Staging: batman-adv: Provide full headers and packets as linear skb

We must ensure that all interesting data is linear and not paged out to
access all information in a header or a full batman-adv related packet.
Otherwise we may drop packets which have non-linear headers but which
hold valid data.

This doesn't affect non-linear skbs which have all headers in a linear
head unless we must process the whole packet like in ogms or vis
packets.

Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 15 insertions, 9 deletions

diff --git a/drivers/staging/batman-adv/hard-interface.c b/drivers/staging/batman-adv/hard-interface.c
index f33c73f72d5..c1863d240f7 100644
--- a/drivers/staging/batman-adv/hard-interface.c
+++ b/drivers/staging/batman-adv/hard-interface.c
@@ -486,7 +486,7 @@ int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
                 goto err_free;
 
         /* packet should hold at least type and version */
-        if (unlikely(skb_headlen(skb) < 2))
+        if (unlikely(!pskb_may_pull(skb, 2)))
                 goto err_free;
 
         /* expect a valid ethernet header here. */
diff --git a/drivers/staging/batman-adv/routing.c b/drivers/staging/batman-adv/routing.c
index 7e993a25349..6009adc80b8 100644
--- a/drivers/staging/batman-adv/routing.c
+++ b/drivers/staging/batman-adv/routing.c
@@ -744,7 +744,7 @@ int recv_bat_packet(struct sk_buff *skb,
         unsigned long flags;
 
         /* drop packet if it has not necessary minimum size */
-        if (skb_headlen(skb) < sizeof(struct batman_packet))
+        if (unlikely(!pskb_may_pull(skb, sizeof(struct batman_packet))))
                 return NET_RX_DROP;
 
         ethhdr = (struct ethhdr *)skb_mac_header(skb);
@@ -761,6 +761,10 @@ int recv_bat_packet(struct sk_buff *skb,
         if (skb_cow(skb, 0) < 0)
                 return NET_RX_DROP;
 
+        /* keep skb linear */
+        if (skb_linearize(skb) < 0)
+                return NET_RX_DROP;
+
         ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
         spin_lock_irqsave(&orig_hash_lock, flags);
@@ -914,11 +918,11 @@ int recv_icmp_packet(struct sk_buff *skb)
         /**
          * we truncate all incoming icmp packets if they don't match our size
          */
-        if (skb_headlen(skb) >= sizeof(struct icmp_packet_rr))
+        if (skb->len >= sizeof(struct icmp_packet_rr))
                 hdr_size = sizeof(struct icmp_packet_rr);
 
         /* drop packet if it has not necessary minimum size */
-        if (skb_headlen(skb) < hdr_size)
+        if (unlikely(!pskb_may_pull(skb, hdr_size)))
                 return NET_RX_DROP;
 
         ethhdr = (struct ethhdr *)skb_mac_header(skb);
@@ -1087,7 +1091,7 @@ static int check_unicast_packet(struct sk_buff *skb, int hdr_size)
         struct ethhdr *ethhdr;
 
         /* drop packet if it has not necessary minimum size */
-        if (skb_headlen(skb) < hdr_size)
+        if (unlikely(!pskb_may_pull(skb, hdr_size)))
                 return -1;
 
         ethhdr = (struct ethhdr *) skb_mac_header(skb);
@@ -1247,7 +1251,7 @@ int recv_bcast_packet(struct sk_buff *skb)
         unsigned long flags;
 
         /* drop packet if it has not necessary minimum size */
-        if (skb_headlen(skb) < hdr_size)
+        if (unlikely(!pskb_may_pull(skb, hdr_size)))
                 return NET_RX_DROP;
 
         ethhdr = (struct ethhdr *)skb_mac_header(skb);
@@ -1320,7 +1324,11 @@ int recv_vis_packet(struct sk_buff *skb)
         struct bat_priv *bat_priv;
         int hdr_size = sizeof(struct vis_packet);
 
-        if (skb_headlen(skb) < hdr_size)
+        /* keep skb linear */
+        if (skb_linearize(skb) < 0)
+                return NET_RX_DROP;
+
+        if (unlikely(!pskb_may_pull(skb, hdr_size)))
                 return NET_RX_DROP;
 
         vis_packet = (struct vis_packet *) skb->data;
@@ -1342,13 +1350,11 @@ int recv_vis_packet(struct sk_buff *skb)
 
         switch (vis_packet->vis_type) {
         case VIS_TYPE_SERVER_SYNC:
-                /* TODO: handle fragmented skbs properly */
                 receive_server_sync_packet(bat_priv, vis_packet,
                                            skb_headlen(skb));
                 break;
 
         case VIS_TYPE_CLIENT_UPDATE:
-                /* TODO: handle fragmented skbs properly */
                 receive_client_update_packet(bat_priv, vis_packet,
                                              skb_headlen(skb));
                 break;