Properly handle outer TCP connection closed in TCPDNS.

If the connection is closed while we're processing the request
we might access TCPDNS outerhandle which is already reset. Check
for this condition and call the callback with ISC_R_CANCELED result.

diff --git a/lib/isc/netmgr/tcpdns.c b/lib/isc/netmgr/tcpdns.c
index 6a20ea4c7c3d04aa7ec7c3c99eb698e6dccd8d7f..63391273cb158312da840555bdd520ba5dc43c40 100644 (file)
--- a/lib/isc/netmgr/tcpdns.c
+++ b/lib/isc/netmgr/tcpdns.c
@@ -596,9 +596,16 @@ isc__nm_tcpdns_send(isc_nmhandle_t *handle, isc_region_t *region,
 
                r.base = (unsigned char *)uvreq->uvbuf.base;
                r.length = uvreq->uvbuf.len;
-
-               isc_nmhandle_attach(sock->outerhandle, &sendhandle);
-               isc_nm_send(sock->outerhandle, &r, tcpdnssend_cb, uvreq);
+               if (sock->outerhandle != NULL) {
+                       isc_nmhandle_attach(sock->outerhandle, &sendhandle);
+                       isc_nm_send(sock->outerhandle, &r, tcpdnssend_cb,
+                                   uvreq);
+               } else {
+                       cb(handle, ISC_R_CANCELED, cbarg);
+                       isc_mem_put(sock->mgr->mctx, uvreq->uvbuf.base,
+                                   uvreq->uvbuf.len);
+                       isc__nm_uvreq_put(&uvreq, sock);
+               }
        } else {
                isc__netievent_tcpdnssend_t *ievent = NULL;