Re: [RFC PATCH] list-objects-filter: disable 'sparse:path' filters

[Jeff Hostetler <git@jeffhostetler.com>]

On 5/24/2019 8:03 AM, Christian Couder wrote:
> If someone wants to use as a filter a sparse file that is in the
> repository, something like "--filter=sparse:oid=<ref>:<path>"
> already works.
> 
> So 'sparse:path' is only interesting if the sparse file is not in
> the repository. In this case though the current implementation has
> a big security issue, as it makes it possible to ask the server to
> read any file, like for example /etc/password, and to explore the
> filesystem, as well as individual lines of files.
> 
> If someone is interested in using a sparse file that is not in the
> repository as a filter, then at the minimum a config option, such
> as "uploadpack.sparsePathFilter", should be implemented first to
> restrict the directory from which the files specified by
> 'sparse:path' can be read.
> 
> For now though, let's just disable 'sparse:path' filters.
> ---
>   list-objects-filter-options.c |  9 ++++++---
>   list-objects-filter-options.h |  2 --
>   list-objects-filter.c         | 22 ----------------------
>   3 files changed, 6 insertions(+), 27 deletions(-)
> 
> diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
> index c0036f7378..007c104b93 100644
> --- a/list-objects-filter-options.c
> +++ b/list-objects-filter-options.c
> @@ -78,9 +78,12 @@ static int gently_parse_list_objects_filter(
>   		return 0;
>   
>   	} else if (skip_prefix(arg, "sparse:path=", &v0)) {
> -		filter_options->choice = LOFC_SPARSE_PATH;
> -		filter_options->sparse_path_value = strdup(v0);
> -		return 0;
> +		if (errbuf) {
> +			strbuf_addstr(
> +				errbuf,
> +				_("sparse:path filters are now disabled"));
> +		}
> +		return 1;
>   	}
>   	/*
>   	 * Please update _git_fetch() in git-completion.bash when you
[...]

We should update git-completion.bash to remove this option.

Jeff