Add time and size limit to remote requests

src/server.go

@@ -8,12 +8,15 @@ import (
 	"net"
 	"strconv"
 	"strings"
+	"time"
 )
 
 const (
-	crlf           = "\r\n"
-	httpOk         = "HTTP/1.1 200 OK" + crlf
-	httpBadRequest = "HTTP/1.1 400 Bad Request" + crlf
+	crlf             = "\r\n"
+	httpOk           = "HTTP/1.1 200 OK" + crlf
+	httpBadRequest   = "HTTP/1.1 400 Bad Request" + crlf
+	httpReadTimeout  = 10 * time.Second
+	maxContentLength = 1024 * 1024
 )
 
 func startHttpServer(port int, channel chan []*action) error {
@@ -52,14 +55,13 @@ func startHttpServer(port int, channel chan []*action) error {
 // * --listen with net/http: 5.7MB
 // * --listen w/o net/http:  3.3MB
 func handleHttpRequest(conn net.Conn, channel chan []*action) string {
-	line := 0
-	headerRead := false
 	contentLength := 0
 	body := ""
 	bad := func(message string) string {
 		message += "\n"
 		return httpBadRequest + fmt.Sprintf("Content-Length: %d%s", len(message), crlf+crlf+message)
 	}
+	conn.SetReadDeadline(time.Now().Add(httpReadTimeout))
 	scanner := bufio.NewScanner(conn)
 	scanner.Split(func(data []byte, atEOF bool) (int, []byte, error) {
 		found := bytes.Index(data, []byte(crlf))
@@ -73,31 +75,41 @@ func handleHttpRequest(conn net.Conn, channel chan []*action) string {
 		return 0, nil, nil
 	})
 
+	section := 0
 	for scanner.Scan() {
 		text := scanner.Text()
-		if line == 0 && !strings.HasPrefix(text, "POST / HTTP") {
-			return bad("invalid request method")
-		}
-		if text == crlf {
-			headerRead = true
-		}
-		if !headerRead {
+		switch section {
+		case 0:
+			if !strings.HasPrefix(text, "POST / HTTP") {
+				return bad("invalid request method")
+			}
+			section++
+		case 1:
+			if text == crlf {
+				if contentLength == 0 {
+					return bad("content-length header missing")
+				}
+				section++
+				continue
+			}
 			pair := strings.SplitN(text, ":", 2)
 			if len(pair) == 2 && strings.ToLower(pair[0]) == "content-length" {
 				length, err := strconv.Atoi(strings.TrimSpace(pair[1]))
-				if err != nil {
+				if err != nil || length <= 0 || length > maxContentLength {
 					return bad("invalid content length")
 				}
 				contentLength = length
 			}
-		} else if contentLength <= 0 {
-			break
-		} else {
+		case 2:
 			body += text
 		}
-		line++
 	}
 
+	if len(body) < contentLength {
+		return bad("incomplete request")
+	}
+	body = body[:contentLength]
+
 	errorMessage := ""
 	actions := parseSingleActionList(strings.Trim(string(body), "\r\n"), func(message string) {
 		errorMessage = message