[NET]: Fix ifmap alignment issues over rtnetlink

Introduces a fixed size variant of ifmap for rtnetlink. Fixes
issues with address size mismatch between kernel and userspace.
Obviously this will fail if userspace provides an address greater
than 32bit.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
SIgned-off-by: David S. Miller <davem@davemloft.net>

include/linux/rtnetlink.h

@@ -577,6 +577,17 @@ struct rtnl_link_stats
 	__u32	tx_compressed;
 };
 
+/* The struct should be in sync with struct ifmap */
+struct rtnl_link_ifmap
+{
+	__u64	mem_start;
+	__u64	mem_end;
+	__u64	base_addr;
+	__u16	irq;
+	__u8	dma;
+	__u8	port;
+};
+
 enum
 {
 	IFLA_UNSPEC,

net/core/rtnetlink.c

@@ -182,7 +182,7 @@ static int rtnetlink_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 	}
 
 	if (1) {
-		struct ifmap map = {
+		struct rtnl_link_ifmap map = {
 			.mem_start   = dev->mem_start,
 			.mem_end     = dev->mem_end,
 			.base_addr   = dev->base_addr,
@@ -277,6 +277,9 @@ static int do_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 		dev_change_flags(dev, ifm->ifi_flags);
 
 	if (ida[IFLA_MAP - 1]) {
+		struct rtnl_link_ifmap *u_map;
+		struct ifmap k_map;
+
 		if (!dev->set_config) {
 			err = -EOPNOTSUPP;
 			goto out;
@@ -287,11 +290,19 @@ static int do_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 			goto out;
 		}
 		
-		if (ida[IFLA_MAP - 1]->rta_len != RTA_LENGTH(sizeof(struct ifmap)))
+		if (ida[IFLA_MAP - 1]->rta_len != RTA_LENGTH(sizeof(*u_map)))
 			goto out;
 
-		err = dev->set_config(dev, (struct ifmap *)
-				RTA_DATA(ida[IFLA_MAP - 1]));
+		u_map = RTA_DATA(ida[IFLA_MAP - 1]);
+
+		k_map.mem_start = (unsigned long) u_map->mem_start;
+		k_map.mem_end = (unsigned long) u_map->mem_end;
+		k_map.base_addr = (unsigned short) u_map->base_addr;
+		k_map.irq = (unsigned char) u_map->irq;
+		k_map.dma = (unsigned char) u_map->dma;
+		k_map.port = (unsigned char) u_map->port;
+
+		err = dev->set_config(dev, &k_map);
 
 		if (err)
 			goto out;