lkml.org 
[lkml]   [2020]   [Mar]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.4 51/93] batman-adv: Fix ICMP RR ethernet access after skb_linearize
Date
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/batman-adv/routing.c | 1 +
1 file changed, 1 insertion(+)

--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -359,6 +359,7 @@ 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)

\
 
 \ /
  Last update: 2020-03-19 14:07    [W:0.345 / U:0.436 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site