splice/tee/vmsplice: validate flags

Long overdue...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/splice.c

@@ -1351,6 +1351,8 @@ SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, iov,
 	struct fd f;
 	long error;
 
+	if (unlikely(flags & ~SPLICE_F_ALL))
+		return -EINVAL;
 	if (unlikely(nr_segs > UIO_MAXIOV))
 		return -EINVAL;
 	else if (unlikely(!nr_segs))
@@ -1401,6 +1403,9 @@ SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in,
 	if (unlikely(!len))
 		return 0;
 
+	if (unlikely(flags & ~SPLICE_F_ALL))
+		return -EINVAL;
+
 	error = -EBADF;
 	in = fdget(fd_in);
 	if (in.file) {
@@ -1729,6 +1734,9 @@ SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags)
 	struct fd in;
 	int error;
 
+	if (unlikely(flags & ~SPLICE_F_ALL))
+		return -EINVAL;
+
 	if (unlikely(!len))
 		return 0;
 

include/linux/splice.h

@@ -20,6 +20,8 @@
 #define SPLICE_F_MORE	(0x04)	/* expect more data */
 #define SPLICE_F_GIFT	(0x08)	/* pages passed in are a gift */
 
+#define SPLICE_F_ALL (SPLICE_F_MOVE|SPLICE_F_NONBLOCK|SPLICE_F_MORE|SPLICE_F_GIFT)
+
 /*
  * Passed to the actors
  */