net: validate variable length ll headers

[pandora-kernel.git] / include / linux / netdevice.h

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 4b04097..700c948 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -293,6 +293,7 @@ struct header_ops {
        void    (*cache_update)(struct hh_cache *hh,
                                const struct net_device *dev,
                                const unsigned char *haddr);
+       bool    (*validate)(const char *ll_header, unsigned int len);
 };
 
 /* These flag bits are private to the generic network queueing
@@ -1119,7 +1120,7 @@ struct net_device {
 
        unsigned int            mtu;    /* interface MTU value          */
        unsigned short          type;   /* interface hardware type      */
-       unsigned short          hard_header_len;        /* hardware hdr length  */
+       unsigned short          hard_header_len; /* maximum hardware hdr length */
 
        /* extra head- and tailroom the hardware may need, but not in all cases
         * can this be guaranteed, especially tailroom. Some cases also use
@@ -1728,6 +1729,24 @@ static inline int dev_rebuild_header(struct sk_buff *skb)
        return dev->header_ops->rebuild(skb);
 }
 
+/* ll_header must have at least hard_header_len allocated */
+static inline bool dev_validate_header(const struct net_device *dev,
+                                      char *ll_header, int len)
+{
+       if (likely(len >= dev->hard_header_len))
+               return true;
+
+       if (capable(CAP_SYS_RAWIO)) {
+               memset(ll_header + len, 0, dev->hard_header_len - len);
+               return true;
+       }
+
+       if (dev->header_ops && dev->header_ops->validate)
+               return dev->header_ops->validate(ll_header, len);
+
+       return false;
+}
+
 typedef int gifconf_func_t(struct net_device * dev, char __user * bufptr, int len);
 extern int             register_gifconf(unsigned int family, gifconf_func_t * gifconf);
 static inline int unregister_gifconf(unsigned int family)