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