diff options
| author | Xie He <xie.he.0141@gmail.com> | 2020-08-08 19:35:48 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-08-11 10:32:05 -0700 |
| commit | c79f428d6f14e754503fa7a3145d62039ccd05c9 (patch) | |
| tree | 7771509e899ef8b08b96552eb21db6d56fbb6a20 | |
| parent | b06c19d9f827f6743122795570bfc0c72db482b0 (diff) | |
drivers/net/wan/x25_asy: Added needed_headroom and a skb->len check
1. Added a skb->len check
This driver expects upper layers to include a pseudo header of 1 byte
when passing down a skb for transmission. This driver will read this
1-byte header. This patch added a skb->len check before reading the
header to make sure the header exists.
2. Added needed_headroom
When this driver transmits data,
first this driver will remove a pseudo header of 1 byte,
then the lapb module will prepend the LAPB header of 2 or 3 bytes.
So the value of needed_headroom in this driver should be 3 - 1.
Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/wan/x25_asy.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/net/wan/x25_asy.c b/drivers/net/wan/x25_asy.c index 84640a0c13f3..de7984463595 100644 --- a/drivers/net/wan/x25_asy.c +++ b/drivers/net/wan/x25_asy.c @@ -307,6 +307,14 @@ static netdev_tx_t x25_asy_xmit(struct sk_buff *skb, return NETDEV_TX_OK; } + /* There should be a pseudo header of 1 byte added by upper layers. + * Check to make sure it is there before reading it. + */ + if (skb->len < 1) { + kfree_skb(skb); + return NETDEV_TX_OK; + } + switch (skb->data[0]) { case X25_IFACE_DATA: break; @@ -752,6 +760,12 @@ static void x25_asy_setup(struct net_device *dev) dev->type = ARPHRD_X25; dev->tx_queue_len = 10; + /* When transmitting data: + * first this driver removes a pseudo header of 1 byte, + * then the lapb module prepends an LAPB header of at most 3 bytes. + */ + dev->needed_headroom = 3 - 1; + /* New-style flags. */ dev->flags = IFF_NOARP; } |