| From | Ben Hutchings <> | Date | Sat, 13 Aug 2016 18:42:51 +0100 | Subject | [PATCH 3.16 255/305] batman-adv: Fix ICMP RR ethernet access after skb_linearize |
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3.16.37-rc1 review patch. If anyone has any objections, please let me know.
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From: Sven Eckelmann <sven@narfation.org>
commit 3b55e4422087f9f7b241031d758a0c65584e4297 upstream.
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: da6b8c20a5b8 ("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> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- net/batman-adv/routing.c | 1 + 1 file changed, 1 insertion(+)
--- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -344,6 +344,7 @@ int batadv_recv_icmp_packet(struct sk_bu if (skb_cow(skb, ETH_HLEN) < 0) goto out; + ethhdr = eth_hdr(skb); icmph = (struct batadv_icmp_header *)skb->data; icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph; if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
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