Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (25 commits)
  virtio: balloon driver
  virtio: Use PCI revision field to indicate virtio PCI ABI version
  virtio: PCI device
  virtio_blk: implement naming for vda-vdz,vdaa-vdzz,vdaaa-vdzzz
  virtio_blk: Dont waste major numbers
  virtio_blk: provide getgeo
  virtio_net: parametrize the napi_weight for virtio receive queue.
  virtio: free transmit skbs when notified, not on next xmit.
  virtio: flush buffers on open
  virtnet: remove double ether_setup
  virtio: Allow virtio to be modular and used by modules
  virtio: Use the sg_phys convenience function.
  virtio: Put the virtio under the virtualization menu
  virtio: handle interrupts after callbacks turned off
  virtio: reset function
  virtio: populate network rings in the probe routine, not open
  virtio: Tweak virtio_net defines
  virtio: Net header needs hdr_len
  virtio: remove unused id field from struct virtio_blk_outhdr
  virtio: clarify NO_NOTIFY flag usage
  ...

1 files changed, 29 insertions, 0 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 98420f9c4b6d..4e354221ec23 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2461,6 +2461,34 @@ int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer)
         return elt;
 }
 
+/**
+ * skb_partial_csum_set - set up and verify partial csum values for packet
+ * @skb: the skb to set
+ * @start: the number of bytes after skb->data to start checksumming.
+ * @off: the offset from start to place the checksum.
+ *
+ * For untrusted partially-checksummed packets, we need to make sure the values
+ * for skb->csum_start and skb->csum_offset are valid so we don't oops.
+ *
+ * This function checks and sets those values and skb->ip_summed: if this
+ * returns false you should drop the packet.
+ */
+bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off)
+{
+        if (unlikely(start > skb->len - 2) ||
+            unlikely((int)start + off > skb->len - 2)) {
+                if (net_ratelimit())
+                        printk(KERN_WARNING
+                               "bad partial csum: csum=%u/%u len=%u\n",
+                               start, off, skb->len);
+                return false;
+        }
+        skb->ip_summed = CHECKSUM_PARTIAL;
+        skb->csum_start = skb_headroom(skb) + start;
+        skb->csum_offset = off;
+        return true;
+}
+
 EXPORT_SYMBOL(___pskb_trim);
 EXPORT_SYMBOL(__kfree_skb);
 EXPORT_SYMBOL(kfree_skb);
@@ -2497,3 +2525,4 @@ EXPORT_SYMBOL(skb_append_datato_frags);
 
 EXPORT_SYMBOL_GPL(skb_to_sgvec);
 EXPORT_SYMBOL_GPL(skb_cow_data);
+EXPORT_SYMBOL_GPL(skb_partial_csum_set);