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authorHerbert Xu <herbert@gondor.apana.org.au>2007-09-16 16:21:42 -0700
committerDavid S. Miller <davem@davemloft.net>2007-09-16 16:21:42 -0700
commit7b797d5b150775d717cb03b5ada28b8bad99afab (patch)
tree086b28889711612bcb2ea80c30e85116f617c0f7 /drivers/net/ppp_generic.c
parentd9cc20484e5e48c6a5deb4387c20fd45bfbdde8c (diff)
downloadlinux-7b797d5b150775d717cb03b5ada28b8bad99afab.tar.gz
[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>
Diffstat (limited to 'drivers/net/ppp_generic.c')
-rw-r--r--drivers/net/ppp_generic.c14
1 files changed, 3 insertions, 11 deletions
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 9293c82ef2af..7e21342becb2 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;