[PATCH v6 12/35] drm/i915: Implement HDCP2.2 receiver authentication
Shankar, Uma
uma.shankar at intel.com
Wed Aug 1 09:41:00 UTC 2018
>-----Original Message-----
>From: C, Ramalingam
>Sent: Saturday, July 14, 2018 8:45 AM
>To: intel-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org;
>daniel at ffwll.ch; seanpaul at chromium.org; Winkler, Tomas
><tomas.winkler at intel.com>; Usyskin, Alexander <alexander.usyskin at intel.com>;
>Shankar, Uma <uma.shankar at intel.com>
>Cc: Sharma, Shashank <shashank.sharma at intel.com>; C, Ramalingam
><ramalingam.c at intel.com>
>Subject: [PATCH v6 12/35] 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_shim defined.
>
>v2:
> Rebased.
>v3:
> No Changes.
>v4:
> %s/PARING/PAIRING
> Coding style fixing [Uma]
>v5:
> Rebased as part of patch reordering.
> Defined the functions for mei services. [Daniel]
>v6:
> Redefined the mei service functions as per comp redesign.
> Required intel_hdcp members are defined [Sean Paul]
>
>Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
>---
> drivers/gpu/drm/i915/intel_drv.h | 34 ++++ drivers/gpu/drm/i915/intel_hdcp.c
>| 370 +++++++++++++++++++++++++++++++++++++-
> 2 files changed, 401 insertions(+), 3 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>index 21683702bcdc..ed429a6fb9ab 100644
>--- a/drivers/gpu/drm/i915/intel_drv.h
>+++ b/drivers/gpu/drm/i915/intel_drv.h
>@@ -384,6 +384,22 @@ 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,
>+ uint8_t 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 Chiper for En/De-Cryption. Not applicable for HDMI.
This should be Cipher.
>+ */
>+ int (*config_stream_type)(struct intel_digital_port *intel_dig_port,
>+ void *buf, size_t size);
> };
>
> struct intel_hdcp {
>@@ -408,6 +424,24 @@ struct intel_hdcp {
>
> /* mei interface related information */
> struct mei_hdcp_data mei_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.
>+ */
>+ uint32_t 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.
>+ */
>+ uint32_t 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 4ace64315baa..ee1e06bac175 100644
>--- a/drivers/gpu/drm/i915/intel_hdcp.c
>+++ b/drivers/gpu/drm/i915/intel_hdcp.c
>@@ -18,6 +18,7 @@
>
> #define KEY_LOAD_TRIES 5
> #define TIME_FOR_ENCRYPT_STATUS_CHANGE 32
>+#define HDCP2_LC_RETRY_CNT 3
Spec says it can be tried upto 1024 times, any specific reasons of limiting it to just 3.
> #define GET_MEI_DDI_INDEX(port) (((port) == PORT_A) ? DDI_A : \
> (enum hdcp_physical_port)(port))
>
>@@ -978,6 +979,191 @@ int intel_hdcp_check_link(struct intel_connector
>*connector)
> return ret;
> }
>
>+static int
>+hdcp2_prepare_ake_init(struct intel_connector *connector,
>+ struct hdcp2_ake_init *ake_data) {
>+ struct mei_hdcp_data *data = &connector->hdcp.mei_data;
>+ struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+ struct i915_component_master *comp = dev_priv->comp_master;
>+ int ret;
>+
>+ if (!comp)
>+ return -EINVAL;
>+
>+ if (!comp->hdcp_ops || !comp->mei_cldev)
>+ return -EINVAL;
>+
>+ if (data->port == INVALID_PORT && connector->encoder)
>+ data->port = GET_MEI_DDI_INDEX(connector->encoder->port);
>+
>+ /* Clear ME FW instance for the port, just incase */
>+ comp->hdcp_ops->close_hdcp_session(comp->mei_cldev, data);
The callback is not yet assigned here, this may cause a crash during bisect.
I would suggest to define the callback functions earlier in the series and then assign them
in subsequent patches or protect it with a NULL check to be safe.
This may not get called till this point due to hdcp2 flag as false in hdcp_init, but this is changed in
0021-drm-i915-Add-HDCP2.2-support-for-HDMI-connectors.patch which will start giving the
above problem from there on till you finally define it in
0035-misc-mei-hdcp-Closing-wired-HDCP2.2-Tx-Session.patch
>+
>+ ret = comp->hdcp_ops->initiate_hdcp2_session(comp->mei_cldev,
>+ data, ake_data);
Same here. Check wherever applicable universally.
>+
>+ return ret;
>+}
>+
>+static int
>+hdcp2_verify_rx_cert_prepare_km(struct intel_connector *connector,
>+ struct hdcp2_ake_send_cert *rx_cert,
>+ bool *paired,
>+ struct hdcp2_ake_no_stored_km *ek_pub_km,
>+ size_t *msg_sz)
>+{
>+ struct mei_hdcp_data *data = &connector->hdcp.mei_data;
>+ struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+ struct i915_component_master *comp = dev_priv->comp_master;
>+ int ret;
>+
>+ if (!comp)
>+ return -EINVAL;
>+
>+ if (!comp->hdcp_ops || !comp->mei_cldev || data->port ==
>INVALID_PORT)
>+ return -EINVAL;
>+
>+ ret = comp->hdcp_ops->verify_receiver_cert_prepare_km(comp-
>>mei_cldev,
>+ data, rx_cert,
>+ paired, ek_pub_km,
>+ msg_sz);
>+ if (ret < 0)
>+ comp->hdcp_ops->close_hdcp_session(comp->mei_cldev, data);
>+
>+ return ret;
>+}
>+
>+static int hdcp2_verify_hprime(struct intel_connector *connector,
>+ struct hdcp2_ake_send_hprime *rx_hprime) {
>+ struct mei_hdcp_data *data = &connector->hdcp.mei_data;
>+ struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+ struct i915_component_master *comp = dev_priv->comp_master;
>+ int ret;
>+
>+ if (!comp)
>+ return -EINVAL;
>+
>+ if (!comp->hdcp_ops || !comp->mei_cldev || data->port ==
>INVALID_PORT)
>+ return -EINVAL;
>+
>+ ret = comp->hdcp_ops->verify_hprime(comp->mei_cldev, data,
>rx_hprime);
>+ if (ret < 0)
>+ comp->hdcp_ops->close_hdcp_session(comp->mei_cldev, data);
>+
>+ return ret;
>+}
>+
>+static int
>+hdcp2_store_pairing_info(struct intel_connector *connector,
>+ struct hdcp2_ake_send_pairing_info *pairing_info) {
>+ struct mei_hdcp_data *data = &connector->hdcp.mei_data;
>+ struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+ struct i915_component_master *comp = dev_priv->comp_master;
>+ int ret;
>+
>+ if (!comp)
>+ return -EINVAL;
>+
>+ if (!comp->hdcp_ops || !comp->mei_cldev || data->port ==
>INVALID_PORT)
>+ return -EINVAL;
>+
>+ ret = comp->hdcp_ops->store_pairing_info(comp->mei_cldev,
>+ data, pairing_info);
>+ if (ret < 0)
>+ comp->hdcp_ops->close_hdcp_session(comp->mei_cldev, data);
>+
>+ return ret;
>+}
>+
>+static int
>+hdcp2_prepare_lc_init(struct intel_connector *connector,
>+ struct hdcp2_lc_init *lc_init)
>+{
>+ struct mei_hdcp_data *data = &connector->hdcp.mei_data;
>+ struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+ struct i915_component_master *comp = dev_priv->comp_master;
>+ int ret;
>+
>+ if (!comp)
>+ return -EINVAL;
>+
>+ if (!comp->hdcp_ops || !comp->mei_cldev || data->port ==
>INVALID_PORT)
>+ return -EINVAL;
>+
>+ ret = comp->hdcp_ops->initiate_locality_check(comp->mei_cldev,
>+ data, lc_init);
>+ if (ret < 0)
>+ comp->hdcp_ops->close_hdcp_session(comp->mei_cldev, data);
>+
>+ return ret;
>+}
>+
>+static int
>+hdcp2_verify_lprime(struct intel_connector *connector,
>+ struct hdcp2_lc_send_lprime *rx_lprime) {
>+ struct mei_hdcp_data *data = &connector->hdcp.mei_data;
>+ struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+ struct i915_component_master *comp = dev_priv->comp_master;
>+ int ret;
>+
>+ if (!comp)
>+ return -EINVAL;
>+
>+ if (!comp->hdcp_ops || !comp->mei_cldev || data->port ==
>INVALID_PORT)
>+ return -EINVAL;
>+
>+ ret = comp->hdcp_ops->verify_lprime(comp->mei_cldev, data,
>rx_lprime);
>+ if (ret < 0)
>+ comp->hdcp_ops->close_hdcp_session(comp->mei_cldev, data);
>+
>+ return ret;
>+}
>+
>+static int hdcp2_prepare_skey(struct intel_connector *connector,
>+ struct hdcp2_ske_send_eks *ske_data) {
>+ struct mei_hdcp_data *data = &connector->hdcp.mei_data;
>+ struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+ struct i915_component_master *comp = dev_priv->comp_master;
>+ int ret;
>+
>+ if (!comp)
>+ return -EINVAL;
>+
>+ if (!comp->hdcp_ops || !comp->mei_cldev || data->port ==
>INVALID_PORT)
>+ return -EINVAL;
>+
>+ ret = comp->hdcp_ops->get_session_key(comp->mei_cldev, data,
>ske_data);
>+ if (ret < 0)
>+ comp->hdcp_ops->close_hdcp_session(comp->mei_cldev, data);
>+
>+ return ret;
>+}
>+
>+static int hdcp2_authenticate_port(struct intel_connector *connector) {
>+ struct mei_hdcp_data *data = &connector->hdcp.mei_data;
>+ struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+ struct i915_component_master *comp = dev_priv->comp_master;
>+ int ret;
>+
>+ if (!comp)
>+ return -EINVAL;
>+
>+ if (!comp->hdcp_ops || !comp->mei_cldev || data->port ==
>INVALID_PORT)
>+ return -EINVAL;
>+
>+ ret = comp->hdcp_ops->enable_hdcp_authentication(comp->mei_cldev,
>data);
>+ if (ret < 0)
>+ comp->hdcp_ops->close_hdcp_session(comp->mei_cldev, data);
>+
>+ return ret;
>+}
>+
> static int hdcp2_close_mei_session(struct intel_connector *connector) {
> struct mei_hdcp_data *data = &connector->hdcp.mei_data; @@ -998,12
>+1184,190 @@ 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));
How are ensuring that this read happens within 200ms as defined by spec ?
>+ 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));
Again how it ensures the 20ms timeout per spec ?
>+ 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) {
>- struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>+ 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;
>+ struct hdcp2_dp_errata_stream_type stream_type_msg;
>+ int ret;
>
>- DRM_ERROR("Sink authentication is done in subsequent patches\n");
>- 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 (!hdcp->is_repeater && shim->config_stream_type) {
>+ /*
>+ * Errata for DP: As Stream type is used for encryption,
>+ * Receiver should be communicated with stream type for the
>+ * decryption of the content.
>+ * Repeater will be communicated with stream type as a
>+ * part of it's auth later in time.
>+ */
>+ stream_type_msg.msg_id =
>HDCP_2_2_ERRATA_DP_STREAM_TYPE;
>+ stream_type_msg.stream_type = hdcp->content_type;
>+
>+ ret = shim->config_stream_type(intel_dig_port,
>&stream_type_msg,
>+ sizeof(stream_type_msg));
>+ if (ret < 0)
>+ return ret;
>+ }
>+
>+ hdcp->mei_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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