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>
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@ -254,9 +254,9 @@ static int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
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struct batadv_orig_node *orig_node,
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unsigned short vid)
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{
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struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
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struct ethhdr *ethhdr;
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struct batadv_unicast_packet *unicast_packet;
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int ret = NET_XMIT_DROP;
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int ret = NET_XMIT_DROP, hdr_size;
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if (!orig_node)
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goto out;
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@ -265,12 +265,16 @@ static int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
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case BATADV_UNICAST:
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if (!batadv_send_skb_prepare_unicast(skb, orig_node))
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goto out;
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hdr_size = sizeof(*unicast_packet);
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break;
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case BATADV_UNICAST_4ADDR:
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if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, skb,
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orig_node,
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packet_subtype))
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goto out;
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hdr_size = sizeof(struct batadv_unicast_4addr_packet);
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break;
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default:
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/* this function supports UNICAST and UNICAST_4ADDR only. It
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@ -279,6 +283,7 @@ static int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
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goto out;
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}
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ethhdr = (struct ethhdr *)(skb->data + hdr_size);
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unicast_packet = (struct batadv_unicast_packet *)skb->data;
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/* inform the destination node that we are still missing a correct route
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