drivers/gpu/drm/drm_hdcp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2019 Intel Corporation.
   4  *
   5  * Authors:
   6  * Ramalingam C <ramalingam.c@intel.com>
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/err.h>
  11 #include <linux/gfp.h>
  12 #include <linux/export.h>
  13 #include <linux/slab.h>
  14 #include <linux/firmware.h>
  15
  16 #include <drm/drm_hdcp.h>
  17 #include <drm/drm_sysfs.h>
  18 #include <drm/drm_print.h>
  19 #include <drm/drm_device.h>
  20 #include <drm/drm_property.h>
  21 #include <drm/drm_mode_object.h>
  22 #include <drm/drm_connector.h>
  23
  24 #include "drm_internal.h"
  25
  26 static inline void drm_hdcp_print_ksv(const u8 *ksv)
  27 {
  28         DRM_DEBUG("\t%#02x, %#02x, %#02x, %#02x, %#02x\n",
  29                   ksv[0], ksv[1], ksv[2], ksv[3], ksv[4]);
  30 }
  31
  32 static u32 drm_hdcp_get_revoked_ksv_count(const u8 *buf, u32 vrls_length)
  33 {
  34         u32 parsed_bytes = 0, ksv_count = 0, vrl_ksv_cnt, vrl_sz;
  35
  36         while (parsed_bytes < vrls_length) {
  37                 vrl_ksv_cnt = *buf;
  38                 ksv_count += vrl_ksv_cnt;
  39
  40                 vrl_sz = (vrl_ksv_cnt * DRM_HDCP_KSV_LEN) + 1;
  41                 buf += vrl_sz;
  42                 parsed_bytes += vrl_sz;
  43         }
  44
  45         /*
  46          * When vrls are not valid, ksvs are not considered.
  47          * Hence SRM will be discarded.
  48          */
  49         if (parsed_bytes != vrls_length)
  50                 ksv_count = 0;
  51
  52         return ksv_count;
  53 }
  54
  55 static u32 drm_hdcp_get_revoked_ksvs(const u8 *buf, u8 **revoked_ksv_list,
  56                                      u32 vrls_length)
  57 {
  58         u32 vrl_ksv_cnt, vrl_ksv_sz, vrl_idx = 0;
  59         u32 parsed_bytes = 0, ksv_count = 0;
  60
  61         do {
  62                 vrl_ksv_cnt = *buf;
  63                 vrl_ksv_sz = vrl_ksv_cnt * DRM_HDCP_KSV_LEN;
  64
  65                 buf++;
  66
  67                 DRM_DEBUG("vrl: %d, Revoked KSVs: %d\n", vrl_idx++,
  68                           vrl_ksv_cnt);
  69                 memcpy((*revoked_ksv_list) + (ksv_count * DRM_HDCP_KSV_LEN),
  70                        buf, vrl_ksv_sz);
  71
  72                 ksv_count += vrl_ksv_cnt;
  73                 buf += vrl_ksv_sz;
  74
  75                 parsed_bytes += (vrl_ksv_sz + 1);
  76         } while (parsed_bytes < vrls_length);
  77
  78         return ksv_count;
  79 }
  80
  81 static inline u32 get_vrl_length(const u8 *buf)
  82 {
  83         return drm_hdcp_be24_to_cpu(buf);
  84 }
  85
  86 static int drm_hdcp_parse_hdcp1_srm(const u8 *buf, size_t count,
  87                                     u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
  88 {
  89         struct hdcp_srm_header *header;
  90         u32 vrl_length, ksv_count;
  91
  92         if (count < (sizeof(struct hdcp_srm_header) +
  93             DRM_HDCP_1_4_VRL_LENGTH_SIZE + DRM_HDCP_1_4_DCP_SIG_SIZE)) {
  94                 DRM_ERROR("Invalid blob length\n");
  95                 return -EINVAL;
  96         }
  97
  98         header = (struct hdcp_srm_header *)buf;
  99         DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
 100                   header->srm_id,
 101                   be16_to_cpu(header->srm_version), header->srm_gen_no);
 102
 103         WARN_ON(header->reserved);
 104
 105         buf = buf + sizeof(*header);
 106         vrl_length = get_vrl_length(buf);
 107         if (count < (sizeof(struct hdcp_srm_header) + vrl_length) ||
 108             vrl_length < (DRM_HDCP_1_4_VRL_LENGTH_SIZE +
 109                           DRM_HDCP_1_4_DCP_SIG_SIZE)) {
 110                 DRM_ERROR("Invalid blob length or vrl length\n");
 111                 return -EINVAL;
 112         }
 113
 114         /* Length of the all vrls combined */
 115         vrl_length -= (DRM_HDCP_1_4_VRL_LENGTH_SIZE +
 116                        DRM_HDCP_1_4_DCP_SIG_SIZE);
 117
 118         if (!vrl_length) {
 119                 DRM_ERROR("No vrl found\n");
 120                 return -EINVAL;
 121         }
 122
 123         buf += DRM_HDCP_1_4_VRL_LENGTH_SIZE;
 124         ksv_count = drm_hdcp_get_revoked_ksv_count(buf, vrl_length);
 125         if (!ksv_count) {
 126                 DRM_DEBUG("Revoked KSV count is 0\n");
 127                 return 0;
 128         }
 129
 130         *revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN, GFP_KERNEL);
 131         if (!*revoked_ksv_list) {
 132                 DRM_ERROR("Out of Memory\n");
 133                 return -ENOMEM;
 134         }
 135
 136         if (drm_hdcp_get_revoked_ksvs(buf, revoked_ksv_list,
 137                                       vrl_length) != ksv_count) {
 138                 *revoked_ksv_cnt = 0;
 139                 kfree(*revoked_ksv_list);
 140                 return -EINVAL;
 141         }
 142
 143         *revoked_ksv_cnt = ksv_count;
 144         return 0;
 145 }
 146
 147 static int drm_hdcp_parse_hdcp2_srm(const u8 *buf, size_t count,
 148                                     u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
 149 {
 150         struct hdcp_srm_header *header;
 151         u32 vrl_length, ksv_count, ksv_sz;
 152
 153         if (count < (sizeof(struct hdcp_srm_header) +
 154             DRM_HDCP_2_VRL_LENGTH_SIZE + DRM_HDCP_2_DCP_SIG_SIZE)) {
 155                 DRM_ERROR("Invalid blob length\n");
 156                 return -EINVAL;
 157         }
 158
 159         header = (struct hdcp_srm_header *)buf;
 160         DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
 161                   header->srm_id & DRM_HDCP_SRM_ID_MASK,
 162                   be16_to_cpu(header->srm_version), header->srm_gen_no);
 163
 164         if (header->reserved)
 165                 return -EINVAL;
 166
 167         buf = buf + sizeof(*header);
 168         vrl_length = get_vrl_length(buf);
 169
 170         if (count < (sizeof(struct hdcp_srm_header) + vrl_length) ||
 171             vrl_length < (DRM_HDCP_2_VRL_LENGTH_SIZE +
 172             DRM_HDCP_2_DCP_SIG_SIZE)) {
 173                 DRM_ERROR("Invalid blob length or vrl length\n");
 174                 return -EINVAL;
 175         }
 176
 177         /* Length of the all vrls combined */
 178         vrl_length -= (DRM_HDCP_2_VRL_LENGTH_SIZE +
 179                        DRM_HDCP_2_DCP_SIG_SIZE);
 180
 181         if (!vrl_length) {
 182                 DRM_ERROR("No vrl found\n");
 183                 return -EINVAL;
 184         }
 185
 186         buf += DRM_HDCP_2_VRL_LENGTH_SIZE;
 187         ksv_count = (*buf << 2) | DRM_HDCP_2_KSV_COUNT_2_LSBITS(*(buf + 1));
 188         if (!ksv_count) {
 189                 DRM_DEBUG("Revoked KSV count is 0\n");
 190                 return 0;
 191         }
 192
 193         *revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN, GFP_KERNEL);
 194         if (!*revoked_ksv_list) {
 195                 DRM_ERROR("Out of Memory\n");
 196                 return -ENOMEM;
 197         }
 198
 199         ksv_sz = ksv_count * DRM_HDCP_KSV_LEN;
 200         buf += DRM_HDCP_2_NO_OF_DEV_PLUS_RESERVED_SZ;
 201
 202         DRM_DEBUG("Revoked KSVs: %d\n", ksv_count);
 203         memcpy(*revoked_ksv_list, buf, ksv_sz);
 204
 205         *revoked_ksv_cnt = ksv_count;
 206         return 0;
 207 }
 208
 209 static inline bool is_srm_version_hdcp1(const u8 *buf)
 210 {
 211         return *buf == (u8)(DRM_HDCP_1_4_SRM_ID << 4);
 212 }
 213
 214 static inline bool is_srm_version_hdcp2(const u8 *buf)
 215 {
 216         return *buf == (u8)(DRM_HDCP_2_SRM_ID << 4 | DRM_HDCP_2_INDICATOR);
 217 }
 218
 219 static int drm_hdcp_srm_update(const u8 *buf, size_t count,
 220                                u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
 221 {
 222         if (count < sizeof(struct hdcp_srm_header))
 223                 return -EINVAL;
 224
 225         if (is_srm_version_hdcp1(buf))
 226                 return drm_hdcp_parse_hdcp1_srm(buf, count, revoked_ksv_list,
 227                                                 revoked_ksv_cnt);
 228         else if (is_srm_version_hdcp2(buf))
 229                 return drm_hdcp_parse_hdcp2_srm(buf, count, revoked_ksv_list,
 230                                                 revoked_ksv_cnt);
 231         else
 232                 return -EINVAL;
 233 }
 234
 235 static int drm_hdcp_request_srm(struct drm_device *drm_dev,
 236                                 u8 **revoked_ksv_list, u32 *revoked_ksv_cnt)
 237 {
 238         char fw_name[36] = "display_hdcp_srm.bin";
 239         const struct firmware *fw;
 240         int ret;
 241
 242         ret = request_firmware_direct(&fw, (const char *)fw_name,
 243                                       drm_dev->dev);
 244         if (ret < 0) {
 245                 *revoked_ksv_cnt = 0;
 246                 *revoked_ksv_list = NULL;
 247                 ret = 0;
 248                 goto exit;
 249         }
 250
 251         if (fw->size && fw->data)
 252                 ret = drm_hdcp_srm_update(fw->data, fw->size, revoked_ksv_list,
 253                                           revoked_ksv_cnt);
 254
 255 exit:
 256         release_firmware(fw);
 257         return ret;
 258 }
 259
 260 /**
 261  * drm_hdcp_check_ksvs_revoked - Check the revoked status of the IDs
 262  *
 263  * @drm_dev: drm_device for which HDCP revocation check is requested
 264  * @ksvs: List of KSVs (HDCP receiver IDs)
 265  * @ksv_count: KSV count passed in through @ksvs
 266  *
 267  * This function reads the HDCP System renewability Message(SRM Table)
 268  * from userspace as a firmware and parses it for the revoked HDCP
 269  * KSVs(Receiver IDs) detected by DCP LLC. Once the revoked KSVs are known,
 270  * revoked state of the KSVs in the list passed in by display drivers are
 271  * decided and response is sent.
 272  *
 273  * SRM should be presented in the name of "display_hdcp_srm.bin".
 274  *
 275  * Format of the SRM table, that userspace needs to write into the binary file,
 276  * is defined at:
 277  * 1. Renewability chapter on 55th page of HDCP 1.4 specification
 278  * https://www.digital-cp.com/sites/default/files/specifications/HDCP%20Specification%20Rev1_4_Secure.pdf
 279  * 2. Renewability chapter on 63rd page of HDCP 2.2 specification
 280  * https://www.digital-cp.com/sites/default/files/specifications/HDCP%20on%20HDMI%20Specification%20Rev2_2_Final1.pdf
 281  *
 282  * Returns:
 283  * Count of the revoked KSVs or -ve error number incase of the failure.
 284  */
 285 int drm_hdcp_check_ksvs_revoked(struct drm_device *drm_dev, u8 *ksvs,
 286                                 u32 ksv_count)
 287 {
 288         u32 revoked_ksv_cnt = 0, i, j;
 289         u8 *revoked_ksv_list = NULL;
 290         int ret = 0;
 291
 292         ret = drm_hdcp_request_srm(drm_dev, &revoked_ksv_list,
 293                                    &revoked_ksv_cnt);
 294         if (ret)
 295                 return ret;
 296
 297         /* revoked_ksv_cnt will be zero when above function failed */
 298         for (i = 0; i < revoked_ksv_cnt; i++)
 299                 for  (j = 0; j < ksv_count; j++)
 300                         if (!memcmp(&ksvs[j * DRM_HDCP_KSV_LEN],
 301                                     &revoked_ksv_list[i * DRM_HDCP_KSV_LEN],
 302                                     DRM_HDCP_KSV_LEN)) {
 303                                 DRM_DEBUG("Revoked KSV is ");
 304                                 drm_hdcp_print_ksv(&ksvs[j * DRM_HDCP_KSV_LEN]);
 305                                 ret++;
 306                         }
 307
 308         kfree(revoked_ksv_list);
 309         return ret;
 310 }
 311 EXPORT_SYMBOL_GPL(drm_hdcp_check_ksvs_revoked);
 312
 313 static struct drm_prop_enum_list drm_cp_enum_list[] = {
 314         { DRM_MODE_CONTENT_PROTECTION_UNDESIRED, "Undesired" },
 315         { DRM_MODE_CONTENT_PROTECTION_DESIRED, "Desired" },
 316         { DRM_MODE_CONTENT_PROTECTION_ENABLED, "Enabled" },
 317 };
 318 DRM_ENUM_NAME_FN(drm_get_content_protection_name, drm_cp_enum_list)
 319
 320 static struct drm_prop_enum_list drm_hdcp_content_type_enum_list[] = {
 321         { DRM_MODE_HDCP_CONTENT_TYPE0, "HDCP Type0" },
 322         { DRM_MODE_HDCP_CONTENT_TYPE1, "HDCP Type1" },
 323 };
 324 DRM_ENUM_NAME_FN(drm_get_hdcp_content_type_name,
 325                  drm_hdcp_content_type_enum_list)
 326
 327 /**
 328  * drm_connector_attach_content_protection_property - attach content protection
 329  * property
 330  *
 331  * @connector: connector to attach CP property on.
 332  * @hdcp_content_type: is HDCP Content Type property needed for connector
 333  *
 334  * This is used to add support for content protection on select connectors.
 335  * Content Protection is intentionally vague to allow for different underlying
 336  * technologies, however it is most implemented by HDCP.
 337  *
 338  * When hdcp_content_type is true enum property called HDCP Content Type is
 339  * created (if it is not already) and attached to the connector.
 340  *
 341  * This property is used for sending the protected content's stream type
 342  * from userspace to kernel on selected connectors. Protected content provider
 343  * will decide their type of their content and declare the same to kernel.
 344  *
 345  * Content type will be used during the HDCP 2.2 authentication.
 346  * Content type will be set to &drm_connector_state.hdcp_content_type.
 347  *
 348  * The content protection will be set to &drm_connector_state.content_protection
 349  *
 350  * When kernel triggered content protection state change like DESIRED->ENABLED
 351  * and ENABLED->DESIRED, will use drm_hdcp_update_content_protection() to update
 352  * the content protection state of a connector.
 353  *
 354  * Returns:
 355  * Zero on success, negative errno on failure.
 356  */
 357 int drm_connector_attach_content_protection_property(
 358                 struct drm_connector *connector, bool hdcp_content_type)
 359 {
 360         struct drm_device *dev = connector->dev;
 361         struct drm_property *prop =
 362                         dev->mode_config.content_protection_property;
 363
 364         if (!prop)
 365                 prop = drm_property_create_enum(dev, 0, "Content Protection",
 366                                                 drm_cp_enum_list,
 367                                                 ARRAY_SIZE(drm_cp_enum_list));
 368         if (!prop)
 369                 return -ENOMEM;
 370
 371         drm_object_attach_property(&connector->base, prop,
 372                                    DRM_MODE_CONTENT_PROTECTION_UNDESIRED);
 373         dev->mode_config.content_protection_property = prop;
 374
 375         if (!hdcp_content_type)
 376                 return 0;
 377
 378         prop = dev->mode_config.hdcp_content_type_property;
 379         if (!prop)
 380                 prop = drm_property_create_enum(dev, 0, "HDCP Content Type",
 381                                         drm_hdcp_content_type_enum_list,
 382                                         ARRAY_SIZE(
 383                                         drm_hdcp_content_type_enum_list));
 384         if (!prop)
 385                 return -ENOMEM;
 386
 387         drm_object_attach_property(&connector->base, prop,
 388                                    DRM_MODE_HDCP_CONTENT_TYPE0);
 389         dev->mode_config.hdcp_content_type_property = prop;
 390
 391         return 0;
 392 }
 393 EXPORT_SYMBOL(drm_connector_attach_content_protection_property);
 394
 395 /**
 396  * drm_hdcp_update_content_protection - Updates the content protection state
 397  * of a connector
 398  *
 399  * @connector: drm_connector on which content protection state needs an update
 400  * @val: New state of the content protection property
 401  *
 402  * This function can be used by display drivers, to update the kernel triggered
 403  * content protection state changes of a drm_connector such as DESIRED->ENABLED
 404  * and ENABLED->DESIRED. No uevent for DESIRED->UNDESIRED or ENABLED->UNDESIRED,
 405  * as userspace is triggering such state change and kernel performs it without
 406  * fail.This function update the new state of the property into the connector's
 407  * state and generate an uevent to notify the userspace.
 408  */
 409 void drm_hdcp_update_content_protection(struct drm_connector *connector,
 410                                         u64 val)
 411 {
 412         struct drm_device *dev = connector->dev;
 413         struct drm_connector_state *state = connector->state;
 414
 415         WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
 416         if (state->content_protection == val)
 417                 return;
 418
 419         state->content_protection = val;
 420         drm_sysfs_connector_status_event(connector,
 421                                  dev->mode_config.content_protection_property);
 422 }
 423 EXPORT_SYMBOL(drm_hdcp_update_content_protection);