enforce limits better

Makefile

@@ -8,7 +8,7 @@ VENDOR_JS=$(REPO)/contrib/js/vendor
 SRND_DIR=$(REPO)/contrib/backends/srndv2
 SRND=$(REPO)/srndv2
 
-all: build
+all: clean build
 
 build: js srnd
 

contrib/backends/srndv2/src/srnd/daemon.go

@@ -596,7 +596,7 @@ func (self *NNTPDaemon) Run() {
 			nntp.Pack()
 			file := self.store.CreateFile(nntp.MessageID())
 			if file != nil {
-				err = nntp.WriteTo(file)
+				err = nntp.WriteTo(file, MaxMessageSize)
 				file.Close()
 				if err == nil {
 					self.loadFromInfeed(nntp.MessageID())

contrib/backends/srndv2/src/srnd/frontend_http.go

@@ -381,7 +381,7 @@ func (self *httpFrontend) poll() {
 			f := self.daemon.store.CreateFile(nntp.MessageID())
 			if f != nil {
 				b := new(bytes.Buffer)
-				err := nntp.WriteTo(b)
+				err := nntp.WriteTo(b, self.daemon.messageSizeLimitFor(nntp.Newsgroup()))
 				if err == nil {
 					r := bufio.NewReader(b)
 					var msg *mail.Message
@@ -955,7 +955,7 @@ func (self *httpFrontend) handle_postRequest(pr *postRequest, b bannedFunc, e er
 		e(errors.New("failed to store article"))
 		return
 	} else {
-		err = nntp.WriteTo(f)
+		err = nntp.WriteTo(f, self.daemon.messageSizeLimitFor(nntp.Newsgroup()))
 		f.Close()
 		if err == nil {
 			go self.daemon.loadFromInfeed(nntp.MessageID())

contrib/backends/srndv2/src/srnd/line.go

@@ -7,17 +7,24 @@ import (
 
 type LineWriter struct {
 	w    io.Writer
+	Left int64
 }
 
-func NewLineWriter(w io.Writer) *LineWriter {
+func NewLineWriter(w io.Writer, limit int64) *LineWriter {
 	return &LineWriter{
 		w:    w,
+		Left: limit,
 	}
 }
 
 func (l *LineWriter) Write(data []byte) (n int, err error) {
-	n = len(data)
+	if l.Left <= 0 {
+		err = ErrOversizedMessage
+		return
+	}
 	data = bytes.Replace(data, []byte{13, 10}, []byte{10}, -1)
-	_, err = l.w.Write(data)
+	n, err = l.w.Write(data)
+	l.Left -= int64(n)
+
 	return
 }

contrib/backends/srndv2/src/srnd/message.go

@@ -83,9 +83,9 @@ type NNTPMessage interface {
 	// all headers
 	Headers() ArticleHeaders
 	// write out everything
-	WriteTo(wr io.Writer) error
+	WriteTo(wr io.Writer, limit int64) error
 	// write out body
-	WriteBody(wr io.Writer) error
+	WriteBody(wr io.Writer, limit int64) error
 	// attach a file
 	Attach(att NNTPAttachment)
 	// get the plaintext message if it exists
@@ -175,7 +175,7 @@ func signArticle(nntp NNTPMessage, seed []byte) (signed *nntpArticle, err error)
 	signed.signedPart = &nntpAttachment{}
 	// write body to sign buffer
 	mw := io.MultiWriter(sha, signed.signedPart)
-	err = nntp.WriteTo(mw)
+	err = nntp.WriteTo(mw, MaxMessageSize)
 	mw.Write([]byte{10})
 	if err == nil {
 		// build keypair
@@ -198,15 +198,20 @@ func signArticle(nntp NNTPMessage, seed []byte) (signed *nntpArticle, err error)
 	return
 }
 
-func (self *nntpArticle) WriteTo(wr io.Writer) (err error) {
+func (self *nntpArticle) WriteTo(wr io.Writer, limit int64) (err error) {
 	// write headers
+	var n int
 	hdrs := self.headers
 	for hdr, hdr_vals := range hdrs {
 		for _, hdr_val := range hdr_vals {
-			wr.Write([]byte(hdr))
+			n, err = wr.Write([]byte(hdr))
-			wr.Write([]byte(": "))
+			limit -= int64(n)
-			wr.Write([]byte(hdr_val))
+			n, err = wr.Write([]byte(": "))
-			_, err = wr.Write([]byte{10})
+			limit -= int64(n)
+			n, err = wr.Write([]byte(hdr_val))
+			limit -= int64(n)
+			n, err = wr.Write([]byte{10})
+			limit -= int64(n)
 			if err != nil {
 				log.Println("error while writing headers", err)
 				return
@@ -214,14 +219,19 @@ func (self *nntpArticle) WriteTo(wr io.Writer) (err error) {
 		}
 	}
 	// done headers
-	_, err = wr.Write([]byte{10})
+	n, err = wr.Write([]byte{10})
+	limit -= int64(n)
 	if err != nil {
 		log.Println("error while writing body", err)
 		return
 	}
 
+	if limit > 0 {
 		// write body
-	err = self.WriteBody(wr)
+		err = self.WriteBody(wr, limit)
+	} else {
+		err = ErrOversizedMessage
+	}
 	return
 }
 
@@ -359,10 +369,15 @@ func (self *nntpArticle) Attach(att NNTPAttachment) {
 	self.attachments = append(self.attachments, att)
 }
 
-func (self *nntpArticle) WriteBody(wr io.Writer) (err error) {
+func (self *nntpArticle) WriteBody(wr io.Writer, limit int64) (err error) {
 	// this is a signed message, don't treat it special
+	var n int
 	if self.signedPart != nil {
-		_, err = wr.Write(self.signedPart.Bytes())
+		n, err = wr.Write(self.signedPart.Bytes())
+		limit -= int64(n)
+		if limit <= 0 {
+			err = ErrOversizedMessage
+		}
 		return
 	}
 	self.Pack()
@@ -375,7 +390,8 @@ func (self *nntpArticle) WriteBody(wr io.Writer) (err error) {
 
 	boundary, ok := params["boundary"]
 	if ok {
-		w := multipart.NewWriter(NewLineWriter(wr))
+		nlw := NewLineWriter(wr, limit)
+		w := multipart.NewWriter(nlw)
 
 		err = w.SetBoundary(boundary)
 		if err == nil {
@@ -411,9 +427,13 @@ func (self *nntpArticle) WriteBody(wr io.Writer) (err error) {
 		}
 		err = w.Close()
 		w = nil
+		if nlw.Left <= 0 {
+			err = ErrOversizedMessage
+		}
 	} else {
+		nlw := NewLineWriter(wr, limit)
 		// write out message
-		_, err = io.WriteString(wr, self.message)
+		_, err = io.WriteString(nlw, self.message)
 	}
 	return err
 }