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From: Junio C Hamano <gitster@pobox•com>
To: Martin Koegler <martin.koegler@chello•at>
Cc: git@vger•kernel.org
Subject: Re: [PATCH] Fix delta integer overflows
Date: Mon, 07 Aug 2017 18:44:16 -0700	[thread overview]
Message-ID: <xmqqvalyn89b.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <xmqq1sonql76.fsf@gitster.mtv.corp.google.com> (Junio C. Hamano's message of "Mon, 07 Aug 2017 11:36:29 -0700")

Junio C Hamano <gitster@pobox•com> writes:

> Martin Koegler <martin.koegler@chello•at> writes:
>
>> From: Martin Koegler <martin.koegler@chello•at>
>>
>> The current delta code produces incorrect pack objects for files > 4GB.
>>
>> Signed-off-by: Martin Koegler <martin.koegler@chello•at>
>> ---
>>  diff-delta.c | 23 ++++++++++++-----------
>>  1 file changed, 12 insertions(+), 11 deletions(-)
>>
>> Just pass any file > 4 GB to the delta-compression [by increasing the delta limits].
>> As file size, a truncated 32bit value will be encoded, leading to broken pack files.
>
> The patch obviously makes the code better and self consistent in
> that "struct delta_index" has src_size as ulong, and this function
> takes trg_size as ulong, and it was plain wrong for the code to
> assume that "i", which is uint, can receive it safely.
>
> In the longer term we might want to move to size_t or even
> uintmax_t, as the ulong on a platform may not be long enough in
> order to express the largest file size the platform can have, but
> this patch (1) is good even without such a change, and (2) gives a
> good foundation to build on if we want such a change on top.
>
> Thanks.  Will queue.

Having said that, I am a bit curious how you came to this patch.
Was the issue found by code inspection, or did you actually have a
real life use case to raise the core.bigFileThreshold configuration
to a value above 4GB?

Thanks.

next prev parent reply	other threads:[~2017-08-08  1:44 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-07 18:10 [PATCH] Fix delta integer overflows Martin Koegler
2017-08-07 18:36 ` Junio C Hamano
2017-08-07 19:39   ` Johannes Schindelin
2017-08-07 19:48     ` Junio C Hamano
2017-08-07 21:10       ` Johannes Schindelin
2017-08-07 21:36         ` Junio C Hamano
2017-08-07 23:02           ` Junio C Hamano
2017-08-08  6:20     ` Martin Koegler
2017-08-08 11:38       ` Johannes Schindelin
2017-08-08  1:44   ` Junio C Hamano [this message]
2017-08-08  6:25     ` Martin Koegler

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