Re: [Bitcoin-development] Re-enabling simple tx replacement
On Sun, Jan 4, 2015 at 2:43 PM, Ross Nicoll j...@jrn.me.uk wrote: Dear all, I've been looking at atomic cross-chain trading ( https://en.bitcoin.it/wiki/Atomic_cross-chain_trading ) between the Bitcoin and Dogecoin blockchains, and have a mostly functional prototype. However as it stands if the refund transaction is relayed before the actual spend transaction, it blocks the legitimate spend transaction from being accepted into the memory pool. Unless there is a serious bug that I am not aware of this is not the case. The unlocked transaction is not relayable and will not be mempooled (well, until right before it locks). I've drafted a patch for this https://github.com/rnicoll/bitcoin/commit/e668d36607f008990ccaac7275e463a6efdd9b5a but have not yet raised a PR, as historically this has lead to a lot of discussion in Github which is better suited to this mailing list. I'm therefore looking for feedback while I continue testing that patch, and any comments would be welcomed. This appears to have absolutely no protection against denial of service, it seems to me that a single user can rapidly update their transaction and exhaust the relay bandwidth of the entire network. -- Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Re-enabling simple tx replacement
On 04/01/15 17:04, Gregory Maxwell wrote: On Sun, Jan 4, 2015 at 2:43 PM, Ross Nicoll j...@jrn.me.uk wrote: Dear all, I've been looking at atomic cross-chain trading ( https://en.bitcoin.it/wiki/Atomic_cross-chain_trading ) between the Bitcoin and Dogecoin blockchains, and have a mostly functional prototype. However as it stands if the refund transaction is relayed before the actual spend transaction, it blocks the legitimate spend transaction from being accepted into the memory pool. Unless there is a serious bug that I am not aware of this is not the case. The unlocked transaction is not relayable and will not be mempooled (well, until right before it locks). Grabbing a simple test case: https://chain.so/tx/BTCTEST/f903a31f2474df737d324c60abf2407e1cf7e052844da4ccffbfab81cf6ac1f8 - that won't lock until 0028 UTC on the 5th. I've tried closing the wallet, moving the wallet.dat file out of the way, and then attempting the spend transaction (which can be locked immediately), and it either rejects it on acceptance to mempool, or it is never included in a block. Compare with https://chain.so/tx/BTCTEST/0b96eb0c9bf8a6ca08bb9d75e44970889db9c6d3122296c0169959f979cc where the refund was not sent first, and the transaction has succeeded. I've drafted a patch for this https://github.com/rnicoll/bitcoin/commit/e668d36607f008990ccaac7275e463a6efdd9b5a but have not yet raised a PR, as historically this has lead to a lot of discussion in Github which is better suited to this mailing list. I'm therefore looking for feedback while I continue testing that patch, and any comments would be welcomed. This appears to have absolutely no protection against denial of service, it seems to me that a single user can rapidly update their transaction and exhaust the relay bandwidth of the entire network. They can only replace a non-final transaction with a final transaction, so the replacement can happen at most once (any later replacement would be attempting to replace a final transaction, and therefore fails). So, while they can expend twice the bandwidth compared to a non-replacement, I don't think that's a major issue? -- Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Re-enabling simple tx replacement
On Sun, Jan 4, 2015 at 5:22 PM, Ross Nicoll j...@jrn.me.uk wrote: Grabbing a simple test case: https://chain.so/tx/BTCTEST/f903a31f2474df737d324c60abf2407e1cf7e052844da4ccffbfab81cf6ac1f8 - that won't lock until 0028 UTC on the 5th. I've tried closing the wallet, moving the wallet.dat file out of the way, and then attempting the spend transaction (which can be locked immediately), and it either rejects it on acceptance to mempool, or it is never included in a block. Can you send me the actual raw transaction (that site doesn't appear have a way to get it, only some cooked json output; which doesn't include the sequence number). As I said, it's a severe bug if unlocked transactions are being relayed or mempooled far in advance. They can only replace a non-final transaction with a final transaction, Ah I missed that the replacement had to be final. Thats indeed a much more sane thing to do than I was thinking (sorry for some reason I saw the +1 and thought it was just checking the sequence number was higher.) I don't think that's a major issue? If they can relay the first one to begin with its an an issue, the replacement just makes it twice an issue. :) -- Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Re-enabling simple tx replacement
On 04/01/15 17:35, Gregory Maxwell wrote: On Sun, Jan 4, 2015 at 5:22 PM, Ross Nicoll j...@jrn.me.uk wrote: Grabbing a simple test case: https://chain.so/tx/BTCTEST/f903a31f2474df737d324c60abf2407e1cf7e052844da4ccffbfab81cf6ac1f8 - that won't lock until 0028 UTC on the 5th. I've tried closing the wallet, moving the wallet.dat file out of the way, and then attempting the spend transaction (which can be locked immediately), and it either rejects it on acceptance to mempool, or it is never included in a block. Can you send me the actual raw transaction (that site doesn't appear have a way to get it, only some cooked json output; which doesn't include the sequence number). As I said, it's a severe bug if unlocked transactions are being relayed or mempooled far in advance. Attached. Sequence number for the input is set to 1, please do tell me if I've misunderstood how it's used. They can only replace a non-final transaction with a final transaction, Ah I missed that the replacement had to be final. Thats indeed a much more sane thing to do than I was thinking (sorry for some reason I saw the +1 and thought it was just checking the sequence number was higher.) I don't think that's a major issue? If they can relay the first one to begin with its an an issue, the replacement just makes it twice an issue. :) I'll set up a few nodes tomorrow and double check it's in fact relaying in the latest version. If it's simply an issue of incorrect relaying, that's significantly simpler at least, and the problem can be tackled through that instead. 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-- Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Re-enabling simple tx replacement
On Sun, Jan 4, 2015 at 5:35 PM, Gregory Maxwell gmaxw...@gmail.com wrote: Can you send me the actual raw transaction (that site doesn't appear have a way to get it, only some cooked json output; which doesn't include the sequence number). Nevermind, I guess. I think I figured out your problem: The behaviour on testnet is busted because the non-mempooling is enforced by IsStandardTx which is bypassed in testnet. We should enforce that elsewhere. This isn't the case on the real network. -- Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Re-enabling simple tx replacement
On Sun, Jan 04, 2015 at 05:44:59PM +, Gregory Maxwell wrote: On Sun, Jan 4, 2015 at 5:35 PM, Gregory Maxwell gmaxw...@gmail.com wrote: Can you send me the actual raw transaction (that site doesn't appear have a way to get it, only some cooked json output; which doesn't include the sequence number). Nevermind, I guess. I think I figured out your problem: The behaviour on testnet is busted because the non-mempooling is enforced by IsStandardTx which is bypassed in testnet. We should enforce that elsewhere. This isn't the case on the real network. Yup. I have a pull-req open to fix this: https://github.com/bitcoin/bitcoin/pull/5521 -- 'peter'[:-1]@petertodd.org 0237ec84e4b02efbdf3bcbf62308c873da802caedd12432f signature.asc Description: Digital signature -- Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
Re: [Bitcoin-development] Re-enabling simple tx replacement
On 04/01/15 17:44, Gregory Maxwell wrote: On Sun, Jan 4, 2015 at 5:35 PM, Gregory Maxwell gmaxw...@gmail.com wrote: Can you send me the actual raw transaction (that site doesn't appear have a way to get it, only some cooked json output; which doesn't include the sequence number). Nevermind, I guess. I think I figured out your problem: The behaviour on testnet is busted because the non-mempooling is enforced by IsStandardTx which is bypassed in testnet. We should enforce that elsewhere. This isn't the case on the real network. Ah, thanks for that. I'll try Peter's patch for testnet tomorrow, sounds like it should fix this for my use case. -- Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net ___ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
