Subject: Re: [PATCH v2 2/3] config.c: don't leak memory in handle_path_include()

From: Junio C Hamano <[email-masked]>
Date: Thu, 21 Oct 2021 16:30:36 -0700

Ævar Arnfjörð Bjarmason  <[email-masked]> writes:

> Fix a memory leak in the error() path in handle_path_include(), this
> allows us to run t1305-config-include.sh under SANITIZE=leak,
> previously 4 tests there would fail. This fixes up a leak in
> 9b25a0b52e0 (config: add include directive, 2012-02-06).
>
> Signed-off-by: Ævar Arnfjörð Bjarmason <[email-masked]>
> ---
>  config.c                  | 7 +++++--
>  t/t1305-config-include.sh | 1 +
>  2 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/config.c b/config.c
> index 2dcbe901b6b..c5873f3a706 100644
> --- a/config.c
> +++ b/config.c
> @@ -148,8 +148,10 @@ static int handle_path_include(const char *path, struct config_include_data *inc

Not a problem introduced by this function, but if you look at this
change with "git show -W", we'd notice that the function name on the
hunk header looks strange.  I think we should add a blank line
before the beginning of the function.

>  	if (!is_absolute_path(path)) {
>  		char *slash;
>  
> -		if (!cf || !cf->path)
> -			return error(_("relative config includes must come from files"));
> +		if (!cf || !cf->path) {
> +			ret = error(_("relative config includes must come from files"));
> +			goto cleanup;
> +		}
>  
>  		slash = find_last_dir_sep(cf->path);
>  		if (slash)
> @@ -167,6 +169,7 @@ static int handle_path_include(const char *path, struct config_include_data *inc
>  		ret = git_config_from_file(git_config_include, path, inc);
>  		inc->depth--;
>  	}
> +cleanup:
>  	strbuf_release(&buf);
>  	free(expanded);
>  	return ret;

Quite straight-forward.  At the point of the new "goto cleanup", the
expanded pointer has already been established, so these two calls
will release the right resource.

Thanks.

> diff --git a/t/t1305-config-include.sh b/t/t1305-config-include.sh
> index ccbb116c016..5cde79ef8c4 100755
> --- a/t/t1305-config-include.sh
> +++ b/t/t1305-config-include.sh
> @@ -1,6 +1,7 @@
>  #!/bin/sh
>  
>  test_description='test config file include directives'
> +TEST_PASSES_SANITIZE_LEAK=true
>  . ./test-lib.sh
>  
>  # Force setup_explicit_git_dir() to run until the end. This is needed