Re: [PATCH] fs: btrfs: fix possible memory leaks in btrfs_get_dev_args_from_path()

[Boris Burkov <boris@bur.io>]

On Mon, Aug 15, 2022 at 11:16:06PM +0800, Zixuan Fu wrote:
> In btrfs_get_dev_args_from_path(), btrfs_get_bdev_and_sb() can fail if the
> path is invalid. In this case, btrfs_get_dev_args_from_path() returns
> directly without freeing args->uuid and args->fsid allocated before, which
> causes memory leaks.
> 
> To fix these possible leaks, when btrfs_get_bdev_and_sb() fails, 
> btrfs_put_dev_args_from_path() is called to clean up the memory.
> 
> Fixes: faa775c41d655 ("btrfs: add a btrfs_get_dev_args_from_path helper")
> Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
> Signed-off-by: Zixuan Fu <r33s3n6@gmail.com>
Reviewed-by: Boris Burkov <boris@bur.io>
> ---
>  fs/btrfs/volumes.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 272901514b0c..064ab2a79c80 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -2345,8 +2345,11 @@ int btrfs_get_dev_args_from_path(struct btrfs_fs_info *fs_info,
>  
>  	ret = btrfs_get_bdev_and_sb(path, FMODE_READ, fs_info->bdev_holder, 0,
>  				    &bdev, &disk_super);
> -	if (ret)
> +	if (ret) {
> +		btrfs_put_dev_args_from_path(args);
>  		return ret;
> +	}
> +
>  	args->devid = btrfs_stack_device_id(&disk_super->dev_item);
>  	memcpy(args->uuid, disk_super->dev_item.uuid, BTRFS_UUID_SIZE);
>  	if (btrfs_fs_incompat(fs_info, METADATA_UUID))
> -- 
> 2.25.1
>