gagent/internal/client/client.go

120 lines
3 KiB
Go

package client
import (
sha "crypto/sha256"
hex "encoding/hex"
fmt "fmt"
log "log"
os "os"
regexp "regexp"
strconv "strconv"
strings "strings"
sync "sync"
time "time"
gs "github.com/dragonheim/gagent/internal/gstructs"
zmq "github.com/pebbe/zmq4"
)
/*
* Client mode will send an agent file to a router for processing
* Clients do not process the agent files, only send them as
* requests to a router. If started without arguments, the client
* will contact the router and attempt to retrieve the results
* of it's most recent request.
* Main is the entrypoint for the client process
*/
func Main(wg *sync.WaitGroup, config gs.GagentConfig) {
log.Printf("[INFO] Starting client\n")
defer wg.Done()
var agent gs.AgentDetails
var err error
if config.CMode {
agent.Script, err = os.ReadFile(config.Agent)
if err != nil {
log.Printf("[ERROR] No such file or directory: %s", config.Agent)
os.Exit(4)
}
log.Printf("[DEBUG] Agent file contents: \n----- -----\n%s\n----- -----\n", agent.Script)
}
agent.Client = config.UUID
tmpsum := sha.Sum256([]byte(agent.Script))
agent.Shasum = fmt.Sprintf("%v", hex.EncodeToString(tmpsum[:]))
log.Printf("[INFO] SHA256 of Agent file: %s", agent.Shasum)
agent.Status = 1
agent.Hints = getTagsFromHints(agent)
agent.Answer = nil
for key := range config.Routers {
/*
* Generate connect string for this router.
*/
rport := config.ClientPort
if config.Routers[key].ClientPort != 0 {
rport = config.Routers[key].ClientPort
}
connectString := "tcp://" + config.Routers[key].RouterAddr + ":" + strconv.Itoa(rport)
wg.Add(1)
go sendAgent(wg, config.UUID, connectString, agent)
}
}
/*
* Parse Agent file for GHINT data to populate the G'Agent hints
*/
func getTagsFromHints(agent gs.AgentDetails) []string {
var tags []string
// Use named capture groups to extract the hints
re := regexp.MustCompile(`^*set\s+GHINT\s*\[\s*split\s*"(?P<Hints>[^"]+)"\s*,\s*\]`)
res := re.FindStringSubmatch(string(agent.Script))
// If we don't have at least 2 matches, we have no hints
if len(res) < 2 {
log.Printf("[ERROR] Agent is missing GHINT tags")
os.Exit(4)
}
// Use named capturing group index
hintsIndex := re.SubexpIndex("Hints")
tags = strings.Split(res[hintsIndex], ",")
log.Printf("[DEBUG] G'Agent hints: %v\n", tags)
return tags
}
func sendAgent(wg *sync.WaitGroup, uuid string, connectString string, agent gs.AgentDetails) {
defer wg.Done()
var mu sync.Mutex
mu.Lock()
sock, _ := zmq.NewSocket(zmq.REQ)
defer sock.Close()
_ = sock.SetIdentity(uuid)
log.Printf("[DEBUG] Attempting to connect to %s\n", connectString)
err := sock.Connect(connectString)
if err != nil {
log.Printf("[ERROR] Failed to connect to %s\n", connectString)
os.Exit(10)
}
log.Printf("[DEBUG] Start sending agent...\n")
agent.Status = 2
status, err := sock.SendMessage(agent)
if err != nil {
log.Printf("[ERROR] Failed to send agent to router\n")
return
}
log.Printf("[DEBUG] Agent send status: %d\n", status)
mu.Unlock()
time.Sleep(10 * time.Second)
}