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From: Duy Nguyen <pclouds@gmail.com>
To: Nicolas Pitre <nico@fluxnic.net>
Cc: Git Mailing List <git@vger.kernel.org>, Jeff King <peff@peff.net>
Subject: Re: pack corruption post-mortem
Date: Sun, 20 Oct 2013 11:44:32 +0700	[thread overview]
Message-ID: <CACsJy8AATr9KfFN6x0E8mYsBmWhVmD=kaXgBmnFTiyww3MS8WQ@mail.gmail.com> (raw)
In-Reply-To: <alpine.LFD.2.03.1310191024000.1951@syhkavp.arg>

On Sat, Oct 19, 2013 at 9:41 PM, Nicolas Pitre <nico@fluxnic.net> wrote:
> On Sat, 19 Oct 2013, Duy Nguyen wrote:
> The SHA1 used in the name of the pack file is actually the SHA1 checksum
> of the SHA1 table.
>
> The path and ident tables are already protected by the CRC32 in the zlib
> deflated stream.
>
> Normal objects are also zlib deflated (except for their header) but you
> need to inflate them in order to have this CRC verified, which the pack
> data copy tries to avoid.  Hence the separate CRC32 in the index file in
> that case.

OK slight change in the subject, what about reading code (i.e.
sha1_file.c)? With v2 crc32 is verified by object inflate code. With
v4 trees or commits, because we store some (or all) data outside of
the deflated stream, we will not benefit from crc32 verifcation
previously done for all trees and commits. Should we perform explict
crc32 check when reading v4 trees and commits (and maybe verify the
sha-1 table too)?
-- 
Duy

  parent reply	other threads:[~2013-10-20  4:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-16  8:34 Jeff King
2013-10-16  8:59 ` Duy Nguyen
2013-10-16 15:41 ` Martin Fick
2013-10-17  0:35   ` Jeff King
2013-10-17 15:47     ` Junio C Hamano
2013-10-25  7:55       ` Jeff King
2013-10-17  1:06   ` Duy Nguyen
2013-10-19 10:32 ` Duy Nguyen
2013-10-19 14:41   ` Nicolas Pitre
2013-10-19 19:17     ` Shawn Pearce
2013-10-20 20:56       ` Nicolas Pitre
2013-10-20  4:44     ` Duy Nguyen [this message]
2013-10-20 21:08       ` Nicolas Pitre
2015-04-01 21:08 ` [PATCH] howto: document more tools for recovery corruption Jeff King
2015-04-01 22:21   ` Junio C Hamano
2015-04-02  0:49     ` Jeff King

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