fcntl: Cast commands with int args explicitly

According to the fcntl API specification commands that expect an
integer, hence not a pointer, always take an int and not long. In
order to avoid access to undefined bits, we should explicitly cast
the argument to int.

Cc: Alexander Viro <[e-mail]>
Cc: Christian Brauner <[e-mail]>
Cc: Jeff Layton <[e-mail]>
Cc: Chuck Lever <[e-mail]>
Cc: Kevin Brodsky <[e-mail]>
Cc: Vincenzo Frascino <[e-mail]>
Cc: Szabolcs Nagy <[e-mail]>
Cc: "Theodore Ts'o" <[e-mail]>
Cc: David Laight <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Luca Vizzarro <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Christian Brauner <[e-mail]>

fs/fcntl.c

···
 
 #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
 
-static int setfl(int fd, struct file * filp, unsigned long arg)
+static int setfl(int fd, struct file * filp, unsigned int arg)
 {
 	struct inode * inode = file_inode(filp);
 	int error = 0;
···
 }
 EXPORT_SYMBOL(__f_setown);
 
-int f_setown(struct file *filp, unsigned long arg, int force)
+int f_setown(struct file *filp, int who, int force)
 {
 	enum pid_type type;
 	struct pid *pid = NULL;
-	int who = arg, ret = 0;
+	int ret = 0;
 
 	type = PIDTYPE_TGID;
 	if (who < 0) {
···
 		struct file *filp)
 {
 	void __user *argp = (void __user *)arg;
+	int argi = (int)arg;
 	struct flock flock;
 	long err = -EINVAL;
 
 	switch (cmd) {
 	case F_DUPFD:
-		err = f_dupfd(arg, filp, 0);
+		err = f_dupfd(argi, filp, 0);
 		break;
 	case F_DUPFD_CLOEXEC:
-		err = f_dupfd(arg, filp, O_CLOEXEC);
+		err = f_dupfd(argi, filp, O_CLOEXEC);
 		break;
 	case F_GETFD:
 		err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
 		break;
 	case F_SETFD:
 		err = 0;
-		set_close_on_exec(fd, arg & FD_CLOEXEC);
+		set_close_on_exec(fd, argi & FD_CLOEXEC);
 		break;
 	case F_GETFL:
 		err = filp->f_flags;
 		break;
 	case F_SETFL:
-		err = setfl(fd, filp, arg);
+		err = setfl(fd, filp, argi);
 		break;
 #if BITS_PER_LONG != 32
 	/* 32-bit arches must use fcntl64() */
···
 		force_successful_syscall_return();
 		break;
 	case F_SETOWN:
-		err = f_setown(filp, arg, 1);
+		err = f_setown(filp, argi, 1);
 		break;
 	case F_GETOWN_EX:
 		err = f_getown_ex(filp, arg);
···
 		break;
 	case F_SETSIG:
 		/* arg == 0 restores default behaviour. */
-		if (!valid_signal(arg)) {
+		if (!valid_signal(argi)) {
 			break;
 		}
 		err = 0;
-		filp->f_owner.signum = arg;
+		filp->f_owner.signum = argi;
 		break;
 	case F_GETLEASE:
 		err = fcntl_getlease(filp);
 		break;
 	case F_SETLEASE:
-		err = fcntl_setlease(fd, filp, arg);
+		err = fcntl_setlease(fd, filp, argi);
 		break;
 	case F_NOTIFY:
-		err = fcntl_dirnotify(fd, filp, arg);
+		err = fcntl_dirnotify(fd, filp, argi);
 		break;
 	case F_SETPIPE_SZ:
 	case F_GETPIPE_SZ:
-		err = pipe_fcntl(filp, cmd, arg);
+		err = pipe_fcntl(filp, cmd, argi);
 		break;
 	case F_ADD_SEALS:
 	case F_GET_SEALS:
-		err = memfd_fcntl(filp, cmd, arg);
+		err = memfd_fcntl(filp, cmd, argi);
 		break;
 	case F_GET_RW_HINT:
 	case F_SET_RW_HINT:

include/linux/fs.h

···
 extern void kill_fasync(struct fasync_struct **, int, int);
 
 extern void __f_setown(struct file *filp, struct pid *, enum pid_type, int force);
-extern int f_setown(struct file *filp, unsigned long arg, int force);
+extern int f_setown(struct file *filp, int who, int force);
 extern void f_delown(struct file *filp);
 extern pid_t f_getown(struct file *filp);
 extern int send_sigurg(struct fown_struct *fown);