Re: [PATCH v2 2/3] ls-refs.c: initialize 'prefixes' before using it

[Jacob Vosmaer <jacob@gitlab.com>]

As the person whose name is on the "From:" line, I approve. And thanks!

On Wed, Jan 20, 2021 at 5:04 PM Taylor Blau <me@ttaylorr.com> wrote:
>
> From: Jacob Vosmaer <jacob@gitlab.com>
>
> Correctly initialize the "prefixes" strvec using strvec_init() instead
> of simply zeroing it via the earlier memset().
>
> There's no way to trigger a crash, since the first 'ref-prefix' command
> will initialize the strvec via the 'ALLOC_GROW' in 'strvec_push_nodup()'
> (the alloc and nr variables are already zero'd, so the call to
> ALLOC_GROW is valid).
>
> If no "ref-prefix" command was given, then the call to
> 'ls-refs.c:ref_match()' will abort early after it reads the zero in
> 'prefixes->nr'. Likewise, strvec_clear() will only call free() on the
> array, which is NULL, so we're safe there, too.
>
> But, all of this is dangerous and requires more reasoning than it would
> if we simply called 'strvec_init()', so do that.
>
> Signed-off-by: Jacob Vosmaer <jacob@gitlab.com>
> Signed-off-by: Taylor Blau <me@ttaylorr.com>
> ---
>  ls-refs.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/ls-refs.c b/ls-refs.c
> index a1e0b473e4..367597d447 100644
> --- a/ls-refs.c
> +++ b/ls-refs.c
> @@ -90,6 +90,7 @@ int ls_refs(struct repository *r, struct strvec *keys,
>         struct ls_refs_data data;
>
>         memset(&data, 0, sizeof(data));
> +       strvec_init(&data.prefixes);
>
>         git_config(ls_refs_config, NULL);
>
> --
> 2.30.0.138.g6d7191ea01
>