I'm not talking about workarounds specifically for nVersion, but for all
the other stuff that is seen as non-standard by bitcoind, such as dust
transactions, disabled op codes and other stuff, otherwise someone could
send one transaction to a libbitcoin node which is accepted and other to
the rest of the network which eventually gets confirmed, meaning the
original to libbitcoin becomes invalid. (Proper precautions for race
attacks should prevent against this though).

The pull request here.

https://github.com/bitcoin/bitcoin/pull/2982/files

seems a bit of a big workaround when the main problem is that the value is
being deserialized as a signed integer, rather than a uint32_t.

https://github.com/bitcoin/bitcoin/blob/481d89979457d69da07edd99fba451fd42a47f5c/src/core.h#L184

Maybe I'm missing something and they're not able to change the CTransaction
nVersion though.

I couldn't find any other documentation about the data type for nVersion
other than here
https://en.bitcoin.it/wiki/Protocol_specification#tx

Thanks
Bob


On 9 September 2013 19:56, Amir Taaki <genjix@???> wrote:

> > No. The proper way is to investigate and see how nVersion affects
> libbitcoin. Not to add workarounds.
>
> On 09/09/13 19:21, Robert Williamson wrote:
> > Pretty scary, I always thought nVersion was uint32_t in the
> > protocol and any signed value would be cast to that before
> > IsStandard.
> >
> > Also, is there any need to improve basic_checks() and is_standard()
> > to match the current bitcoind implementation at the current time,
> > or is it best to just allow bitcoind nodes in the network to filter
> > out non-standard transactions and only use basic checks to ensure
> > we never accept something invalid and cause libbitcoin to follow a
> > blockchain fork?
> >
> > https://github.com/spesmilo/libbitcoin/blob/master/src/validate.cpp#L53
> >
> > I like
> > https://github.com/spesmilo/libbitcoin/blob/master/src/validate.cpp#L78,
> >
> >
> even though it is never called, it has a very http://xkcd.com/221 feel
> > to it.
> >
> >
> >
> >
> >
> > On 9 September 2013 14:09, Amir Taaki <genjix@???
> > <mailto:genjix@riseup.net>> wrote:
> >
> > my wallet crashed bitcoind!
> >
> > https://github.com/bitcoin/bitcoin/pull/2982
> >
> >
> https://github.com/spesmilo/sx/commit/f5e3ca9485438adc5bea93eba34e3f56e606f151
> >
> > -------- Original Message -------- Subject: Re: Strange
> > transactions Date: Mon, 09 Sep 2013 13:44:19 +0200 From: Amir Taaki
> > <genjix@??? <mailto:genjix@riseup.net>> To: Gregory Maxwell
> > <gmaxwell@??? <mailto:gmaxwell@gmail.com>>
> >
> > ah I forgot to set it. Thanks.
> >
> > On 09/09/13 13:42, Gregory Maxwell wrote:
> >> On Mon, Sep 9, 2013 at 4:38 AM, Amir Taaki <genjix@???
> > <mailto:genjix@riseup.net>>
> >> wrote:
> >>> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
> >>>
> >>> Both from here http://i.imgur.com/YUzk1cM.png
> >
> >> Cool. Any idea why they have negative nversion?
> >
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