1 files changed, 14 insertions, 8 deletions

diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 5fafc6b81671..997a783522ec 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -208,20 +208,26 @@ sysctl_kern_randompid(SYSCTL_HANDLER_ARGS)
 	pid = randompid;
 	error = sysctl_handle_int(oidp, &pid, 0, req);
 	if (error == 0 && req->newptr != NULL) {
-		if (pid < 0 || pid > pid_max - 100)	/* out of range */
-			pid = pid_max - 100;
-		else if (pid < 2)			/* NOP */
-			pid = 0;
-		else if (pid < 100)			/* Make it reasonable */
-			pid = 100;
-		randompid = pid;
+		if (pid == 0)
+			randompid = 0;
+		else if (pid == 1)
+			/* generate a random PID modulus between 100 and 1123 */
+			randompid = 100 + arc4random() % 1024;
+		else if (pid < 0 || pid > pid_max - 100)
+			/* out of range */
+			randompid = pid_max - 100;
+		else if (pid < 100)	 
+			/* Make it reasonable */
+			randompid = 100;
+		else
+			randompid = pid;
 	}
 	sx_xunlock(&allproc_lock);
 	return (error);
 }
 
 SYSCTL_PROC(_kern, OID_AUTO, randompid, CTLTYPE_INT|CTLFLAG_RW,
-    0, 0, sysctl_kern_randompid, "I", "Random PID modulus");
+    0, 0, sysctl_kern_randompid, "I", "Random PID modulus. Special values: 0: disable, 1: choose random value");
 
 static int
 fork_findpid(int flags)