Tweak event prioritization logic and defaults

2020-08-27 15:21:38 -07:00 · 2020-08-27 15:21:38 -07:00 · 301bdcef86
--- a/Config.h
+++ b/Config.h
@ -25,10 +25,14 @@
 class Config {
 public:
    Config() = default;
-    explicit Config(std::unordered_map<std::string, std::string> map): _map(map) {}
+    explicit Config(std::unordered_map<std::string, std::string> map): _map(std::move(map)) {}

    void Load(const std::string& path);

+    void SetString(const std::string& name, const std::string& value) {
+        _map[name] = value;
+    }
+
    bool HasKey(const std::string& name) const;
    bool GetBool(const std::string& name) const;
    double GetDouble(const std::string& name) const;
--- a/EventPrioritizer.cpp
+++ b/EventPrioritizer.cpp
@ -18,6 +18,54 @@

 #include "Logger.h"
 #include "Translate.h"
+#include "StringUtils.h"
+
+template <typename T>
+inline bool field_to_int(const EventRecordField& field, T& val, int base) {
+    errno = 0;
+    val = static_cast<T>(strtol(field.RawValuePtr(), nullptr, base));
+    return errno == 0;
+}
+
+template <typename T>
+inline bool field_to_uint(const EventRecordField& field, T& val, int base) {
+    errno = 0;
+    val = static_cast<T>(strtoul(field.RawValuePtr(), nullptr, base));
+    return errno == 0;
+}
+
+void interpret_syscall_field(std::string& syscall_name, const EventRecord& record) {
+    static std::string_view SV_SYSCALL = "syscall";
+    static std::string_view SV_ARCH = "arch";
+
+    auto syscall_field = record.FieldByName(SV_SYSCALL);
+    if (!syscall_field) {
+        syscall_name = "unknown-syscall()";
+        return;
+    }
+    auto arch_field = record.FieldByName(SV_ARCH);
+    if (!arch_field) {
+        syscall_name = "unknown-syscall(" + std::string(syscall_field.RawValue()) + ")";
+        return;
+    }
+    uint32_t arch;
+    if (!field_to_uint(arch_field, arch, 16)) {
+        arch = 0;
+    }
+    auto mt = ArchToMachine(arch);
+    if (mt == MachineType::UNKNOWN) {
+        syscall_name = "unknown-syscall(" + std::string(syscall_field.RawValue()) + ")";
+        return;
+    }
+
+    int syscall;
+    if (field_to_int(syscall_field, syscall, 10)) {
+        SyscallToName(mt, syscall, syscall_name);
+    } else {
+        syscall_name = "unknown-syscall(" + std::string(syscall_field.RawValue()) + ")";
+    }
+}
+

 bool EventPrioritizer::LoadFromConfig(Config& config) {

@ -38,13 +86,35 @@ bool EventPrioritizer::LoadFromConfig(Config& config) {
            auto rt_name = std::string(it->name.GetString(), it->name.GetStringLength());
            auto rt = RecordNameToType(rt_name);
            if (rt == RecordType::UNKNOWN) {
-                Logger::Warn("Invalid Record Type Name in 'event_priority_by_record_type' in config: %s", rt_name.c_str());
+                Logger::Warn("Invalid Record Type Name in 'event_priority_by_record_type' in config: %s",
+                             rt_name.c_str());
                return false;
            }
            _record_type_priorities.emplace(std::make_pair(rt, it->value.GetUint()));
        }
    }

+    if (config.HasKey("event_priority_by_record_type_category")) {
+        auto doc = config.GetJSON("event_priority_by_record_type_category");
+        if (!doc.IsObject()) {
+            return false;
+        }
+        for (auto it = doc.MemberBegin(); it != doc.MemberEnd(); ++it) {
+            if (!it->name.IsString() || !it->value.IsInt()) {
+                Logger::Warn("Invalid value in 'event_priority_by_record_type' in config");
+                return false;
+            }
+            auto rt_name = std::string(it->name.GetString(), it->name.GetStringLength());
+            auto rt = RecordTypeCategoryNameToCategory(rt_name);
+            if (rt == RecordTypeCategory::UNKNOWN) {
+                Logger::Warn("Invalid Record Type Category Name in 'event_priority_by_record_type_category' in config: %s",
+                             rt_name.c_str());
+                return false;
+            }
+            _record_type_category_priorities.emplace(std::make_pair(rt, it->value.GetUint()));
+        }
+    }
+
    if (config.HasKey("event_priority_by_syscall")) {
        auto doc = config.GetJSON("event_priority_by_syscall");
        if (!doc.IsObject()) {
@ -55,17 +125,8 @@ bool EventPrioritizer::LoadFromConfig(Config& config) {
                Logger::Warn("Invalid value in 'event_priority_by_syscall' in config");
                return false;
            }
-            auto sc = std::string(it->name.GetString(), it->name.GetStringLength());
-            auto sc_num = SyscallNameToNumber(DetectMachine(), sc);
-            if (sc_num < 0) {
-                errno = 0;
-                sc_num = static_cast<int>(strtol(sc.c_str(), nullptr, 10));
-                if (errno != 0) {
-                    Logger::Warn("Invalid Syscall in 'event_priority_by_syscall' in config: %s", sc.c_str());
-                    return false;
-                }
-            }
-            _syscall_priorities.emplace(std::make_pair(sc_num, it->value.GetUint()));
+            auto sc_name = std::string(it->name.GetString(), it->name.GetStringLength());
+            _syscall_priorities.emplace(std::make_pair(sc_name, it->value.GetUint()));
        }
    }

@ -73,27 +134,34 @@ bool EventPrioritizer::LoadFromConfig(Config& config) {
 }

 uint16_t EventPrioritizer::Prioritize(const Event& event) {
-    static std::string_view SV_SYSCALL = "syscall";
+    static std::string S_STAR = "*";

    auto rec1 = event.begin();

-    if (static_cast<RecordType>(rec1.RecordType()) == RecordType::SYSCALL) {
-        auto syscall_field = rec1.FieldByName(SV_SYSCALL);
-        if (syscall_field) {
-            errno = 0;
-            int syscall = static_cast<int>(strtol(syscall_field.RawValuePtr(), nullptr, 10));
-            if (errno == 0) {
-                auto itr = _syscall_priorities.find(syscall);
-                if (itr != _syscall_priorities.end()) {
-                    return itr->second;
-                }
-            }
+    if (static_cast<RecordType>(rec1.RecordType()) == RecordType::AUOMS_EXECVE) {
+
+    } else if (static_cast<RecordType>(rec1.RecordType()) == RecordType::SYSCALL ||
+        static_cast<RecordType>(rec1.RecordType()) == RecordType::AUOMS_SYSCALL) {
+        _syscall_name.resize(0);
+        interpret_syscall_field(_syscall_name, rec1);
+        auto itr = _syscall_priorities.find(_syscall_name);
+        if (itr != _syscall_priorities.end()) {
+            return itr->second;
+        }
+        itr = _syscall_priorities.find(S_STAR);
+        if (itr != _syscall_priorities.end()) {
+            return itr->second;
        }
    } else {
        auto itr = _record_type_priorities.find(static_cast<RecordType>(rec1.RecordType()));
        if (itr != _record_type_priorities.end()) {
            return itr->second;
        }
+        auto rtc = RecordTypeToCategory(static_cast<RecordType>(rec1.RecordType()));
+        auto itr2 = _record_type_category_priorities.find(rtc);
+        if (itr2 != _record_type_category_priorities.end()) {
+            return itr2->second;
+        }
    }

    return _default_priority;
--- a/EventPrioritizer.h
+++ b/EventPrioritizer.h
@ -25,7 +25,7 @@

 class EventPrioritizer: public IEventPrioritizer {
 public:
-    EventPrioritizer(uint16_t default_priority): _default_priority(default_priority)  {}
+    explicit EventPrioritizer(uint16_t default_priority): _default_priority(default_priority)  {}

    bool LoadFromConfig(Config& config);

@ -34,7 +34,9 @@ public:
 private:
    uint16_t _default_priority;
    std::unordered_map<RecordType, uint16_t> _record_type_priorities;
-    std::unordered_map<int, uint16_t> _syscall_priorities;
+    std::unordered_map<RecordTypeCategory, uint16_t> _record_type_category_priorities;
+    std::unordered_map<std::string, uint16_t> _syscall_priorities;
+    std::string _syscall_name;
 };


--- a/Interpret.cpp
+++ b/Interpret.cpp
@ -233,6 +233,8 @@ bool InterpretSockaddrField(std::string& out, const EventRecord& record, const E
 }

 bool InterpretField(std::string& out, const EventRecord& record, const EventRecordField& field, field_type_t field_type) {
+    static std::string_view SV_ARCH = "arch";
+
    switch (field_type) {
        case field_type_t::ARCH: {
            uint32_t arch;
@ -249,9 +251,9 @@ bool InterpretField(std::string& out, const EventRecord& record, const EventReco
            return true;
        }
        case field_type_t::SYSCALL: {
-            auto arch_field = record.FieldByName("arch");
+            auto arch_field = record.FieldByName(SV_ARCH);
            if (!arch_field) {
-                out = "unknown-syscall(" + std::string() + ")";
+                out = "unknown-syscall(" + std::string(field.RawValue()) + ")";
                return true;
            }
            uint32_t arch;
--- a/RecordType.h
+++ b/RecordType.h
@ -259,8 +259,65 @@ enum class RecordType: int {
    AUOMS_EXECVE              = 14688,
 };

+enum class RecordTypeCategory: int {
+    UNKNOWN = 0,
+    KERNEL = 1,
+    USER_MSG = 2,
+    DAEMON = 3,
+    EVENT = 4,
+    SELINUX = 5,
+    APPARMOR = 6,
+    KERN_CRYPTO_MSG = 7,
+    KERN_ANOM_MSG = 8,
+    INTEGRITY_MSG = 9,
+    ANOM_MSG = 10,
+    ANOM_RESP = 11,
+    USER_LSPP_MSG = 12,
+    CRYPTO_MSG = 13,
+    VIRT_MSG = 14,
+    USER_MSG2 = 15,
+    AUOMS_MSG = 16,
+};
+
 constexpr bool IsSingleRecordEvent(RecordType rtype) {
    return rtype != RecordType::EOE && (rtype < RecordType::FIRST_EVENT || rtype >= RecordType::FIRST_ANOM_MSG || rtype == RecordType::KERNEL);
 }

+constexpr RecordTypeCategory RecordTypeToCategory(RecordType rtype) {
+    if (rtype < RecordType::FIRST_USER_MSG) {
+        return RecordTypeCategory::KERNEL;
+    } else if (rtype >= RecordType::FIRST_USER_MSG && rtype <= RecordType::LAST_USER_MSG) {
+        return RecordTypeCategory::USER_MSG;
+    } else if (rtype >= RecordType::FIRST_DAEMON && rtype <= RecordType::LAST_DAEMON) {
+        return RecordTypeCategory::DAEMON;
+    } else if (rtype >= RecordType::FIRST_EVENT && rtype <= RecordType::LAST_EVENT) {
+        return RecordTypeCategory::EVENT;
+    } else if (rtype >= RecordType::FIRST_SELINUX && rtype <= RecordType::LAST_SELINUX) {
+        return RecordTypeCategory::SELINUX;
+    } else if (rtype >= RecordType::FIRST_APPARMOR && rtype <= RecordType::LAST_APPARMOR) {
+        return RecordTypeCategory::APPARMOR;
+    } else if (rtype >= RecordType::FIRST_KERN_CRYPTO_MSG && rtype <= RecordType::LAST_KERN_CRYPTO_MSG) {
+        return RecordTypeCategory::KERN_CRYPTO_MSG;
+    } else if (rtype >= RecordType::FIRST_KERN_ANOM_MSG && rtype <= RecordType::LAST_KERN_ANOM_MSG) {
+        return RecordTypeCategory::KERN_ANOM_MSG;
+    } else if (rtype >= RecordType::INTEGRITY_FIRST_MSG && rtype <= RecordType::INTEGRITY_LAST_MSG) {
+        return RecordTypeCategory::INTEGRITY_MSG;
+    } else if (rtype >= RecordType::FIRST_ANOM_MSG && rtype <= RecordType::LAST_ANOM_MSG) {
+        return RecordTypeCategory::ANOM_MSG;
+    } else if (rtype >= RecordType::FIRST_ANOM_RESP && rtype <= RecordType::LAST_ANOM_RESP) {
+        return RecordTypeCategory::ANOM_RESP;
+    } else if (rtype >= RecordType::FIRST_USER_LSPP_MSG && rtype <= RecordType::LAST_USER_LSPP_MSG) {
+        return RecordTypeCategory::USER_LSPP_MSG;
+    } else if (rtype >= RecordType::FIRST_CRYPTO_MSG && rtype <= RecordType::LAST_CRYPTO_MSG) {
+        return RecordTypeCategory::CRYPTO_MSG;
+    } else if (rtype >= RecordType::FIRST_VIRT_MSG && rtype <= RecordType::LAST_VIRT_MSG) {
+        return RecordTypeCategory::VIRT_MSG;
+    } else if (rtype >= RecordType::FIRST_USER_MSG2 && rtype <= RecordType::LAST_USER_MSG2) {
+        return RecordTypeCategory::USER_MSG2;
+    } else if (rtype >= RecordType::FIRST_AUOMS_MSG && rtype <= RecordType::LAST_AUOMS_MSG) {
+        return RecordTypeCategory::AUOMS_MSG;
+    } else {
+        return RecordTypeCategory::UNKNOWN;
+    }
+}
 #endif //AUOMS_RECORDTYPE_H
--- a/Translate.h
+++ b/Translate.h
@ -39,6 +39,8 @@ int SyscallNameToNumber(MachineType mtype, const std::string_view& syscall_name)
 std::string_view RecordTypeToName(RecordType code, std::string& unknown_str);
 std::string RecordTypeToName(RecordType code);
 RecordType RecordNameToType(const std::string_view& name);
+std::string RecordTypeCategoryToName(RecordTypeCategory code);
+RecordTypeCategory RecordTypeCategoryNameToCategory(const std::string_view& name);

 field_type_t FieldNameToType(const std::string_view& name);
 field_type_t FieldNameToType(RecordType rtype, const std::string_view& name, const std::string_view& val);
--- a/TranslateRecordType.cpp
+++ b/TranslateRecordType.cpp
@ -226,6 +226,26 @@ static StringTable<RecordType> s_record_type_table(RecordType ::UNKNOWN, {
        {"AUOMS_EXECVE", RecordType::AUOMS_EXECVE},
 });

+static StringTable<RecordTypeCategory> s_record_type_category_table(RecordTypeCategory::UNKNOWN, {
+        {"UNKNOWN", RecordTypeCategory::UNKNOWN},
+        {"KERNEL", RecordTypeCategory::KERNEL},
+        {"USER_MSG", RecordTypeCategory::USER_MSG},
+        {"DAEMON", RecordTypeCategory::DAEMON},
+        {"EVENT", RecordTypeCategory::EVENT},
+        {"SELINUX", RecordTypeCategory::SELINUX},
+        {"APPARMOR", RecordTypeCategory::APPARMOR},
+        {"KERN_CRYPTO_MSG", RecordTypeCategory::KERN_CRYPTO_MSG},
+        {"KERN_ANOM_MSG", RecordTypeCategory::KERN_ANOM_MSG},
+        {"INTEGRITY_MSG", RecordTypeCategory::INTEGRITY_MSG},
+        {"ANOM_MSG", RecordTypeCategory::ANOM_MSG},
+        {"ANOM_RESP", RecordTypeCategory::ANOM_RESP},
+        {"USER_LSPP_MSG", RecordTypeCategory::USER_LSPP_MSG},
+        {"CRYPTO_MSG", RecordTypeCategory::CRYPTO_MSG},
+        {"VIRT_MSG", RecordTypeCategory::VIRT_MSG},
+        {"USER_MSG2", RecordTypeCategory::USER_MSG2},
+        {"AUOMS_MSG", RecordTypeCategory::AUOMS_MSG},
+});
+
 std::string_view RecordTypeToName(RecordType code, std::string& unknown_str) {
    auto str = s_record_type_table.ToString(code);
    if (str.empty()) {
@ -263,3 +283,15 @@ RecordType RecordNameToType(const std::string_view& name) {
        return s_record_type_table.ToInt(name);
    }
 }
+
+std::string RecordTypeCategoryToName(RecordTypeCategory code) {
+    std::string str(s_record_type_category_table.ToString(code));
+    if (str.empty()) {
+        str = "UNKNOWN";
+    }
+    return str;
+}
+
+RecordTypeCategory RecordTypeCategoryNameToCategory(const std::string_view& name) {
+    return s_record_type_category_table.ToInt(name);
+}
--- a/auoms.cpp
+++ b/auoms.cpp
@ -274,7 +274,27 @@ int main(int argc, char**argv) {
        Logger::OpenSyslog("auoms", LOG_DAEMON);
    }

-    auto event_prioritizer = std::make_shared<EventPrioritizer>(num_priorities-1);
+    if (!config.HasKey("event_priority_by_syscall")) {
+        config.SetString("event_priority_by_syscall", R"json({"execve":2,"execveat":2,"*":3})json");
+    }
+
+    if (!config.HasKey("event_priority_by_record_type")) {
+        config.SetString("event_priority_by_record_type", R"json({"AUOMS_EXECVE":2,"AUOMS_SYSCALL":3,"AUOMS_PROCESS_INVENTORY":1})json");
+    }
+
+    if (!config.HasKey("event_priority_by_record_type_category")) {
+        config.SetString("event_priority_by_record_type_category", R"json({"AUOMS_MSG":0, "USER_MSG":1,"SELINUX":1,"APPARMOR":1})json");
+    }
+
+    int default_priority = 4;
+    if (config.HasKey("default_event_priority")) {
+        default_priority = static_cast<uint16_t>(config.GetUint64("default_event_priority"));
+    }
+    if (default_priority > num_priorities-1) {
+        default_priority = num_priorities-1;
+    }
+
+    auto event_prioritizer = std::make_shared<EventPrioritizer>(default_priority);
    if (!event_prioritizer->LoadFromConfig(config)) {
        Logger::Error("Failed to load EventPrioritizer config, exiting");
        exit(1);
--- a/auomscollect.cpp
+++ b/auomscollect.cpp
@ -457,7 +457,23 @@ int main(int argc, char**argv) {
        Logger::OpenSyslog("auomscollect", LOG_DAEMON);
    }

-    auto event_prioritizer = std::make_shared<EventPrioritizer>(num_priorities-1);
+    if (!config.HasKey("event_priority_by_syscall")) {
+        config.SetString("event_priority_by_syscall", R"json({"execve":2,"execveat":2,"*":3})json");
+    }
+
+    if (!config.HasKey("event_priority_by_record_type_category")) {
+        config.SetString("event_priority_by_record_type_category", R"json({"AUOMS_MSG":0, "USER_MSG":1,"SELINUX":1,"APPARMOR":1})json");
+    }
+
+    int default_priority = 4;
+    if (config.HasKey("default_event_priority")) {
+        default_priority = static_cast<uint16_t>(config.GetUint64("default_event_priority"));
+    }
+    if (default_priority > num_priorities-1) {
+        default_priority = num_priorities-1;
+    }
+
+    auto event_prioritizer = std::make_shared<EventPrioritizer>(default_priority);
    if (!event_prioritizer->LoadFromConfig(config)) {
        Logger::Error("Failed to load EventPrioritizer config, exiting");
        exit(1);