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// Copyright 2020 gRPC authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <grpc/support/port_platform.h>
#include "absl/memory/memory.h"
#include "src/core/lib/security/authorization/cel_authorization_engine.h"
namespace grpc_core {
namespace {
// Symbols for traversing Envoy Attributes
constexpr char kUrlPath[] = "url_path";
constexpr char kHost[] = "host";
constexpr char kMethod[] = "method";
constexpr char kHeaders[] = "headers";
constexpr char kSourceAddress[] = "source_address";
constexpr char kSourcePort[] = "source_port";
constexpr char kDestinationAddress[] = "destination_address";
constexpr char kDestinationPort[] = "destination_port";
constexpr char kSpiffeId[] = "spiffe_id";
constexpr char kCertServerName[] = "cert_server_name";
} // namespace
std::unique_ptr<CelAuthorizationEngine>
CelAuthorizationEngine::CreateCelAuthorizationEngine(
const std::vector<envoy_config_rbac_v3_RBAC*>& rbac_policies) {
if (rbac_policies.empty() || rbac_policies.size() > 2) {
gpr_log(GPR_ERROR,
"Invalid rbac policies vector. Must contain either one or two rbac "
"policies.");
return nullptr;
} else if (rbac_policies.size() == 2 &&
(envoy_config_rbac_v3_RBAC_action(rbac_policies[0]) != kDeny ||
envoy_config_rbac_v3_RBAC_action(rbac_policies[1]) != kAllow)) {
gpr_log(GPR_ERROR,
"Invalid rbac policies vector. Must contain one deny \
policy and one allow policy, in that order.");
return nullptr;
} else {
return absl::make_unique<CelAuthorizationEngine>(rbac_policies);
}
}
CelAuthorizationEngine::CelAuthorizationEngine(
const std::vector<envoy_config_rbac_v3_RBAC*>& rbac_policies) {
for (const auto& rbac_policy : rbac_policies) {
// Extract array of policies and store their condition fields in either
// allow_if_matched_ or deny_if_matched_, depending on the policy action.
upb::Arena temp_arena;
size_t policy_num = UPB_MAP_BEGIN;
const envoy_config_rbac_v3_RBAC_PoliciesEntry* policy_entry;
while ((policy_entry = envoy_config_rbac_v3_RBAC_policies_next(
rbac_policy, &policy_num)) != nullptr) {
const upb_strview policy_name_strview =
envoy_config_rbac_v3_RBAC_PoliciesEntry_key(policy_entry);
const std::string policy_name(policy_name_strview.data,
policy_name_strview.size);
const envoy_config_rbac_v3_Policy* policy =
envoy_config_rbac_v3_RBAC_PoliciesEntry_value(policy_entry);
const google_api_expr_v1alpha1_Expr* condition =
envoy_config_rbac_v3_Policy_condition(policy);
// Parse condition to make a pointer tied to the lifetime of arena_.
size_t serial_len;
const char* serialized = google_api_expr_v1alpha1_Expr_serialize(
condition, temp_arena.ptr(), &serial_len);
const google_api_expr_v1alpha1_Expr* parsed_condition =
google_api_expr_v1alpha1_Expr_parse(serialized, serial_len,
arena_.ptr());
if (envoy_config_rbac_v3_RBAC_action(rbac_policy) == kAllow) {
allow_if_matched_.insert(std::make_pair(policy_name, parsed_condition));
} else {
deny_if_matched_.insert(std::make_pair(policy_name, parsed_condition));
}
}
}
}
std::unique_ptr<mock_cel::Activation> CelAuthorizationEngine::CreateActivation(
const EvaluateArgs& args) {
std::unique_ptr<mock_cel::Activation> activation;
for (const auto& elem : envoy_attributes_) {
if (elem == kUrlPath) {
absl::string_view url_path(args.GetPath());
if (!url_path.empty()) {
activation->InsertValue(kUrlPath,
mock_cel::CelValue::CreateStringView(url_path));
}
} else if (elem == kHost) {
absl::string_view host(args.GetHost());
if (!host.empty()) {
activation->InsertValue(kHost,
mock_cel::CelValue::CreateStringView(host));
}
} else if (elem == kMethod) {
absl::string_view method(args.GetMethod());
if (!method.empty()) {
activation->InsertValue(kMethod,
mock_cel::CelValue::CreateStringView(method));
}
} else if (elem == kHeaders) {
std::multimap<absl::string_view, absl::string_view> headers =
args.GetHeaders();
std::vector<std::pair<mock_cel::CelValue, mock_cel::CelValue>>
header_items;
for (const auto& header_key : header_keys_) {
auto header_item = headers.find(header_key);
if (header_item != headers.end()) {
header_items.push_back(
std::pair<mock_cel::CelValue, mock_cel::CelValue>(
mock_cel::CelValue::CreateStringView(header_key),
mock_cel::CelValue::CreateStringView(header_item->second)));
}
}
headers_ = mock_cel::ContainerBackedMapImpl::Create(
absl::Span<std::pair<mock_cel::CelValue, mock_cel::CelValue>>(
header_items));
activation->InsertValue(kHeaders,
mock_cel::CelValue::CreateMap(headers_.get()));
} else if (elem == kSourceAddress) {
absl::string_view source_address(args.GetPeerAddress());
if (!source_address.empty()) {
activation->InsertValue(
kSourceAddress,
mock_cel::CelValue::CreateStringView(source_address));
}
} else if (elem == kSourcePort) {
activation->InsertValue(
kSourcePort, mock_cel::CelValue::CreateInt64(args.GetPeerPort()));
} else if (elem == kDestinationAddress) {
absl::string_view destination_address(args.GetLocalAddress());
if (!destination_address.empty()) {
activation->InsertValue(
kDestinationAddress,
mock_cel::CelValue::CreateStringView(destination_address));
}
} else if (elem == kDestinationPort) {
activation->InsertValue(kDestinationPort, mock_cel::CelValue::CreateInt64(
args.GetLocalPort()));
} else if (elem == kSpiffeId) {
absl::string_view spiffe_id(args.GetSpiffeId());
if (!spiffe_id.empty()) {
activation->InsertValue(
kSpiffeId, mock_cel::CelValue::CreateStringView(spiffe_id));
}
} else if (elem == kCertServerName) {
absl::string_view cert_server_name(args.GetCommonName());
if (!cert_server_name.empty()) {
activation->InsertValue(
kCertServerName,
mock_cel::CelValue::CreateStringView(cert_server_name));
}
} else {
gpr_log(GPR_ERROR,
"Error: Authorization engine does not support evaluating "
"attribute %s.",
elem.c_str());
}
}
return activation;
}
} // namespace grpc_core
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