[Intel-gfx] [PATCH v6 12/35] drm/i915: Implement HDCP2.2 receiver authentication
Ramalingam C
ramalingam.c at intel.com
Thu Aug 30 06:34:14 UTC 2018
On Wednesday 01 August 2018 03:11 PM, Shankar, Uma wrote:
>
>> -----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.
Spec says we can retry Locality check upto 1024 times.
We decided to stick to 3 times as per the observations in the experiments.
>
>> #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
Uma,
comp->hdcp_ops and comp->mei_cldev are initialized at component binding
of the mei_hdcp module. So until the component binding happens at mei_hdcp,
members of the comp->hdcp_ops wont be utilized.
>> +
>> + 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 ?
shim->read_2_2_msg() waits for the required timeout for each HDCP2.2 msgs.
--Ram.
>> + 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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