From b6930dfa9ba4224d03988377a22f83ee1f0aef55 Mon Sep 17 00:00:00 2001
From: Florian Pose <fp@igh.de>
Date: Mon, 5 May 2014 13:49:45 +0200
Subject: [PATCH] Fixed possible NULL pointer dereference; thanks to Matthieu
 Bec.

---
 master/master.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/master/master.c b/master/master.c
index 97e00712..2b94b19a 100644
--- a/master/master.c
+++ b/master/master.c
@@ -2651,6 +2651,7 @@ int ecrt_master_get_slave(ec_master_t *master, uint16_t slave_position,
 {
     const ec_slave_t *slave;
     unsigned int i;
+    int ret = 0;
 
     if (down_interruptible(&master->master_sem)) {
         return -EINTR;
@@ -2658,6 +2659,11 @@ int ecrt_master_get_slave(ec_master_t *master, uint16_t slave_position,
 
     slave = ec_master_find_slave_const(master, 0, slave_position);
 
+    if (slave == NULL) {
+       ret = -ENOENT;
+       goto out_get_slave;
+    }
+
     slave_info->position = slave->ring_position;
     slave_info->vendor_id = slave->sii.vendor_id;
     slave_info->product_code = slave->sii.product_code;
@@ -2694,9 +2700,10 @@ int ecrt_master_get_slave(ec_master_t *master, uint16_t slave_position,
         slave_info->name[0] = 0;
     }
 
+out_get_slave:
     up(&master->master_sem);
 
-    return 0;
+    return ret;
 }
 
 /*****************************************************************************/