From ad5822c6b1401111bbdbc5e77fe097a3f1b2b3cb Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Mon, 28 Jan 2019 17:36:31 +0100
Subject: erts: Add magic port control numbers

to increase the probablity of a nice badarg
from erlang:port_control.
---
 erts/emulator/drivers/unix/ttsl_drv.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'erts/emulator/drivers/unix')

diff --git a/erts/emulator/drivers/unix/ttsl_drv.c b/erts/emulator/drivers/unix/ttsl_drv.c
index 28c6cc0f94..d2a524cb6c 100644
--- a/erts/emulator/drivers/unix/ttsl_drv.c
+++ b/erts/emulator/drivers/unix/ttsl_drv.c
@@ -394,6 +394,8 @@ static ErlDrvSSizeT ttysl_control(ErlDrvData drv_data,
 {
     char resbuff[2*sizeof(Uint32)];
     ErlDrvSizeT res_size;
+
+    command -= ERTS_TTYSL_DRV_CONTROL_MAGIC_NUMBER;
     switch (command) {
     case CTRL_OP_GET_WINSIZE:
 	{
@@ -419,7 +421,7 @@ static ErlDrvSSizeT ttysl_control(ErlDrvData drv_data,
 	}
 	break;
     default:
-	return 0;
+	return -1;
     }
     if (rlen < res_size) {
 	*rbuf = driver_alloc(res_size);
-- 
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