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

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>-----Original Message-----
>From: C, Ramalingam
>Sent: Thursday, January 31, 2019 12:29 PM
>To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx;
>daniel.vetter@xxxxxxxx; Winkler, Tomas <tomas.winkler@xxxxxxxxx>; Shankar,
>Uma <uma.shankar@xxxxxxxxx>
>Cc: C, Ramalingam <ramalingam.c@xxxxxxxxx>
>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@xxxxxxxxx>
>Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>

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

>---
> 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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