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authorAntonio Quartulli <antonio@meshcoding.com>2014-02-15 21:50:37 +0100
committerAntonio Quartulli <antonio@meshcoding.com>2014-02-17 17:17:02 +0100
commit70b271a78beba787155d6696aacd7c4d4a251c50 (patch)
treebb8f4e8e8f9833d993b8f09638a063d6290f5281 /net
parenta5a5cb8cab526af2f6cbe9715f8ca843192f0d81 (diff)
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batman-adv: fix potential kernel paging error for unicast transmissions
batadv_send_skb_prepare_unicast(_4addr) might reallocate the skb's data. If it does then our ethhdr pointer is not valid anymore in batadv_send_skb_unicast(), resulting in a kernel paging error. Fixing this by refetching the ethhdr pointer after the potential reallocation. Signed-off-by: Linus Lüssing <linus.luessing@web.de> Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
Diffstat (limited to 'net')
-rw-r--r--net/batman-adv/send.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/net/batman-adv/send.c b/net/batman-adv/send.c
index 579f5f00a385..843febd1e519 100644
--- a/net/batman-adv/send.c
+++ b/net/batman-adv/send.c
@@ -254,9 +254,9 @@ static int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node,
unsigned short vid)
{
- struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
+ struct ethhdr *ethhdr;
struct batadv_unicast_packet *unicast_packet;
- int ret = NET_XMIT_DROP;
+ int ret = NET_XMIT_DROP, hdr_size;
if (!orig_node)
goto out;
@@ -265,12 +265,16 @@ static int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
case BATADV_UNICAST:
if (!batadv_send_skb_prepare_unicast(skb, orig_node))
goto out;
+
+ hdr_size = sizeof(*unicast_packet);
break;
case BATADV_UNICAST_4ADDR:
if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, skb,
orig_node,
packet_subtype))
goto out;
+
+ hdr_size = sizeof(struct batadv_unicast_4addr_packet);
break;
default:
/* this function supports UNICAST and UNICAST_4ADDR only. It
@@ -279,6 +283,7 @@ static int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
goto out;
}
+ ethhdr = (struct ethhdr *)(skb->data + hdr_size);
unicast_packet = (struct batadv_unicast_packet *)skb->data;
/* inform the destination node that we are still missing a correct route