gigaset: linearize skb

The code of the Gigaset driver assumes that sk_buff-s coming
from the ISDN4Linux subsystem are always linear. Explicitly
calling skb_linearize() is cheap if they are, but much more
robust in case they ever aren't.

Impact: robustness improvement
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/isdn/gigaset/i4l.c b/drivers/isdn/gigaset/i4l.c
index 9b22f9c..322f16e 100644 (file)
--- a/drivers/isdn/gigaset/i4l.c
+++ b/drivers/isdn/gigaset/i4l.c
@@ -51,6 +51,12 @@ static int writebuf_from_LL(int driverID, int channel, int ack,
                return -ENODEV;
        }
        bcs = &cs->bcs[channel];
+
+       /* can only handle linear sk_buffs */
+       if (skb_linearize(skb) < 0) {
+               dev_err(cs->dev, "%s: skb_linearize failed\n", __func__);
+               return -ENOMEM;
+       }
        len = skb->len;
 
        gig_dbg(DEBUG_LLDATA,