commit a36602f1e65cd6bace6ed9405b0ce359de4a27d1
Author: Miroslav Lichvar <mlichvar@redhat.com>
Date:   Thu Jan 3 15:23:54 2019 +0100

    unicast: limit message rate and grant duration
    
    Deny service requests with logInterMessagePeriod smaller than -7 (128
    packets per second) or larger than 16. This limits the network and CPU
    consumption per address and prevents undefined shifts in the calculation
    of the interval.
    
    Also, limit the maximum grant duration to one hour.
    
    Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>

diff --git a/unicast_service.c b/unicast_service.c
index 9c9b95b..c6c17c6 100644
--- a/unicast_service.c
+++ b/unicast_service.c
@@ -31,6 +31,9 @@
 #include "unicast_service.h"
 #include "util.h"
 
+#define MIN_LOG_INTER_MESSAGE_PERIOD -7
+#define MAX_LOG_INTER_MESSAGE_PERIOD 16
+#define MAX_DURATION 3600
 #define QUEUE_LEN 16
 
 struct unicast_client_address {
@@ -289,6 +292,15 @@ int unicast_service_add(struct port *p, struct ptp_message *m,
 		return SERVICE_DENIED;
 	}
 
+	if (req->logInterMessagePeriod < MIN_LOG_INTER_MESSAGE_PERIOD ||
+	    req->logInterMessagePeriod > MAX_LOG_INTER_MESSAGE_PERIOD) {
+		return SERVICE_DENIED;
+	}
+
+	if (req->durationField > MAX_DURATION) {
+		req->durationField = MAX_DURATION;
+	}
+
 	LIST_FOREACH(itmp, &p->unicast_service->intervals, list) {
 		/*
 		 * Remember the interval of interest.