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From: Pieter Wuille <pieter.wuille@gmail.com>
To: Peter Todd <pete@petertodd.org>
Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] SCRIPT_VERIFY_STRICTENC and CHECKSIG NOT
Date: Thu, 6 Nov 2014 02:47:29 -0800	[thread overview]
Message-ID: <CAPg+sBgBhemhPid0LcB9NAHckSmwPuQRRp-6CBVOe5CcOUH8NA@mail.gmail.com> (raw)
In-Reply-To: <20141106103820.GA17096@savin.petertodd.org>

On Thu, Nov 6, 2014 at 2:38 AM, Peter Todd <pete@petertodd.org> wrote:
> However the implementation of the STRICTENC flag simply makes pubkey
> formats it doesn't recognize act as through the signature was invalid,
> rather than failing the transaction. Similar to the invalid due to too
> many sigops DoS attack I found before, this lets you fill up the mempool
> with garbage transactions that will never be mined. OTOH I don't see any
> way to exploit this in a v0.9.x IsStandard() transaction, so we haven't
> shipped code that actually has this vulnerability. (dunno about
> alt-implementations)

Yeah, there's even a comment in script/interpreter.h currently about
how STRICTENC is not softfork safe. I didn't realize that this would
lead to the mempool accepting invalid transactions (I thought there
was a second validity check with the actual consensus rules; if not,
maybe we need to add that).

> I suggest we either change STRICTENC to simply fail unrecognized pubkeys
> immediately - similar to how non-standard signatures are treated - or
> fail the script if the pubkey is non-standard and signature verification
> succeeds.

Sounds good to me, I disliked those semantics too.

-- 
Pieter



  parent reply	other threads:[~2014-11-06 10:47 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-06 10:38 [Bitcoin-development] SCRIPT_VERIFY_STRICTENC and CHECKSIG NOT Peter Todd
2014-11-06 10:45 ` Peter Todd
2014-11-06 12:39   ` Marius Hanne
2014-11-06 10:47 ` Pieter Wuille [this message]
2014-11-06 10:51   ` Pieter Wuille
2014-11-06 11:04   ` Peter Todd

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