btrfs: defrag: reject unknown flags of btrfs_ioctl_defrag_range_args

commit 173431b274a9a54fc10b273b46e67f46bcf62d2e upstream.

Add extra sanity check for btrfs_ioctl_defrag_range_args::flags.

This is not really to enhance fuzzing tests, but as a preparation for
future expansion on btrfs_ioctl_defrag_range_args.

In the future we're going to add new members, allowing more fine tuning
for btrfs defrag.  Without the -ENONOTSUPP error, there would be no way
to detect if the kernel supports those new defrag features.

CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index e611b3a..2643835 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2608,6 +2608,10 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
                                ret = -EFAULT;
                                goto out;
                        }
+                       if (range.flags & ~BTRFS_DEFRAG_RANGE_FLAGS_SUPP) {
+                               ret = -EOPNOTSUPP;
+                               goto out;
+                       }
                        /* compression requires us to start the IO */
                        if ((range.flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
                                range.flags |= BTRFS_DEFRAG_RANGE_START_IO;

diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index dbb8b96..6f776fa 100644 (file)
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -612,6 +612,9 @@ struct btrfs_ioctl_clone_range_args {
  */
 #define BTRFS_DEFRAG_RANGE_COMPRESS 1
 #define BTRFS_DEFRAG_RANGE_START_IO 2
+#define BTRFS_DEFRAG_RANGE_FLAGS_SUPP  (BTRFS_DEFRAG_RANGE_COMPRESS |          \
+                                        BTRFS_DEFRAG_RANGE_START_IO)
+
 struct btrfs_ioctl_defrag_range_args {
        /* start of the defrag operation */
        __u64 start;