[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: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu 2007-09-16 16:21:42 -07:00 committed by David S. Miller
parent d9cc20484e
commit 7b797d5b15
1 changed files with 2 additions and 10 deletions

View File

@ -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;
if (skb_cow_head(skb, PPP_HDRLEN))
goto outf;
ns = alloc_skb(skb->len + dev->hard_header_len, GFP_ATOMIC);
if (ns == 0)
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;