, GFP_KERNEL);
 497                 if (!bigbuffer) {
 498                         result = -ENOMEM;
 499                         goto err;
 500                 }
 501                 result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno,
 502                     bigbuffer, length);
 503                 if (result < 0) {
 504                         dev_err(ddev, "unable to read config index %d "
 505                             "descriptor/%s\n", cfgno, "all");
 506                         kfree(bigbuffer);
 507                         goto err;
 508                 }
 509                 if (result < length) {
 510                         dev_warn(ddev, "config index %d descriptor too short "
 511                             "(expected %i, got %i)\n", cfgno, length, result);
 512                         length = result;
 513                 }
 514
 515                 dev->rawdescriptors[cfgno] = bigbuffer;
 516
 517                 result = usb_parse_configuration(&dev->dev, cfgno,
 518                     &dev->config[cfgno], bigbuffer, length);
 519                 if (result < 0) {
 520                         ++cfgno;
 521                         goto err;
 522                 }
 523         }
 524         result = 0;
 525
 526 err:
 527         kfree(buffer);
 528         dev->descriptor.bNumConfigurations = cfgno;
 529 err2:
 530         if (result == -ENOMEM)
 531                 dev_err(ddev, "out of memory\n");
 532         return result;
 533 }