| Message ID | 20201031003731.461437-5-xie.he.0141@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,v5,1/5] net: hdlc_fr: Simpify fr_rx by using "goto rx_drop" to drop frames | expand |
diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c index eb83116aa9df..98444f1d8cc3 100644 --- a/drivers/net/wan/hdlc_fr.c +++ b/drivers/net/wan/hdlc_fr.c @@ -882,7 +882,7 @@ static int fr_rx(struct sk_buff *skb) struct pvc_device *pvc; struct net_device *dev; - if (skb->len <= 4 || fh->ea1 || data[2] != FR_UI) + if (skb->len < 4 || fh->ea1 || !fh->ea2 || data[2] != FR_UI) goto rx_error; dlci = q922_to_dlci(skb->data);
1. Change the skb->len check from "<= 4" to "< 4". At first we only need to ensure a 4-byte header is present. We indeed normally need the 5th byte, too, but it'd be more logical and cleaner to check its existence when we actually need it. 2. Add an fh->ea2 check to the initial checks in fr_rx. fh->ea2 == 1 means the second address byte is the final address byte. We only support the case where the address length is 2 bytes. If the address length is not 2 bytes, the control field and the protocol field would not be the 3rd and 4th byte as we assume. (Say if it is 3 bytes, then the control field and the protocol field would be the 4th and 5th byte instead.) Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Cc: Krzysztof Halasa <khc@pm.waw.pl> Signed-off-by: Xie He <xie.he.0141@gmail.com> --- drivers/net/wan/hdlc_fr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)