From: Gavin Andresen <gavinandresen@gmail•com>
To: Luke-Jr <luke@dashjr•org>
Cc: bitcoin-development@lists•sourceforge.net
Subject: Re: [Bitcoin-development] Newly introduced DoS
Date: Mon, 26 Sep 2011 17:38:41 -0400 [thread overview]
Message-ID: <CABsx9T0TN+Nzzjod7xNJk4PNHnWPMWZUVsTHP3Yxq0C_-EgBLQ@mail.gmail.com> (raw)
In-Reply-To: <201109261655.59768.luke@dashjr.org>
> The first one I was referring to is a *transaction* with "non-standard" sig op
> count, which is AFAIK allowed in blocks, just not accepted by the mainline
> rules.
I sit corrected. The context is:
// Checking ECDSA signatures is a CPU bottleneck, so to avoid
denial-of-service
// attacks disallow transactions with more than one SigOp per 34
bytes.
// 34 bytes because a TxOut is:
// 20-byte address + 8 byte bitcoin amount + 5 bytes of ops + 1
byte script length
if (GetSigOpCount() > nSize / 34 || nSize < 100)
return DoS(10, error("AcceptToMemoryPool() : transaction with
out-of-bounds SigOpCount"));
I'm having trouble imagining some future world where valid,
new-versions-agree-to-relay-transactions have more than one SigOp per
34 bytes; can you give an example?
> Maybe the person spending it sees it matured beyond 100 confirmations, and you
> only see 99. An attacker could use these things to get nodes to ban each
> other.
That would imply you're on a blockchain fork of more than 99 blocks
with respect to the person spending the transaction, in which case I'd
argue you have much bigger problems and it is a good idea for the DoS
code to kick in and kick either you or them off the network...
--
--
Gavin Andresen
next prev parent reply other threads:[~2011-09-26 21:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-26 19:17 Luke-Jr
2011-09-26 20:47 ` Gavin Andresen
2011-09-26 20:55 ` Luke-Jr
2011-09-26 21:38 ` Gavin Andresen [this message]
2011-09-26 21:53 ` Luke-Jr
2011-09-26 22:34 ` theymos
2011-09-27 0:07 ` Gavin Andresen
2011-09-27 20:08 ` Luke-Jr
2011-09-27 20:23 ` Gregory Maxwell
2011-09-27 20:39 ` Gavin Andresen
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