batman-adv: Fix ICMP RR ethernet access after skb_linearize
The skb_linearize may reallocate the skb. This makes the calculated pointer
for ethhdr invalid. But it the pointer is used later to fill in the RR
field of the batadv_icmp_packet_rr packet.
Instead re-evaluate eth_hdr after the skb_linearize+skb_cow to fix the
pointer and avoid the invalid read.
Fixes: da6b8c20a5
("batman-adv: generalize batman-adv icmp packet handling")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
baceced932
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3b55e44220
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@ -374,6 +374,7 @@ int batadv_recv_icmp_packet(struct sk_buff *skb,
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if (skb_cow(skb, ETH_HLEN) < 0)
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goto out;
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ethhdr = eth_hdr(skb);
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icmph = (struct batadv_icmp_header *)skb->data;
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icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
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if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
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