2019-04-13 16:16:41

by Colin King

Subject: [PATCH] mwifiex: check for null return from skb_copy

From: Colin Ian King <[email protected]>

It is possible for skb_copy to return a null pointer and currently
this will cause a null pointer dereference when the function
mwifiex_uap_queue_bridged_pkt is called. Fix this by checking for
a null return from skb_copy and return -ENOMEM.

Addresses-Coverity: ("Dereference null return")
Fixes: 838e4f449297 ("mwifiex: improve uAP RX handling")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/net/wireless/marvell/mwifiex/uap_txrx.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/net/wireless/marvell/mwifiex/uap_txrx.c b/drivers/net/wireless/marvell/mwifiex/uap_txrx.c
index 5ce85d5727e4..b262dc78d638 100644
--- a/drivers/net/wireless/marvell/mwifiex/uap_txrx.c
+++ b/drivers/net/wireless/marvell/mwifiex/uap_txrx.c
@@ -256,6 +256,8 @@ int mwifiex_handle_uap_rx_forward(struct mwifiex_private *priv,

if (is_multicast_ether_addr(ra)) {
skb_uap = skb_copy(skb, GFP_ATOMIC);
+ if (!skb_uap)
+ return -ENOMEM;
mwifiex_uap_queue_bridged_pkt(priv, skb_uap);
} else {
if (mwifiex_get_sta_entry(priv, ra)) {
--
2.20.1

2019-04-13 19:30:38

by Dan Carpenter

Subject: Re: [PATCH] mwifiex: check for null return from skb_copy

On Sat, Apr 13, 2019 at 05:14:38PM +0100, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> It is possible for skb_copy to return a null pointer and currently
> this will cause a null pointer dereference when the function
> mwifiex_uap_queue_bridged_pkt is called. Fix this by checking for
> a null return from skb_copy and return -ENOMEM.
>
> Addresses-Coverity: ("Dereference null return")
> Fixes: 838e4f449297 ("mwifiex: improve uAP RX handling")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> drivers/net/wireless/marvell/mwifiex/uap_txrx.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/net/wireless/marvell/mwifiex/uap_txrx.c b/drivers/net/wireless/marvell/mwifiex/uap_txrx.c
> index 5ce85d5727e4..b262dc78d638 100644
> --- a/drivers/net/wireless/marvell/mwifiex/uap_txrx.c
> +++ b/drivers/net/wireless/marvell/mwifiex/uap_txrx.c
> @@ -256,6 +256,8 @@ int mwifiex_handle_uap_rx_forward(struct mwifiex_private *priv,
>
> if (is_multicast_ether_addr(ra)) {
> skb_uap = skb_copy(skb, GFP_ATOMIC);
> + if (!skb_uap)
> + return -ENOMEM;

I think we would want to free dev_kfree_skb_any(skb) before returning.

> mwifiex_uap_queue_bridged_pkt(priv, skb_uap);
> } else {
> if (mwifiex_get_sta_entry(priv, ra)) {

regards,
dan carpenter

2019-06-01 17:30:59

by Ganapathi Bhat

Subject: RE: [EXT] Re: [PATCH] mwifiex: check for null return from skb_copy

Hi Dan,

> > if (is_multicast_ether_addr(ra)) {
> > skb_uap = skb_copy(skb, GFP_ATOMIC);
> > + if (!skb_uap)
> > + return -ENOMEM;
>
> I think we would want to free dev_kfree_skb_any(skb) before returning.
I think if the pointer is NULL, no need to free it;

Regards,
Ganapathi

2019-06-01 21:11:01

by Dan Carpenter

Subject: Re: [EXT] Re: [PATCH] mwifiex: check for null return from skb_copy

On Sat, Jun 01, 2019 at 05:29:26PM +0000, Ganapathi Bhat wrote:
> Hi Dan,
>
> > > if (is_multicast_ether_addr(ra)) {
> > > skb_uap = skb_copy(skb, GFP_ATOMIC);
> > > + if (!skb_uap)
> > > + return -ENOMEM;
> >
> > I think we would want to free dev_kfree_skb_any(skb) before returning.
> I think if the pointer is NULL, no need to free it;

You're misreading skb vs skb_uap. "skb_uap" is NULL but "skb" is
non-NULL and I'm pretty sure we should free it.

regards,
dan carpenter