diff options
| author | Sven Eckelmann <sven@narfation.org> | 2020-03-18 00:27:00 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-03-20 09:06:26 +0100 |
| commit | 39bd75b20ee158642e4c65751aaa45e2210bf15c (patch) | |
| tree | 1e1d750cb9b7c389ab5e1a163df89e4f66e675eb | |
| parent | e82b225aa8e02e8a2baea0643bebfe7e781696df (diff) | |
batman-adv: Fix ICMP RR ethernet access after skb_linearize
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/batman-adv/routing.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c index de24ab1cf67f..477899ba7616 100644 --- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -359,6 +359,7 @@ int batadv_recv_icmp_packet(struct sk_buff *skb, 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) |