Re: [Bitcoin-development] bitcoin pull requests

2013-04-04 Thread Mike Hearn
My general hope/vague plan for bitcoinj based wallets is to get them all on
to automatic updates with threshold signatures. Combined with regular
audits of the initial downloads for new users, that should give a pretty
safe result that is immune to a developer going rogue.


On Wed, Apr 3, 2013 at 7:12 PM, grarpamp grarp...@gmail.com wrote:

  Users will have available multisig addresses which require
  transactions to be signed off by a wallet HSM. (E.g. a keyfob

 Hardware is a good thing. But only if you do the crypto in the
 hardware and trust the hardware and its attack models ;) For
 instance, the fingerprint readers you see everywhere... many
 of them just present the raw fingerprint scan to the host (and
 host software), instead of hashing the fingerprint internally and
 using that as primitive in crypto exchanges with the host. They
 cheaped out and/or didn't think. So oops, there went both your
 security (host replay) and your personal privacy (biometrics),
 outside of your control. All with no protection against physical
 fingerprint lifting.

  This doesn't remove the need to improve repository integrity. ... but
  repository integrity is a general problem that is applicable to many
  things (after all, what does it matter if you can't compromise Bitcoin
  if you can compromise boost, openssl, or gcc?)

 Yes, that case would matter zero to the end product. However
 having a strong repo permits better auditing of the BTC codebase.
 That's a good thing, and eliminates the need to talk chicken and
 egg.

  It's probably best
  that Bitcoin specalists stay focused on Bitcoin security measures, and
  other people interested in repository security come and help out
  improving it.  An obvious area of improvement might be oddity
  detection and alerting:  It's weird that I can rewrite history on
  github, so long as I do it quickly, without anyone noticing.

 If no one is verifying the repo, sure, even entire repos could be
 swapped out for seemingly identical ones.

 Many repos do not have any strong internal verification structures
 at all, and they run on filesystems that accept bitrot.
 Take a look at some OS's... OpenBSD and FreeBSD, supposedly
 the more secure ones out there... both use legacy repos on FFS.
 Seems rather ironic in the lol department.

 Thankfully some people out there are finally getting a clue on these
 issues, making and learning the tools, converting and migrating
 things, working on top down signed build and distribution chain, etc...
 so maybe in ten years the opensource world will be much farther
 ahead. Or at least have a strong audit trail.


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Re: [Bitcoin-development] bitcoin pull requests

2013-04-04 Thread Mike Hearn
By the way, I have a download of the Bitcoin-Qt client and signature
verification running in a cron job.


On Thu, Apr 4, 2013 at 10:11 AM, Mike Hearn m...@plan99.net wrote:

 My general hope/vague plan for bitcoinj based wallets is to get them all
 on to automatic updates with threshold signatures. Combined with regular
 audits of the initial downloads for new users, that should give a pretty
 safe result that is immune to a developer going rogue.


 On Wed, Apr 3, 2013 at 7:12 PM, grarpamp grarp...@gmail.com wrote:

  Users will have available multisig addresses which require
  transactions to be signed off by a wallet HSM. (E.g. a keyfob

 Hardware is a good thing. But only if you do the crypto in the
 hardware and trust the hardware and its attack models ;) For
 instance, the fingerprint readers you see everywhere... many
 of them just present the raw fingerprint scan to the host (and
 host software), instead of hashing the fingerprint internally and
 using that as primitive in crypto exchanges with the host. They
 cheaped out and/or didn't think. So oops, there went both your
 security (host replay) and your personal privacy (biometrics),
 outside of your control. All with no protection against physical
 fingerprint lifting.

  This doesn't remove the need to improve repository integrity. ... but
  repository integrity is a general problem that is applicable to many
  things (after all, what does it matter if you can't compromise Bitcoin
  if you can compromise boost, openssl, or gcc?)

 Yes, that case would matter zero to the end product. However
 having a strong repo permits better auditing of the BTC codebase.
 That's a good thing, and eliminates the need to talk chicken and
 egg.

  It's probably best
  that Bitcoin specalists stay focused on Bitcoin security measures, and
  other people interested in repository security come and help out
  improving it.  An obvious area of improvement might be oddity
  detection and alerting:  It's weird that I can rewrite history on
  github, so long as I do it quickly, without anyone noticing.

 If no one is verifying the repo, sure, even entire repos could be
 swapped out for seemingly identical ones.

 Many repos do not have any strong internal verification structures
 at all, and they run on filesystems that accept bitrot.
 Take a look at some OS's... OpenBSD and FreeBSD, supposedly
 the more secure ones out there... both use legacy repos on FFS.
 Seems rather ironic in the lol department.

 Thankfully some people out there are finally getting a clue on these
 issues, making and learning the tools, converting and migrating
 things, working on top down signed build and distribution chain, etc...
 so maybe in ten years the opensource world will be much farther
 ahead. Or at least have a strong audit trail.


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Re: [Bitcoin-development] bitcoin pull requests

2013-04-03 Thread grarpamp
 gpg signing commits, like the Linux kernel

 Though, honestly, when I ACK that means I read the code, which is more
 important than the author really.  github seems fine for that still,
 though I do wonder if there is a race possible,

 * just before I click pull, sneak rebases the branch to something evil


You might want to look at http://www.monotone.ca/, it does a good job
of integrating crypto and review primitives into the workflow.
It also has some reliable network distribution models (netsync) that work
well over things like Tor, in case a new developer (or old Satoshi) doesn't
wish to be in the public light.

http://www.monotone.ca/monotone.html

Once you have the crypto, it always boils down to human risk factors,
rogue, password, cracks, etc which are harder.

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Re: [Bitcoin-development] bitcoin pull requests

2013-04-03 Thread Gavin Andresen
I would rather we spend time working to make users' bitcoins safe EVEN IF
their bitcoin software is compromised.

Eliminate the if you get a bad bitcoin-qt.exe somehow you're in big
trouble risk entirely, instead of worrying about unlikely scenarios like a
timing attack in between ACKs/pulls. Eliminate one piece of software as the
possible single point of failure...

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Re: [Bitcoin-development] bitcoin pull requests

2013-04-03 Thread grarpamp
 Users will have available multisig addresses which require
 transactions to be signed off by a wallet HSM. (E.g. a keyfob

Hardware is a good thing. But only if you do the crypto in the
hardware and trust the hardware and its attack models ;) For
instance, the fingerprint readers you see everywhere... many
of them just present the raw fingerprint scan to the host (and
host software), instead of hashing the fingerprint internally and
using that as primitive in crypto exchanges with the host. They
cheaped out and/or didn't think. So oops, there went both your
security (host replay) and your personal privacy (biometrics),
outside of your control. All with no protection against physical
fingerprint lifting.

 This doesn't remove the need to improve repository integrity. ... but
 repository integrity is a general problem that is applicable to many
 things (after all, what does it matter if you can't compromise Bitcoin
 if you can compromise boost, openssl, or gcc?)

Yes, that case would matter zero to the end product. However
having a strong repo permits better auditing of the BTC codebase.
That's a good thing, and eliminates the need to talk chicken and
egg.

 It's probably best
 that Bitcoin specalists stay focused on Bitcoin security measures, and
 other people interested in repository security come and help out
 improving it.  An obvious area of improvement might be oddity
 detection and alerting:  It's weird that I can rewrite history on
 github, so long as I do it quickly, without anyone noticing.

If no one is verifying the repo, sure, even entire repos could be
swapped out for seemingly identical ones.

Many repos do not have any strong internal verification structures
at all, and they run on filesystems that accept bitrot.
Take a look at some OS's... OpenBSD and FreeBSD, supposedly
the more secure ones out there... both use legacy repos on FFS.
Seems rather ironic in the lol department.

Thankfully some people out there are finally getting a clue on these
issues, making and learning the tools, converting and migrating
things, working on top down signed build and distribution chain, etc...
so maybe in ten years the opensource world will be much farther
ahead. Or at least have a strong audit trail.

--
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Re: [Bitcoin-development] bitcoin pull requests

2013-04-02 Thread Jeff Garzik
On Tue, Apr 2, 2013 at 11:41 PM, Wladimir laa...@gmail.com wrote:
 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?

Correct, that rules out github, AFAICS.

Though, honestly, when I ACK that means I read the code, which is more
important than the author really.  github seems fine for that still,
though I do wonder if there is a race possible,

* sneak uploads innocent branch sneak/bitcoin.git #innocent
* sneak creates pull req
* just before I click pull, sneak rebases the branch to something evil

-- 
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exMULTI, Inc.
jgar...@exmulti.com

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Re: [Bitcoin-development] bitcoin pull requests

2013-04-01 Thread Petr Praus
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.


On 1 April 2013 03:26, Melvin Carvalho melvincarva...@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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Re: [Bitcoin-development] bitcoin pull requests

2013-04-01 Thread Melvin Carvalho
On 1 April 2013 20:28, Petr Praus p...@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 melvincarva...@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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Re: [Bitcoin-development] bitcoin pull requests

2013-04-01 Thread Melvin Carvalho
On 2 April 2013 00:10, Will w...@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 melvincarva...@gmail.com wrote:




 On 1 April 2013 20:28, Petr Praus p...@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 melvincarva...@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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Re: [Bitcoin-development] bitcoin pull requests

2013-04-01 Thread Roy Badami
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 w...@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 melvincarva...@gmail.com wrote:
 
 
 
 
  On 1 April 2013 20:28, Petr Praus p...@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 melvincarva...@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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  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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Re: [Bitcoin-development] bitcoin pull requests

2013-04-01 Thread Roy Badami
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 w...@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 melvincarva...@gmail.com wrote:
  
  
  
  
   On 1 April 2013 20:28, Petr Praus p...@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 melvincarva...@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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