socket: Split out a getsockname helper for io_uring

Similar to getsockopt, split out a helper to check security and issue
the operation from the main handler that can be used by io_uring.

Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: krisman

include/linux/socket.h

@@ -453,6 +453,8 @@ extern int __sys_connect(int fd, struct sockaddr __user *uservaddr,
 			 int addrlen);
 extern int __sys_listen(int fd, int backlog);
 extern int __sys_listen_socket(struct socket *sock, int backlog);
+extern int do_getsockname(struct socket *sock, int peer,
+			  struct sockaddr __user *usockaddr, int __user *usockaddr_len);
 extern int __sys_getsockname(int fd, struct sockaddr __user *usockaddr,
 			     int __user *usockaddr_len, int peer);
 extern int __sys_socketpair(int family, int type, int protocol,

net/socket.c

@@ -2127,39 +2127,43 @@ SYSCALL_DEFINE3(connect, int, fd, struct sockaddr __user *, uservaddr,
 	return __sys_connect(fd, uservaddr, addrlen);
 }
 
-/*
- *	Get the remote or local address ('name') of a socket object. Move the
- *	obtained name to user space.
- */
-int __sys_getsockname(int fd, struct sockaddr __user *usockaddr,
-		      int __user *usockaddr_len, int peer)
+int do_getsockname(struct socket *sock, int peer,
+		   struct sockaddr __user *usockaddr, int __user *usockaddr_len)
 {
-	struct socket *sock;
 	struct sockaddr_storage address;
-	CLASS(fd, f)(fd);
 	int err;
 
-	if (fd_empty(f))
-		return -EBADF;
-	sock = sock_from_file(fd_file(f));
-	if (unlikely(!sock))
-		return -ENOTSOCK;
-
 	if (peer)
 		err = security_socket_getpeername(sock);
 	else
 		err = security_socket_getsockname(sock);
 	if (err)
 		return err;
-
 	err = READ_ONCE(sock->ops)->getname(sock, (struct sockaddr *)&address, peer);
 	if (err < 0)
 		return err;
-
 	/* "err" is actually length in this case */
 	return move_addr_to_user(&address, err, usockaddr, usockaddr_len);
 }
 
+/*
+ *	Get the remote or local address ('name') of a socket object. Move the
+ *	obtained name to user space.
+ */
+int __sys_getsockname(int fd, struct sockaddr __user *usockaddr,
+		      int __user *usockaddr_len, int peer)
+{
+	struct socket *sock;
+	CLASS(fd, f)(fd);
+
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+	return do_getsockname(sock, peer, usockaddr, usockaddr_len);
+}
+
 SYSCALL_DEFINE3(getsockname, int, fd, struct sockaddr __user *, usockaddr,
 		int __user *, usockaddr_len)
 {