tree cba3b2ee49afcb899343f01c4de77bf020176e69
parent 9d4619c492c84e4c1e6d7127f1cbf55da04599d0
author Bjørn Mork <bjorn@mork.no> 1399066020 +0200
committer David S. Miller <davem@davemloft.net> 1399317571 -0400

net: cdc_ncm: fix buffer overflow

Commit 4d619f625a60 ("net: cdc_ncm: no point in filling up the NTBs
if we send ZLPs") changed the padding logic for devices with the ZLP
flag set.  This meant that frames of any size will be sent without
additional padding, except for the single byte added if the size is
a multiple of the USB packet size. But if the unpadded size is
identical to the maximum frame size, and the maximum size is a
multiplum of the USB packet size, then this one-byte padding will
overflow the buffer.

Prevent padding if already at maximum frame size, letting usbnet
transmit a ZLP instead in this case.

Fixes: 4d619f625a60 ("net: cdc_ncm: no point in filling up the NTBs if we send ZLPs")
Reported by: Yu-an Shih <yshih@nvidia.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>