net,socket: introduce DECLARE_SOCKADDR helper to catch overflow at build time
proto_ops->getname implies copying protocol specific data
into storage unit (particulary to __kernel_sockaddr_storage).
So when we implement new protocol support we should keep such
a detail in mind (which is easy to forget about).
Lets introduce DECLARE_SOCKADDR helper which check if
storage unit is not overfowed at build time.
Eventually inet_getname is switched to use DECLARE_SOCKADDR
(to show example of usage).
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/net.h b/include/linux/net.h
index b42bb60..4da9d57 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -199,6 +199,9 @@
struct pipe_inode_info *pipe, size_t len, unsigned int flags);
};
+#define DECLARE_SOCKADDR(type, dst, src) \
+ type dst = ({ __sockaddr_check_size(sizeof(*dst)); (type) src; })
+
struct net_proto_family {
int family;
int (*create)(struct net *net, struct socket *sock, int protocol);
diff --git a/include/linux/socket.h b/include/linux/socket.h
index 59966f1..7b3aae2 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -24,6 +24,9 @@
#include <linux/types.h> /* pid_t */
#include <linux/compiler.h> /* __user */
+#define __sockaddr_check_size(size) \
+ BUILD_BUG_ON(((size) > sizeof(struct __kernel_sockaddr_storage)))
+
#ifdef __KERNEL__
# ifdef CONFIG_PROC_FS
struct seq_file;
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 04a14b1..538e84d 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -685,7 +685,7 @@
{
struct sock *sk = sock->sk;
struct inet_sock *inet = inet_sk(sk);
- struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
+ DECLARE_SOCKADDR(struct sockaddr_in *, sin, uaddr);
sin->sin_family = AF_INET;
if (peer) {