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Commit 7b797d5b authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
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[PPP] generic: Call skb_cow_head before scribbling over skb 



It's rude to write over data that other people are still using.  So call
skb_cow_head before PPP proceeds to modify the skb data.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d9cc2048

drivers/net/ppp_generic.c

+3 −11
Original line number Diff line number Diff line
@@ -899,17 +899,9 @@ ppp_start_xmit(struct sk_buff *skb, struct net_device *dev) 


	/* Put the 2-byte PPP protocol number on the front,

	   making sure there is room for the address and control fields. */

	if (skb_headroom(skb) < PPP_HDRLEN) {

		struct sk_buff *ns;



		ns = alloc_skb(skb->len + dev->hard_header_len, GFP_ATOMIC);

		if (ns == 0)

	if (skb_cow_head(skb, PPP_HDRLEN))

		goto outf;

		skb_reserve(ns, dev->hard_header_len);

		skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);

		kfree_skb(skb);

		skb = ns;

	}



	pp = skb_push(skb, 2);

	proto = npindex_to_proto[npi];

	pp[0] = proto >> 8;