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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/cert/ct_log_response_parser.h"
#include <memory>
#include <string_view>
#include "base/base64.h"
#include "base/containers/span.h"
#include "base/json/json_value_converter.h"
#include "base/logging.h"
#include "base/time/time.h"
#include "base/values.h"
#include "net/cert/ct_serialization.h"
#include "net/cert/signed_tree_head.h"
namespace net::ct {
namespace {
// Structure for making JSON decoding easier. The string fields
// are base64-encoded so will require further decoding.
struct JsonSignedTreeHead {
int tree_size;
double timestamp;
std::string sha256_root_hash;
DigitallySigned signature;
static void RegisterJSONConverter(
base::JSONValueConverter<JsonSignedTreeHead>* converted);
};
bool ConvertSHA256RootHash(std::string_view s, std::string* result) {
return base::Base64Decode(s, result) && result->size() == kSthRootHashLength;
}
bool ConvertTreeHeadSignature(std::string_view s, DigitallySigned* result) {
std::string tree_head_signature;
if (!base::Base64Decode(s, &tree_head_signature)) {
return false;
}
std::string_view sp(tree_head_signature);
return DecodeDigitallySigned(&sp, result);
}
void JsonSignedTreeHead::RegisterJSONConverter(
base::JSONValueConverter<JsonSignedTreeHead>* converter) {
converter->RegisterIntField("tree_size", &JsonSignedTreeHead::tree_size);
converter->RegisterDoubleField("timestamp", &JsonSignedTreeHead::timestamp);
converter->RegisterCustomField("sha256_root_hash",
&JsonSignedTreeHead::sha256_root_hash,
&ConvertSHA256RootHash);
converter->RegisterCustomField<DigitallySigned>(
"tree_head_signature",
&JsonSignedTreeHead::signature,
&ConvertTreeHeadSignature);
}
bool IsJsonSTHStructurallyValid(const JsonSignedTreeHead& sth) {
return sth.tree_size >= 0 && sth.timestamp >= 0 &&
!sth.sha256_root_hash.empty() && !sth.signature.signature_data.empty();
}
// Structure for making JSON decoding easier. The string fields
// are base64-encoded so will require further decoding.
struct JsonConsistencyProof {
std::vector<std::unique_ptr<std::string>> proof_nodes;
static void RegisterJSONConverter(
base::JSONValueConverter<JsonConsistencyProof>* converter);
};
bool ConvertIndividualProofNode(const base::Value* value, std::string* result) {
const std::string* b64_encoded_node = value->GetIfString();
return b64_encoded_node && ConvertSHA256RootHash(*b64_encoded_node, result);
}
void JsonConsistencyProof::RegisterJSONConverter(
base::JSONValueConverter<JsonConsistencyProof>* converter) {
converter->RegisterRepeatedCustomValue<std::string>(
"consistency", &JsonConsistencyProof::proof_nodes,
&ConvertIndividualProofNode);
}
} // namespace
bool FillSignedTreeHead(const base::Value& json_signed_tree_head,
SignedTreeHead* signed_tree_head) {
JsonSignedTreeHead parsed_sth;
base::JSONValueConverter<JsonSignedTreeHead> converter;
if (!converter.Convert(json_signed_tree_head, &parsed_sth) ||
!IsJsonSTHStructurallyValid(parsed_sth)) {
return false;
}
signed_tree_head->version = SignedTreeHead::V1;
signed_tree_head->tree_size = parsed_sth.tree_size;
signed_tree_head->timestamp =
base::Time::FromMillisecondsSinceUnixEpoch(parsed_sth.timestamp);
signed_tree_head->signature = parsed_sth.signature;
base::as_writable_byte_span(signed_tree_head->sha256_root_hash)
.copy_from(base::as_byte_span(parsed_sth.sha256_root_hash)
.first(kSthRootHashLength));
return true;
}
bool FillConsistencyProof(const base::Value& json_consistency_proof,
std::vector<std::string>* consistency_proof) {
JsonConsistencyProof parsed_proof;
base::JSONValueConverter<JsonConsistencyProof> converter;
if (!converter.Convert(json_consistency_proof, &parsed_proof)) {
return false;
}
const base::Value::Dict* dict_value = json_consistency_proof.GetIfDict();
if (!dict_value || !dict_value->Find("consistency")) {
return false;
}
consistency_proof->reserve(parsed_proof.proof_nodes.size());
for (const auto& proof_node : parsed_proof.proof_nodes) {
consistency_proof->push_back(*proof_node);
}
return true;
}
} // namespace net::ct
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