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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
[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>
authored by Herbert Xu and committed by David S. Miller 7b797d5b d9cc2048
+2
-10
drivers/net/ppp_generic.c
+2
-10
drivers/net/ppp_generic.c
···
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899
900
900
/* Put the 2-byte PPP protocol number on the front,
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making sure there is room for the address and control fields. */
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-
if (skb_headroom(skb) < PPP_HDRLEN) {
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-
struct sk_buff *ns;
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+
if (skb_cow_head(skb, PPP_HDRLEN))
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+
goto outf;
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-
ns = alloc_skb(skb->len + dev->hard_header_len, GFP_ATOMIC);
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if (ns == 0)
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goto outf;
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-
skb_reserve(ns, dev->hard_header_len);
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-
skb_copy_bits(skb, 0, skb_put(ns, skb->len), skb->len);
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-
kfree_skb(skb);
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-
skb = ns;
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-
}
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pp = skb_push(skb, 2);
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proto = npindex_to_proto[npi];
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pp[0] = proto >> 8;