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key_system_config_selector.cc
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key_system_config_selector.cc
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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/blink/key_system_config_selector.h"
#include <stddef.h>
#include <utility>
#include "base/bind.h"
#include "base/logging.h"
#include "base/metrics/histogram_macros.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "build/build_config.h"
#include "media/base/cdm_config.h"
#include "media/base/key_system_names.h"
#include "media/base/key_systems.h"
#include "media/base/logging_override_if_enabled.h"
#include "media/base/media_permission.h"
#include "media/base/mime_util.h"
#include "media/media_buildflags.h"
#include "third_party/blink/public/platform/url_conversion.h"
#include "third_party/blink/public/platform/web_media_key_system_configuration.h"
#include "third_party/blink/public/platform/web_string.h"
#include "third_party/blink/public/platform/web_vector.h"
#include "third_party/blink/public/web/modules/media/webmediaplayer_util.h"
#include "url/gurl.h"
#include "url/origin.h"
namespace media {
using EmeFeatureRequirement =
blink::WebMediaKeySystemConfiguration::Requirement;
using EmeEncryptionScheme =
blink::WebMediaKeySystemMediaCapability::EncryptionScheme;
namespace {
EmeConfigRule GetSessionTypeConfigRule(EmeSessionTypeSupport support) {
switch (support) {
case EmeSessionTypeSupport::INVALID:
NOTREACHED();
return EmeConfigRule::NOT_SUPPORTED;
case EmeSessionTypeSupport::NOT_SUPPORTED:
return EmeConfigRule::NOT_SUPPORTED;
case EmeSessionTypeSupport::SUPPORTED_WITH_IDENTIFIER:
return EmeConfigRule::IDENTIFIER_AND_PERSISTENCE_REQUIRED;
case EmeSessionTypeSupport::SUPPORTED:
return EmeConfigRule::PERSISTENCE_REQUIRED;
}
NOTREACHED();
return EmeConfigRule::NOT_SUPPORTED;
}
EmeConfigRule GetDistinctiveIdentifierConfigRule(
EmeFeatureSupport support,
EmeFeatureRequirement requirement) {
if (support == EmeFeatureSupport::INVALID) {
NOTREACHED();
return EmeConfigRule::NOT_SUPPORTED;
}
// For NOT_ALLOWED and REQUIRED, the result is as expected. For OPTIONAL, we
// return the most restrictive rule that is not more restrictive than for
// NOT_ALLOWED or REQUIRED. Those values will be checked individually when
// the option is resolved.
//
// NOT_ALLOWED OPTIONAL REQUIRED
// NOT_SUPPORTED I_NOT_ALLOWED I_NOT_ALLOWED NOT_SUPPORTED
// REQUESTABLE I_NOT_ALLOWED SUPPORTED I_REQUIRED
// ALWAYS_ENABLED NOT_SUPPORTED I_REQUIRED I_REQUIRED
DCHECK(support == EmeFeatureSupport::NOT_SUPPORTED ||
support == EmeFeatureSupport::REQUESTABLE ||
support == EmeFeatureSupport::ALWAYS_ENABLED);
DCHECK(requirement == EmeFeatureRequirement::kNotAllowed ||
requirement == EmeFeatureRequirement::kOptional ||
requirement == EmeFeatureRequirement::kRequired);
if ((support == EmeFeatureSupport::NOT_SUPPORTED &&
requirement == EmeFeatureRequirement::kRequired) ||
(support == EmeFeatureSupport::ALWAYS_ENABLED &&
requirement == EmeFeatureRequirement::kNotAllowed)) {
return EmeConfigRule::NOT_SUPPORTED;
}
if (support == EmeFeatureSupport::REQUESTABLE &&
requirement == EmeFeatureRequirement::kOptional) {
return EmeConfigRule::SUPPORTED;
}
if (support == EmeFeatureSupport::NOT_SUPPORTED ||
requirement == EmeFeatureRequirement::kNotAllowed) {
return EmeConfigRule::IDENTIFIER_NOT_ALLOWED;
}
return EmeConfigRule::IDENTIFIER_REQUIRED;
}
EmeConfigRule GetPersistentStateConfigRule(EmeFeatureSupport support,
EmeFeatureRequirement requirement) {
if (support == EmeFeatureSupport::INVALID) {
NOTREACHED();
return EmeConfigRule::NOT_SUPPORTED;
}
// For NOT_ALLOWED and REQUIRED, the result is as expected. For OPTIONAL, we
// return the most restrictive rule that is not more restrictive than for
// NOT_ALLOWED or REQUIRED. Those values will be checked individually when
// the option is resolved.
//
// Note that even though a distinctive identifier can not be required for
// persistent state, it may still be required for persistent sessions.
//
// NOT_ALLOWED OPTIONAL REQUIRED
// NOT_SUPPORTED P_NOT_ALLOWED P_NOT_ALLOWED NOT_SUPPORTED
// REQUESTABLE P_NOT_ALLOWED SUPPORTED P_REQUIRED
// ALWAYS_ENABLED NOT_SUPPORTED P_REQUIRED P_REQUIRED
DCHECK(support == EmeFeatureSupport::NOT_SUPPORTED ||
support == EmeFeatureSupport::REQUESTABLE ||
support == EmeFeatureSupport::ALWAYS_ENABLED);
DCHECK(requirement == EmeFeatureRequirement::kNotAllowed ||
requirement == EmeFeatureRequirement::kOptional ||
requirement == EmeFeatureRequirement::kRequired);
if ((support == EmeFeatureSupport::NOT_SUPPORTED &&
requirement == EmeFeatureRequirement::kRequired) ||
(support == EmeFeatureSupport::ALWAYS_ENABLED &&
requirement == EmeFeatureRequirement::kNotAllowed)) {
return EmeConfigRule::NOT_SUPPORTED;
}
if (support == EmeFeatureSupport::REQUESTABLE &&
requirement == EmeFeatureRequirement::kOptional) {
return EmeConfigRule::SUPPORTED;
}
if (support == EmeFeatureSupport::NOT_SUPPORTED ||
requirement == EmeFeatureRequirement::kNotAllowed) {
return EmeConfigRule::PERSISTENCE_NOT_ALLOWED;
}
return EmeConfigRule::PERSISTENCE_REQUIRED;
}
bool IsPersistentSessionType(blink::WebEncryptedMediaSessionType sessionType) {
switch (sessionType) {
case blink::WebEncryptedMediaSessionType::kTemporary:
return false;
case blink::WebEncryptedMediaSessionType::kPersistentLicense:
return true;
case blink::WebEncryptedMediaSessionType::kPersistentUsageRecord:
return true;
case blink::WebEncryptedMediaSessionType::kUnknown:
break;
}
NOTREACHED();
return false;
}
bool IsSupportedMediaType(const std::string& container_mime_type,
const std::string& codecs,
bool use_aes_decryptor) {
DVLOG(3) << __func__ << ": container_mime_type=" << container_mime_type
<< ", codecs=" << codecs
<< ", use_aes_decryptor=" << use_aes_decryptor;
std::vector<std::string> codec_vector;
SplitCodecs(codecs, &codec_vector);
#if BUILDFLAG(ENABLE_PLATFORM_HEVC) && BUILDFLAG(USE_CHROMEOS_PROTECTED_MEDIA)
// EME HEVC is supported on CrOS under these build flags, but it is not
// supported for clear playback. Remove the HEVC codec strings to avoid asking
// IsSupported*MediaFormat() about HEVC. EME support for HEVC profiles
// is described via KeySystemProperties::GetSupportedCodecs().
// TODO(1156282): Decouple the rest of clear vs EME codec support.
if (base::ToLowerASCII(container_mime_type) == "video/mp4" &&
!codec_vector.empty()) {
auto it = codec_vector.begin();
while (it != codec_vector.end()) {
VideoCodecProfile profile;
uint8_t level_idc;
if (ParseHEVCCodecId(*it, &profile, &level_idc))
codec_vector.erase(it);
else
++it;
}
// Avoid calling IsSupported*MediaFormat() with an empty vector. For
// "video/mp4", this will return MaybeSupported, which we would otherwise
// consider "false" below.
if (codec_vector.empty())
return true;
}
#endif
// AesDecryptor decrypts the stream in the demuxer before it reaches the
// decoder so check whether the media format is supported when clear.
SupportsType support_result =
use_aes_decryptor
? IsSupportedMediaFormat(container_mime_type, codec_vector)
: IsSupportedEncryptedMediaFormat(container_mime_type, codec_vector);
return (support_result == IsSupported);
}
} // namespace
struct KeySystemConfigSelector::SelectionRequest {
std::string key_system;
blink::WebVector<blink::WebMediaKeySystemConfiguration>
candidate_configurations;
SelectConfigCB cb;
bool was_permission_requested = false;
bool is_permission_granted = false;
};
// Accumulates configuration rules to determine if a feature (additional
// configuration rule) can be added to an accumulated configuration.
class KeySystemConfigSelector::ConfigState {
public:
ConfigState(bool was_permission_requested, bool is_permission_granted)
: was_permission_requested_(was_permission_requested),
is_permission_granted_(is_permission_granted) {}
bool IsPermissionGranted() const { return is_permission_granted_; }
// Permission is possible if it has not been denied.
bool IsPermissionPossible() const {
return is_permission_granted_ || !was_permission_requested_;
}
bool IsIdentifierRequired() const { return is_identifier_required_; }
bool IsIdentifierRecommended() const { return is_identifier_recommended_; }
bool AreHwSecureCodecsRequired() const {
return are_hw_secure_codecs_required_;
}
// Checks whether a rule is compatible with all previously added rules.
bool IsRuleSupported(EmeConfigRule rule) const {
switch (rule) {
case EmeConfigRule::NOT_SUPPORTED:
return false;
case EmeConfigRule::IDENTIFIER_NOT_ALLOWED:
return !is_identifier_required_;
case EmeConfigRule::IDENTIFIER_REQUIRED:
// TODO(sandersd): Confirm if we should be refusing these rules when
// permission has been denied (as the spec currently says).
return !is_identifier_not_allowed_ && IsPermissionPossible();
case EmeConfigRule::IDENTIFIER_RECOMMENDED:
return true;
case EmeConfigRule::PERSISTENCE_NOT_ALLOWED:
return !is_persistence_required_;
case EmeConfigRule::PERSISTENCE_REQUIRED:
return !is_persistence_not_allowed_;
case EmeConfigRule::IDENTIFIER_AND_PERSISTENCE_REQUIRED:
return (!is_identifier_not_allowed_ && IsPermissionPossible() &&
!is_persistence_not_allowed_);
case EmeConfigRule::HW_SECURE_CODECS_NOT_ALLOWED:
return !are_hw_secure_codecs_required_;
case EmeConfigRule::HW_SECURE_CODECS_REQUIRED:
return !are_hw_secure_codecs_not_allowed_;
case EmeConfigRule::SUPPORTED:
return true;
}
NOTREACHED();
return false;
}
// Add a rule to the accumulated configuration state.
void AddRule(EmeConfigRule rule) {
DCHECK(IsRuleSupported(rule));
switch (rule) {
case EmeConfigRule::NOT_SUPPORTED:
NOTREACHED();
return;
case EmeConfigRule::IDENTIFIER_NOT_ALLOWED:
is_identifier_not_allowed_ = true;
return;
case EmeConfigRule::IDENTIFIER_REQUIRED:
is_identifier_required_ = true;
return;
case EmeConfigRule::IDENTIFIER_RECOMMENDED:
is_identifier_recommended_ = true;
return;
case EmeConfigRule::PERSISTENCE_NOT_ALLOWED:
is_persistence_not_allowed_ = true;
return;
case EmeConfigRule::PERSISTENCE_REQUIRED:
is_persistence_required_ = true;
return;
case EmeConfigRule::IDENTIFIER_AND_PERSISTENCE_REQUIRED:
is_identifier_required_ = true;
is_persistence_required_ = true;
return;
case EmeConfigRule::HW_SECURE_CODECS_NOT_ALLOWED:
are_hw_secure_codecs_not_allowed_ = true;
return;
case EmeConfigRule::HW_SECURE_CODECS_REQUIRED:
are_hw_secure_codecs_required_ = true;
return;
case EmeConfigRule::SUPPORTED:
return;
}
NOTREACHED();
}
private:
// Whether permission to use a distinctive identifier was requested. If set,
// |is_permission_granted_| represents the final decision.
// (Not changed by adding rules.)
bool was_permission_requested_;
// Whether permission to use a distinctive identifier has been granted.
// (Not changed by adding rules.)
bool is_permission_granted_;
// Whether a rule has been added that requires or blocks a distinctive
// identifier.
bool is_identifier_required_ = false;
bool is_identifier_not_allowed_ = false;
// Whether a rule has been added that recommends a distinctive identifier.
bool is_identifier_recommended_ = false;
// Whether a rule has been added that requires or blocks persistent state.
bool is_persistence_required_ = false;
bool is_persistence_not_allowed_ = false;
// Whether a rule has been added that requires or blocks hardware-secure
// codecs.
bool are_hw_secure_codecs_required_ = false;
bool are_hw_secure_codecs_not_allowed_ = false;
};
KeySystemConfigSelector::KeySystemConfigSelector(
KeySystems* key_systems,
MediaPermission* media_permission)
: key_systems_(key_systems),
media_permission_(media_permission),
is_supported_media_type_cb_(base::BindRepeating(&IsSupportedMediaType)) {
DCHECK(key_systems_);
DCHECK(media_permission_);
}
KeySystemConfigSelector::~KeySystemConfigSelector() = default;
// TODO(sandersd): Move contentType parsing from Blink to here so that invalid
// parameters can be rejected. http://crbug.com/449690, http://crbug.com/690131
bool KeySystemConfigSelector::IsSupportedContentType(
const std::string& key_system,
EmeMediaType media_type,
const std::string& container_mime_type,
const std::string& codecs,
KeySystemConfigSelector::ConfigState* config_state) {
DVLOG(3) << __func__ << ": key_system = " << key_system
<< ", container_mime_type = " << container_mime_type
<< ", codecs = " << codecs;
// From RFC6838: "Both top-level type and subtype names are case-insensitive."
std::string container_lower = base::ToLowerASCII(container_mime_type);
// contentTypes must provide a codec string unless the container implies a
// particular codec. For EME, none of the currently supported containers
// imply a codec, so |codecs| must be provided.
if (codecs.empty()) {
DVLOG(3) << "KeySystemConfig for " << container_mime_type
<< " does not specify necessary codecs.";
return false;
}
// Check that |container_mime_type| and |codecs| are supported by Chrome. This
// is done primarily to validate extended codecs, but it also ensures that the
// CDM cannot support codecs that Chrome does not (which could complicate the
// robustness algorithm).
if (!is_supported_media_type_cb_.Run(
container_lower, codecs,
key_systems_->CanUseAesDecryptor(key_system))) {
DVLOG(3) << "Container mime type and codecs are not supported";
return false;
}
// Before checking CDM support, split |codecs| into a vector of codecs.
std::vector<std::string> codec_vector;
SplitCodecs(codecs, &codec_vector);
// Check that |container_lower| and |codec_vector| are supported by the CDM.
EmeConfigRule codecs_rule = key_systems_->GetContentTypeConfigRule(
key_system, media_type, container_lower, codec_vector);
if (!config_state->IsRuleSupported(codecs_rule)) {
DVLOG(3) << "Container mime type and codecs are not supported by CDM";
return false;
}
config_state->AddRule(codecs_rule);
return true;
}
EmeConfigRule KeySystemConfigSelector::GetEncryptionSchemeConfigRule(
const std::string& key_system,
const EmeEncryptionScheme encryption_scheme) {
switch (encryption_scheme) {
// https://w3c.github.io/encrypted-media/#dom-mediakeysystemmediacapability-encryptionscheme
// "A value which is null or not present indicates to the user agent that
// no specific encryption scheme is required by the application, and
// therefore any encryption scheme is acceptable."
// To fully implement this, we need to get the config rules for both kCenc
// and kCbcs, which could be conflicting, and choose a final config rule
// somehow. If we end up choosing the rule for kCbcs, we could actually
// break legacy players which serves kCenc streams. Therefore, for backward
// compatibility and simplicity, we treat kNotSpecified the same as kCenc.
case EmeEncryptionScheme::kNotSpecified:
case EmeEncryptionScheme::kCenc:
return key_systems_->GetEncryptionSchemeConfigRule(
key_system, EncryptionScheme::kCenc);
case EmeEncryptionScheme::kCbcs:
case EmeEncryptionScheme::kCbcs_1_9:
return key_systems_->GetEncryptionSchemeConfigRule(
key_system, EncryptionScheme::kCbcs);
case EmeEncryptionScheme::kUnrecognized:
// https://w3c.github.io/encrypted-media/#get-supported-capabilities-for-audio-video-type
// "If encryption scheme is non-null and is not recognized or not
// supported by implementation, continue to the next iteration."
// The value provided was an empty string or some other value that is
// not recognized, so treat it as a scheme that is not supported.
return EmeConfigRule::NOT_SUPPORTED;
}
NOTREACHED();
return EmeConfigRule::NOT_SUPPORTED;
}
bool KeySystemConfigSelector::GetSupportedCapabilities(
const std::string& key_system,
EmeMediaType media_type,
const blink::WebVector<blink::WebMediaKeySystemMediaCapability>&
requested_media_capabilities,
// Corresponds to the partial configuration, plus restrictions.
KeySystemConfigSelector::ConfigState* config_state,
std::vector<blink::WebMediaKeySystemMediaCapability>*
supported_media_capabilities) {
// From "3.1.1.3 Get Supported Capabilities for Audio/Video Type".
// https://w3c.github.io/encrypted-media/#get-supported-capabilities-for-audio-video-type
// 1. Let local accumulated capabilities be a local copy of partial
// configuration.
// (Skipped as we directly update |config_state|. This is safe because we
// only do so when at least one requested media capability is supported.)
// 2. Let supported media capabilities be an empty sequence of
// MediaKeySystemMediaCapability dictionaries.
DCHECK_EQ(supported_media_capabilities->size(), 0ul);
// 3. For each requested media capability in requested media capabilities:
for (size_t i = 0; i < requested_media_capabilities.size(); i++) {
// 3.1. Let content type be requested media capability's contentType member.
// 3.2. Let robustness be requested media capability's robustness member.
const blink::WebMediaKeySystemMediaCapability& capability =
requested_media_capabilities[i];
// 3.3. If contentType is the empty string, return null.
if (capability.mime_type.IsEmpty()) {
DVLOG(2) << "Rejecting requested configuration because "
<< "a capability contentType was empty.";
return false;
}
// Corresponds to the local accumulated configuration, plus restrictions.
ConfigState proposed_config_state = *config_state;
// 3.4-3.11. (Implemented by IsSupportedContentType().)
if (!capability.mime_type.ContainsOnlyASCII() ||
!capability.codecs.ContainsOnlyASCII() ||
!IsSupportedContentType(
key_system, media_type, capability.mime_type.Ascii(),
capability.codecs.Ascii(), &proposed_config_state)) {
DVLOG(3) << "The current capability is not supported.";
continue;
}
// 3.12. If robustness is not the empty string and contains an unrecognized
// value or a value not supported by implementation, continue to the
// next iteration. String comparison is case-sensitive.
// Note: If the robustness is empty, we still try to get the config rule
// from |key_systems_| for the empty robustness.
std::string requested_robustness_ascii;
if (!capability.robustness.IsEmpty()) {
if (!capability.robustness.ContainsOnlyASCII())
continue;
requested_robustness_ascii = capability.robustness.Ascii();
}
EmeConfigRule robustness_rule = key_systems_->GetRobustnessConfigRule(
key_system, media_type, requested_robustness_ascii);
// 3.13. If the user agent and implementation definitely support playback of
// encrypted media data for the combination of container, media types,
// robustness and local accumulated configuration in combination with
// restrictions:
if (!proposed_config_state.IsRuleSupported(robustness_rule)) {
DVLOG(3) << "The current robustness rule is not supported.";
continue;
}
proposed_config_state.AddRule(robustness_rule);
// Check for encryption scheme support.
// https://github.com/WICG/encrypted-media-encryption-scheme/blob/master/explainer.md.
EmeConfigRule encryption_scheme_rule =
GetEncryptionSchemeConfigRule(key_system, capability.encryption_scheme);
if (!proposed_config_state.IsRuleSupported(encryption_scheme_rule)) {
DVLOG(3) << "The current encryption scheme rule is not supported.";
continue;
}
// 3.13.1. Add requested media capability to supported media capabilities.
supported_media_capabilities->push_back(capability);
// 3.13.2. Add requested media capability to the {audio|video}Capabilities
// member of local accumulated configuration.
proposed_config_state.AddRule(encryption_scheme_rule);
// This is used as an intermediate variable so that |proposed_config_state|
// is updated in the next iteration of the for loop.
//
// Since |config_state| is also the output parameter, this also updates the
// "partial configuration" as specified in
// "3.1.1.2. Get Supported Configuration and Consent"
// https://w3c.github.io/encrypted-media/#get-supported-configuration-and-consent
// Step 16.3 and 17.3: Set the {video|audio}Capabilities member of
// accumulated configuration to {video|audio} capabilities.
//
// TODO(xhwang): Refactor this to be more consistent with the spec steps.
*config_state = proposed_config_state;
}
// 4. If supported media capabilities is empty, return null.
if (supported_media_capabilities->empty()) {
DVLOG(2) << "Rejecting requested configuration because "
<< "no capabilities were supported.";
return false;
}
// 5. Return media type capabilities.
// Note: |supported_media_capabilities| has already been populated.
return true;
}
KeySystemConfigSelector::ConfigurationSupport
KeySystemConfigSelector::GetSupportedConfiguration(
const std::string& key_system,
const blink::WebMediaKeySystemConfiguration& candidate,
ConfigState* config_state,
blink::WebMediaKeySystemConfiguration* accumulated_configuration) {
DVLOG(3) << __func__;
// From
// http://w3c.github.io/encrypted-media/#get-supported-configuration-and-consent
// 1. Let accumulated configuration be a new MediaKeySystemConfiguration
// dictionary. (Done by caller.)
// 2. Set the label member of accumulated configuration to equal the label
// member of candidate configuration.
accumulated_configuration->label = candidate.label;
// 3. If the initDataTypes member of candidate configuration is non-empty,
// run the following steps:
if (!candidate.init_data_types.empty()) {
// 3.1. Let supported types be an empty sequence of DOMStrings.
std::vector<EmeInitDataType> supported_types;
// 3.2. For each value in candidate configuration's initDataTypes member:
for (size_t i = 0; i < candidate.init_data_types.size(); i++) {
// 3.2.1. Let initDataType be the value.
EmeInitDataType init_data_type = candidate.init_data_types[i];
// 3.2.2. If the implementation supports generating requests based on
// initDataType, add initDataType to supported types. String
// comparison is case-sensitive. The empty string is never
// supported.
if (key_systems_->IsSupportedInitDataType(key_system, init_data_type)) {
supported_types.push_back(init_data_type);
}
}
// 3.3. If supported types is empty, return null.
if (supported_types.empty()) {
DVLOG(2) << "Rejecting requested configuration because "
<< "no initDataType values were supported.";
return CONFIGURATION_NOT_SUPPORTED;
}
// 3.4. Set the initDataTypes member of accumulated configuration to
// supported types.
accumulated_configuration->init_data_types = supported_types;
}
// 4. Let distinctive identifier requirement be the value of candidate
// configuration's distinctiveIdentifier member.
EmeFeatureRequirement distinctive_identifier =
candidate.distinctive_identifier;
// 5. If distinctive identifier requirement is "optional" and Distinctive
// Identifiers are not allowed according to restrictions, set distinctive
// identifier requirement to "not-allowed".
EmeFeatureSupport distinctive_identifier_support =
key_systems_->GetDistinctiveIdentifierSupport(key_system);
if (distinctive_identifier == EmeFeatureRequirement::kOptional) {
if (distinctive_identifier_support == EmeFeatureSupport::INVALID ||
distinctive_identifier_support == EmeFeatureSupport::NOT_SUPPORTED) {
distinctive_identifier = EmeFeatureRequirement::kNotAllowed;
}
}
// 6. Follow the steps for distinctive identifier requirement from the
// following list:
// - "required": If the implementation does not support use of
// Distinctive Identifier(s) in combination with accumulated
// configuration and restrictions, return NotSupported.
// - "optional": Continue with the following steps.
// - "not-allowed": If the implementation requires use Distinctive
// Identifier(s) or Distinctive Permanent Identifier(s) in
// combination with accumulated configuration and restrictions,
// return NotSupported.
// We also reject OPTIONAL when distinctive identifiers are ALWAYS_ENABLED and
// permission has already been denied. This would happen anyway later.
EmeConfigRule di_rule = GetDistinctiveIdentifierConfigRule(
distinctive_identifier_support, distinctive_identifier);
if (!config_state->IsRuleSupported(di_rule)) {
DVLOG(2) << "Rejecting requested configuration because "
<< "the distinctiveIdentifier requirement was not supported.";
return CONFIGURATION_NOT_SUPPORTED;
}
config_state->AddRule(di_rule);
// 7. Set the distinctiveIdentifier member of accumulated configuration to
// equal distinctive identifier requirement.
accumulated_configuration->distinctive_identifier = distinctive_identifier;
// 8. Let persistent state requirement be equal to the value of candidate
// configuration's persistentState member.
EmeFeatureRequirement persistent_state = candidate.persistent_state;
// 9. If persistent state requirement is "optional" and persisting state is
// not allowed according to restrictions, set persistent state requirement
// to "not-allowed".
EmeFeatureSupport persistent_state_support =
key_systems_->GetPersistentStateSupport(key_system);
if (persistent_state == EmeFeatureRequirement::kOptional) {
if (persistent_state_support == EmeFeatureSupport::INVALID ||
persistent_state_support == EmeFeatureSupport::NOT_SUPPORTED) {
persistent_state = EmeFeatureRequirement::kNotAllowed;
}
}
// 10. Follow the steps for persistent state requirement from the following
// list:
// - "required": If the implementation does not support persisting
// state in combination with accumulated configuration and
// restrictions, return NotSupported.
// - "optional": Continue with the following steps.
// - "not-allowed": If the implementation requires persisting state in
// combination with accumulated configuration and restrictions,
// return NotSupported.
EmeConfigRule ps_rule =
GetPersistentStateConfigRule(persistent_state_support, persistent_state);
if (!config_state->IsRuleSupported(ps_rule)) {
DVLOG(2) << "Rejecting requested configuration because "
<< "the persistentState requirement was not supported.";
return CONFIGURATION_NOT_SUPPORTED;
}
config_state->AddRule(ps_rule);
// 11. Set the persistentState member of accumulated configuration to equal
// the value of persistent state requirement.
accumulated_configuration->persistent_state = persistent_state;
// 12. Follow the steps for the first matching condition from the following
// list:
// - If the sessionTypes member is present in candidate configuration,
// let session types be candidate configuration's sessionTypes member.
// - Otherwise, let session types be [ "temporary" ].
// (Done in MediaKeySystemAccessInitializer.)
blink::WebVector<blink::WebEncryptedMediaSessionType> session_types =
candidate.session_types;
// 13. For each value in session types:
for (size_t i = 0; i < session_types.size(); i++) {
// 13.1. Let session type be the value.
blink::WebEncryptedMediaSessionType session_type = session_types[i];
if (session_type == blink::WebEncryptedMediaSessionType::kUnknown) {
DVLOG(2) << "Rejecting requested configuration because "
<< "session type was not recognized.";
return CONFIGURATION_NOT_SUPPORTED;
}
// 13.2. If accumulated configuration's persistentState value is
// "not-allowed" and the Is persistent session type? algorithm
// returns true for session type return NotSupported.
if (accumulated_configuration->persistent_state ==
EmeFeatureRequirement::kNotAllowed &&
IsPersistentSessionType(session_type)) {
DVLOG(2) << "Rejecting requested configuration because persistent "
"sessions are not allowed.";
return CONFIGURATION_NOT_SUPPORTED;
}
// 13.3. If the implementation does not support session type in combination
// with accumulated configuration and restrictions for other reasons,
// return NotSupported.
EmeConfigRule session_type_rule = EmeConfigRule::NOT_SUPPORTED;
switch (session_type) {
case blink::WebEncryptedMediaSessionType::kUnknown:
NOTREACHED();
return CONFIGURATION_NOT_SUPPORTED;
case blink::WebEncryptedMediaSessionType::kTemporary:
session_type_rule = EmeConfigRule::SUPPORTED;
break;
case blink::WebEncryptedMediaSessionType::kPersistentLicense:
session_type_rule = GetSessionTypeConfigRule(
key_systems_->GetPersistentLicenseSessionSupport(key_system));
break;
case blink::WebEncryptedMediaSessionType::kPersistentUsageRecord:
session_type_rule = GetSessionTypeConfigRule(
key_systems_->GetPersistentUsageRecordSessionSupport(key_system));
break;
}
if (!config_state->IsRuleSupported(session_type_rule)) {
DVLOG(2) << "Rejecting requested configuration because "
<< "a required session type was not supported.";
return CONFIGURATION_NOT_SUPPORTED;
}
config_state->AddRule(session_type_rule);
// 13.4. If accumulated configuration's persistentState value is "optional"
// and the result of running the Is persistent session type?
// algorithm on session type is true, change accumulated
// configuration's persistentState value to "required".
if (accumulated_configuration->persistent_state ==
EmeFeatureRequirement::kOptional &&
IsPersistentSessionType(session_type)) {
accumulated_configuration->persistent_state =
EmeFeatureRequirement::kRequired;
}
}
// 14. Set the sessionTypes member of accumulated configuration to
// session types.
accumulated_configuration->session_types = session_types;
// 15. If the videoCapabilities and audioCapabilities members in candidate
// configuration are both empty, return NotSupported.
if (candidate.video_capabilities.empty() &&
candidate.audio_capabilities.empty()) {
DVLOG(2) << "Rejecting requested configuration because "
<< "neither audioCapabilities nor videoCapabilities is specified";
return CONFIGURATION_NOT_SUPPORTED;
}
// 16. If the videoCapabilities member in candidate configuration is
// non-empty:
std::vector<blink::WebMediaKeySystemMediaCapability> video_capabilities;
if (!candidate.video_capabilities.empty()) {
// 16.1. Let video capabilities be the result of executing the Get
// Supported Capabilities for Audio/Video Type algorithm on Video,
// candidate configuration's videoCapabilities member, accumulated
// configuration, and restrictions.
// 16.2. If video capabilities is null, return NotSupported.
if (!GetSupportedCapabilities(key_system, EmeMediaType::VIDEO,
candidate.video_capabilities, config_state,
&video_capabilities)) {
DVLOG(2) << "Rejecting requested configuration because the specified "
"videoCapabilities are not supported.";
return CONFIGURATION_NOT_SUPPORTED;
}
// 16.3. Set the videoCapabilities member of accumulated configuration
// to video capabilities.
accumulated_configuration->video_capabilities = video_capabilities;
} else {
// Otherwise set the videoCapabilities member of accumulated configuration
// to an empty sequence.
accumulated_configuration->video_capabilities = video_capabilities;
}
// 17. If the audioCapabilities member in candidate configuration is
// non-empty:
std::vector<blink::WebMediaKeySystemMediaCapability> audio_capabilities;
if (!candidate.audio_capabilities.empty()) {
// 17.1. Let audio capabilities be the result of executing the Get
// Supported Capabilities for Audio/Video Type algorithm on Audio,
// candidate configuration's audioCapabilities member, accumulated
// configuration, and restrictions.
// 17.2. If audio capabilities is null, return NotSupported.
if (!GetSupportedCapabilities(key_system, EmeMediaType::AUDIO,
candidate.audio_capabilities, config_state,
&audio_capabilities)) {
DVLOG(2) << "Rejecting requested configuration because the specified "
"audioCapabilities are not supported.";
return CONFIGURATION_NOT_SUPPORTED;
}
// 17.3. Set the audioCapabilities member of accumulated configuration
// to audio capabilities.
accumulated_configuration->audio_capabilities = audio_capabilities;
} else {
// Otherwise set the audioCapabilities member of accumulated configuration
// to an empty sequence.
accumulated_configuration->audio_capabilities = audio_capabilities;
}
// 18. If accumulated configuration's distinctiveIdentifier value is
// "optional", follow the steps for the first matching condition
// from the following list:
// - If the implementation requires use Distinctive Identifier(s) or
// Distinctive Permanent Identifier(s) for any of the combinations
// in accumulated configuration, change accumulated configuration's
// distinctiveIdentifier value to "required".
// - Otherwise, change accumulated configuration's
// distinctiveIdentifier value to "not-allowed".
if (accumulated_configuration->distinctive_identifier ==
EmeFeatureRequirement::kOptional) {
EmeConfigRule not_allowed_rule = GetDistinctiveIdentifierConfigRule(
key_systems_->GetDistinctiveIdentifierSupport(key_system),
EmeFeatureRequirement::kNotAllowed);
EmeConfigRule required_rule = GetDistinctiveIdentifierConfigRule(
key_systems_->GetDistinctiveIdentifierSupport(key_system),
EmeFeatureRequirement::kRequired);
bool not_allowed_supported =
config_state->IsRuleSupported(not_allowed_rule);
bool required_supported = config_state->IsRuleSupported(required_rule);
// If a distinctive identifier is recommend and that is a possible outcome,
// prefer that.
if (required_supported && config_state->IsIdentifierRecommended() &&
config_state->IsPermissionPossible()) {
not_allowed_supported = false;
}
if (not_allowed_supported) {
accumulated_configuration->distinctive_identifier =
EmeFeatureRequirement::kNotAllowed;
config_state->AddRule(not_allowed_rule);
} else if (required_supported) {
accumulated_configuration->distinctive_identifier =
EmeFeatureRequirement::kRequired;
config_state->AddRule(required_rule);
} else {
// We should not have passed step 6.
NOTREACHED();
return CONFIGURATION_NOT_SUPPORTED;
}
}
// 19. If accumulated configuration's persistentState value is "optional",
// follow the steps for the first matching condition from the following
// list:
// - If the implementation requires persisting state for any of the
// combinations in accumulated configuration, change accumulated
// configuration's persistentState value to "required".
// - Otherwise, change accumulated configuration's persistentState
// value to "not-allowed".
if (accumulated_configuration->persistent_state ==
EmeFeatureRequirement::kOptional) {
EmeConfigRule not_allowed_rule = GetPersistentStateConfigRule(
key_systems_->GetPersistentStateSupport(key_system),
EmeFeatureRequirement::kNotAllowed);
EmeConfigRule required_rule = GetPersistentStateConfigRule(
key_systems_->GetPersistentStateSupport(key_system),
EmeFeatureRequirement::kRequired);
// |distinctiveIdentifier| should not be affected after it is decided.
DCHECK(not_allowed_rule == EmeConfigRule::NOT_SUPPORTED ||
not_allowed_rule == EmeConfigRule::PERSISTENCE_NOT_ALLOWED);
DCHECK(required_rule == EmeConfigRule::NOT_SUPPORTED ||
required_rule == EmeConfigRule::PERSISTENCE_REQUIRED);
bool not_allowed_supported =
config_state->IsRuleSupported(not_allowed_rule);
bool required_supported = config_state->IsRuleSupported(required_rule);
if (not_allowed_supported) {
accumulated_configuration->persistent_state =
EmeFeatureRequirement::kNotAllowed;
config_state->AddRule(not_allowed_rule);
} else if (required_supported) {
accumulated_configuration->persistent_state =
EmeFeatureRequirement::kRequired;
config_state->AddRule(required_rule);
} else {
// We should not have passed step 5.
NOTREACHED();
return CONFIGURATION_NOT_SUPPORTED;
}
}
// 20. If implementation in the configuration specified by the combination of
// the values in accumulated configuration is not supported or not allowed
// in the origin, return NotSupported.
// TODO(jrummell): can we check that the CDM can't be loaded by the origin?
// 21. If accumulated configuration's distinctiveIdentifier value is
// "required" and the Distinctive Identifier(s) associated with
// accumulated configuration are not unique per origin and profile
// and clearable:
// 21.1. Update restrictions to reflect that all configurations described
// by accumulated configuration do not have user consent.
// 21.2. Return ConsentDenied and restrictions.
// (Not required as data is unique per origin and clearable.)
// 22. Let consent status and updated restrictions be the result of running
// the Get Consent Status algorithm on accumulated configuration,
// restrictions and origin and follow the steps for the value of consent
// status from the following list:
// - "ConsentDenied": Return ConsentDenied and updated restrictions.
// - "InformUser": Inform the user that accumulated configuration is
// in use in the origin including, specifically, the information
// that Distinctive Identifier(s) and/or Distinctive Permanent
// Identifier(s) as appropriate will be used if the
// distinctiveIdentifier member of accumulated configuration is
// "required". Continue to the next step.
// - "Allowed": Continue to the next step.
// Accumulated configuration's distinctiveIdentifier should be "required" or
// "notallowed"" due to step 18. If it is "required", prompt the user for
// consent unless it has already been granted.
if (accumulated_configuration->distinctive_identifier ==
EmeFeatureRequirement::kRequired) {
// The caller is responsible for resolving what to do if permission is
// required but has been denied (it should treat it as NOT_SUPPORTED).
if (!config_state->IsPermissionGranted())
return CONFIGURATION_REQUIRES_PERMISSION;
}
// 23. Return accumulated configuration.
return CONFIGURATION_SUPPORTED;
}
void KeySystemConfigSelector::SelectConfig(
const blink::WebString& key_system,
const blink::WebVector<blink::WebMediaKeySystemConfiguration>&
candidate_configurations,
SelectConfigCB cb) {
// Continued from requestMediaKeySystemAccess(), step 6, from
// https://w3c.github.io/encrypted-media/#requestmediakeysystemaccess
//
// 6.1 If keySystem is not one of the Key Systems supported by the user
// agent, reject promise with a NotSupportedError. String comparison
// is case-sensitive.
if (!key_system.ContainsOnlyASCII()) {
std::move(cb).Run(Status::kUnsupportedKeySystem, nullptr, nullptr);
return;
}
key_systems_->UpdateIfNeeded();
std::string key_system_ascii = key_system.Ascii();
if (!key_systems_->IsSupportedKeySystem(key_system_ascii)) {
#if defined(OS_MAC) && defined(ARCH_CPU_ARM_FAMILY)
// CDM support on Mac ARM is known not ready yet, so Chrome uses an
// architecture translation of the CDM on that platform. If the CDM isn't a
// supported key system, then it might be due to the fact the translation
// system isn't yet installed. Notify the browser process so that it can
// offer installation of the translation system to the user.
media_permission_->NotifyUnsupportedPlatform();
std::move(cb).Run(Status::kUnsupportedPlatform, nullptr, nullptr);
#else
std::move(cb).Run(Status::kUnsupportedKeySystem, nullptr, nullptr);
#endif
return;
}
const bool is_encrypted_media_enabled =
media_permission_->IsEncryptedMediaEnabled();
// Only report this UMA at most once per renderer process.
static bool has_reported_encrypted_media_enabled_uma = false;
if (!has_reported_encrypted_media_enabled_uma) {
has_reported_encrypted_media_enabled_uma = true;
UMA_HISTOGRAM_BOOLEAN("Media.EME.EncryptedMediaEnabled",
is_encrypted_media_enabled);
}
// According to Section 9 "Common Key Systems": All user agents MUST support
// the common key systems described in this section.
// 9.1 Clear Key
//
// Therefore, always support Clear Key key system and only check settings for
// other key systems.
if (!is_encrypted_media_enabled && !IsClearKey(key_system_ascii)) {
std::move(cb).Run(Status::kUnsupportedKeySystem, nullptr, nullptr);
return;
}
// 6.2-6.4. Implemented by OnSelectConfig().
// TODO(sandersd): This should be async, ideally not on the main thread.
auto request = std::make_unique<SelectionRequest>();
request->key_system = key_system_ascii;
request->candidate_configurations = candidate_configurations;
request->cb = std::move(cb);
SelectConfigInternal(std::move(request));
}
void KeySystemConfigSelector::SelectConfigInternal(
std::unique_ptr<SelectionRequest> request) {
DVLOG(3) << __func__;
// Continued from requestMediaKeySystemAccess(), step 6, from
// https://w3c.github.io/encrypted-media/#requestmediakeysystemaccess
//
// 6.2. Let implementation be the implementation of keySystem.
// (|key_systems_| fills this role.)
// 6.3. For each value in supportedConfigurations:
for (size_t i = 0; i < request->candidate_configurations.size(); i++) {
// 6.3.1. Let candidate configuration be the value.
// 6.3.2. Let supported configuration be the result of executing the Get
// Supported Configuration algorithm on implementation, candidate
// configuration, and origin.
// 6.3.3. If supported configuration is not NotSupported, [initialize