Re: [PATCH v2 2/7] reftable: reject 0 object_id_len

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 18, 2022, 00:32 UTC
Message-ID: <xmqqwnht3tgt.fsf@gitster.g>
In-Reply-To: <4c1a19fc4aef2742e2733b804221186aa164f721.1645106124.git.gitgitgadget@gmail.com>

"Han-Wen Nienhuys via GitGitGadget" <gitgitgadget@gmail.com> writes:

> From: Han-Wen Nienhuys <hanwen@google.com>
>
> The spec says 2 <= object_id_len <= 31. We are lenient and allow 1,
> but we forbid 0, so we can we can be sure that we never read a

s/we can we can/we can/;

Show 23 quoted lines

> 0-length key.
>
> Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
> ---
>  reftable/reader.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/reftable/reader.c b/reftable/reader.c
> index 00906e7a2de..54b4025105c 100644
> --- a/reftable/reader.c
> +++ b/reftable/reader.c
> @@ -155,6 +155,11 @@ static int parse_footer(struct reftable_reader *r, uint8_t *footer,
>  	r->log_offsets.is_present = (first_block_typ == BLOCK_TYPE_LOG ||
>  				     r->log_offsets.offset > 0);
>  	r->obj_offsets.is_present = r->obj_offsets.offset > 0;
> +	if (r->obj_offsets.is_present && !r->object_id_len) {
> +		err = REFTABLE_FORMAT_ERROR;
> +		goto done;
> +	}
> +
>  	err = 0;
>  done:
>  	return err;