đź“… Original date posted:2017-01-03
đź“ť Original message:No, there could only have not more than 201 opcodes in a script. So you may have 198 OP_2DUP at most, i.e. 198 * 520 * 2 = 206kB
For OP_CAT, just check if the returned item is within the 520 bytes limit.
> On 3 Jan 2017, at 11:27, Jeremy via bitcoin-dev <bitcoin-dev at lists.linuxfoundation.org> wrote:
>
> It is an unfortunate script, but can't actually ​do that much​ it seems​. The MAX_SCRIPT_ELEMENT_SIZE = 520 Bytes.​ Thus, it would seem the worst you could do with this would be to (10000-520*2)*520*2 bytes ~=~ 10 MB.
>
> ​Much more concerning would be the op_dup/op_cat style bug, which under a similar script ​would certainly cause out of memory errors :)
>
>
>
> --
> @JeremyRubin <https://twitter.com/JeremyRubin>; <https://twitter.com/JeremyRubin>;
> On Mon, Jan 2, 2017 at 4:39 PM, Steve Davis via bitcoin-dev <bitcoin-dev at lists.linuxfoundation.org <mailto:bitcoin-dev at lists.linuxfoundation.org>> wrote:
> Hi all,
>
> Suppose someone were to use the following pk_script:
>
> [op_2dup, op_2dup, op_2dup, op_2dup, op_2dup, ...(to limit)..., op_2dup, op_hash160, <addr_hash>, op_equalverify, op_checksig]
>
> This still seems to be valid AFAICS, and may be a potential attack vector?
>
> Thanks.
>
>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev at lists.linuxfoundation.org <mailto:bitcoin-dev at lists.linuxfoundation.org>
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>;
>
>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev at lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20170103/fe247bca/attachment-0001.html>;
Johnson Lau [ARCHIVE] /
npub1fy…p2mv9
2023-06-07 17:55:18
in reply to nevent1q…dmhn
Author Public Key
npub1fyh6gqhg8zgyhhywkty047s64z2a7fjr307enrr3kqwtnk64plmsup2mv9Published at
2023-06-07 17:55:18Event JSON
{
"id": "a199a683ae6e0460422ddf056028cfdb746ed859a7b693a11a8e5768fd220900",
"pubkey": "492fa402e838904bdc8eb2c8fafa1aa895df26438bfd998c71b01cb9db550ff7",
"created_at": 1686160518,
"kind": 1,
"tags": [
[
"e",
"043f6ae3bedb0353c85b6fa3949c825b98fc4c39925e6a24626844479be4b554",
"",
"root"
],
[
"e",
"09ac1ac8da19d49779c72f7e715e1acb008a54fefde00763c77da2383a5d08a0",
"",
"reply"
],
[
"p",
"01f53a3166b3b23139201763777e070fcfed5555ad7555f7e90114c0c9e0e8b4"
]
],
"content": "📅 Original date posted:2017-01-03\n📝 Original message:No, there could only have not more than 201 opcodes in a script. So you may have 198 OP_2DUP at most, i.e. 198 * 520 * 2 = 206kB\n\nFor OP_CAT, just check if the returned item is within the 520 bytes limit.\n\n\u003e On 3 Jan 2017, at 11:27, Jeremy via bitcoin-dev \u003cbitcoin-dev at lists.linuxfoundation.org\u003e wrote:\n\u003e \n\u003e It is an unfortunate script, but can't actually ​do that much​ it seems​. The MAX_SCRIPT_ELEMENT_SIZE = 520 Bytes.​ Thus, it would seem the worst you could do with this would be to (10000-520*2)*520*2 bytes ~=~ 10 MB.\n\u003e \n\u003e ​Much more concerning would be the op_dup/op_cat style bug, which under a similar script ​would certainly cause out of memory errors :)\n\u003e \n\u003e \n\u003e \n\u003e --\n\u003e @JeremyRubin \u003chttps://twitter.com/JeremyRubin\u003e \u003chttps://twitter.com/JeremyRubin\u003e\n\u003e On Mon, Jan 2, 2017 at 4:39 PM, Steve Davis via bitcoin-dev \u003cbitcoin-dev at lists.linuxfoundation.org \u003cmailto:bitcoin-dev at lists.linuxfoundation.org\u003e\u003e wrote:\n\u003e Hi all,\n\u003e \n\u003e Suppose someone were to use the following pk_script:\n\u003e \n\u003e [op_2dup, op_2dup, op_2dup, op_2dup, op_2dup, ...(to limit)..., op_2dup, op_hash160, \u003caddr_hash\u003e, op_equalverify, op_checksig]\n\u003e \n\u003e This still seems to be valid AFAICS, and may be a potential attack vector?\n\u003e \n\u003e Thanks.\n\u003e \n\u003e \n\u003e _______________________________________________\n\u003e bitcoin-dev mailing list\n\u003e bitcoin-dev at lists.linuxfoundation.org \u003cmailto:bitcoin-dev at lists.linuxfoundation.org\u003e\n\u003e https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev \u003chttps://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev\u003e\n\u003e \n\u003e \n\u003e _______________________________________________\n\u003e bitcoin-dev mailing list\n\u003e bitcoin-dev at lists.linuxfoundation.org\n\u003e https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev\n\n-------------- next part --------------\nAn HTML attachment was scrubbed...\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20170103/fe247bca/attachment-0001.html\u003e",
"sig": "d1b1f5d58257ccf311bd37346b74f42d8bc0957befe418542962e3461e029c393df3bcf56d29807a2d4bff4cded40d97437931dbc9ffc8b26a85aa5673849b73"
}