[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 <yuehaib...@huawei.com>
---
 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