From 1ba5d0ff36f765a571c83b55b13ec44f4050fb5b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= Date: Fri, 30 May 2014 09:31:04 +0200 Subject: [PATCH] net: cdc_ncm: always reallocate tx_curr_skb when tx_max increases MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We are calling usbnet_start_xmit() to flush any remaining data, depending on the side effect that tx_curr_skb is set to NULL, ensuring a new allocation using the updated tx_max. But this side effect will only happen if there were any cached data ready to transmit. If not, then an empty tx_curr_skb is still allocated using the old tx_max size. Free it to avoid a buffer overrun. Fixes: 68864abf08f0 ("net: cdc_ncm: support rx_max/tx_max updates when running") Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller --- drivers/net/usb/cdc_ncm.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index 2bbbd65591c7..ff5b3a854898 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -268,6 +268,11 @@ static void cdc_ncm_update_rxtx_max(struct usbnet *dev, u32 new_rx, u32 new_tx) if (netif_running(dev->net) && val > ctx->tx_max) { netif_tx_lock_bh(dev->net); usbnet_start_xmit(NULL, dev->net); + /* make sure tx_curr_skb is reallocated if it was empty */ + if (ctx->tx_curr_skb) { + dev_kfree_skb_any(ctx->tx_curr_skb); + ctx->tx_curr_skb = NULL; + } ctx->tx_max = val; netif_tx_unlock_bh(dev->net); } else {