net: use common macro for assering skb->cb[] available size in protocol families

As part of an effort to move skb->dropcount to skb->cb[] use a common
macro in protocol families using skb->cb[] for ancillary data to
validate available room in skb->cb[].

Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

9 files changed, 13 insertions, 14 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index ab186b1d31ff..a2502d248641 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2078,6 +2078,9 @@ static inline int sock_intr_errno(long timeo)
         return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
 }
 
+#define sock_skb_cb_check_size(size) \
+        BUILD_BUG_ON((size) > FIELD_SIZEOF(struct sk_buff, cb))
+
 void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
                            struct sk_buff *skb);
 void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index ce22e0cfa923..4b904c97a068 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -711,10 +711,9 @@ EXPORT_SYMBOL_GPL(bt_debugfs);
 
 static int __init bt_init(void)
 {
-        struct sk_buff *skb;
         int err;
 
-        BUILD_BUG_ON(sizeof(struct bt_skb_cb) > sizeof(skb->cb));
+        sock_skb_cb_check_size(sizeof(struct bt_skb_cb));
 
         BT_INFO("Core ver %s", VERSION);
 
diff --git a/net/can/bcm.c b/net/can/bcm.c
index ee9ffd956552..d559f922326d 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -328,7 +328,7 @@ static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
          *  containing the interface index.
          */
 
-        BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
+        sock_skb_cb_check_size(sizeof(struct sockaddr_can));
         addr = (struct sockaddr_can *)skb->cb;
         memset(addr, 0, sizeof(*addr));
         addr->can_family  = AF_CAN;
diff --git a/net/can/raw.c b/net/can/raw.c
index 00c13ef23661..94601b7ff0a3 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -95,8 +95,8 @@ struct raw_sock {
  */
 static inline unsigned int *raw_flags(struct sk_buff *skb)
 {
-        BUILD_BUG_ON(sizeof(skb->cb) <= (sizeof(struct sockaddr_can) +
-                                         sizeof(unsigned int)));
+        sock_skb_cb_check_size(sizeof(struct sockaddr_can) +
+                               sizeof(unsigned int));
 
         /* return pointer after struct sockaddr_can */
         return (unsigned int *)(&((struct sockaddr_can *)skb->cb)[1]);
@@ -135,7 +135,7 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
          *  containing the interface index.
          */
 
-        BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
+        sock_skb_cb_check_size(sizeof(struct sockaddr_can));
         addr = (struct sockaddr_can *)skb->cb;
         memset(addr, 0, sizeof(*addr));
         addr->can_family  = AF_CAN;
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index d2e49baaff63..4ce954cc94a4 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1675,7 +1675,7 @@ static int __init inet_init(void)
         struct list_head *r;
         int rc = -EINVAL;
 
-        BUILD_BUG_ON(sizeof(struct inet_skb_parm) > FIELD_SIZEOF(struct sk_buff, cb));
+        sock_skb_cb_check_size(sizeof(struct inet_skb_parm));
 
         rc = proto_register(&tcp_prot, 1);
         if (rc)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 9d72a0fcd928..4b57ea8dabc7 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3005,12 +3005,11 @@ static void __init tcp_init_mem(void)
 
 void __init tcp_init(void)
 {
-        struct sk_buff *skb = NULL;
         unsigned long limit;
         int max_rshare, max_wshare, cnt;
         unsigned int i;
 
-        BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb));
+        sock_skb_cb_check_size(sizeof(struct tcp_skb_cb));
 
         percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
         percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index e8c4400f23e9..6bafcc2c79e3 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -824,7 +824,7 @@ static int __init inet6_init(void)
         struct list_head *r;
         int err = 0;
 
-        BUILD_BUG_ON(sizeof(struct inet6_skb_parm) > FIELD_SIZEOF(struct sk_buff, cb));
+        sock_skb_cb_check_size(sizeof(struct inet6_skb_parm));
 
         /* Register the socket-side information for inet6_create.  */
         for (r = &inetsw6[0]; r < &inetsw6[SOCK_MAX]; ++r)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 7eea30b9c8e5..9cdb414cd231 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1816,8 +1816,7 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
                 skb = nskb;
         }
 
-        BUILD_BUG_ON(sizeof(*PACKET_SKB_CB(skb)) + MAX_ADDR_LEN - 8 >
-                     sizeof(skb->cb));
+        sock_skb_cb_check_size(sizeof(*PACKET_SKB_CB(skb)) + MAX_ADDR_LEN - 8);
 
         sll = &PACKET_SKB_CB(skb)->sa.ll;
         sll->sll_hatype = dev->type;
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 8f34b27d5775..53b7acde9aa3 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1322,8 +1322,7 @@ static __init int sctp_init(void)
         int max_share;
         int order;
 
-        BUILD_BUG_ON(sizeof(struct sctp_ulpevent) >
-                     sizeof(((struct sk_buff *) 0)->cb));
+        sock_skb_cb_check_size(sizeof(struct sctp_ulpevent));
 
         /* Allocate bind_bucket and chunk caches. */
         status = -ENOBUFS;