diff -r d5785050f61d src/pkg/http/request.go
--- a/src/pkg/http/request.go	Sun Jul 31 15:37:01 2011 -0700
+++ b/src/pkg/http/request.go	Thu Aug 18 11:44:38 2011 -0700
@@ -523,6 +523,14 @@
 	r.Header.Set("Authorization", "Basic "+base64.StdEncoding.EncodeToString([]byte(s)))
 }
 
+type badRequestError struct {
+	e os.Error
+}
+
+func (e *badRequestError) String() string {
+	return "Bad request: " + e.String()
+}
+
 // ReadRequest reads and parses a request from b.
 func ReadRequest(b *bufio.Reader) (req *Request, err os.Error) {
 
@@ -540,16 +548,16 @@
 
 	var f []string
 	if f = strings.SplitN(s, " ", 3); len(f) < 3 {
-		return nil, &badStringError{"malformed HTTP request", s}
+		return nil, &badRequestError{&badStringError{"malformed HTTP request", s}}
 	}
 	req.Method, req.RawURL, req.Proto = f[0], f[1], f[2]
 	var ok bool
 	if req.ProtoMajor, req.ProtoMinor, ok = ParseHTTPVersion(req.Proto); !ok {
-		return nil, &badStringError{"malformed HTTP version", req.Proto}
+		return nil, &badRequestError{&badStringError{"malformed HTTP version", req.Proto}}
 	}
 
 	if req.URL, err = ParseRequestURL(req.RawURL); err != nil {
-		return nil, err
+		return nil, &badRequestError{err}
 	}
 
 	// Subsequent lines: Key: value.
diff -r d5785050f61d src/pkg/http/server.go
--- a/src/pkg/http/server.go	Sun Jul 31 15:37:01 2011 -0700
+++ b/src/pkg/http/server.go	Thu Aug 18 11:44:38 2011 -0700
@@ -191,6 +191,23 @@
 // It is like time.RFC1123 but hard codes GMT as the time zone.
 const TimeFormat = "Mon, 02 Jan 2006 15:04:05 GMT"
 
+type nopCloser struct{}
+
+func (_ nopCloser) Read(b []byte) (int, os.Error) {
+	return 0, os.NewError("Tried to read a noCloser")
+}
+
+func (_ nopCloser) Close() os.Error {
+	return nil
+}
+
+var badRequest = &Request{
+	Proto:      "HTTP/1.1",
+	ProtoMajor: 1,
+	ProtoMinor: 1,
+	Body:       new(nopCloser),
+}
+
 // Read next request from connection.
 func (c *conn) readRequest() (w *response, err os.Error) {
 	if c.hijacked {
@@ -198,12 +215,15 @@
 	}
 	var req *Request
 	if req, err = ReadRequest(c.buf.Reader); err != nil {
-		return nil, err
+		if _, ok := err.(*badRequestError); !ok {
+			return nil, err
+		}
+		req = badRequest
+	} else {
+		req.RemoteAddr = c.remoteAddr
+		req.TLS = c.tlsState
 	}
 
-	req.RemoteAddr = c.remoteAddr
-	req.TLS = c.tlsState
-
 	w = new(response)
 	w.conn = c
 	w.req = req
@@ -509,6 +529,13 @@
 
 		// Expect 100 Continue support
 		req := w.req
+		if req == badRequest {
+			w.Header().Set("Connection", "close")
+			w.WriteHeader(StatusBadRequest)
+			fmt.Fprintln(w, "Bad Request")
+			w.finishRequest()
+			break
+		}
 		if req.expectsContinue() {
 			if req.ProtoAtLeast(1, 1) {
 				// Wrap the Body reader with one that replies on the connection