[PATCH net-next v4 3/5] net: hdlc_fr: Improve the initial checks when we receive an skb
From: Xie He <hidden>
Date: 2020-10-30 02:30:26
Also in:
lkml
Subsystem:
generic hdlc (wan) drivers, networking drivers, the rest · Maintainers:
Krzysztof Halasa, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Cc: Krzysztof Halasa <khc@pm.waw.pl> Signed-off-by: Xie He <redacted> --- drivers/net/wan/hdlc_fr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
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);
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2.27.0