RE: [PATCH v10 09/40] drm/i915: Implement HDCP2.2 receiver authentication

Shankar, Uma
2019-02-04T14:20:09Z

>-----Original Message-----
>From: C, Ramalingam
>Sent: Thursday, January 31, 2019 12:29 PM
>To: intel-gfx@lists.freedesktop.org; dri-devel@lists.freedesktop.org;
>daniel.vetter@ffwll.ch; Winkler, Tomas <tomas.winkler@intel.com>; Shankar,
>Uma <uma.shankar@intel.com>
>Cc: C, Ramalingam <ramalingam.c@intel.com>
>Subject: [PATCH v10 09/40] drm/i915: Implement HDCP2.2 receiver
>authentication
>
>Implements HDCP2.2 authentication for hdcp2.2 receivers, with following steps:
> Authentication and Key exchange (AKE).
> Locality Check (LC).
> Session Key Exchange(SKE).
> DP Errata for stream type configuration for receivers.
>
>At AKE, the HDCP Receiver’s public key certificate is verified by the HDCP
>Transmitter. A Master Key k m is exchanged.
>
>At LC, the HDCP Transmitter enforces locality on the content by requiring that the
>Round Trip Time (RTT) between a pair of messages is not more than 20 ms.
>
>At SKE, The HDCP Transmitter exchanges Session Key ks with the HDCP Receiver.
>
>In DP HDCP2.2 encryption and decryption logics use the stream type as one of the
>parameter. So Before enabling the Encryption DP HDCP2.2 receiver needs to be
>communicated with stream type. This is added to spec as ERRATA.
>
>This generic implementation is complete only with the hdcp2 specific functions
>defined at hdcp_shim.
>
>v2: Rebased.
>v3:
> %s/PARING/PAIRING
> Coding style fixing [Uma]
>v4:
> Rebased as part of patch reordering.
> Defined the functions for mei services. [Daniel]
>v5:
> Redefined the mei service functions as per comp redesign.
> Required intel_hdcp members are defined [Sean Paul]
>v6:
> Typo of cipher is Fixed [Uma]
> %s/uintxx_t/uxx
> Check for comp_master is removed.
>v7:
> Adjust to the new interface.
> Avoid using bool structure members. [Tomas]
>v8: Rebased.
>v9:
> bool is used in struct intel_hdcp [Daniel]
> config_stream_type is redesigned [Daniel]
>
>Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
>Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Looks ok to me.
Reviewed-by: Uma Shankar <uma.shankar@intel.com>

>---
> drivers/gpu/drm/i915/intel_drv.h | 34 +++++++
>drivers/gpu/drm/i915/intel_hdcp.c | 197
>+++++++++++++++++++++++++++++++++++---
> 2 files changed, 216 insertions(+), 15 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>index 31c7a4577ca9..e6792304520a 100644
>--- a/drivers/gpu/drm/i915/intel_drv.h
>+++ b/drivers/gpu/drm/i915/intel_drv.h
>@@ -393,6 +393,22 @@ struct intel_hdcp_shim {
> /* Detects whether Panel is HDCP2.2 capable */
> int (*hdcp_2_2_capable)(struct intel_digital_port *intel_dig_port,
> bool *capable);
>+
>+ /* Write HDCP2.2 messages */
>+ int (*write_2_2_msg)(struct intel_digital_port *intel_dig_port,
>+ void *buf, size_t size);
>+
>+ /* Read HDCP2.2 messages */
>+ int (*read_2_2_msg)(struct intel_digital_port *intel_dig_port,
>+ u8 msg_id, void *buf, size_t size);
>+
>+ /*
>+ * Implementation of DP HDCP2.2 Errata for the communication of
>stream
>+ * type to Receivers. In DP HDCP2.2 Stream type is one of the input to
>+ * the HDCP2.2 Cipher for En/De-Cryption. Not applicable for HDMI.
>+ */
>+ int (*config_stream_type)(struct intel_digital_port *intel_dig_port,
>+ bool is_repeater, u8 type);
> };
>
> struct intel_hdcp {
>@@ -420,6 +436,24 @@ struct intel_hdcp {
> */
> u8 content_type;
> struct hdcp_port_data port_data;
>+
>+ bool is_paired;
>+ bool is_repeater;
>+
>+ /*
>+ * Count of ReceiverID_List received. Initialized to 0 at AKE_INIT.
>+ * Incremented after processing the RepeaterAuth_Send_ReceiverID_List.
>+ * When it rolls over re-auth has to be triggered.
>+ */
>+ u32 seq_num_v;
>+
>+ /*
>+ * Count of RepeaterAuth_Stream_Manage msg propagated.
>+ * Initialized to 0 on AKE_INIT. Incremented after every successful
>+ * transmission of RepeaterAuth_Stream_Manage message. When it rolls
>+ * over re-Auth has to be triggered.
>+ */
>+ u32 seq_num_m;
> };
>
> struct intel_connector {
>diff --git a/drivers/gpu/drm/i915/intel_hdcp.c
>b/drivers/gpu/drm/i915/intel_hdcp.c
>index fbf8b7893bfa..1c81e17dc6c4 100644
>--- a/drivers/gpu/drm/i915/intel_hdcp.c
>+++ b/drivers/gpu/drm/i915/intel_hdcp.c
>@@ -17,6 +17,7 @@
>
> #define KEY_LOAD_TRIES 5
> #define ENCRYPT_STATUS_CHANGE_TIMEOUT_MS 50
>+#define HDCP2_LC_RETRY_CNT 3
>
> static
> bool intel_hdcp_is_ksv_valid(u8 *ksv)
>@@ -853,7 +854,7 @@ bool is_hdcp_supported(struct drm_i915_private
>*dev_priv, enum port port)
> return INTEL_GEN(dev_priv) >= 9 && port < PORT_E; }
>
>-static __attribute__((unused)) int
>+static int
> hdcp2_prepare_ake_init(struct intel_connector *connector,
> struct hdcp2_ake_init *ake_data) { @@ -878,7 +879,7 @@
>hdcp2_prepare_ake_init(struct intel_connector *connector,
> return ret;
> }
>
>-static __attribute__((unused)) int
>+static int
> hdcp2_verify_rx_cert_prepare_km(struct intel_connector *connector,
> struct hdcp2_ake_send_cert *rx_cert,
> bool *paired,
>@@ -908,9 +909,8 @@ hdcp2_verify_rx_cert_prepare_km(struct intel_connector
>*connector,
> return ret;
> }
>
>-static __attribute__((unused)) int
>-hdcp2_verify_hprime(struct intel_connector *connector,
>- struct hdcp2_ake_send_hprime *rx_hprime)
>+static int hdcp2_verify_hprime(struct intel_connector *connector,
>+ struct hdcp2_ake_send_hprime *rx_hprime)
> {
> struct hdcp_port_data *data = &connector->hdcp.port_data;
> struct drm_i915_private *dev_priv = to_i915(connector->base.dev); @@
>-933,7 +933,7 @@ hdcp2_verify_hprime(struct intel_connector *connector,
> return ret;
> }
>
>-static __attribute__((unused)) int
>+static int
> hdcp2_store_pairing_info(struct intel_connector *connector,
> struct hdcp2_ake_send_pairing_info *pairing_info) {
>@@ -958,7 +958,7 @@ hdcp2_store_pairing_info(struct intel_connector
>*connector,
> return ret;
> }
>
>-static __attribute__((unused)) int
>+static int
> hdcp2_prepare_lc_init(struct intel_connector *connector,
> struct hdcp2_lc_init *lc_init)
> {
>@@ -983,7 +983,7 @@ hdcp2_prepare_lc_init(struct intel_connector
>*connector,
> return ret;
> }
>
>-static __attribute__((unused)) int
>+static int
> hdcp2_verify_lprime(struct intel_connector *connector,
> struct hdcp2_lc_send_lprime *rx_lprime) { @@ -1008,9
>+1008,8 @@ hdcp2_verify_lprime(struct intel_connector *connector,
> return ret;
> }
>
>-static __attribute__((unused))
>-int hdcp2_prepare_skey(struct intel_connector *connector,
>- struct hdcp2_ske_send_eks *ske_data)
>+static int hdcp2_prepare_skey(struct intel_connector *connector,
>+ struct hdcp2_ske_send_eks *ske_data)
> {
> struct hdcp_port_data *data = &connector->hdcp.port_data;
> struct drm_i915_private *dev_priv = to_i915(connector->base.dev); @@
>-1087,8 +1086,7 @@ hdcp2_verify_mprime(struct intel_connector *connector,
> return ret;
> }
>
>-static __attribute__((unused))
>-int hdcp2_authenticate_port(struct intel_connector *connector)
>+static int hdcp2_authenticate_port(struct intel_connector *connector)
> {
> struct hdcp_port_data *data = &connector->hdcp.port_data;
> struct drm_i915_private *dev_priv = to_i915(connector->base.dev); @@
>-1137,11 +1135,180 @@ static int hdcp2_deauthenticate_port(struct
>intel_connector *connector)
> return hdcp2_close_mei_session(connector);
> }
>
>+/* Authentication flow starts from here */ static int
>+hdcp2_authentication_key_exchange(struct intel_connector *connector) {
>+ struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
>+ struct intel_hdcp *hdcp = &connector->hdcp;
>+ union {
>+ struct hdcp2_ake_init ake_init;
>+ struct hdcp2_ake_send_cert send_cert;
>+ struct hdcp2_ake_no_stored_km no_stored_km;
>+ struct hdcp2_ake_send_hprime send_hprime;
>+ struct hdcp2_ake_send_pairing_info pairing_info;
>+ } msgs;
>+ const struct intel_hdcp_shim *shim = hdcp->shim;
>+ size_t size;
>+ int ret;
>+
>+ /* Init for seq_num */
>+ hdcp->seq_num_v = 0;
>+ hdcp->seq_num_m = 0;
>+
>+ ret = hdcp2_prepare_ake_init(connector, &msgs.ake_init);
>+ if (ret < 0)
>+ return ret;
>+
>+ ret = shim->write_2_2_msg(intel_dig_port, &msgs.ake_init,
>+ sizeof(msgs.ake_init));
>+ if (ret < 0)
>+ return ret;
>+
>+ ret = shim->read_2_2_msg(intel_dig_port, HDCP_2_2_AKE_SEND_CERT,
>+ &msgs.send_cert, sizeof(msgs.send_cert));
>+ if (ret < 0)
>+ return ret;
>+
>+ if (msgs.send_cert.rx_caps[0] != HDCP_2_2_RX_CAPS_VERSION_VAL)
>+ return -EINVAL;
>+
>+ hdcp->is_repeater =
>HDCP_2_2_RX_REPEATER(msgs.send_cert.rx_caps[2]);
>+
>+ /*
>+ * Here msgs.no_stored_km will hold msgs corresponding to the km
>+ * stored also.
>+ */
>+ ret = hdcp2_verify_rx_cert_prepare_km(connector, &msgs.send_cert,
>+ &hdcp->is_paired,
>+ &msgs.no_stored_km, &size);
>+ if (ret < 0)
>+ return ret;
>+
>+ ret = shim->write_2_2_msg(intel_dig_port, &msgs.no_stored_km, size);
>+ if (ret < 0)
>+ return ret;
>+
>+ ret = shim->read_2_2_msg(intel_dig_port,
>HDCP_2_2_AKE_SEND_HPRIME,
>+ &msgs.send_hprime,
>sizeof(msgs.send_hprime));
>+ if (ret < 0)
>+ return ret;
>+
>+ ret = hdcp2_verify_hprime(connector, &msgs.send_hprime);
>+ if (ret < 0)
>+ return ret;
>+
>+ if (!hdcp->is_paired) {
>+ /* Pairing is required */
>+ ret = shim->read_2_2_msg(intel_dig_port,
>+ HDCP_2_2_AKE_SEND_PAIRING_INFO,
>+ &msgs.pairing_info,
>+ sizeof(msgs.pairing_info));
>+ if (ret < 0)
>+ return ret;
>+
>+ ret = hdcp2_store_pairing_info(connector, &msgs.pairing_info);
>+ if (ret < 0)
>+ return ret;
>+ hdcp->is_paired = true;
>+ }
>+
>+ return 0;
>+}
>+
>+static int hdcp2_locality_check(struct intel_connector *connector) {
>+ struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
>+ struct intel_hdcp *hdcp = &connector->hdcp;
>+ union {
>+ struct hdcp2_lc_init lc_init;
>+ struct hdcp2_lc_send_lprime send_lprime;
>+ } msgs;
>+ const struct intel_hdcp_shim *shim = hdcp->shim;
>+ int tries = HDCP2_LC_RETRY_CNT, ret, i;
>+
>+ for (i = 0; i < tries; i++) {
>+ ret = hdcp2_prepare_lc_init(connector, &msgs.lc_init);
>+ if (ret < 0)
>+ continue;
>+
>+ ret = shim->write_2_2_msg(intel_dig_port, &msgs.lc_init,
>+ sizeof(msgs.lc_init));
>+ if (ret < 0)
>+ continue;
>+
>+ ret = shim->read_2_2_msg(intel_dig_port,
>+ HDCP_2_2_LC_SEND_LPRIME,
>+ &msgs.send_lprime,
>+ sizeof(msgs.send_lprime));
>+ if (ret < 0)
>+ continue;
>+
>+ ret = hdcp2_verify_lprime(connector, &msgs.send_lprime);
>+ if (!ret)
>+ break;
>+ }
>+
>+ return ret;
>+}
>+
>+static int hdcp2_session_key_exchange(struct intel_connector
>+*connector) {
>+ struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
>+ struct intel_hdcp *hdcp = &connector->hdcp;
>+ struct hdcp2_ske_send_eks send_eks;
>+ int ret;
>+
>+ ret = hdcp2_prepare_skey(connector, &send_eks);
>+ if (ret < 0)
>+ return ret;
>+
>+ ret = hdcp->shim->write_2_2_msg(intel_dig_port, &send_eks,
>+ sizeof(send_eks));
>+ if (ret < 0)
>+ return ret;
>+
>+ return 0;
>+}
>+
> static int hdcp2_authenticate_sink(struct intel_connector *connector) {
>- DRM_ERROR("Sink authentication is done in subsequent patches\n");
>+ struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
>+ struct intel_hdcp *hdcp = &connector->hdcp;
>+ const struct intel_hdcp_shim *shim = hdcp->shim;
>+ int ret;
>
>- return -EINVAL;
>+ ret = hdcp2_authentication_key_exchange(connector);
>+ if (ret < 0) {
>+ DRM_DEBUG_KMS("AKE Failed. Err : %d\n", ret);
>+ return ret;
>+ }
>+
>+ ret = hdcp2_locality_check(connector);
>+ if (ret < 0) {
>+ DRM_DEBUG_KMS("Locality Check failed. Err : %d\n", ret);
>+ return ret;
>+ }
>+
>+ ret = hdcp2_session_key_exchange(connector);
>+ if (ret < 0) {
>+ DRM_DEBUG_KMS("SKE Failed. Err : %d\n", ret);
>+ return ret;
>+ }
>+
>+ if (shim->config_stream_type) {
>+ ret = shim->config_stream_type(intel_dig_port,
>+ hdcp->is_repeater,
>+ hdcp->content_type);
>+ if (ret < 0)
>+ return ret;
>+ }
>+
>+ hdcp->port_data.streams[0].stream_type = hdcp->content_type;
>+ ret = hdcp2_authenticate_port(connector);
>+ if (ret < 0)
>+ return ret;
>+
>+ return ret;
> }
>
> static int hdcp2_enable_encryption(struct intel_connector *connector)
>--
>2.7.4

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