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From:   Junio C Hamano <gitster@pobox.com>
To:     Han Xin <chiyutianyi@gmail.com>
Cc:     Git List <git@vger.kernel.org>, Han Xin <hanxin.hx@alibaba-inc.com>
Subject: Re: [PATCH v2] receive-pack: not receive pack file with large object
References: <20210930121058.5771-1-chiyutianyi@gmail.com>
        <20210930132004.16075-1-chiyutianyi@gmail.com>
Date:   Thu, 30 Sep 2021 09:49:45 -0700
In-Reply-To: <20210930132004.16075-1-chiyutianyi@gmail.com> (Han Xin's message
        of "Thu, 30 Sep 2021 21:20:04 +0800")
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Han Xin <chiyutianyi@gmail.com> writes:

> @@ -519,6 +520,8 @@ static void *unpack_raw_entry(struct object_entry *obj,
>  		shift += 7;
>  	}
>  	obj->size = size;
> +	if (max_input_object_size && size > max_input_object_size)
> +		die(_("object exceeds maximum allowed size "));
>  
>  	switch (obj->type) {
>  	case OBJ_REF_DELTA:

Here obj->size is the inflated payload size of a single entry in the
packfile.  If it happens to be represented as a base object
(i.e. without delta, just deflated), it would be close to the size
of the blob in the working tree (but LF->CRLF conversion and the
like may further inflate it), but if it is a delta object, this size
is just the size of the delta data we feed patch_delta() with, and
has no relevance to the actual "file size".

Sure, it is called max_INPUT_object_size and we can say we are not
limiting the final disk size, and that might be a workable excuse
to check based on the obj->size here, but then its usefulness from
the point of view of end users, who decide to set the variable to
limit "some" usage, becomes dubious.

So...