[v4,06/13] drm: HDCP SRM binary sysfs for subsystem

Submitted by Ramalingam C on April 5, 2019, 8:42 a.m.

Details

Message ID 20190405084302.5548-7-ramalingam.c@intel.com
State New
Headers show
Series "HDCP2.2 Phase II" ( rev: 5 ) in Intel GFX

Not browsing as part of any series.

Commit Message

Ramalingam C April 5, 2019, 8:42 a.m.
A common binary sysfs called "hdcp_srm" is created at /sys/class/drm
with only write permission.

SRM table is parsed and stored at drm_hdcp.c, with functions exported
for the services for revocation check from drivers (which
implements the HDCP authentication)

This patch handles the HDCP1.4 and 2.2 versions of SRM table.

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Suggested-by: Daniel Vetter <daniel@ffwll.ch>
---
 drivers/gpu/drm/Makefile       |   2 +-
 drivers/gpu/drm/drm_hdcp.c     | 351 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_internal.h |   4 +
 drivers/gpu/drm/drm_sysfs.c    |   2 +
 include/drm/drm_hdcp.h         |  35 ++++
 5 files changed, 393 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/drm_hdcp.c

Patch hide | download patch | download mbox

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index e630eccb951c..ef6e484c964b 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -19,7 +19,7 @@  drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
 		drm_plane.o drm_color_mgmt.o drm_print.o \
 		drm_dumb_buffers.o drm_mode_config.o drm_vblank.o \
 		drm_syncobj.o drm_lease.o drm_writeback.o drm_client.o \
-		drm_atomic_uapi.o
+		drm_atomic_uapi.o drm_hdcp.o
 
 drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
 drm-$(CONFIG_DRM_VM) += drm_vm.o
diff --git a/drivers/gpu/drm/drm_hdcp.c b/drivers/gpu/drm/drm_hdcp.c
new file mode 100644
index 000000000000..2f0367d6be64
--- /dev/null
+++ b/drivers/gpu/drm/drm_hdcp.c
@@ -0,0 +1,351 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Intel Corporation.
+ *
+ * Authors:
+ * Ramalingam C <ramalingam.c@intel.com>
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gfp.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+
+#include <drm/drm_hdcp.h>
+#include <drm/drm_sysfs.h>
+#include <drm/drm_print.h>
+
+struct hdcp_srm {
+	u8 *srm_buf;
+	size_t received_srm_sz;
+	u32 revocated_ksv_cnt;
+	u8 *revocated_ksv_list;
+
+	/* Mutex to protect above struct member */
+	struct mutex mutex;
+} *srm_data;
+
+static inline void drm_hdcp_print_ksv(const char *ksv)
+{
+	DRM_DEBUG("\t%#04x, %#04x, %#04x, %#04x, %#04x\n", *ksv & 0xff,
+		  *(ksv + 1) & 0xff, *(ksv + 2) & 0xff, *(ksv + 3) & 0xff,
+		  *(ksv + 4) & 0xff);
+}
+
+static u32 drm_hdcp_get_revocated_ksv_count(const char *buf, u32 vrls_length)
+{
+	u32 parsed_bytes = 0, ksv_count = 0, vrl_ksv_cnt, vrl_sz;
+
+	do {
+		vrl_ksv_cnt = *buf;
+		ksv_count += vrl_ksv_cnt;
+
+		vrl_sz = (vrl_ksv_cnt * DRM_HDCP_KSV_LEN) + 1;
+		buf += vrl_sz;
+		parsed_bytes += vrl_sz;
+	} while (parsed_bytes < vrls_length);
+
+	return ksv_count;
+}
+
+static u32 drm_hdcp_get_revocated_ksvs(const char *buf, u8 *revocated_ksv_list,
+				       u32 vrls_length)
+{
+	u32 parsed_bytes = 0, ksv_count = 0;
+	u32 vrl_ksv_cnt, vrl_ksv_sz, vrl_idx = 0;
+
+	do {
+		vrl_ksv_cnt = *buf;
+		vrl_ksv_sz = vrl_ksv_cnt * DRM_HDCP_KSV_LEN;
+
+		buf++;
+
+		DRM_DEBUG("vrl: %d, Revoked KSVs: %d\n", vrl_idx++,
+			  vrl_ksv_cnt);
+		memcpy(revocated_ksv_list, buf, vrl_ksv_sz);
+
+		ksv_count += vrl_ksv_cnt;
+		revocated_ksv_list += vrl_ksv_sz;
+		buf += vrl_ksv_sz;
+
+		parsed_bytes += (vrl_ksv_sz + 1);
+	} while (parsed_bytes < vrls_length);
+
+	return ksv_count;
+}
+
+static int drm_hdcp_parse_hdcp1_srm(const char *buf, size_t count)
+{
+	struct hdcp_srm_header *header;
+	u32 vrl_length, ksv_count;
+
+	if (count < (sizeof(struct hdcp_srm_header) +
+	    DRM_HDCP_1_4_VRL_LENGTH_SIZE + DRM_HDCP_1_4_DCP_SIG_SIZE)) {
+		DRM_ERROR("Invalid blob length\n");
+		return -EINVAL;
+	}
+
+	header = (struct hdcp_srm_header *)buf;
+	mutex_lock(&srm_data->mutex);
+	DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
+		  header->spec_indicator.srm_id,
+		  __swab16(header->srm_version), header->srm_gen_no);
+
+	WARN_ON(header->spec_indicator.reserved_hi ||
+		header->spec_indicator.reserved_lo);
+
+	if (header->spec_indicator.srm_id != DRM_HDCP_1_4_SRM_ID) {
+		DRM_ERROR("Invalid srm_id\n");
+		mutex_unlock(&srm_data->mutex);
+		return -EINVAL;
+	}
+
+	buf = buf + sizeof(*header);
+	vrl_length = (*buf << 16 | *(buf + 1) << 8 | *(buf + 2));
+	if (count < (sizeof(struct hdcp_srm_header) + vrl_length) ||
+	    vrl_length < (DRM_HDCP_1_4_VRL_LENGTH_SIZE +
+			  DRM_HDCP_1_4_DCP_SIG_SIZE)) {
+		DRM_ERROR("Invalid blob length or vrl length\n");
+		mutex_unlock(&srm_data->mutex);
+		return -EINVAL;
+	}
+
+	/* Length of the all vrls combined */
+	vrl_length -= (DRM_HDCP_1_4_VRL_LENGTH_SIZE +
+		       DRM_HDCP_1_4_DCP_SIG_SIZE);
+
+	if (!vrl_length) {
+		DRM_ERROR("No vrl found\n");
+		mutex_unlock(&srm_data->mutex);
+		return -EINVAL;
+	}
+
+	buf += DRM_HDCP_1_4_VRL_LENGTH_SIZE;
+	ksv_count = drm_hdcp_get_revocated_ksv_count(buf, vrl_length);
+	if (!ksv_count) {
+		DRM_DEBUG("Revocated KSV count is 0\n");
+		mutex_unlock(&srm_data->mutex);
+		return count;
+	}
+
+	kfree(srm_data->revocated_ksv_list);
+	srm_data->revocated_ksv_list = kzalloc(ksv_count * DRM_HDCP_KSV_LEN,
+					       GFP_KERNEL);
+	if (!srm_data->revocated_ksv_list) {
+		DRM_ERROR("Out of Memory\n");
+		mutex_unlock(&srm_data->mutex);
+		return -ENOMEM;
+	}
+
+	if (drm_hdcp_get_revocated_ksvs(buf, srm_data->revocated_ksv_list,
+					vrl_length) != ksv_count) {
+		srm_data->revocated_ksv_cnt = 0;
+		kfree(srm_data->revocated_ksv_list);
+		mutex_unlock(&srm_data->mutex);
+		return -EINVAL;
+	}
+
+	srm_data->revocated_ksv_cnt = ksv_count;
+	mutex_unlock(&srm_data->mutex);
+	return count;
+}
+
+static int drm_hdcp_parse_hdcp2_srm(const char *buf, size_t count)
+{
+	struct hdcp2_srm_header *header;
+	u32 vrl_length, ksv_count, ksv_sz;
+
+	mutex_lock(&srm_data->mutex);
+	if (count < (sizeof(struct hdcp2_srm_header) +
+	    DRM_HDCP_2_VRL_LENGTH_SIZE + DRM_HDCP_2_DCP_SIG_SIZE)) {
+		DRM_ERROR("Invalid blob length\n");
+		mutex_unlock(&srm_data->mutex);
+		return -EINVAL;
+	}
+
+	header = (struct hdcp2_srm_header *)buf;
+	DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
+		  header->spec_indicator.srm_id,
+		  __swab16(header->srm_version), header->srm_gen_no);
+
+	if (header->spec_indicator.reserved)
+		return -EINVAL;
+
+	buf = buf + sizeof(*header);
+	vrl_length = (*buf << 16 | *(buf + 1) << 8 | *(buf + 2));
+
+	if (count < (sizeof(struct hdcp2_srm_header) + vrl_length) ||
+	    vrl_length < (DRM_HDCP_2_VRL_LENGTH_SIZE +
+	    DRM_HDCP_2_DCP_SIG_SIZE)) {
+		DRM_ERROR("Invalid blob length or vrl length\n");
+		mutex_unlock(&srm_data->mutex);
+		return -EINVAL;
+	}
+
+	/* Length of the all vrls combined */
+	vrl_length -= (DRM_HDCP_2_VRL_LENGTH_SIZE +
+		       DRM_HDCP_2_DCP_SIG_SIZE);
+
+	if (!vrl_length) {
+		DRM_ERROR("No vrl found\n");
+		mutex_unlock(&srm_data->mutex);
+		return -EINVAL;
+	}
+
+	buf += DRM_HDCP_2_VRL_LENGTH_SIZE;
+	ksv_count = (*buf << 2) | DRM_HDCP_2_KSV_COUNT_2_LSBITS(*(buf + 1));
+	if (!ksv_count) {
+		DRM_DEBUG("Revocated KSV count is 0\n");
+		mutex_unlock(&srm_data->mutex);
+		return count;
+	}
+
+	kfree(srm_data->revocated_ksv_list);
+	srm_data->revocated_ksv_list = kzalloc(ksv_count * DRM_HDCP_KSV_LEN,
+					       GFP_KERNEL);
+	if (!srm_data->revocated_ksv_list) {
+		DRM_ERROR("Out of Memory\n");
+		mutex_unlock(&srm_data->mutex);
+		return -ENOMEM;
+	}
+
+	ksv_sz = ksv_count * DRM_HDCP_KSV_LEN;
+	buf += DRM_HDCP_2_NO_OF_DEV_PLUS_RESERVED_SZ;
+
+	DRM_DEBUG("Revoked KSVs: %d\n", ksv_count);
+	memcpy(srm_data->revocated_ksv_list, buf, ksv_sz);
+
+	srm_data->revocated_ksv_cnt = ksv_count;
+	mutex_unlock(&srm_data->mutex);
+	return count;
+}
+
+static inline bool is_srm_version_hdcp1(const char *buf)
+{
+	return ((u8)*buf) == DRM_HDCP_1_4_SRM_ID << 4;
+}
+
+static inline bool is_srm_version_hdcp2(const char *buf)
+{
+	return ((u8)*buf) == (DRM_HDCP_2_SRM_ID << 4 |
+			     DRM_HDCP_2_INDICATOR);
+}
+
+static ssize_t drm_hdcp_srm_update(const char *buf, size_t count)
+{
+	if (is_srm_version_hdcp1(buf))
+		return (ssize_t)drm_hdcp_parse_hdcp1_srm(buf, count);
+	else if (is_srm_version_hdcp2(buf))
+		return (ssize_t)drm_hdcp_parse_hdcp2_srm(buf, count);
+
+	return (ssize_t)-EINVAL;
+}
+
+/* Check if any of the KSV is revocated by DCP LLC through SRM table */
+bool drm_hdcp_ksvs_revocated(u8 *ksvs, u32 ksv_count)
+{
+	u32 rev_ksv_cnt, cnt, i, j;
+	u8 *rev_ksv_list;
+
+	if (!srm_data)
+		return false;
+
+	mutex_lock(&srm_data->mutex);
+	rev_ksv_cnt = srm_data->revocated_ksv_cnt;
+	rev_ksv_list = srm_data->revocated_ksv_list;
+
+	/* If the Revocated ksv list is empty */
+	if (!rev_ksv_cnt || !rev_ksv_list) {
+		mutex_unlock(&srm_data->mutex);
+		return false;
+	}
+
+	for  (cnt = 0; cnt < ksv_count; cnt++) {
+		rev_ksv_list = srm_data->revocated_ksv_list;
+		for (i = 0; i < rev_ksv_cnt; i++) {
+			for (j = 0; j < DRM_HDCP_KSV_LEN; j++)
+				if (*(ksvs + j) != *(rev_ksv_list + j)) {
+					break;
+				} else if (j == (DRM_HDCP_KSV_LEN - 1)) {
+					DRM_DEBUG("Revocated KSV is ");
+					drm_hdcp_print_ksv(ksvs);
+					mutex_unlock(&srm_data->mutex);
+					return true;
+				}
+			/* Move the offset to next KSV in the revocated list */
+			rev_ksv_list += DRM_HDCP_KSV_LEN;
+		}
+
+		/* Iterate to next ksv_offset */
+		ksvs += DRM_HDCP_KSV_LEN;
+	}
+	mutex_unlock(&srm_data->mutex);
+	return false;
+}
+EXPORT_SYMBOL_GPL(drm_hdcp_ksvs_revocated);
+
+static ssize_t
+drm_hdcp_srm_write(struct file *filp, struct kobject *kobj,
+		   struct bin_attribute *attr, char *buf,
+		   loff_t offset, size_t count)
+{
+	int ret;
+
+	if (count > DRM_HDCP_SRM_GEN1_MAX_BYTES) {
+		DRM_ERROR("Invalid length of SRM\n");
+		return -EINVAL;
+	}
+
+	ret = drm_hdcp_srm_update((const char *)buf, count);
+	if (ret < 0)
+		return ret;
+
+	memcpy((void *)srm_data->srm_buf, (const void *)buf, count);
+
+	return count;
+}
+
+static const struct bin_attribute srm_attrs = {
+	.attr = {.name = "hdcp_srm", .mode = S_IWUSR},
+	.read = NULL,
+	.write = drm_hdcp_srm_write,
+	.mmap = NULL,
+	.private = (void *)0
+};
+
+int drm_setup_hdcp_srm(struct class *drm_class)
+{
+	int ret;
+
+	srm_data = kzalloc(sizeof(*srm_data), GFP_KERNEL);
+	if (!srm_data)
+		return -ENOMEM;
+
+	srm_data->srm_buf = kcalloc(DRM_HDCP_SRM_GEN1_MAX_BYTES,
+				    sizeof(u8), GFP_KERNEL);
+	if (!srm_data->srm_buf) {
+		kfree(srm_data);
+		return -ENOMEM;
+	}
+	mutex_init(&srm_data->mutex);
+
+	ret = class_create_bin_file(drm_class, &srm_attrs);
+	if (ret) {
+		DRM_ERROR("SRM bin sysfs creation failed. %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+void drm_teardown_hdcp_srm(struct class *drm_class)
+{
+	if (srm_data) {
+		kfree(srm_data->srm_buf);
+		kfree(srm_data->revocated_ksv_list);
+		kfree(srm_data);
+	}
+
+	class_remove_bin_file(drm_class, &srm_attrs);
+}
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index 251d67e04c2d..15d6bfc764da 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -191,3 +191,7 @@  int drm_syncobj_signal_ioctl(struct drm_device *dev, void *data,
 void drm_framebuffer_print_info(struct drm_printer *p, unsigned int indent,
 				const struct drm_framebuffer *fb);
 int drm_framebuffer_debugfs_init(struct drm_minor *minor);
+
+/* drm_hdcp.c */
+int drm_setup_hdcp_srm(struct class *drm_class);
+void drm_teardown_hdcp_srm(struct class *drm_class);
diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
index ecb7b33002bb..18b1ac442997 100644
--- a/drivers/gpu/drm/drm_sysfs.c
+++ b/drivers/gpu/drm/drm_sysfs.c
@@ -78,6 +78,7 @@  int drm_sysfs_init(void)
 	}
 
 	drm_class->devnode = drm_devnode;
+	drm_setup_hdcp_srm(drm_class);
 	return 0;
 }
 
@@ -90,6 +91,7 @@  void drm_sysfs_destroy(void)
 {
 	if (IS_ERR_OR_NULL(drm_class))
 		return;
+	drm_teardown_hdcp_srm(drm_class);
 	class_remove_file(drm_class, &class_attr_version.attr);
 	class_destroy(drm_class);
 	drm_class = NULL;
diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h
index f243408ecf26..5cb21dd6797b 100644
--- a/include/drm/drm_hdcp.h
+++ b/include/drm/drm_hdcp.h
@@ -265,4 +265,39 @@  void drm_hdcp2_u32_to_seq_num(u8 seq_num[HDCP_2_2_SEQ_NUM_LEN], u32 val)
 	seq_num[2] = val;
 }
 
+#define DRM_HDCP_SRM_GEN1_MAX_BYTES		(5 * 1024)
+#define DRM_HDCP_1_4_SRM_ID			0x8
+#define DRM_HDCP_1_4_VRL_LENGTH_SIZE		3
+#define DRM_HDCP_1_4_DCP_SIG_SIZE		40
+
+struct hdcp_srm_header {
+	struct {
+		u8 reserved_hi:4;
+		u8 srm_id:4;
+		u8 reserved_lo;
+	} spec_indicator;
+	u16 srm_version;
+	u8 srm_gen_no;
+} __packed;
+
+#define DRM_HDCP_2_SRM_ID			0x9
+#define DRM_HDCP_2_INDICATOR			0x1
+#define DRM_HDCP_2_VRL_LENGTH_SIZE		3
+#define DRM_HDCP_2_DCP_SIG_SIZE			384
+#define DRM_HDCP_2_NO_OF_DEV_PLUS_RESERVED_SZ	4
+
+#define DRM_HDCP_2_KSV_COUNT_2_LSBITS(byte)	(((byte) & 0xC) >> 6)
+
+struct hdcp2_srm_header {
+	struct {
+		u8 hdcp2_indicator:4;
+		u8 srm_id:4;
+		u8 reserved;
+	} spec_indicator;
+	u16 srm_version;
+	u8 srm_gen_no;
+} __packed;
+
+bool drm_hdcp_ksvs_revocated(u8 *ksvs, u32 ksv_count);
+
 #endif