[PATCH v6 03/10] drm: revocation check at drm subsystem
Ramalingam C
ramalingam.c at intel.com
Thu May 2 13:22:56 UTC 2019
On every hdcp revocation check request SRM is read from fw file
/lib/firmware/display_hdcp_srm.bin
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.
v2:
moved the uAPI to request_firmware_direct() [Daniel]
v3:
kdoc added. [Daniel]
srm_header unified and bit field definitions are removed. [Daniel]
locking improved. [Daniel]
vrl length violation is fixed. [Daniel]
Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
Suggested-by: Daniel Vetter <daniel at ffwll.ch>
---
Documentation/gpu/drm-kms-helpers.rst | 6 +
drivers/gpu/drm/Makefile | 2 +-
drivers/gpu/drm/drm_hdcp.c | 342 ++++++++++++++++++++++++++
drivers/gpu/drm/drm_internal.h | 4 +
drivers/gpu/drm/drm_sysfs.c | 2 +
include/drm/drm_hdcp.h | 24 ++
6 files changed, 379 insertions(+), 1 deletion(-)
create mode 100644 drivers/gpu/drm/drm_hdcp.c
diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst
index 14102ae035dc..0fe726a6ee67 100644
--- a/Documentation/gpu/drm-kms-helpers.rst
+++ b/Documentation/gpu/drm-kms-helpers.rst
@@ -181,6 +181,12 @@ Panel Helper Reference
.. kernel-doc:: drivers/gpu/drm/drm_panel_orientation_quirks.c
:export:
+HDCP Helper Functions Reference
+===============================
+
+.. kernel-doc:: drivers/gpu/drm/drm_hdcp.c
+ :export:
+
Display Port Helper Functions Reference
=======================================
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 72f5036d9bfa..dd02e9dec810 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -17,7 +17,7 @@ drm-y := drm_auth.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-$(CONFIG_DRM_LEGACY) += drm_legacy_misc.o drm_bufs.o drm_context.o drm_dma.o drm_scatter.o drm_lock.o
drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
diff --git a/drivers/gpu/drm/drm_hdcp.c b/drivers/gpu/drm/drm_hdcp.c
new file mode 100644
index 000000000000..dc0e13409221
--- /dev/null
+++ b/drivers/gpu/drm/drm_hdcp.c
@@ -0,0 +1,342 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Intel Corporation.
+ *
+ * Authors:
+ * Ramalingam C <ramalingam.c at intel.com>
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gfp.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/firmware.h>
+
+#include <drm/drm_hdcp.h>
+#include <drm/drm_sysfs.h>
+#include <drm/drm_print.h>
+#include <drm/drm_device.h>
+
+struct hdcp_srm {
+ u8 *srm_buf;
+ size_t received_srm_sz;
+ u32 revoked_ksv_cnt;
+ u8 *revoked_ksv_list;
+
+ /* Mutex to protect above struct member */
+ struct mutex mutex;
+} *srm_data;
+
+static inline void drm_hdcp_print_ksv(const u8 *ksv)
+{
+ DRM_DEBUG("\t%#02x, %#02x, %#02x, %#02x, %#02x\n",
+ ksv[0], ksv[1], ksv[2], ksv[3], ksv[4]);
+}
+
+static u32 drm_hdcp_get_revoked_ksv_count(const u8 *buf, u32 vrls_length)
+{
+ u32 parsed_bytes = 0, ksv_count = 0, vrl_ksv_cnt, vrl_sz;
+
+ while (parsed_bytes < vrls_length) {
+ 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;
+ }
+
+ /*
+ * When vrls are not valid, ksvs are not considered.
+ * Hence SRM will be discarded.
+ */
+ if (parsed_bytes != vrls_length)
+ ksv_count = 0;
+
+ return ksv_count;
+}
+
+static u32 drm_hdcp_get_revoked_ksvs(const u8 *buf, u8 *revoked_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(revoked_ksv_list, buf, vrl_ksv_sz);
+
+ ksv_count += vrl_ksv_cnt;
+ revoked_ksv_list += vrl_ksv_sz;
+ buf += vrl_ksv_sz;
+
+ parsed_bytes += (vrl_ksv_sz + 1);
+ } while (parsed_bytes < vrls_length);
+
+ return ksv_count;
+}
+
+static inline u32 get_vrl_length(const u8 *buf)
+{
+ return (u32)(buf[0] << 16 | buf[1] << 8 | buf[2]);
+}
+
+static int drm_hdcp_parse_hdcp1_srm(const u8 *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;
+ DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
+ header->srm_id,
+ __swab16(header->srm_version), header->srm_gen_no);
+
+ WARN_ON(header->reserved);
+
+ buf = buf + sizeof(*header);
+ vrl_length = get_vrl_length(buf);
+ 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");
+ 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");
+ return -EINVAL;
+ }
+
+ buf += DRM_HDCP_1_4_VRL_LENGTH_SIZE;
+ ksv_count = drm_hdcp_get_revoked_ksv_count(buf, vrl_length);
+ if (!ksv_count) {
+ DRM_DEBUG("Revoked KSV count is 0\n");
+ return count;
+ }
+
+ kfree(srm_data->revoked_ksv_list);
+ srm_data->revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN,
+ GFP_KERNEL);
+ if (!srm_data->revoked_ksv_list) {
+ DRM_ERROR("Out of Memory\n");
+ return -ENOMEM;
+ }
+
+ if (drm_hdcp_get_revoked_ksvs(buf, srm_data->revoked_ksv_list,
+ vrl_length) != ksv_count) {
+ srm_data->revoked_ksv_cnt = 0;
+ kfree(srm_data->revoked_ksv_list);
+ return -EINVAL;
+ }
+
+ srm_data->revoked_ksv_cnt = ksv_count;
+ return count;
+}
+
+static int drm_hdcp_parse_hdcp2_srm(const u8 *buf, size_t count)
+{
+ struct hdcp_srm_header *header;
+ u32 vrl_length, ksv_count, ksv_sz;
+
+ if (count < (sizeof(struct hdcp_srm_header) +
+ DRM_HDCP_2_VRL_LENGTH_SIZE + DRM_HDCP_2_DCP_SIG_SIZE)) {
+ DRM_ERROR("Invalid blob length\n");
+ return -EINVAL;
+ }
+
+ header = (struct hdcp_srm_header *)buf;
+ DRM_DEBUG("SRM ID: 0x%x, SRM Ver: 0x%x, SRM Gen No: 0x%x\n",
+ header->srm_id & DRM_HDCP_SRM_ID_MASK,
+ __swab16(header->srm_version), header->srm_gen_no);
+
+ if (header->reserved)
+ return -EINVAL;
+
+ buf = buf + sizeof(*header);
+ vrl_length = get_vrl_length(buf);
+
+ if (count < (sizeof(struct hdcp_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");
+ 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");
+ 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("Revoked KSV count is 0\n");
+ return count;
+ }
+
+ kfree(srm_data->revoked_ksv_list);
+ srm_data->revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN,
+ GFP_KERNEL);
+ if (!srm_data->revoked_ksv_list) {
+ DRM_ERROR("Out of Memory\n");
+ 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->revoked_ksv_list, buf, ksv_sz);
+
+ srm_data->revoked_ksv_cnt = ksv_count;
+ return count;
+}
+
+static inline bool is_srm_version_hdcp1(const u8 *buf)
+{
+ return *buf == (u8)(DRM_HDCP_1_4_SRM_ID << 4);
+}
+
+static inline bool is_srm_version_hdcp2(const u8 *buf)
+{
+ return *buf == (u8)(DRM_HDCP_2_SRM_ID << 4 | DRM_HDCP_2_INDICATOR);
+}
+
+static ssize_t drm_hdcp_srm_update(const u8 *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;
+}
+
+void drm_hdcp_request_srm(struct drm_device *drm_dev)
+{
+ char fw_name[36] = "display_hdcp_srm.bin";
+ const struct firmware *fw;
+
+ int ret;
+
+ ret = request_firmware_direct(&fw, (const char *)fw_name,
+ drm_dev->dev);
+ if (ret < 0)
+ goto exit;
+
+ if (fw->size && fw->data)
+ drm_hdcp_srm_update(fw->data, fw->size);
+
+exit:
+ release_firmware(fw);
+}
+
+/**
+ * drm_hdcp_check_ksvs_revoked - Check the revoked status of the IDs
+ *
+ * @drm_dev: drm_device for which HDCP revocation check is requested
+ * @ksvs: List of KSVs (HDCP receiver IDs)
+ * @ksv_count: KSV count passed in through @ksvs
+ *
+ * This function reads the HDCP System renewability Message(SRM Table)
+ * from userspace as a firmware and parses it for the revoked HDCP
+ * KSVs(Receiver IDs) detected by DCP LLC. Once the revoked KSVs are known,
+ * revoked state of the KSVs in the list passed in by display drivers are
+ * decided and response is sent.
+ *
+ * SRM should be presented in the name of "display_hdcp_srm.bin".
+ *
+ * Returns:
+ * TRUE on any of the KSV is revoked, else FALSE.
+ */
+bool drm_hdcp_check_ksvs_revoked(struct drm_device *drm_dev, 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);
+ drm_hdcp_request_srm(drm_dev);
+
+ rev_ksv_cnt = srm_data->revoked_ksv_cnt;
+ rev_ksv_list = srm_data->revoked_ksv_list;
+
+ /* If the Revoked 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->revoked_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("Revoked KSV is ");
+ drm_hdcp_print_ksv(ksvs);
+ mutex_unlock(&srm_data->mutex);
+ return true;
+ }
+ /* Move the offset to next KSV in the revoked 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_check_ksvs_revoked);
+
+int drm_setup_hdcp_srm(struct class *drm_class)
+{
+ 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);
+
+ return 0;
+}
+
+void drm_teardown_hdcp_srm(struct class *drm_class)
+{
+ if (srm_data) {
+ kfree(srm_data->srm_buf);
+ kfree(srm_data->revoked_ksv_list);
+ kfree(srm_data);
+ }
+}
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index e19ac7ca602d..476a422414f6 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -201,3 +201,7 @@ int drm_syncobj_query_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..292998a2497f 100644
--- a/include/drm/drm_hdcp.h
+++ b/include/drm/drm_hdcp.h
@@ -265,4 +265,28 @@ 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_SRM_ID_MASK (0xF << 4)
+#define DRM_HDCP_1_4_VRL_LENGTH_SIZE 3
+#define DRM_HDCP_1_4_DCP_SIG_SIZE 40
+#define DRM_HDCP_2_SRM_ID 0x9
+#define DRM_HDCP_2_INDICATOR 0x1
+#define DRM_HDCP_2_INDICATOR_MASK 0xF
+#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 hdcp_srm_header {
+ u8 srm_id;
+ u8 reserved;
+ u16 srm_version;
+ u8 srm_gen_no;
+} __packed;
+
+struct drm_device;
+
+bool drm_hdcp_check_ksvs_revoked(struct drm_device *dev,
+ u8 *ksvs, u32 ksv_count);
#endif
--
2.19.1
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