diff mbox series

[net-next,v3,3/4] net: hdlc_fr: Improve the initial checks when we receive an skb

Message ID 20201028184310.7017-4-xie.he.0141@gmail.com
State Superseded
Headers show
Series net: hdlc_fr: Add support for any Ethertype | expand

Commit Message

Xie He Oct. 28, 2020, 6:43 p.m. UTC
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.

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(-)
diff mbox series

Patch

diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c
index ac65f5c435ef..3639c2bfb141 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);