[pve-devel] [PATCH v2 http-server 3/4] fix #4494: anyevent: redirect HTTP to HTTPS

[Max Carrara]

Allow HTTP connections up until the request's header has been
parsed and processed. If no TLS handshake has been completed
beforehand, the server now responds with either a
'301 Moved Permanently' or a '308 Permanent Redirect' as noted in the
MDN web docs[1].

This is done after the header was parsed; for the redirect to work,
the `Host` header field of the request is used to create the
`Location` field of the response. This makes redirections independent
of how the server is accessed (e.g. via IP, localhost, FQDN, ...)
possible.

Upon redirection the client is immediately disconnected; otherwise,
they would have to wait for the connection to time out until
they may reconnect via TLS again.

[1] https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/301

Signed-off-by: Max Carrara <m.carrara at proxmox.com>
---
 src/PVE/APIServer/AnyEvent.pm | 46 +++++++++++++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/src/PVE/APIServer/AnyEvent.pm b/src/PVE/APIServer/AnyEvent.pm
index 636502b..d1bba3c 100644
--- a/src/PVE/APIServer/AnyEvent.pm
+++ b/src/PVE/APIServer/AnyEvent.pm
@@ -1318,7 +1318,7 @@ sub unshift_read_header {
 		    if $state->{key};
 
 		$self->process_header($reqstate) or return;
-		# header processing complete - authenticate now
+		$self->ensure_tls_connection($reqstate) or return;
 		$self->authenticate_and_handle_request($reqstate) or return;
 
 	    } elsif ($line =~ /^([^:\s]+)\s*:\s*(.*)/) {
@@ -1388,6 +1388,43 @@ sub process_header {
     return 1;
 }
 
+sub ensure_tls_connection {
+    my ($self, $reqstate) = @_;
+
+    # Skip if server doesn't use TLS
+    if (!$self->{tls_ctx}) {
+	return 1;
+    }
+
+    # TLS session exists, so the handshake has succeeded
+    if ($reqstate->{hdl}->{tls}) {
+	return 1;
+    }
+
+    my $request = $reqstate->{request};
+    my $method = $request->method();
+
+    my $h_host = $reqstate->{request}->header('Host');
+
+    die "Header field 'Host' not found in request\n"
+	if !$h_host;
+
+    my $secure_host = "https://" . ($h_host =~ s/^http(s)?:\/\///r);
+
+    my $header = HTTP::Headers->new('Location' => $secure_host . $request->uri());
+
+    if ($method eq 'GET' || $method eq 'HEAD') {
+	$self->error($reqstate, 301, 'Moved Permanently', $header);
+    } else {
+	$self->error($reqstate, 308, 'Permanent Redirect', $header);
+    }
+
+    # disconnect the client so they may immediately connect again via HTTPS
+    $self->client_do_disconnect($reqstate);
+
+    return;
+}
+
 sub authenticate_and_handle_request {
     my ($self, $reqstate) = @_;
 
@@ -1795,11 +1832,16 @@ sub accept_connections {
 		    };
 		    if (my $err = $@) { syslog('err', "$err"); }
 		},
-		($self->{tls_ctx} ? (tls => "accept", tls_ctx => $self->{tls_ctx}) : ()));
+	    );
 	    $handle_creation = 0;
 
 	    $self->dprint("ACCEPT FH" .  $clientfh->fileno() . " CONN$self->{conn_count}");
 
+	    if ($self->{tls_ctx}) {
+		$self->dprint("Setting TLS to autostart");
+		$reqstate->{hdl}->unshift_read(tls_autostart => $self->{tls_ctx}, "accept");
+	    }
+
 	    $self->push_request_header($reqstate);
 	}
     };
-- 
2.30.2