Be more cautious about use for privilege ports (<1024).

Ports < 1024 are a scarce resource and should not be used
carelessly.  Technically they should be not used at all without
registration with IANA, but sometimes we need them despite that.

So: for the socket that RPC services listen on, don't use a <1024 port
by default.  There is no need.

For sockets that we send messages on, that are long-lived, and that might
need to appear 'privileged', avoid using a number that is registered in
/etc/services if possible.

1 files changed, 10 insertions, 0 deletions

diff --git a/utils/statd/sm-notify.c b/utils/statd/sm-notify.c
index bb6c2ef..1059a88 100644
--- a/utils/statd/sm-notify.c
+++ b/utils/statd/sm-notify.c
@@ -215,7 +215,9 @@ notify(void)
 	nsm_address local_addr;
 	time_t	failtime = 0;
 	int	sock = -1;
+	int retry_cnt = 0;
 
+ retry:
 	sock = socket(AF_INET, SOCK_DGRAM, 0);
 	if (sock < 0) {
 		perror("socket");
@@ -248,7 +250,15 @@ notify(void)
 			exit(1);
 		}
 	} else {
+		struct servent *se;
 		(void) bindresvport(sock, (struct sockaddr_in *) &local_addr);
+		/* try to avoid known ports */
+		se = getservbyport(local_addr.sin_port, "udp");
+		if (se && retry_cnt < 100) {
+			retry_cnt++;
+			close(sock);
+			goto retry;
+		}
 	}
 
 	if (opt_max_retry)