Btrfs: NUL-terminate path buffer in DEV_INFO ioctl result

A device with name of length BTRFS_DEVICE_PATH_NAME_MAX or longer
would not be NUL-terminated in the DEV_INFO ioctl result buffer.

Signed-off-by: Jim Meyering <meyering@redhat.com>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 9ebb2c7..3d8ab27 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2263,10 +2263,12 @@ static long btrfs_ioctl_dev_info(struct btrfs_root *root, void __user *arg)
        di_args->bytes_used = dev->bytes_used;
        di_args->total_bytes = dev->total_bytes;
        memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
-       if (dev->name)
+       if (dev->name) {
                strncpy(di_args->path, dev->name, sizeof(di_args->path));
-       else
+               di_args->path[sizeof(di_args->path) - 1] = 0;
+       } else {
                di_args->path[0] = '\0';
+       }
 
 out:
        if (ret == 0 && copy_to_user(arg, di_args, sizeof(*di_args)))