Re: [patch] btrfs: array overflow in btrfs_ioctl_rm_dev_v2()

[Anand Jain <anand.jain@oracle.com>]

Thanks Dan.
  Chris pointed out as well. We are working on it..
  Just one concern when device is added the max device length is
  BTRFS_PATH_NAME_MAX. However below fix is proper from the vol_args
  perspective.

Thanks,  Anand


On 02/18/2016 01:01 PM, Dan Carpenter wrote:
> We were putting the NUL terminator at BTRFS_PATH_NAME_MAX (4087) bytes
> instead of BTRFS_SUBVOL_NAME_MAX (4039) so it corrupted memory.
>
> Fixes: 22af1a869288 ('btrfs: introduce device delete by devid')
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 5224fc8..77c61b4 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -2700,7 +2700,7 @@ static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
>   	if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID) {
>   		ret = btrfs_rm_device(root, NULL, vol_args->devid);
>   	} else {
> -		vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
> +		vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
>   		ret = btrfs_rm_device(root, vol_args->name, 0);
>   	}
>   	mutex_unlock(&root->fs_info->volume_mutex);
> --
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