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|
package ebpf
import (
"sync"
"time"
"github.com/evilsocket/opensnitch/daemon/procmon"
)
// NewExecEvent constructs a new execEvent from the arguments.
func NewExecEvent(pid, ppid, uid uint32, path string, comm [16]byte) *execEvent {
ev := &execEvent{
Type: EV_TYPE_EXEC,
PID: pid,
PPID: ppid,
UID: uid,
Comm: comm,
}
length := MaxPathLen
if len(path) < MaxPathLen {
length = len(path)
}
copy(ev.Filename[:], path[:length])
return ev
}
type execEventItem struct {
Proc procmon.Process
Event execEvent
LastSeen int64
}
type eventsStore struct {
execEvents map[uint32]*execEventItem
sync.RWMutex
}
// NewEventsStore creates a new store of events.
func NewEventsStore() *eventsStore {
return &eventsStore{
execEvents: make(map[uint32]*execEventItem),
}
}
func (e *eventsStore) add(key uint32, event execEvent, proc procmon.Process) {
e.Lock()
defer e.Unlock()
e.execEvents[key] = &execEventItem{
Proc: proc,
Event: event,
}
}
func (e *eventsStore) isInStore(key uint32) (item *execEventItem, found bool) {
e.RLock()
defer e.RUnlock()
item, found = e.execEvents[key]
return
}
func (e *eventsStore) delete(key uint32) {
e.Lock()
defer e.Unlock()
delete(e.execEvents, key)
}
func (e *eventsStore) DeleteOldItems() {
e.Lock()
defer e.Unlock()
for k, item := range e.execEvents {
if item.Proc.IsAlive() == false {
delete(e.execEvents, k)
}
}
}
//-----------------------------------------------------------------------------
type ebpfCacheItem struct {
Key []byte
Proc procmon.Process
LastSeen int64
}
type ebpfCacheType struct {
Items map[interface{}]*ebpfCacheItem
sync.RWMutex
}
var (
maxTTL = 40 // Seconds
maxCacheItems = 5000
ebpfCache *ebpfCacheType
ebpfCacheTicker *time.Ticker
)
// NewEbpfCacheItem creates a new cache item.
func NewEbpfCacheItem(key []byte, proc procmon.Process) *ebpfCacheItem {
return &ebpfCacheItem{
Key: key,
Proc: proc,
LastSeen: time.Now().UnixNano(),
}
}
func (i *ebpfCacheItem) isValid() bool {
lastSeen := time.Now().Sub(
time.Unix(0, i.LastSeen),
)
return int(lastSeen.Seconds()) < maxTTL
}
// NewEbpfCache creates a new cache store.
func NewEbpfCache() *ebpfCacheType {
ebpfCacheTicker = time.NewTicker(1 * time.Minute)
return &ebpfCacheType{
Items: make(map[interface{}]*ebpfCacheItem, 0),
}
}
func (e *ebpfCacheType) addNewItem(key interface{}, itemKey []byte, proc procmon.Process) {
e.Lock()
e.Items[key] = NewEbpfCacheItem(itemKey, proc)
e.Unlock()
}
func (e *ebpfCacheType) isInCache(key interface{}) (item *ebpfCacheItem, found bool) {
leng := e.Len()
e.Lock()
item, found = e.Items[key]
if found {
if item.isValid() {
e.update(key, item)
} else {
found = false
delete(e.Items, key)
}
}
e.Unlock()
if leng > maxCacheItems {
e.DeleteOldItems()
}
return
}
func (e *ebpfCacheType) update(key interface{}, item *ebpfCacheItem) {
item.LastSeen = time.Now().UnixNano()
e.Items[key] = item
}
func (e *ebpfCacheType) Len() int {
e.RLock()
defer e.RUnlock()
return len(e.Items)
}
func (e *ebpfCacheType) DeleteOldItems() {
length := e.Len()
e.Lock()
defer e.Unlock()
for k, item := range e.Items {
if length > maxCacheItems || (item != nil && !item.isValid()) {
delete(e.Items, k)
}
}
}
func (e *ebpfCacheType) delete(key interface{}) {
e.Lock()
defer e.Unlock()
if key, found := e.Items[key]; found {
delete(e.Items, key)
}
}
func (e *ebpfCacheType) clear() {
if e == nil {
return
}
e.Lock()
defer e.Unlock()
for k := range e.Items {
delete(e.Items, k)
}
if ebpfCacheTicker != nil {
ebpfCacheTicker.Stop()
}
}
|
