Disclosure of hindered block propagation due to mutated blocks
Before Bitcoin Core v25.0, a peer sending mutated blocks could clear the
download state of other peers that also announced the block to us, which would
hinder block propagation.
This issue is considered Medium severity.
Details
Bitcoin Core treats a block as mutated when, for example, the Merkle root in the
header or the witness commitment in the coinbase transaction doesn’t match the
transactions in the block.
Before Bitcoin Core v25.0, a peer could clear the block download state of
other peers by sending an unrequested mutated block. This was a problem for, for
example, compact block relay. After receiving a compact block and while waiting
for a response to a getblocktxn request to reconstruct the full block,
receiving the mutated block would let Bitcoin Core forget about the compact
block reconstruction state. A blocktxn response arriving after the mutated
block couldn’t be used to reconstruct the block. This hindered block propagation.
This was fixed in #27608 by
making sure that a peer can only affect its own block download state and not the
download state of other peers.
Attribution
Credit goes to Suhas Daftuar for noticing the problem and working on a fix.
Timeline
2023-05-08 - A problem with mutated blocks is first reported in the #bitcoin-core-dev IRC channel.
2023-05-10 - Fix is merged (#27608)
2023-05-25 - v25.0 is released
2024-10-09 - Public disclosure
https://bitcoincore.org/en/2024/10/08/disclose-mutated-blocks-hindering-propagation/
#Eenentwintig #Nieuws #News #BitcoinNews
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npub10e…g0kj9
2024-10-09 18:00:39
Author Public Key
npub10en2rrs3t9qvgyxjj7c8ku8cmypvmrvrzzthpyd4zzqpwqfdkl7qqg0kj9Published at
2024-10-09 18:00:39Event JSON
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"pubkey": "7e66a18e115940c410d297b07b70f8d902cd8d8310977091b5108017012db7fc",
"created_at": 1728496839,
"kind": 1,
"tags": [],
"content": "Disclosure of hindered block propagation due to mutated blocks\n\nBefore Bitcoin Core v25.0, a peer sending mutated blocks could clear the\ndownload state of other peers that also announced the block to us, which would\nhinder block propagation.\nThis issue is considered Medium severity.\nDetails\nBitcoin Core treats a block as mutated when, for example, the Merkle root in the\nheader or the witness commitment in the coinbase transaction doesn’t match the\ntransactions in the block.\nBefore Bitcoin Core v25.0, a peer could clear the block download state of\nother peers by sending an unrequested mutated block. This was a problem for, for\nexample, compact block relay. After receiving a compact block and while waiting\nfor a response to a getblocktxn request to reconstruct the full block,\nreceiving the mutated block would let Bitcoin Core forget about the compact\nblock reconstruction state. A blocktxn response arriving after the mutated\nblock couldn’t be used to reconstruct the block. This hindered block propagation.\nThis was fixed in #27608 by\nmaking sure that a peer can only affect its own block download state and not the\ndownload state of other peers.\nAttribution\nCredit goes to Suhas Daftuar for noticing the problem and working on a fix.\nTimeline\n2023-05-08 - A problem with mutated blocks is first reported in the #bitcoin-core-dev IRC channel.\n2023-05-10 - Fix is merged (#27608)\n2023-05-25 - v25.0 is released\n2024-10-09 - Public disclosure\n\nhttps://bitcoincore.org/en/2024/10/08/disclose-mutated-blocks-hindering-propagation/\n\n#Eenentwintig #Nieuws #News #BitcoinNews",
"sig": "754ff6336a5084ef453b25e2c5b7ac543c675789569426e168e65aad8ab84e58a25f03d92fa305f14513a7ba21a41889859dce46bc970b54018c4fe7a897ac5d"
}