ipv4: ip_check_defrag should not assume that skb_network_offset is zero
ip_check_defrag() may be used by af_packet to defragment outgoing packets. skb_network_offset() of af_packet's outgoing packets is not zero. Signed-off-by: Alexander Drozdov <al.drozdov@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -659,27 +659,30 @@ EXPORT_SYMBOL(ip_defrag);
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struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
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{
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struct iphdr iph;
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int netoff;
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u32 len;
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if (skb->protocol != htons(ETH_P_IP))
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return skb;
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if (skb_copy_bits(skb, 0, &iph, sizeof(iph)) < 0)
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netoff = skb_network_offset(skb);
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if (skb_copy_bits(skb, netoff, &iph, sizeof(iph)) < 0)
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return skb;
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if (iph.ihl < 5 || iph.version != 4)
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return skb;
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len = ntohs(iph.tot_len);
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if (skb->len < len || len < (iph.ihl * 4))
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if (skb->len < netoff + len || len < (iph.ihl * 4))
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return skb;
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if (ip_is_fragment(&iph)) {
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skb = skb_share_check(skb, GFP_ATOMIC);
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if (skb) {
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if (!pskb_may_pull(skb, iph.ihl*4))
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if (!pskb_may_pull(skb, netoff + iph.ihl * 4))
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return skb;
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if (pskb_trim_rcsum(skb, len))
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if (pskb_trim_rcsum(skb, netoff + len))
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return skb;
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memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
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if (ip_defrag(skb, user))
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