From: Gustavo Grieco <gustavo.grieco@imag.fr>
To: Junio C Hamano <gitster@pobox.com>
Cc: git@vger.kernel.org
Subject: Re: Stack read out-of-bounds in parse_sha1_header_extended using git 2.10.0
Date: Tue, 27 Sep 2016 04:13:22 +0200 (CEST) [thread overview]
Message-ID: <140080419.8376708.1474942402912.JavaMail.zimbra@imag.fr> (raw)
In-Reply-To: <xmqqtwd2sf9t.fsf@gitster.mtv.corp.google.com>
Btw, this other test case will trigger a similar issue, but in another line of code:
To reproduce:
$ git init ; mkdir -p .git/objects/b2 ; printf 'eJwNwoENgDAIBECkDsII5Z8CHagLGPePXu59zjHGRIOZG3OzI/lnRc4KemXDPdYSml6iQ+4ATIZ+nAEK4g==' | base64 -d > .git/objects/b2/93584ddd61af21260be75ee9f73e9d53f08cd0
Then:
$ git fsck
notice: HEAD points to an unborn branch (master)
=================================================================
==24569==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffe7645fda0 at pc 0x0000006fe799 bp 0x7ffe7645fc40 sp 0x7ffe7645fc30
READ of size 1 at 0x7ffe7645fda0 thread T0
#0 0x6fe798 in parse_sha1_header_extended /home/g/Work/Code/git-2.10.0/sha1_file.c:1714
...
It will be nice to test the current patch.
----- Original Message -----
> Junio C Hamano <gitster@pobox.com> writes:
>
> > I am inclined to say that it has no security implications. You have
> > to be able to write a bogus loose object in an object store you
> > already have write access to in the first place, in order to cause
> > this ...
>
> Note that you could social-engineer others to fetch from you and
> feed a small enough update that results in loose objects created in
> their repositories, without you having a direct write access to the
> repository.
>
> The codepath under discussion in this thread however cannot be used
> as an attack vector via that route, because the "fetch from
> elsewhere" codepath runs verification of the incoming data stream
> before storing the results (either in loose object files, or in a
> packfile) on disk.
>
>
next prev parent reply other threads:[~2016-09-27 2:13 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1399913289.8224468.1474810664933.JavaMail.zimbra@imag.fr>
2016-09-25 14:12 ` Stack read out-of-bounds in parse_sha1_header_extended using git 2.10.0 Gustavo Grieco
2016-09-26 0:10 ` Junio C Hamano
2016-09-26 4:29 ` [PATCH] unpack_sha1_header(): detect malformed object header Junio C Hamano
2016-09-26 14:03 ` Jeff King
2016-09-26 16:15 ` Junio C Hamano
2016-09-26 17:33 ` Junio C Hamano
2016-09-26 17:35 ` Jeff King
2016-09-26 17:39 ` Junio C Hamano
2016-09-26 17:34 ` Junio C Hamano
2016-09-26 17:38 ` Jeff King
2016-09-26 13:50 ` Stack read out-of-bounds in parse_sha1_header_extended using git 2.10.0 Jeff King
2016-09-26 17:48 ` Gustavo Grieco
2016-09-26 17:55 ` Junio C Hamano
2016-09-26 18:01 ` Gustavo Grieco
2016-09-26 18:06 ` Junio C Hamano
2016-09-26 18:10 ` Junio C Hamano
2016-09-27 2:13 ` Gustavo Grieco [this message]
2016-09-27 7:19 ` Jeff King
2016-09-27 2:30 ` Possible integer overflow parsing malformed objects in " Gustavo Grieco
2016-09-27 8:07 ` Jeff King
2016-09-27 15:57 ` Junio C Hamano
2016-09-27 19:14 ` Gustavo Grieco
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=140080419.8376708.1474942402912.JavaMail.zimbra@imag.fr \
--to=gustavo.grieco@imag.fr \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).