From: Emily Shaffer <emilyshaffer@google.com>
To: Jeff King <peff@peff.net>
Cc: Junio C Hamano <gitster@pobox.com>, git@vger.kernel.org
Subject: Re: [RFC PATCH] unpack-trees: watch for out-of-range index position
Date: Thu, 9 Jan 2020 14:46:41 -0800 [thread overview]
Message-ID: <20200109224641.GF181522@google.com> (raw)
In-Reply-To: <20200109075250.GA3978837@coredump.intra.peff.net>
On Thu, Jan 09, 2020 at 02:52:50AM -0500, Jeff King wrote:
> On Wed, Jan 08, 2020 at 12:35:29PM -0800, Junio C Hamano wrote:
>
> > >> It does not sound like a BUG to me, either, but the new condition
> > >> does look correct to me, too. We can turn it into die() later if
> > >> somebody truly cares ;-)
> > >>
> > >> Thanks, both. Will queue.
> > >
> > > Thanks much for the quick turnaround. If I hear more noise I'll give it
> > > a try with die() or error code instead, but for now I'll move on to the
> > > next bug on my list. :)
> >
> > By the way, it is somewhat sad that we proceeded that far in the
> > first place---such a corrupt on-disk index would have caused an
> > early die() if we did not get rid of the trailing-hash integrity
> > check.
>
> Perhaps. The integrity check only protects against an index that was
> modified after the fact, not one that was generated by a buggy Git. I'm
> not sure we know how the index that led to this patch got into this
> state (though it sounds like Emily has a copy and could check the hash
> on it), but other cache-tree segfault I found recently was with an index
> with an intact integrity hash.
Yeah, I can do that, although I'm not sure how. The index itself is very
small - it only contains one file and one tree extension - so I'll go
ahead and paste some poking and prodding, and if it's not what you
wanted then please let me know what else to run.
$ g fsck --cache
Checking object directories: 100% (256/256), done.
Checking objects: 100% (20/20), done.
broken link from commit 153a9a100eae7fdba5989ce39a5dd1782075517f
to commit cca7ecaa5d8c398f41bfec7938cc6a526803579b
broken link from commit 7d6bb91e31d18eadfaf855a9fb7ad6ba81b8b6d9
to commit 03087a617bfe55f862cb1ef43273a2bd08e8b6d6
missing commit 03087a617bfe55f862cb1ef43273a2bd08e8b6d6
missing commit cca7ecaa5d8c398f41bfec7938cc6a526803579b
dangling commit 5e2c635433bc46b13061b276e481f63b1f6642c8
$ hexdump -C .git/index
00000000 44 49 52 43 00 00 00 02 00 00 00 01 5d 89 5e 22 |DIRC........].^"|
00000010 23 bf a3 c4 5d 89 5e 22 23 bf a3 c4 00 00 fe 02 |#...].^"#.......|
00000020 02 c8 f5 83 00 00 81 a4 00 06 c1 dc 00 01 5f 53 |.............._S|
00000030 00 00 06 b3 78 88 a4 f4 22 34 7d ad b0 c4 73 0f |....x..."4}...s.|
00000040 c5 bc f6 ea 1d 2d f0 3a 00 09 52 45 41 44 4d 45 |.....-.:..README|
00000050 2e 6d 64 00 54 52 45 45 00 00 00 3a 00 31 37 20 |.md.TREE...:.17 |
00000060 31 0a da 7f 67 25 40 7d 4e ce 9f d3 72 ce 4c e8 |1...g%@}N...r.L.|
00000070 40 6d 5d ad e9 79 67 69 74 6c 69 6e 74 00 34 20 |@m]..ygitlint.4 |
00000080 30 0a 93 63 25 17 69 e6 d6 92 78 97 55 4b 0f 8b |0..c%.i...x.UK..|
00000090 ff a0 e8 2d 6d 71 32 d1 69 fc f2 38 42 f8 5a 6e |...-mq2.i..8B.Zn|
000000a0 05 35 d6 94 41 c0 9f c7 ba 43 |.5..A....C|
000000aa
$ find .git/objects -type f
.git/objects/pack/pack-5e5d5e7c3cbd60a99b4c0295a2935885fbb235a1.idx
.git/objects/pack/pack-5e5d5e7c3cbd60a99b4c0295a2935885fbb235a1.pack
.git/objects/15/3a9a100eae7fdba5989ce39a5dd1782075517f
.git/objects/5e/2c635433bc46b13061b276e481f63b1f6642c8
(By the way, cat-file barfs on both those loose objects, for the reason fsck
reveals.)
I hope that's helpful.
- Emily
next prev parent reply other threads:[~2020-01-09 22:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-08 2:31 [RFC PATCH] unpack-trees: watch for out-of-range index position Emily Shaffer
2020-01-08 7:15 ` Jeff King
2020-01-08 17:30 ` Junio C Hamano
2020-01-08 19:38 ` Emily Shaffer
2020-01-08 20:35 ` Junio C Hamano
2020-01-09 7:52 ` Jeff King
2020-01-09 22:46 ` Emily Shaffer [this message]
2020-01-10 6:37 ` Jeff King
2020-01-10 23:07 ` Emily Shaffer
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