resolved: set io events after receiving EAGAIN for TLS

During handshake and TLS session closing, messages needs to be exchanged. Therefore this patch overrides the requested IO events for the TCP stream when the TLS is waiting for sending or receiving of messages during theses periods. This fixes issues with correctly closing the TLS stream and prevents the handshake from hanging in rare cases (not seen yet).

1 files changed, 9 insertions, 4 deletions

diff --git a/src/resolve/resolved-dnstls-gnutls.c b/src/resolve/resolved-dnstls-gnutls.c
index 9c348cef67..36ee570b46 100644
--- a/src/resolve/resolved-dnstls-gnutls.c
+++ b/src/resolve/resolved-dnstls-gnutls.c
@@ -86,23 +86,28 @@ int dnstls_stream_on_io(DnsStream *stream) {
 
         if (stream->dnstls_data.shutdown) {
                 r = gnutls_bye(stream->dnstls_data.session, GNUTLS_SHUT_RDWR);
-                if (r == GNUTLS_E_AGAIN)
+                if (r == GNUTLS_E_AGAIN) {
+                        stream->dnstls_events = gnutls_record_get_direction(stream->dnstls_data.session) == 1 ? EPOLLOUT : EPOLLIN;
                         return -EAGAIN;
-                else if (r < 0)
+                } else if (r < 0)
                         log_debug("Failed to invoke gnutls_bye: %s", gnutls_strerror(r));
 
+                stream->dnstls_events = 0;
                 stream->dnstls_data.shutdown = false;
                 dns_stream_unref(stream);
                 return DNSTLS_STREAM_CLOSED;
         } else if (stream->dnstls_data.handshake < 0) {
                 stream->dnstls_data.handshake = gnutls_handshake(stream->dnstls_data.session);
-                if (stream->dnstls_data.handshake == GNUTLS_E_AGAIN)
+                if (stream->dnstls_data.handshake == GNUTLS_E_AGAIN) {
+                        stream->dnstls_events = gnutls_record_get_direction(stream->dnstls_data.session) == 1 ? EPOLLOUT : EPOLLIN;
                         return -EAGAIN;
-                else if (stream->dnstls_data.handshake < 0) {
+                } else if (stream->dnstls_data.handshake < 0) {
                         log_debug("Failed to invoke gnutls_handshake: %s", gnutls_strerror(stream->dnstls_data.handshake));
                         if (gnutls_error_is_fatal(stream->dnstls_data.handshake))
                                 return -ECONNREFUSED;
                 }
+
+                stream->dnstls_events = 0;
         }
 
         return 0;