add missing null check

I have a unbound forward zone configured on my router for my $DAYJOB.
The address associated with the zone is only accessible when the router
is connected to a VPN. If the VPN connection is absent, trying to
resolve any domain that must be handled by the zone crashes unbound.
Turns out there's a missing NULL check in `comm_point_send_udp_msg()`.
The same routine already has `if (addr) {} else {}` branches so I guess
protecting the call to `log_addr()` using the same conditional is
reasonable

I have also committed the same fix to unbound shipped with OpenBSD[1].

[1] https://marc.info/?l=openbsd-cvs&m=160993335615698&w=2

diff --git a/util/netevent.c b/util/netevent.c
index a5c3fe6667db7147bb6176580ed5ee1c74abe426..a2c0e6073e368b98e71e4355144db50c6e6db543 100644 (file)
--- a/util/netevent.c
+++ b/util/netevent.c
@@ -388,8 +388,9 @@ comm_point_send_udp_msg(struct comm_point *c, sldns_buffer* packet,
                } else {
                        verbose(VERB_OPS, "send failed: %s", sock_strerror(errno));
                }
-               log_addr(VERB_OPS, "remote address is",
-                       (struct sockaddr_storage*)addr, addrlen);
+               if(addr)
+                       log_addr(VERB_OPS, "remote address is",
+                               (struct sockaddr_storage*)addr, addrlen);
                return 0;
        } else if((size_t)sent != sldns_buffer_remaining(packet)) {
                log_err("sent %d in place of %d bytes",