From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Shawn O. Pearce" <spearce@spearce.org>
Subject: Re: Public repro case! Re: [PATCH/RFC] Allow writing loose objects
	that are corrupted in a pack file
Date: Wed, 7 Jan 2009 19:01:15 -0800
Message-ID: <20090108030115.GF10790@spearce.org>
References: <1231282320.8870.52.camel@starfruit> <alpine.LFD.2.00.0901062005290.26118@xanadu.home> <1231292360.8870.61.camel@starfruit> <alpine.LFD.2.00.0901062026500.3057@localhost.localdomain> <1231314099.8870.415.camel@starfruit> <alpine.LFD.2.00.0901070743070.3057@localhost.localdomain> <1231368935.8870.584.camel@starfruit> <alpine.LFD.2.00.0901071520330.3057@localhost.localdomain> <1231374514.8870.621.camel@starfruit> <alpine.LFD.2.00.0901071836290.3283@localhost.localdomain>
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Cc: "R. Tyler Ballance" <tyler@slide.com>,
	Nicolas Pitre <nico@cam.org>,
	Jan =?iso-8859-1?Q?Kr=FCger?= <jk@jk.gs>,
	Git ML <git@vger.kernel.org>, kb@slide.com
To: Linus Torvalds <torvalds@linux-foundation.org>
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Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Wed, 7 Jan 2009, R. Tyler Ballance wrote:
> >
> >         tyler@grapefruit:~/source/git/linux-2.6> git pull
> >         error: failed to read object be1b87c70af69acfadb8a27a7a76dfb61de92643 at offset 1850923
> >         from .git/objects/pack/pack-dbe154052997a05499eb6b4fd90b924da68e799a.pack
> >         fatal: object be1b87c70af69acfadb8a27a7a76dfb61de92643 is corrupted
> 
> Btw, this is an interesting error message, mostly because of what is 
> _not_ there.
> 
> In particular, it doesn't report any reason _why_ it failed to read the 
> object, which as far as I can tell can happen for only one reason: 
> unpack_compressed_entry() returns NULL, and that path is the only thing 
> that can do so without a message.
> 
> And it only does it if zlib fails.

Ok, well, in this case I've been able to reproduce a zlib inflate
failure on the base object in a 2 deep delta chain.  We got back:

  #define Z_STREAM_ERROR (-2)

this causes the buffer to be freed and NULL to come back out of
unpack_compressed_entry(), and then everything is corrupt...

-- 
Shawn.