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// Copyright 2015 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 "components/safe_browsing_db/safe_browsing_api_handler_util.h"
#include <stddef.h>
#include <memory>
#include <string>
#include "base/json/json_reader.h"
#include "base/metrics/histogram_macros.h"
#include "base/strings/string_number_conversions.h"
#include "base/values.h"
#include "components/safe_browsing_db/metadata.pb.h"
#include "components/safe_browsing_db/util.h"
namespace safe_browsing {
namespace {
// JSON metatdata keys. These are are fixed in the Java-side API.
const char kJsonKeyMatches[] = "matches";
const char kJsonKeyThreatType[] = "threat_type";
// Do not reorder or delete. Make sure changes are reflected in
// SB2RemoteCallThreatSubType.
enum UmaThreatSubType {
UMA_THREAT_SUB_TYPE_NOT_SET = 0,
UMA_THREAT_SUB_TYPE_POTENTIALLY_HALMFUL_APP_LANDING = 1,
UMA_THREAT_SUB_TYPE_POTENTIALLY_HALMFUL_APP_DISTRIBUTION = 2,
UMA_THREAT_SUB_TYPE_UNKNOWN = 3,
UMA_THREAT_SUB_TYPE_SOCIAL_ENGINEERING_ADS = 4,
UMA_THREAT_SUB_TYPE_SOCIAL_ENGINEERING_LANDING = 5,
UMA_THREAT_SUB_TYPE_PHISHING = 6,
UMA_THREAT_SUB_TYPE_MAX_VALUE
};
void ReportUmaThreatSubType(SBThreatType threat_type,
UmaThreatSubType sub_type) {
if (threat_type == SB_THREAT_TYPE_URL_MALWARE) {
UMA_HISTOGRAM_ENUMERATION(
"SB2.RemoteCall.ThreatSubType.PotentiallyHarmfulApp", sub_type,
UMA_THREAT_SUB_TYPE_MAX_VALUE);
} else {
UMA_HISTOGRAM_ENUMERATION("SB2.RemoteCall.ThreatSubType.SocialEngineering",
sub_type, UMA_THREAT_SUB_TYPE_MAX_VALUE);
}
}
// Parse the appropriate "*_pattern_type" key from the metadata.
// Returns NONE if no pattern type was found.
ThreatPatternType ParseThreatSubType(
const base::DictionaryValue* match,
SBThreatType threat_type) {
std::string pattern_key;
if (threat_type == SB_THREAT_TYPE_URL_MALWARE) {
pattern_key = "pha_pattern_type";
} else {
DCHECK(threat_type == SB_THREAT_TYPE_URL_PHISHING);
pattern_key = "se_pattern_type";
}
std::string pattern_type;
if (!match->GetString(pattern_key, &pattern_type)) {
ReportUmaThreatSubType(threat_type, UMA_THREAT_SUB_TYPE_NOT_SET);
return ThreatPatternType::NONE;
}
if (threat_type == SB_THREAT_TYPE_URL_MALWARE) {
if (pattern_type == "LANDING") {
ReportUmaThreatSubType(
threat_type, UMA_THREAT_SUB_TYPE_POTENTIALLY_HALMFUL_APP_LANDING);
return ThreatPatternType::MALWARE_LANDING;
} else if (pattern_type == "DISTRIBUTION") {
ReportUmaThreatSubType(
threat_type,
UMA_THREAT_SUB_TYPE_POTENTIALLY_HALMFUL_APP_DISTRIBUTION);
return ThreatPatternType::MALWARE_DISTRIBUTION;
} else {
ReportUmaThreatSubType(threat_type, UMA_THREAT_SUB_TYPE_UNKNOWN);
return ThreatPatternType::NONE;
}
} else {
DCHECK(threat_type == SB_THREAT_TYPE_URL_PHISHING);
if (pattern_type == "SOCIAL_ENGINEERING_ADS") {
ReportUmaThreatSubType(threat_type,
UMA_THREAT_SUB_TYPE_SOCIAL_ENGINEERING_ADS);
return ThreatPatternType::SOCIAL_ENGINEERING_ADS;
} else if (pattern_type == "SOCIAL_ENGINEERING_LANDING") {
ReportUmaThreatSubType(threat_type,
UMA_THREAT_SUB_TYPE_SOCIAL_ENGINEERING_LANDING);
return ThreatPatternType::SOCIAL_ENGINEERING_LANDING;
} else if (pattern_type == "PHISHING") {
ReportUmaThreatSubType(threat_type, UMA_THREAT_SUB_TYPE_PHISHING);
return ThreatPatternType::PHISHING;
} else {
ReportUmaThreatSubType(threat_type, UMA_THREAT_SUB_TYPE_UNKNOWN);
return ThreatPatternType::NONE;
}
}
}
// Parse the optional "UserPopulation" key from the metadata.
// Returns empty string if none was found.
std::string ParseUserPopulation(const base::DictionaryValue* match) {
std::string population_id;
if (!match->GetString("UserPopulation", &population_id))
return std::string();
else
return population_id;
}
int GetThreatSeverity(int java_threat_num) {
// Assign higher numbers to more severe threats.
switch (java_threat_num) {
case JAVA_THREAT_TYPE_POTENTIALLY_HARMFUL_APPLICATION:
return 2;
case JAVA_THREAT_TYPE_SOCIAL_ENGINEERING:
return 1;
default:
// Unknown threat type
return -1;
}
}
SBThreatType JavaToSBThreatType(int java_threat_num) {
switch (java_threat_num) {
case JAVA_THREAT_TYPE_POTENTIALLY_HARMFUL_APPLICATION:
return SB_THREAT_TYPE_URL_MALWARE;
case JAVA_THREAT_TYPE_SOCIAL_ENGINEERING:
return SB_THREAT_TYPE_URL_PHISHING;
default:
// Unknown threat type
return SB_THREAT_TYPE_SAFE;
}
}
} // namespace
// Valid examples:
// {"matches":[{"threat_type":"5"}]}
// or
// {"matches":[{"threat_type":"4", "pha_pattern_type":"LANDING"},
// {"threat_type":"5"}]}
// or
// {"matches":[{"threat_type":"4", "UserPopulation":"YXNvZWZpbmFqO..."}]
UmaRemoteCallResult ParseJsonFromGMSCore(const std::string& metadata_str,
SBThreatType* worst_threat,
ThreatMetadata* metadata) {
*worst_threat = SB_THREAT_TYPE_SAFE; // Default to safe.
*metadata = ThreatMetadata(); // Default values.
if (metadata_str.empty())
return UMA_STATUS_JSON_EMPTY;
// Pick out the "matches" list.
std::unique_ptr<base::Value> value = base::JSONReader::Read(metadata_str);
const base::ListValue* matches = nullptr;
if (!value.get() || !value->IsType(base::Value::Type::DICTIONARY) ||
!(static_cast<base::DictionaryValue*>(value.get()))
->GetList(kJsonKeyMatches, &matches) ||
!matches) {
return UMA_STATUS_JSON_FAILED_TO_PARSE;
}
// Go through each matched threat type and pick the most severe.
int worst_threat_num = -1;
const base::DictionaryValue* worst_match = nullptr;
for (size_t i = 0; i < matches->GetSize(); i++) {
// Get the threat number
const base::DictionaryValue* match;
std::string threat_num_str;
int java_threat_num = -1;
if (!matches->GetDictionary(i, &match) ||
!match->GetString(kJsonKeyThreatType, &threat_num_str) ||
!base::StringToInt(threat_num_str, &java_threat_num)) {
continue; // Skip malformed list entries
}
if (GetThreatSeverity(java_threat_num) >
GetThreatSeverity(worst_threat_num)) {
worst_threat_num = java_threat_num;
worst_match = match;
}
}
*worst_threat = JavaToSBThreatType(worst_threat_num);
if (*worst_threat == SB_THREAT_TYPE_SAFE || !worst_match)
return UMA_STATUS_JSON_UNKNOWN_THREAT;
// Fill in the metadata
metadata->threat_pattern_type =
ParseThreatSubType(worst_match, *worst_threat);
metadata->population_id = ParseUserPopulation(worst_match);
return UMA_STATUS_UNSAFE; // success
}
} // namespace safe_browsing
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