net: Make accesses to ->br_port safe for sparse RCU

The new versions of the rcu_dereference() APIs requires that any pointers
passed to one of these APIs be fully defined.  The ->br_port field
in struct net_device points to a struct net_bridge_port, which is an
incomplete type.  This commit therefore changes ->br_port to be a void*,
and introduces a br_port() helper function to convert the type to struct
net_bridge_port, and applies this new helper function where required.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: David Miller <davem@davemloft.net>
Cc: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>

diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index 938b7e8..d001d78 100644 (file)
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -101,6 +101,9 @@ struct __fdb_entry {
 
 #include <linux/netdevice.h>
 
+/* br_handle_frame_hook() needs the following forward declaration. */
+struct net_bridge_port;
+
 extern void brioctl_set(int (*ioctl_hook)(struct net *, unsigned int, void __user *));
 extern struct sk_buff *(*br_handle_frame_hook)(struct net_bridge_port *p,
                                               struct sk_buff *skb);

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 2663743..845710b 100644 (file)
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -246,7 +246,7 @@ int br_fdb_test_addr(struct net_device *dev, unsigned char *addr)
                return 0;
 
        rcu_read_lock();
-       fdb = __br_fdb_get(dev->br_port->br, addr);
+       fdb = __br_fdb_get(br_port(dev)->br, addr);
        ret = fdb && fdb->dst->dev != dev &&
                fdb->dst->state == BR_STATE_FORWARDING;
        rcu_read_unlock();

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 0f4a74b..3255188 100644 (file)
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -268,6 +268,11 @@ static inline int br_is_root_bridge(const struct net_bridge *br)
        return !memcmp(&br->bridge_id, &br->designated_root, 8);
 }
 
+static inline struct net_bridge_port *br_port(const struct net_device *dev)
+{
+       return rcu_dereference(dev->br_port);
+}
+
 /* br_device.c */
 extern void br_dev_setup(struct net_device *dev);
 extern netdev_tx_t br_dev_xmit(struct sk_buff *skb,

diff --git a/net/bridge/netfilter/ebt_redirect.c b/net/bridge/netfilter/ebt_redirect.c
index 9e19166..a39df0a 100644 (file)
--- a/net/bridge/netfilter/ebt_redirect.c
+++ b/net/bridge/netfilter/ebt_redirect.c
@@ -25,7 +25,7 @@ ebt_redirect_tg(struct sk_buff *skb, const struct xt_action_param *par)
 
        if (par->hooknum != NF_BR_BROUTING)
                memcpy(eth_hdr(skb)->h_dest,
-                      par->in->br_port->br->dev->dev_addr, ETH_ALEN);
+                      br_port(par->in)->br->dev->dev_addr, ETH_ALEN);
        else
                memcpy(eth_hdr(skb)->h_dest, par->in->dev_addr, ETH_ALEN);
        skb->pkt_type = PACKET_HOST;

diff --git a/net/bridge/netfilter/ebt_ulog.c b/net/bridge/netfilter/ebt_ulog.c
index ae3c7ce..5a4996b 100644 (file)
--- a/net/bridge/netfilter/ebt_ulog.c
+++ b/net/bridge/netfilter/ebt_ulog.c
@@ -178,7 +178,7 @@ static void ebt_ulog_packet(unsigned int hooknr, const struct sk_buff *skb,
                strcpy(pm->physindev, in->name);
                /* If in isn't a bridge, then physindev==indev */
                if (in->br_port)
-                       strcpy(pm->indev, in->br_port->br->dev->name);
+                       strcpy(pm->indev, br_port(in)->br->dev->name);
                else
                        strcpy(pm->indev, in->name);
        } else
@@ -187,7 +187,7 @@ static void ebt_ulog_packet(unsigned int hooknr, const struct sk_buff *skb,
        if (out) {
                /* If out exists, then out is a bridge port */
                strcpy(pm->physoutdev, out->name);
-               strcpy(pm->outdev, out->br_port->br->dev->name);
+               strcpy(pm->outdev, br_port(out)->br->dev->name);
        } else
                pm->outdev[0] = pm->physoutdev[0] = '\0';
 

diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 59ca00e..4c2aab8 100644 (file)
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -141,10 +141,10 @@ ebt_basic_match(const struct ebt_entry *e, const struct ethhdr *h,
        if (FWINV2(ebt_dev_check(e->out, out), EBT_IOUT))
                return 1;
        if ((!in || !in->br_port) ? 0 : FWINV2(ebt_dev_check(
-          e->logical_in, in->br_port->br->dev), EBT_ILOGICALIN))
+          e->logical_in, br_port(in)->br->dev), EBT_ILOGICALIN))
                return 1;
        if ((!out || !out->br_port) ? 0 : FWINV2(ebt_dev_check(
-          e->logical_out, out->br_port->br->dev), EBT_ILOGICALOUT))
+          e->logical_out, br_port(out)->br->dev), EBT_ILOGICALOUT))
                return 1;
 
        if (e->bitmask & EBT_SOURCEMAC) {

diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index fc9a211..78957cf 100644 (file)
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -404,7 +404,7 @@ __build_packet_message(struct nfulnl_instance *inst,
                                     htonl(indev->ifindex));
                        /* this is the bridge group "brX" */
                        NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_INDEV,
-                                    htonl(indev->br_port->br->dev->ifindex));
+                                    htonl(br_port(indev)->br->dev->ifindex));
                } else {
                        /* Case 2: indev is bridge group, we need to look for
                         * physical device (when called from ipv4) */
@@ -431,7 +431,7 @@ __build_packet_message(struct nfulnl_instance *inst,
                                     htonl(outdev->ifindex));
                        /* this is the bridge group "brX" */
                        NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_OUTDEV,
-                                    htonl(outdev->br_port->br->dev->ifindex));
+                                    htonl(br_port(outdev)->br->dev->ifindex));
                } else {
                        /* Case 2: indev is a bridge group, we need to look
                         * for physical device (when called from ipv4) */

diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 12e1ab3..c3c1749 100644 (file)
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -297,7 +297,7 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue,
                                     htonl(indev->ifindex));
                        /* this is the bridge group "brX" */
                        NLA_PUT_BE32(skb, NFQA_IFINDEX_INDEV,
-                                    htonl(indev->br_port->br->dev->ifindex));
+                                    htonl(br_port(indev)->br->dev->ifindex));
                } else {
                        /* Case 2: indev is bridge group, we need to look for
                         * physical device (when called from ipv4) */
@@ -322,7 +322,7 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue,
                                     htonl(outdev->ifindex));
                        /* this is the bridge group "brX" */
                        NLA_PUT_BE32(skb, NFQA_IFINDEX_OUTDEV,
-                                    htonl(outdev->br_port->br->dev->ifindex));
+                                    htonl(br_port(outdev)->br->dev->ifindex));
                } else {
                        /* Case 2: outdev is bridge group, we need to look for
                         * physical output device (when called from ipv4) */