[PATCH] hw/net: prevent potential NULL dereference

[Oleg Sviridov]

Pointer, returned from function 'spapr_vio_find_by_reg', may be NULL and is 
dereferenced immediately after.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Oleg Sviridov <oleg.sviridov@red-soft.ru>
---
 hw/net/spapr_llan.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/net/spapr_llan.c b/hw/net/spapr_llan.c
index ecb30b7c76..f40b733229 100644
--- a/hw/net/spapr_llan.c
+++ b/hw/net/spapr_llan.c
@@ -770,6 +770,10 @@ static target_ulong h_change_logical_lan_mac(PowerPCCPU 
*cpu,
     SpaprVioVlan *dev = VIO_SPAPR_VLAN_DEVICE(sdev);
     int i;
 
+    if (!dev) {
+        return H_PARAMETER;
+    }
+
     for (i = 0; i < ETH_ALEN; i++) {
         dev->nicconf.macaddr.a[ETH_ALEN - i - 1] = macaddr & 0xff;
         macaddr >>= 8;
-- 
2.44.0