Re: [PATCH v2] net: thunderx: nicvf_main: Fix potential NULL pointer dereferences

From: Gustavo A. R. Silva
Date: Wed Apr 04 2018 - 02:41:45 EST

On 04/04/2018 01:36 AM, Eric Dumazet wrote:

On 04/03/2018 03:04 PM, Gustavo A. R. Silva wrote:
Add null check on kmalloc() return value in order to prevent
a null pointer dereference.

Addresses-Coverity-ID: 1467429 ("Dereference null return value")
Fixes: 37c3347eb247 ("net: thunderx: add ndo_set_rx_mode callback implementation for VF")
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
Changes in v2:
- Add a null check on a second kmalloc a few lines below. Thanks to
Eric Dumazet for pointing this out.

drivers/net/ethernet/cavium/thunder/nicvf_main.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
index 1e9a31f..f7b5ca5 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
@@ -1999,10 +1999,14 @@ static void nicvf_set_rx_mode(struct net_device *netdev)
struct xcast_addr *xaddr;
mc_list = kmalloc(sizeof(*mc_list), GFP_ATOMIC);
+ if (unlikely(!mc_list))
+ return;
netdev_hw_addr_list_for_each(ha, &netdev->mc) {
xaddr = kmalloc(sizeof(*xaddr),
+ if (unlikely(!xaddr))
+ return;

So now you leak memory :/

Oh god. I'm sorry.

I had problems with this file since the beginning.

I'll send v3 shortly.