[IPV4]: Prevent oops when printing martian source

In some cases, we may be generating packets with a source address that
qualifies as martian. This can happen when we're in the middle of setting
up the network, and netfilter decides to reject a packet with an RST.
The IPv4 routing code would try to print a warning and oops, because
locally generated packets do not have a valid skb->mac.raw pointer
at this point.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 726ea5e..d675ff8 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1685,7 +1685,7 @@ static void ip_handle_martian_source(struct net_device *dev,
                printk(KERN_WARNING "martian source %u.%u.%u.%u from "
                        "%u.%u.%u.%u, on dev %s\n",
                        NIPQUAD(daddr), NIPQUAD(saddr), dev->name);
-               if (dev->hard_header_len) {
+               if (dev->hard_header_len && skb->mac.raw) {
                        int i;
                        unsigned char *p = skb->mac.raw;
                        printk(KERN_WARNING "ll header: ");