[Bitcoin-development] bitcoin pull requests

Wed Apr 3 03:41:26 UTC 2013

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 <roy at 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 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 <will at 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) 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 <melvincarvalho at gmail.com>
> wrote:
> > > >
> > > >>
> > > >>
> > > >>
> > > >> On 1 April 2013 20:28, Petr Praus <petr at praus.net> 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 <melvincarvalho at gmail.com>
> 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 ...
> > > >>>>
> > > >>>>
> > > >>>>
> ------------------------------------------------------------------------------
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> > > >>>> _______________________________________________
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> > > >>>>
> > > >>>
> > > >>
> > > >>
> > > >>
> ------------------------------------------------------------------------------
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> > > >> 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.
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> > > >>
> > > >>
> > > >
> >
> > >
> ------------------------------------------------------------------------------
> > > 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
> >
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> >
> >
> >
> ------------------------------------------------------------------------------
> > 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
> > _______________________________________________
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> >
>
>
> ------------------------------------------------------------------------------
> 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
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