[PATCH net-next] net: fddi: fix a possible null-ptr-deref

[YueHaibing]

bp->SharedMemAddr is set to NULL while bp->SharedMemSize less than 0,
then memset will trigger null-ptr-deref.

Fix it use pci_zalloc_consistent when bp->SharedMemSize is greater than 0.

Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
---
 drivers/net/fddi/skfp/skfddi.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/net/fddi/skfp/skfddi.c b/drivers/net/fddi/skfp/skfddi.c
index 2414f1d..90164e0 100644
--- a/drivers/net/fddi/skfp/skfddi.c
+++ b/drivers/net/fddi/skfp/skfddi.c
@@ -407,23 +407,21 @@ static  int skfp_driver_init(struct net_device *dev)
 	if (bp->SharedMemSize > 0) {
 		bp->SharedMemSize += 16;	// for descriptor alignment
 
-		bp->SharedMemAddr = pci_alloc_consistent(&bp->pdev,
-							 bp->SharedMemSize,
-							 &bp->SharedMemDMA);
+		bp->SharedMemAddr = pci_zalloc_consistent(&bp->pdev,
+							  bp->SharedMemSize,
+							  &bp->SharedMemDMA);
 		if (!bp->SharedMemAddr) {
 			printk("could not allocate mem for ");
 			printk("hardware module: %ld byte\n",
 			       bp->SharedMemSize);
 			goto fail;
 		}
-		bp->SharedMemHeap = 0;	// Nothing used yet.
 
 	} else {
 		bp->SharedMemAddr = NULL;
-		bp->SharedMemHeap = 0;
 	}			// SharedMemSize > 0
 
-	memset(bp->SharedMemAddr, 0, bp->SharedMemSize);
+	bp->SharedMemHeap = 0;
 
 	card_stop(smc);		// Reset adapter.
 
-- 
2.7.0