Forward user-agent and other headers on redirect

We don't use sensitive headers so don't need to be concerned about
crossing domain boundaries. So simply always copy all headers to
subsequent requests in the redirect chain.

Closes #2805

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>

client.go

@@ -265,6 +265,15 @@ func NewClientFromInfo(info ConnectInfo) (*Client, error) {
 		},
 	}
 	c.Name = info.Name
+
+	// Setup redirect policy
+	c.Http.CheckRedirect = func(req *http.Request, via []*http.Request) error {
+		// Replicate the headers
+		req.Header = via[len(via)-1].Header
+
+		return nil
+	}
+
 	var err error
 	if strings.HasPrefix(info.RemoteConfig.Addr, "unix:") {
 		err = connectViaUnix(c, &info.RemoteConfig)

lxd/daemon.go

@@ -137,6 +137,14 @@ func (d *Daemon) httpClient(certificate string) (*http.Client, error) {
 		Transport: tr,
 	}
 
+	// Setup redirect policy
+	myhttp.CheckRedirect = func(req *http.Request, via []*http.Request) error {
+		// Replicate the headers
+		req.Header = via[len(via)-1].Header
+
+		return nil
+	}
+
 	return &myhttp, nil
 }