From 9d2c9488cedb666bc8206fbdcdc1575e0fbc5929 Mon Sep 17 00:00:00 2001 From: Linus Lüssing Date: Tue, 6 Aug 2013 20:21:15 +0200 Subject: batman-adv: fix potential kernel paging errors for unicast transmissions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There are several functions which might reallocate skb data. Currently some places keep reusing their old ethhdr pointer regardless of whether they became invalid after such a reallocation or not. This potentially leads to kernel paging errors. This patch fixes these by refetching the ethdr pointer after the potential reallocations. Signed-off-by: Linus Lüssing Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli --- net/batman-adv/gateway_client.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'net/batman-adv/gateway_client.c') diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index f105219f4a4b..7614af31daff 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -508,6 +508,7 @@ out: return 0; } +/* this call might reallocate skb data */ static bool batadv_is_type_dhcprequest(struct sk_buff *skb, int header_len) { int ret = false; @@ -568,6 +569,7 @@ out: return ret; } +/* this call might reallocate skb data */ bool batadv_gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len) { struct ethhdr *ethhdr; @@ -619,6 +621,12 @@ bool batadv_gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len) if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr))) return false; + + /* skb->data might have been reallocated by pskb_may_pull() */ + ethhdr = (struct ethhdr *)skb->data; + if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) + ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN); + udphdr = (struct udphdr *)(skb->data + *header_len); *header_len += sizeof(*udphdr); @@ -634,12 +642,14 @@ bool batadv_gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len) return true; } +/* this call might reallocate skb data */ bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, - struct sk_buff *skb, struct ethhdr *ethhdr) + struct sk_buff *skb) { struct batadv_neigh_node *neigh_curr = NULL, *neigh_old = NULL; struct batadv_orig_node *orig_dst_node = NULL; struct batadv_gw_node *curr_gw = NULL; + struct ethhdr *ethhdr; bool ret, out_of_range = false; unsigned int header_len = 0; uint8_t curr_tq_avg; @@ -648,6 +658,7 @@ bool batadv_gw_out_of_range(struct batadv_priv *bat_priv, if (!ret) goto out; + ethhdr = (struct ethhdr *)skb->data; orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source, ethhdr->h_dest); if (!orig_dst_node) -- cgit v1.2.3