Re: [PATCH] Fix leak in credential_apply_config

From: Derrick Stolee <stolee@gmail.com>
Date: Aug 20, 2021, 14:58 UTC
Message-ID: <ffa1786e-f69f-3d76-98dc-7fa5cdbd31c0@gmail.com>
In-Reply-To: <20210820084413.1503711-1-mh@glandium.org>

On 8/20/2021 4:44 AM, Mike Hommey wrote:

Show 6 quoted lines

>  	normalized_url = url_normalize(url.buf, &config.url);
>  
>  	git_config(urlmatch_config_entry, &config);
> +	string_list_clear(&config.vars, 1);
>  	free(normalized_url);
>  	strbuf_release(&url);

A good find! This is obviously correct and a valuable change to make. If you are interested in doing a little extra work, then I think there is something more we could do here.

I took a look at the rest of "struct urlmatch_config" to see if anything else needed to be cleared, and it turns out that config.url.url is an allocated string, but happens to be equal to normalized_url, which is freed here.

Perhaps the optimal organization would be to have a clear_urlmatch_config() method that clears all allocated data within the config, and change things like url_normalize() return a 'const char *' to make it clear that the url should be freed somewhere else.

It would help unify the handling of code that is somewhat duplicated (but slightly different each time) across credential_apply_config(), http_init(), get_urlmatch(), and cmd__urlmatch_normalization().

Thanks, -Stolee