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authorJim Baxter <jim_baxter@mentor.com>2017-05-08 13:49:57 +0100
committerDavid S. Miller <davem@davemloft.net>2017-05-08 16:01:10 -0400
commitaeca3a77b1e0ed06a095933b89c86aed007383eb (patch)
tree17c512c5adb4fa015607454c29a1c9095f508bfb /drivers
parentb210aeaedfc47ab8a86fbdcad46caf1e49cc0e37 (diff)
net: cdc_ncm: Fix TX zero padding
The zero padding that is added to NTB's does not zero the memory correctly. This is because the skb_put modifies the value of skb_out->len which results in the memset command not setting any memory to zero as (ctx->tx_max - skb_out->len) == 0. I have resolved this by storing the size of the memory to be zeroed before the skb_put and using this in the memset call. Signed-off-by: Jim Baxter <jim_baxter@mentor.com> Reviewed-by: Bjørn Mork <bjorn@mork.no> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/usb/cdc_ncm.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index bb3f71f9fbde..b5cec1824a78 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -1088,6 +1088,7 @@ cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign)
u16 n = 0, index, ndplen;
u8 ready2send = 0;
u32 delayed_ndp_size;
+ size_t padding_count;
/* When our NDP gets written in cdc_ncm_ndp(), then skb_out->len gets updated
* accordingly. Otherwise, we should check here.
@@ -1244,11 +1245,13 @@ cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign)
* a ZLP after full sized NTBs.
*/
if (!(dev->driver_info->flags & FLAG_SEND_ZLP) &&
- skb_out->len > ctx->min_tx_pkt)
- memset(skb_put(skb_out, ctx->tx_max - skb_out->len), 0,
- ctx->tx_max - skb_out->len);
- else if (skb_out->len < ctx->tx_max && (skb_out->len % dev->maxpacket) == 0)
+ skb_out->len > ctx->min_tx_pkt) {
+ padding_count = ctx->tx_max - skb_out->len;
+ memset(skb_put(skb_out, padding_count), 0, padding_count);
+ } else if (skb_out->len < ctx->tx_max &&
+ (skb_out->len % dev->maxpacket) == 0) {
*skb_put(skb_out, 1) = 0; /* force short packet */
+ }
/* set final frame length */
nth16 = (struct usb_cdc_ncm_nth16 *)skb_out->data;