From: "Shawn O. Pearce" <spearce@spearce.org>
To: Robin Rosenberg <robin.rosenberg.lists@dewire.com>
Cc: "Adam W. Hawks" <awhawks@writeme.com>, git@vger.kernel.org
Subject: Re: [ JGIT ] incompatiblity found in DirCache
Date: Fri, 11 Sep 2009 08:05:23 -0700 [thread overview]
Message-ID: <20090911150522.GI1033@spearce.org> (raw)
In-Reply-To: <200909092311.07145.robin.rosenberg.lists@dewire.com>
Robin Rosenberg <robin.rosenberg.lists@dewire.com> wrote:
> onsdag 09 september 2009 20:55:39 skrev "Adam W. Hawks" <awhawks@writeme.com>:
> > When using the DirCache interface to the index you can create a
> > invalid/corrupt tree for git 1.6.5.
> >
> > The problem seems to be you can add a path to the index that starts
> > with a "/" and DirCache creates a entry with a mode but no path.
> > This causes git 1.6.5 to fail with a corrupt tree.
>
> I think there are more ways of entering bad stuff. Preventing a
> deliberate programmatic creation of invalid trees is probably not
> the most important thing, but then again, validating the data to
> prevent e.g. the EGit plugin from doing it by mistake due to bugs
> could probably be worthwhile.
We already check for and fail fast on a 0 mode in DirCache, as this
mode is also not valid in the index, or in a git tree.
We should be doing the same thing for an empty path name. "a//b" is
not a valid path in the index, as "" is not a valid tree entry path.
For the same reason, "/a" is not a valid path in the index.
Unfortunately our API also allows you to try and create a name of
"a\u0000b", which is a valid Java string, but will create a corrupt
tree. \u0000 in a name with more than 4095 bytes will also create
a corrupt index (shorter strings are semi-valid because shorter
strings use a Pascal like string format, and longer ones use a C
like string format). Though C git is unable to access a path whose
name contains "\u0000", no matter how long the string is.
I think we should try a bit harder in DirCache to prevent these sorts
of really bad entries from being constructed by application code.
Yes, applications should not do this, but I think the library also
should not write known bogus trash to the disk and claim it is OK.
I'll try to work up a patch for this today.
--
Shawn.
prev parent reply other threads:[~2009-09-11 15:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-09 18:55 [ JGIT ] incompatiblity found in DirCache Adam W. Hawks
2009-09-09 21:11 ` Robin Rosenberg
2009-09-11 15:05 ` Shawn O. Pearce [this message]
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