Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1UNEZs-0001AH-2x for bitcoin-development@lists.sourceforge.net; Wed, 03 Apr 2013 03:41:36 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.214.43 as permitted sender) client-ip=209.85.214.43; envelope-from=laanwj@gmail.com; helo=mail-bk0-f43.google.com; Received: from mail-bk0-f43.google.com ([209.85.214.43]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1UNEZo-00049E-Pq for bitcoin-development@lists.sourceforge.net; Wed, 03 Apr 2013 03:41:36 +0000 Received: by mail-bk0-f43.google.com with SMTP id jm2so545857bkc.30 for ; Tue, 02 Apr 2013 20:41:26 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.205.34.195 with SMTP id st3mr14810bkb.16.1364960486292; Tue, 02 Apr 2013 20:41:26 -0700 (PDT) Received: by 10.204.37.203 with HTTP; Tue, 2 Apr 2013 20:41:26 -0700 (PDT) In-Reply-To: <20130401225417.GV65880@giles.gnomon.org.uk> References: <20130401225107.GU65880@giles.gnomon.org.uk> <20130401225417.GV65880@giles.gnomon.org.uk> Date: Wed, 3 Apr 2013 05:41:26 +0200 Message-ID: From: Wladimir To: Roy Badami Content-Type: multipart/alternative; boundary=bcaec52c69cbeb2e8b04d96ca096 X-Spam-Score: -0.6 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (laanwj[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature X-Headers-End: 1UNEZo-00049E-Pq Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] bitcoin pull requests X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 03 Apr 2013 03:41:36 -0000 --bcaec52c69cbeb2e8b04d96ca096 Content-Type: text/plain; charset=UTF-8 Maybe now that bitcoin is growing out of the toy phase it's an idea to start gpg signing commits, like the Linux kernel ( https://lwn.net/Articles/466468/). But I suppose then we can't use github anymore to merge as-is and need manual steps? Wladimir On Tue, Apr 2, 2013 at 12:54 AM, Roy Badami wrote: > And the moment I hit send I realised it's not necessarily true. > Conceivably, a collision attack might help you craft two commits (one > good, one bad) with the same hash. > > But I still maintain what I just posted is true: if someone gets > malicious code into the repo, it's going to be by social engineering, > not by breaking the cyrpto. > > roy > > > On Mon, Apr 01, 2013 at 11:51:07PM +0100, Roy Badami wrote: > > The attack Schneier is talking about is a collision attack (i.e. it > > creates two messages with the same hash, but you don't get to choose > > either of the messages). It's not a second preimage attack, which is > > what you would need to be able to create a message that hashes to the > > same value of an existing message. > > > > (And it neither have anything to do with the birthday paradox, BTW - > > which relates to the chance of eventually finding two messages that > > hash to the same value by pure change) > > > > If someone gets malicious code into the repo, it's going to be by > > social engineering, not by breaking the cyrpto. > > > > roy > > > > On Tue, Apr 02, 2013 at 12:27:51AM +0200, Melvin Carvalho wrote: > > > On 2 April 2013 00:10, Will wrote: > > > > > > > The threat of a SHA1 collision attack to insert a malicious pull > request > > > > are tiny compared with the other threats - e.g. github being > compromised, > > > > one of the core developers' passwords being compromised, one of the > core > > > > developers going rogue, sourceforge (distribution site) being > compromised > > > > etc etc... believe me there's a lot more to worry about than a SHA1 > > > > attack... > > > > > > > > Not meaning to scare, just to put things in perspective - this is > why we > > > > all need to peer review each others commits and keep an eye out for > > > > suspicious commits, leverage the benefits of this project being open > source > > > > and easily peer reviewed. > > > > > > > > > > Very good points, and I think you're absolutely right. > > > > > > But just running the numbers, to get the picture, based of scheiner's > > > statistics: > > > > > > http://www.schneier.com/blog/archives/2012/10/when_will_we_se.html > > > > > > We're talking about a million terrahashes = 2^60 right? > > > > > > With the block chain, you only have a 10 minute window, but with source > > > code you have a longer time to prepare. > > > > > > Couldnt this be done with an ASIC in about a week? > > > > > > > > > > > > > > > > > Will > > > > > > > > > > > > On 1 April 2013 23:52, Melvin Carvalho > wrote: > > > > > > > >> > > > >> > > > >> > > > >> On 1 April 2013 20:28, Petr Praus wrote: > > > >> > > > >>> An attacker would have to find a collision between two specific > pieces > > > >>> of code - his malicious code and a useful innoculous code that > would be > > > >>> accepted as pull request. This is the second, much harder case in > the > > > >>> birthday problem. When people talk about SHA-1 being broken they > actually > > > >>> mean the first case in the birthday problem - find any two > arbitrary values > > > >>> that hash to the same value. So, no I don't think it's a feasible > attack > > > >>> vector any time soon. > > > >>> > > > >>> Besides, with that kind of hashing power, it might be more > feasible to > > > >>> cause problems in the chain by e.g. constantly splitting it. > > > >>> > > > >> > > > >> OK, maybe im being *way* too paranoid here ... but what if someone > had > > > >> access to github, could they replace one file with one they had > prepared at > > > >> some point? > > > >> > > > >> > > > >>> > > > >>> > > > >>> On 1 April 2013 03:26, Melvin Carvalho > wrote: > > > >>> > > > >>>> I was just looking at: > > > >>>> > > > >>>> https://bitcointalk.org/index.php?topic=4571.0 > > > >>>> > > > >>>> I'm just curious if there is a possible attack vector here based > on the > > > >>>> fact that git uses the relatively week SHA1 > > > >>>> > > > >>>> Could a seemingly innocuous pull request generate another file > with a > > > >>>> backdoor/nonce combination that slips under the radar? > > > >>>> > > > >>>> Apologies if this has come up before ... > > > >>>> > > > >>>> > > > >>>> > ------------------------------------------------------------------------------ > > > >>>> Own the Future-Intel® Level Up Game Demo Contest 2013 > > > >>>> Rise to greatness in Intel's independent game demo contest. > > > >>>> Compete for recognition, cash, and the chance to get your game > > > >>>> on Steam. $5K grand prize plus 10 genre and skill prizes. > > > >>>> Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d > > > >>>> _______________________________________________ > > > >>>> Bitcoin-development mailing list > > > >>>> Bitcoin-development@lists.sourceforge.net > > > >>>> https://lists.sourceforge.net/lists/listinfo/bitcoin-development > > > >>>> > > > >>>> > > > >>> > > > >> > > > >> > > > >> > ------------------------------------------------------------------------------ > > > >> Own the Future-Intel® Level Up Game Demo Contest 2013 > > > >> Rise to greatness in Intel's independent game demo contest. > > > >> Compete for recognition, cash, and the chance to get your game > > > >> on Steam. $5K grand prize plus 10 genre and skill prizes. > > > >> Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d > > > >> _______________________________________________ > > > >> Bitcoin-development mailing list > > > >> Bitcoin-development@lists.sourceforge.net > > > >> https://lists.sourceforge.net/lists/listinfo/bitcoin-development > > > >> > > > >> > > > > > > > > > > ------------------------------------------------------------------------------ > > > Own the Future-Intel® Level Up Game Demo Contest 2013 > > > Rise to greatness in Intel's independent game demo contest. > > > Compete for recognition, cash, and the chance to get your game > > > on Steam. $5K grand prize plus 10 genre and skill prizes. > > > Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d > > > > > _______________________________________________ > > > Bitcoin-development mailing list > > > Bitcoin-development@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > > > > > > > ------------------------------------------------------------------------------ > > Own the Future-Intel® Level Up Game Demo Contest 2013 > > Rise to greatness in Intel's independent game demo contest. > > Compete for recognition, cash, and the chance to get your game > > on Steam. $5K grand prize plus 10 genre and skill prizes. > > Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d > > _______________________________________________ > > Bitcoin-development mailing list > > Bitcoin-development@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > > > > > ------------------------------------------------------------------------------ > Own the Future-Intel® Level Up Game Demo Contest 2013 > Rise to greatness in Intel's independent game demo contest. > Compete for recognition, cash, and the chance to get your game > on Steam. $5K grand prize plus 10 genre and skill prizes. > Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > --bcaec52c69cbeb2e8b04d96ca096 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

Maybe now that bitcoin is growing out of th= e toy phase it's an idea to start gpg signing commits, like the Linux k= ernel (https://lwn.net/Article= s/466468/).

But I suppose then we can't use github anymore to merge = as-is and need manual steps?

Wladimir




On Tue, Apr 2, 2013 at 12:54 AM, Roy Badami <roy@gnomon.org.uk> wrote:
And the moment I hit send I realised it's not necessarily true.
Conceivably, a collision attack might help you craft two commits (one
good, one bad) with the same hash.

But I still maintain what I just posted is true: if someone gets
malicious code into the repo, it's going to be= by social engineering,
not by breaking the cyrpto.

roy


On Mon, Apr 01, 2013 at 11:51= :07PM +0100, Roy Badami wrote:
> The attack Schneier is talking about is a collision attack (i.e. it > creates two messages with the same hash, but you don't get to choo= se
> either of the messages). =C2=A0It's not a second preimage attack, = which is
> what you would need to be able to create a message that hashes to the<= br> > same value of an existing message.
>
> (And it neither have anything to do with the birthday paradox, BTW - > which relates to the chance of eventually finding two messages that > hash to the same value by pure change)
>
> If someone gets malicious code into the repo, it's going to be by<= br> > social engineering, not by breaking the cyrpto.
>
> roy
>
> On Tue, Apr 02, 2013 at 12:27:51AM +0200, Melvin Carvalho wrote:
> > On 2 April 2013 00:10, Will <will@phase.net> wrote:
> >
> > > The threat of a SHA1 collision attack to insert a malicious = pull request
> > > are tiny compared with the other threats - e.g. github being= compromised,
> > > one of the core developers' passwords being compromised,= one of the core
> > > developers going rogue, sourceforge (distribution site) bein= g compromised
> > > etc etc... believe me there's a lot more to worry about = than a SHA1
> > > attack...
> > >
> > > Not meaning to scare, just to put things in perspective - th= is is why we
> > > all need to peer review each others commits and keep an eye = out for
> > > suspicious commits, leverage the benefits of this project be= ing open source
> > > and easily peer reviewed.
> > >
> >
> > Very good points, and I think you're absolutely right.
> >
> > But just running the numbers, to get the picture, based of schein= er's
> > statistics:
> >
> > http://www.schneier.com/blog/archives/2012/= 10/when_will_we_se.html
> >
> > We're talking about a million terrahashes =3D 2^60 right?
> >
> > With the block chain, you only have a 10 minute window, but with = source
> > code you have a longer time to prepare.
> >
> > Couldnt this be done with an ASIC in about a week?
> >
> >
> >
> > >
> > > Will
> > >
> > >
> > > On 1 April 2013 23:52, Melvin Carvalho <melvincarvalho@gmail.com> wrote:
> > >
> > >>
> > >>
> > >>
> > >> On 1 April 2013 20:28, Petr Praus <petr@praus.net> wrote:
> > >>
> > >>> An attacker would have to find a collision between t= wo specific pieces
> > >>> of code - his malicious code and a useful innoculous= code that would be
> > >>> accepted as pull request. This is the second, much h= arder case in the
> > >>> birthday problem. When people talk about SHA-1 being= broken they actually
> > >>> mean the first case in the birthday problem - find a= ny two arbitrary values
> > >>> that hash to the same value. So, no I don't thin= k it's a feasible attack
> > >>> vector any time soon.
> > >>>
> > >>> Besides, with that kind of hashing power, it might b= e more feasible to
> > >>> cause problems in the chain by e.g. constantly split= ting it.
> > >>>
> > >>
> > >> OK, maybe im being *way* too paranoid here ... but what = if someone had
> > >> access to github, could they replace one file with one t= hey had prepared at
> > >> some point?
> > >>
> > >>
> > >>>
> > >>>
> > >>> On 1 April 2013 03:26, Melvin Carvalho <melvincarvalho@gmail.com> wrote= :
> > >>>
> > >>>> =C2=A0I was just looking at:
> > >>>>
> > >>>> https://bitcointalk.org/index.php?topic=3D45= 71.0
> > >>>>
> > >>>> I'm just curious if there is a possible atta= ck vector here based on the
> > >>>> fact that git uses the relatively week SHA1
> > >>>>
> > >>>> Could a seemingly innocuous pull request generat= e another file with a
> > >>>> backdoor/nonce combination that slips under the = radar?
> > >>>>
> > >>>> Apologies if this has come up before ...
> > >>>>
> > >>>>
> > >>>> ------------------------------------------------= ------------------------------
> > >>>> Own the Future-Intel&reg; Level Up Game Demo= Contest 2013
> > >>>> Rise to greatness in Intel's independent gam= e demo contest.
> > >>>> Compete for recognition, cash, and the chance to= get your game
> > >>>> on Steam. $5K grand prize plus 10 genre and skil= l prizes.
> > >>>> Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_le= velupd2d
> > >>>> _______________________________________________<= br> > > >>>> Bitcoin-development mailing list
> > >>>> Bitcoin-development@lists.sourceforge.net
> > >>>> https://lists.sourceforge.ne= t/lists/listinfo/bitcoin-development
> > >>>>
> > >>>>
> > >>>
> > >>
> > >>
> > >> --------------------------------------------------------= ----------------------
> > >> Own the Future-Intel&reg; Level Up Game Demo Contest= 2013
> > >> Rise to greatness in Intel's independent game demo c= ontest.
> > >> Compete for recognition, cash, and the chance to get you= r game
> > >> on Steam. $5K grand prize plus 10 genre and skill prizes= .
> > >> Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d=
> > >> _______________________________________________
> > >> Bitcoin-development mailing list
> > >> Bitcoin-development@lists.sourceforge.net
> > >> https://lists.sourceforge.net/lists/= listinfo/bitcoin-development
> > >>
> > >>
> > >
>
> > -----------------------------------------------------------------= -------------
> > Own the Future-Intel&reg; Level Up Game Demo Contest 2013
> > Rise to greatness in Intel's independent game demo contest. > > Compete for recognition, cash, and the chance to get your game > > on Steam. $5K grand prize plus 10 genre and skill prizes.
> > Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d
>
> > _______________________________________________
> > Bitcoin-development mailing list
> > Bitc= oin-development@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/= bitcoin-development
>
>
> ----------------------------------------------------------------------= --------
> Own the Future-Intel&reg; Level Up Game Demo Contest 2013
> Rise to greatness in Intel's independent game demo contest.
> Compete for recognition, cash, and the chance to get your game
> on Steam. $5K grand prize plus 10 genre and skill prizes.
> Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-d= evelopment@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitco= in-development
>

---------------------------------------------------------------------------= ---
Own the Future-Intel&reg; Level Up Game Demo Contest 2013
Rise to greatness in Intel's independent game demo contest.
Compete for recognition, cash, and the chance to get your game
on Steam. $5K grand prize plus 10 genre and skill prizes.
Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d
_______________________________________________
Bitcoin-development mailing list
Bitcoin-develo= pment@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bitcoin-de= velopment

--bcaec52c69cbeb2e8b04d96ca096--