Commit 77124c44 authored by Xie He's avatar Xie He Committed by Jakub Kicinski

net: hdlc_fr: Improve the initial checks when we receive an skb

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: default avatarXie He <xie.he.0141@gmail.com>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent efc79039
......@@ -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);
......
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