Merge tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull 'struct fd' class updates from Al Viro:
 "The bulk of struct fd memory safety stuff

  Making sure that struct fd instances are destroyed in the same scope
  where they'd been created, getting rid of reassignments and passing
  them by reference, converting to CLASS(fd{,_pos,_raw}).

  We are getting very close to having the memory safety of that stuff
  trivial to verify"

* tag 'pull-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits)
  deal with the last remaing boolean uses of fd_file()
  css_set_fork(): switch to CLASS(fd_raw, ...)
  memcg_write_event_control(): switch to CLASS(fd)
  assorted variants of irqfd setup: convert to CLASS(fd)
  do_pollfd(): convert to CLASS(fd)
  convert do_select()
  convert vfs_dedupe_file_range().
  convert cifs_ioctl_copychunk()
  convert media_request_get_by_fd()
  convert spu_run(2)
  switch spufs_calls_{get,put}() to CLASS() use
  convert cachestat(2)
  convert do_preadv()/do_pwritev()
  fdget(), more trivial conversions
  fdget(), trivial conversions
  privcmd_ioeventfd_assign(): don't open-code eventfd_ctx_fdget()
  o2hb_region_dev_store(): avoid goto around fdget()/fdput()
  introduce "fd_pos" class, convert fdget_pos() users to it.
  fdget_raw() users: switch to CLASS(fd_raw)
  convert vmsplice() to CLASS(fd)
  ...

3 files changed, 148 insertions, 174 deletions

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index e39479f1c9a4..b231b27d8268 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -694,20 +694,18 @@ EXPORT_SYMBOL_GPL(get_net_ns);
 
 struct net *get_net_ns_by_fd(int fd)
 {
-	struct fd f = fdget(fd);
-	struct net *net = ERR_PTR(-EINVAL);
+	CLASS(fd, f)(fd);
 
-	if (!fd_file(f))
+	if (fd_empty(f))
 		return ERR_PTR(-EBADF);
 
 	if (proc_ns_file(fd_file(f))) {
 		struct ns_common *ns = get_proc_ns(file_inode(fd_file(f)));
 		if (ns->ops == &netns_operations)
-			net = get_net(container_of(ns, struct net, ns));
+			return get_net(container_of(ns, struct net, ns));
 	}
-	fdput(f);
 
-	return net;
+	return ERR_PTR(-EINVAL);
 }
 EXPORT_SYMBOL_GPL(get_net_ns_by_fd);
 #endif
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index f84aad420d44..8953c4dc3f08 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1165,11 +1165,16 @@ static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
 	return sock;
 }
 
-struct sock *netlink_getsockbyfilp(struct file *filp)
+struct sock *netlink_getsockbyfd(int fd)
 {
-	struct inode *inode = file_inode(filp);
+	CLASS(fd, f)(fd);
+	struct inode *inode;
 	struct sock *sock;
 
+	if (fd_empty(f))
+		return ERR_PTR(-EBADF);
+
+	inode = file_inode(fd_file(f));
 	if (!S_ISSOCK(inode->i_mode))
 		return ERR_PTR(-ENOTSOCK);
 
diff --git a/net/socket.c b/net/socket.c
index 042451f01c65..87a573a704c5 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -509,7 +509,7 @@ static int sock_map_fd(struct socket *sock, int flags)
 
 struct socket *sock_from_file(struct file *file)
 {
-	if (file->f_op == &socket_file_ops)
+	if (likely(file->f_op == &socket_file_ops))
 		return file->private_data;	/* set in sock_alloc_file */
 
 	return NULL;
@@ -549,24 +549,6 @@ struct socket *sockfd_lookup(int fd, int *err)
 }
 EXPORT_SYMBOL(sockfd_lookup);
 
-static struct socket *sockfd_lookup_light(int fd, int *err, int *fput_needed)
-{
-	struct fd f = fdget(fd);
-	struct socket *sock;
-
-	*err = -EBADF;
-	if (fd_file(f)) {
-		sock = sock_from_file(fd_file(f));
-		if (likely(sock)) {
-			*fput_needed = f.word & FDPUT_FPUT;
-			return sock;
-		}
-		*err = -ENOTSOCK;
-		fdput(f);
-	}
-	return NULL;
-}
-
 static ssize_t sockfs_listxattr(struct dentry *dentry, char *buffer,
 				size_t size)
 {
@@ -1858,16 +1840,20 @@ int __sys_bind(int fd, struct sockaddr __user *umyaddr, int addrlen)
 {
 	struct socket *sock;
 	struct sockaddr_storage address;
-	int err, fput_needed;
-
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (sock) {
-		err = move_addr_to_kernel(umyaddr, addrlen, &address);
-		if (!err)
-			err = __sys_bind_socket(sock, &address, addrlen);
-		fput_light(sock->file, fput_needed);
-	}
-	return err;
+	CLASS(fd, f)(fd);
+	int err;
+
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	err = move_addr_to_kernel(umyaddr, addrlen, &address);
+	if (unlikely(err))
+		return err;
+
+	return __sys_bind_socket(sock, &address, addrlen);
 }
 
 SYSCALL_DEFINE3(bind, int, fd, struct sockaddr __user *, umyaddr, int, addrlen)
@@ -1896,15 +1882,16 @@ int __sys_listen_socket(struct socket *sock, int backlog)
 
 int __sys_listen(int fd, int backlog)
 {
+	CLASS(fd, f)(fd);
 	struct socket *sock;
-	int err, fput_needed;
 
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (sock) {
-		err = __sys_listen_socket(sock, backlog);
-		fput_light(sock->file, fput_needed);
-	}
-	return err;
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	return __sys_listen_socket(sock, backlog);
 }
 
 SYSCALL_DEFINE2(listen, int, fd, int, backlog)
@@ -2014,17 +2001,12 @@ static int __sys_accept4_file(struct file *file, struct sockaddr __user *upeer_s
 int __sys_accept4(int fd, struct sockaddr __user *upeer_sockaddr,
 		  int __user *upeer_addrlen, int flags)
 {
-	int ret = -EBADF;
-	struct fd f;
+	CLASS(fd, f)(fd);
 
-	f = fdget(fd);
-	if (fd_file(f)) {
-		ret = __sys_accept4_file(fd_file(f), upeer_sockaddr,
+	if (fd_empty(f))
+		return -EBADF;
+	return __sys_accept4_file(fd_file(f), upeer_sockaddr,
 					 upeer_addrlen, flags);
-		fdput(f);
-	}
-
-	return ret;
 }
 
 SYSCALL_DEFINE4(accept4, int, fd, struct sockaddr __user *, upeer_sockaddr,
@@ -2076,20 +2058,18 @@ out:
 
 int __sys_connect(int fd, struct sockaddr __user *uservaddr, int addrlen)
 {
-	int ret = -EBADF;
-	struct fd f;
+	struct sockaddr_storage address;
+	CLASS(fd, f)(fd);
+	int ret;
 
-	f = fdget(fd);
-	if (fd_file(f)) {
-		struct sockaddr_storage address;
+	if (fd_empty(f))
+		return -EBADF;
 
-		ret = move_addr_to_kernel(uservaddr, addrlen, &address);
-		if (!ret)
-			ret = __sys_connect_file(fd_file(f), &address, addrlen, 0);
-		fdput(f);
-	}
+	ret = move_addr_to_kernel(uservaddr, addrlen, &address);
+	if (ret)
+		return ret;
 
-	return ret;
+	return __sys_connect_file(fd_file(f), &address, addrlen, 0);
 }
 
 SYSCALL_DEFINE3(connect, int, fd, struct sockaddr __user *, uservaddr,
@@ -2108,26 +2088,25 @@ int __sys_getsockname(int fd, struct sockaddr __user *usockaddr,
 {
 	struct socket *sock;
 	struct sockaddr_storage address;
-	int err, fput_needed;
+	CLASS(fd, f)(fd);
+	int err;
 
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (!sock)
-		goto out;
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
 
 	err = security_socket_getsockname(sock);
 	if (err)
-		goto out_put;
+		return err;
 
 	err = READ_ONCE(sock->ops)->getname(sock, (struct sockaddr *)&address, 0);
 	if (err < 0)
-		goto out_put;
-	/* "err" is actually length in this case */
-	err = move_addr_to_user(&address, err, usockaddr, usockaddr_len);
+		return err;
 
-out_put:
-	fput_light(sock->file, fput_needed);
-out:
-	return err;
+	/* "err" is actually length in this case */
+	return move_addr_to_user(&address, err, usockaddr, usockaddr_len);
 }
 
 SYSCALL_DEFINE3(getsockname, int, fd, struct sockaddr __user *, usockaddr,
@@ -2146,26 +2125,25 @@ int __sys_getpeername(int fd, struct sockaddr __user *usockaddr,
 {
 	struct socket *sock;
 	struct sockaddr_storage address;
-	int err, fput_needed;
+	CLASS(fd, f)(fd);
+	int err;
 
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (sock != NULL) {
-		const struct proto_ops *ops = READ_ONCE(sock->ops);
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
 
-		err = security_socket_getpeername(sock);
-		if (err) {
-			fput_light(sock->file, fput_needed);
-			return err;
-		}
+	err = security_socket_getpeername(sock);
+	if (err)
+		return err;
 
-		err = ops->getname(sock, (struct sockaddr *)&address, 1);
-		if (err >= 0)
-			/* "err" is actually length in this case */
-			err = move_addr_to_user(&address, err, usockaddr,
-						usockaddr_len);
-		fput_light(sock->file, fput_needed);
-	}
-	return err;
+	err = READ_ONCE(sock->ops)->getname(sock, (struct sockaddr *)&address, 1);
+	if (err < 0)
+		return err;
+
+	/* "err" is actually length in this case */
+	return move_addr_to_user(&address, err, usockaddr, usockaddr_len);
 }
 
 SYSCALL_DEFINE3(getpeername, int, fd, struct sockaddr __user *, usockaddr,
@@ -2186,14 +2164,17 @@ int __sys_sendto(int fd, void __user *buff, size_t len, unsigned int flags,
 	struct sockaddr_storage address;
 	int err;
 	struct msghdr msg;
-	int fput_needed;
 
 	err = import_ubuf(ITER_SOURCE, buff, len, &msg.msg_iter);
 	if (unlikely(err))
 		return err;
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (!sock)
-		goto out;
+
+	CLASS(fd, f)(fd);
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
 
 	msg.msg_name = NULL;
 	msg.msg_control = NULL;
@@ -2203,7 +2184,7 @@ int __sys_sendto(int fd, void __user *buff, size_t len, unsigned int flags,
 	if (addr) {
 		err = move_addr_to_kernel(addr, addr_len, &address);
 		if (err < 0)
-			goto out_put;
+			return err;
 		msg.msg_name = (struct sockaddr *)&address;
 		msg.msg_namelen = addr_len;
 	}
@@ -2211,12 +2192,7 @@ int __sys_sendto(int fd, void __user *buff, size_t len, unsigned int flags,
 	if (sock->file->f_flags & O_NONBLOCK)
 		flags |= MSG_DONTWAIT;
 	msg.msg_flags = flags;
-	err = __sock_sendmsg(sock, &msg);
-
-out_put:
-	fput_light(sock->file, fput_needed);
-out:
-	return err;
+	return __sock_sendmsg(sock, &msg);
 }
 
 SYSCALL_DEFINE6(sendto, int, fd, void __user *, buff, size_t, len,
@@ -2251,14 +2227,18 @@ int __sys_recvfrom(int fd, void __user *ubuf, size_t size, unsigned int flags,
 	};
 	struct socket *sock;
 	int err, err2;
-	int fput_needed;
 
 	err = import_ubuf(ITER_DEST, ubuf, size, &msg.msg_iter);
 	if (unlikely(err))
 		return err;
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (!sock)
-		goto out;
+
+	CLASS(fd, f)(fd);
+
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
 
 	if (sock->file->f_flags & O_NONBLOCK)
 		flags |= MSG_DONTWAIT;
@@ -2270,9 +2250,6 @@ int __sys_recvfrom(int fd, void __user *ubuf, size_t size, unsigned int flags,
 		if (err2 < 0)
 			err = err2;
 	}
-
-	fput_light(sock->file, fput_needed);
-out:
 	return err;
 }
 
@@ -2347,17 +2324,16 @@ int __sys_setsockopt(int fd, int level, int optname, char __user *user_optval,
 {
 	sockptr_t optval = USER_SOCKPTR(user_optval);
 	bool compat = in_compat_syscall();
-	int err, fput_needed;
 	struct socket *sock;
+	CLASS(fd, f)(fd);
 
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (!sock)
-		return err;
-
-	err = do_sock_setsockopt(sock, compat, level, optname, optval, optlen);
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
 
-	fput_light(sock->file, fput_needed);
-	return err;
+	return do_sock_setsockopt(sock, compat, level, optname, optval, optlen);
 }
 
 SYSCALL_DEFINE5(setsockopt, int, fd, int, level, int, optname,
@@ -2413,20 +2389,17 @@ EXPORT_SYMBOL(do_sock_getsockopt);
 int __sys_getsockopt(int fd, int level, int optname, char __user *optval,
 		int __user *optlen)
 {
-	int err, fput_needed;
 	struct socket *sock;
-	bool compat;
+	CLASS(fd, f)(fd);
 
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (!sock)
-		return err;
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
 
-	compat = in_compat_syscall();
-	err = do_sock_getsockopt(sock, compat, level, optname,
+	return do_sock_getsockopt(sock, in_compat_syscall(), level, optname,
 				 USER_SOCKPTR(optval), USER_SOCKPTR(optlen));
-
-	fput_light(sock->file, fput_needed);
-	return err;
 }
 
 SYSCALL_DEFINE5(getsockopt, int, fd, int, level, int, optname,
@@ -2452,15 +2425,16 @@ int __sys_shutdown_sock(struct socket *sock, int how)
 
 int __sys_shutdown(int fd, int how)
 {
-	int err, fput_needed;
 	struct socket *sock;
+	CLASS(fd, f)(fd);
 
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (sock != NULL) {
-		err = __sys_shutdown_sock(sock, how);
-		fput_light(sock->file, fput_needed);
-	}
-	return err;
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	return __sys_shutdown_sock(sock, how);
 }
 
 SYSCALL_DEFINE2(shutdown, int, fd, int, how)
@@ -2676,22 +2650,21 @@ long __sys_sendmsg_sock(struct socket *sock, struct msghdr *msg,
 long __sys_sendmsg(int fd, struct user_msghdr __user *msg, unsigned int flags,
 		   bool forbid_cmsg_compat)
 {
-	int fput_needed, err;
 	struct msghdr msg_sys;
 	struct socket *sock;
 
 	if (forbid_cmsg_compat && (flags & MSG_CMSG_COMPAT))
 		return -EINVAL;
 
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (!sock)
-		goto out;
+	CLASS(fd, f)(fd);
 
-	err = ___sys_sendmsg(sock, msg, &msg_sys, flags, NULL, 0);
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
 
-	fput_light(sock->file, fput_needed);
-out:
-	return err;
+	return ___sys_sendmsg(sock, msg, &msg_sys, flags, NULL, 0);
 }
 
 SYSCALL_DEFINE3(sendmsg, int, fd, struct user_msghdr __user *, msg, unsigned int, flags)
@@ -2706,7 +2679,7 @@ SYSCALL_DEFINE3(sendmsg, int, fd, struct user_msghdr __user *, msg, unsigned int
 int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen,
 		   unsigned int flags, bool forbid_cmsg_compat)
 {
-	int fput_needed, err, datagrams;
+	int err, datagrams;
 	struct socket *sock;
 	struct mmsghdr __user *entry;
 	struct compat_mmsghdr __user *compat_entry;
@@ -2722,9 +2695,13 @@ int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen,
 
 	datagrams = 0;
 
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (!sock)
-		return err;
+	CLASS(fd, f)(fd);
+
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
 
 	used_address.name_len = UINT_MAX;
 	entry = mmsg;
@@ -2761,8 +2738,6 @@ int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen,
 		cond_resched();
 	}
 
-	fput_light(sock->file, fput_needed);
-
 	/* We only return an error if no datagrams were able to be sent */
 	if (datagrams != 0)
 		return datagrams;
@@ -2884,22 +2859,21 @@ long __sys_recvmsg_sock(struct socket *sock, struct msghdr *msg,
 long __sys_recvmsg(int fd, struct user_msghdr __user *msg, unsigned int flags,
 		   bool forbid_cmsg_compat)
 {
-	int fput_needed, err;
 	struct msghdr msg_sys;
 	struct socket *sock;
 
 	if (forbid_cmsg_compat && (flags & MSG_CMSG_COMPAT))
 		return -EINVAL;
 
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (!sock)
-		goto out;
+	CLASS(fd, f)(fd);
 
-	err = ___sys_recvmsg(sock, msg, &msg_sys, flags, 0);
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
 
-	fput_light(sock->file, fput_needed);
-out:
-	return err;
+	return ___sys_recvmsg(sock, msg, &msg_sys, flags, 0);
 }
 
 SYSCALL_DEFINE3(recvmsg, int, fd, struct user_msghdr __user *, msg,
@@ -2916,7 +2890,7 @@ static int do_recvmmsg(int fd, struct mmsghdr __user *mmsg,
 			  unsigned int vlen, unsigned int flags,
 			  struct timespec64 *timeout)
 {
-	int fput_needed, err, datagrams;
+	int err = 0, datagrams;
 	struct socket *sock;
 	struct mmsghdr __user *entry;
 	struct compat_mmsghdr __user *compat_entry;
@@ -2931,16 +2905,18 @@ static int do_recvmmsg(int fd, struct mmsghdr __user *mmsg,
 
 	datagrams = 0;
 
-	sock = sockfd_lookup_light(fd, &err, &fput_needed);
-	if (!sock)
-		return err;
+	CLASS(fd, f)(fd);
+
+	if (fd_empty(f))
+		return -EBADF;
+	sock = sock_from_file(fd_file(f));
+	if (unlikely(!sock))
+		return -ENOTSOCK;
 
 	if (likely(!(flags & MSG_ERRQUEUE))) {
 		err = sock_error(sock->sk);
-		if (err) {
-			datagrams = err;
-			goto out_put;
-		}
+		if (err)
+			return err;
 	}
 
 	entry = mmsg;
@@ -2997,12 +2973,10 @@ static int do_recvmmsg(int fd, struct mmsghdr __user *mmsg,
 	}
 
 	if (err == 0)
-		goto out_put;
+		return datagrams;
 
-	if (datagrams == 0) {
-		datagrams = err;
-		goto out_put;
-	}
+	if (datagrams == 0)
+		return err;
 
 	/*
 	 * We may return less entries than requested (vlen) if the
@@ -3017,9 +2991,6 @@ static int do_recvmmsg(int fd, struct mmsghdr __user *mmsg,
 		 */
 		WRITE_ONCE(sock->sk->sk_err, -err);
 	}
-out_put:
-	fput_light(sock->file, fput_needed);
-
 	return datagrams;
 }