drivers/usb/core/config.c

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