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[6/7] batman-adv: Provide full headers and packets as linear skb

Message ID 1280697613-32001-7-git-send-email-sven.eckelmann@gmx.de (mailing list archive)
State Accepted, archived
Headers

Commit Message

Sven Eckelmann Aug. 1, 2010, 9:20 p.m. UTC 
  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>
---
 batman-adv/hard-interface.c |    2 +-
 batman-adv/routing.c        |   22 ++++++++++++++--------
 2 files changed, 15 insertions(+), 9 deletions(-)
diff mbox

Patch

diff --git a/batman-adv/hard-interface.c b/batman-adv/hard-interface.c
index fdabe4f..23a2595 100644
--- a/batman-adv/hard-interface.c
+++ b/batman-adv/hard-interface.c
@@ -490,7 +490,7 @@  int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
 		goto err_out;
 
 	/* 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/batman-adv/routing.c b/batman-adv/routing.c
index 7667c55..8f3b6fb 100644
--- a/batman-adv/routing.c
+++ b/batman-adv/routing.c
@@ -756,7 +756,7 @@  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);
@@ -773,6 +773,10 @@  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);
@@ -926,11 +930,11 @@  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);
@@ -1099,7 +1103,7 @@  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);
@@ -1259,7 +1263,7 @@  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);
@@ -1332,7 +1336,11 @@  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;
@@ -1354,13 +1362,11 @@  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;