[PATCH 6/7] [PPP] generic: Call skb_cow_head before scribbling over skb
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: 2007-08-31 09:11:39
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2007-09-16 · Re: [PATCH 6/7] [PPP] generic: Call skb_cow_head before scribbling over skb · David Miller <davem@davemloft.net>
[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> --- drivers/net/ppp_generic.c | 14 +++----------- 1 files changed, 3 insertions(+), 11 deletions(-)
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 9293c82..7e21342 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c@@ -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) - 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; - } + if (skb_cow_head(skb, PPP_HDRLEN)) + goto outf; + pp = skb_push(skb, 2); proto = npindex_to_proto[npi]; pp[0] = proto >> 8;