| From | Ben Hutchings <> | Date | Tue, 05 May 2015 02:16:39 +0100 | Subject | [PATCH 3.2 193/221] ipv4: ip_check_defrag should not assume that skb_network_offset is zero |
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3.2.69-rc1 review patch. If anyone has any objections, please let me know.
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From: Alexander Drozdov <al.drozdov@gmail.com>
[ Upstream commit 3e32e733d1bbb3f227259dc782ef01d5706bdae0 ]
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> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- net/ipv4/ip_fragment.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
--- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -692,27 +692,30 @@ EXPORT_SYMBOL(ip_defrag); struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user) { struct iphdr iph; + int netoff; u32 len; if (skb->protocol != htons(ETH_P_IP)) return skb; - if (skb_copy_bits(skb, 0, &iph, sizeof(iph)) < 0) + netoff = skb_network_offset(skb); + + if (skb_copy_bits(skb, netoff, &iph, sizeof(iph)) < 0) return skb; if (iph.ihl < 5 || iph.version != 4) return skb; len = ntohs(iph.tot_len); - if (skb->len < len || len < (iph.ihl * 4)) + if (skb->len < netoff + len || len < (iph.ihl * 4)) return skb; if (ip_is_fragment(&iph)) { skb = skb_share_check(skb, GFP_ATOMIC); if (skb) { - if (!pskb_may_pull(skb, iph.ihl*4)) + if (!pskb_may_pull(skb, netoff + iph.ihl * 4)) return skb; - if (pskb_trim_rcsum(skb, len)) + if (pskb_trim_rcsum(skb, netoff + len)) return skb; memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); if (ip_defrag(skb, user))
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