[PATCH v2] brcmfmac: Ensure pointer correctly set if skb data location changes

[PATCH v2] brcmfmac: Ensure pointer correctly set if skb data location changes

[James Hughes]

The incoming skb header may be resized if header space is
insufficient, which might change the data adddress in the skb.
Ensure that a cached pointer to that data is correctly set by
moving assignment to after any possible changes.

Signed-off-by: James Hughes <james.hughes@raspberrypi.org>

Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
---
Changes in v2

Moved the assignment below the len check - saves a few cycles 
if the length check fails. 


 drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
index 5eaac13e2317..9b7c19a508ac 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
@@ -198,7 +198,7 @@ static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff *skb,
 	int ret;
 	struct brcmf_if *ifp = netdev_priv(ndev);
 	struct brcmf_pub *drvr = ifp->drvr;
-	struct ethhdr *eh = (struct ethhdr *)(skb->data);
+	struct ethhdr *eh;
 
 	brcmf_dbg(DATA, "Enter, bsscfgidx=%d\n", ifp->bsscfgidx);
 
@@ -236,6 +236,8 @@ static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff *skb,
 		goto done;
 	}
 
+	eh = (struct ethhdr *)(skb->data);
+
 	if (eh->h_proto == htons(ETH_P_PAE))
 		atomic_inc(&ifp->pend_8021x_cnt);
 
-- 
2.11.0

Re: [PATCH v2] brcmfmac: Ensure pointer correctly set if skb data location changes

[Arend Van Spriel]

On 24-4-2017 13:40, James Hughes wrote:
> The incoming skb header may be resized if header space is
> insufficient, which might change the data adddress in the skb.
> Ensure that a cached pointer to that data is correctly set by
> moving assignment to after any possible changes.

Hi Kalle,

This one should go on 4.12 queue as well.

Thanks,
Arend

> Signed-off-by: James Hughes <james.hughes-FnsA7b+Nu9XbIbC87yuRow@public.gmane.org>
> 
> Acked-by: Arend van Spriel <arend.vanspriel-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
> ---

Re: [v2] brcmfmac: Ensure pointer correctly set if skb data location changes

[Kalle Valo]

James Hughes <james.hughes@raspberrypi.org> wrote:
> The incoming skb header may be resized if header space is
> insufficient, which might change the data adddress in the skb.
> Ensure that a cached pointer to that data is correctly set by
> moving assignment to after any possible changes.
> 
> Signed-off-by: James Hughes <james.hughes@raspberrypi.org>
> 
> Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>

Patch applied to wireless-drivers-next.git, thanks.

455a1eb4654c brcmfmac: Ensure pointer correctly set if skb data location changes

-- 
https://patchwork.kernel.org/patch/9696045/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches