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@intel.com Suggested-by: Daniel Vetter daniel@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@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