caif: Ldisc add permission check and mem-alloc error check

Changes:
   o Added permission checks for installing. CAP_SYS_ADMIN and
     CAP_SYS_TTY_CONFIG can install the ldisc.
   o Check if allocation of skb was successful.

Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/net/caif/caif_serial.c b/drivers/net/caif/caif_serial.c
index 38c0186cfbc2..09257ca8f563 100644
--- a/drivers/net/caif/caif_serial.c
+++ b/drivers/net/caif/caif_serial.c
@@ -197,7 +197,8 @@ static void ldisc_receive(struct tty_struct *tty, const u8 *data,
 
         /* Get a suitable caif packet and copy in data. */
         skb = netdev_alloc_skb(ser->dev, count+1);
-        BUG_ON(skb == NULL);
+        if (skb == NULL)
+                return;
         p = skb_put(skb, count);
         memcpy(p, data, count);
 
@@ -315,6 +316,8 @@ static int ldisc_open(struct tty_struct *tty)
         /* No write no play */
         if (tty->ops->write == NULL)
                 return -EOPNOTSUPP;
+        if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_TTY_CONFIG))
+                return -EPERM;
 
         sprintf(name, "cf%s", tty->name);
         dev = alloc_netdev(sizeof(*ser), name, caifdev_setup);