fix(l1 follower, rollup verifier): blockhash mismatch #1192

jonastheis · 2025-05-29T07:40:15Z

1. Purpose or design rationale of this PR

This PR fixes the problem of mismatching block hashes due to the missing header fields difficulty and extraData in DA. It should be reviewed in conjunction with #903, which provides a way to prepare this missing data and describes the format in more detail.

Specifically, this PR implements a missing header fields manager that:

lazily downloads the missing header data if not present
verifies SHA256 checksum of the missing header fields data with hardcoded checksum that is part of the chain config
provides functionality to read the missing header fields when syncing from DA

Tested on Sepolia:

make nccc_geth && ./build/bin/geth --scroll-sepolia --scroll-mpt \
--datadir "tmp/sepolia-test" \
--gcmode archive \
--http --http.addr "0.0.0.0" --http.port 8545 --http.api "eth,net,web3,debug,scroll" --http.vhosts "*" \
--da.sync=true \
--da.blob.blobscan "https://api.sepolia.blobscan.com/blobs/" \
--da.blob.beaconnode "<beacon node>" \
--l1.endpoint "<L1 endpoint>" \
--verbosity 3

INFO [06-02|10:38:58.797] Downloading missing header fields. This might take a while... url=https://scroll-block-missing-metadata.s3.us-west-2.amazonaws.com/534351.bin
INFO [06-02|10:38:59.560] Downloading missing header fields... 0 MB / 801 MB 
INFO [06-02|10:39:04.586] Downloading missing header fields... 7 MB / 801 MB
[...]
INFO [06-02|10:42:25.322] L1 sync progress                         L1 processed=4,041,836 L1 finalized=8,459,461 progress(%)=47.779 L2 height=4370 L2 hash=0x89432d03f5f784437327a599d16a32bbc787d344e8bd5f5963c6f21c38479e0a

After a restart the header file is not downloaded again. The L1 syncing process can just continue. As can be seen the generated block hash matches.

$ cast block 4370 --rpc-url=https://sepolia-rpc.scroll.io


baseFeePerGas
difficulty           2
extraData            0xd883040321846765746888676f312e31392e31856c696e757800000000000000d83352a5203d2199e97ef277d284adeb6a0304925e8ccdc2abe09c402b8d6d1a3433bbc09a57ffd77be1dc366341a889e01918ad49c1cb54f4ed56c465c3183600
gasLimit             8000000
gasUsed              55018
hash                 0x89432d03f5f784437327a599d16a32bbc787d344e8bd5f5963c6f21c38479e0a
logsBloom            0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000400000000000000000000000000000000000000000000000000800000000000000000000000000000000000000000000000000000000000c00000000000000000000000000000000000000000000800000000000000000000200000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000100000000000000000200000000000000000200000000000000000000000000000000000000000000000000000000000000000000000000000000
miner                0x0000000000000000000000000000000000000000
mixHash              0x0000000000000000000000000000000000000000000000000000000000000000
nonce                0x0000000000000000
number               4370
parentHash           0x8b0b592d47119997ec6f6d5db399f712084ae8a3ab107122f66053c32d334db4
parentBeaconRoot
transactionsRoot     0x59e4d1a6e7e106a488aaef32bdac3ba8bbf0fe9e86f696000edfb777bf112c17
receiptsRoot         0x96551d06a025e4f35423661be2b1272341f87b5e362f33c39758fd4979fc3a7a
sha3Uncles           0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347
size                 991
stateRoot            0x18dcddc6754f95f0209089b0e139858cf27e4420b5e7077a4893e1775486762e
timestamp            1691652216 (Thu, 10 Aug 2023 07:23:36 +0000)
withdrawalsRoot
totalDifficulty      8741
blobGasUsed
excessBlobGas
requestsHash
transactions:        [
	0x3ad69e516079396cbd3240d0b229c06c881ca63b69333eafc97792a6bfb747c5
]

Synced to the latest finalized block:

Tested on mainnet:

make nccc_geth && ./build/bin/geth --scroll --scroll-mpt \
--datadir "tmp/mainnet-test" \
--gcmode archive \
--http --http.addr "0.0.0.0" --http.port 8545 --http.api "eth,net,web3,debug,scroll" --http.vhosts "*" \
--da.sync=true \
--da.blob.beaconnode "<beacon node>" \
--l1.endpoint "<L1 RPC>" \
--verbosity 3

INFO [06-02|12:40:19.157] Downloading missing header fields. This might take a while... url=https://scroll-block-missing-metadata.s3.us-west-2.amazonaws.com/534352.bin
INFO [06-02|12:40:20.179] Downloading missing header fields... 0 MB / 1407 MB 
INFO [06-02|12:40:25.206] Downloading missing header fields... 16 MB / 1407 MB 
[...]
INFO [06-02|10:42:25.322] L1 sync progress                         L1 processed=4,041,836 L1 finalized=8,459,461 progress(%)=47.779 L2 height=141498 L2 hash=0x8828523c2aca67fc54fc52ea45fd3b10743001e7cbc5d0e704cfb3d53ab7b9c7

After a restart the header file is not downloaded again. The L1 syncing process can just continue. As can be seen the generated block hash matches.

$ cast block 141498 --rpc-url=https://rpc.scroll.io


baseFeePerGas
difficulty           2
extraData            0xd883050001846765746888676f312e31392e31856c696e757800000000000000760fcd08267675948a9bd19199347296df16cdf0bb82cd7f36795629ca36ce750cfcd76ee934237b28fdb541e34bf09e41f01447e8e4b9f33601c1195499f59301
gasLimit             10000000
gasUsed              159943
hash                 0x8828523c2aca67fc54fc52ea45fd3b10743001e7cbc5d0e704cfb3d53ab7b9c7
logsBloom            0x00000000000000000000000000000000000000000000000000000000000002000000000000000000000040000000000000000000000000000000000000000000000000000000000000000008000008000000000000000009000000000000000000000000020008000000000000000800000000000000000000000010000420000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000002000000000008000000000000000000000000000000000000000020000000000000002000000000000000000000020000000000000000000000000100
miner                0x0000000000000000000000000000000000000000
mixHash              0x0000000000000000000000000000000000000000000000000000000000000000
nonce                0x0000000000000000
number               141498
parentHash           0xb57533a8ef8414506bd8af48884ab7283a653fe1485ea84156921237b0d6691e
parentBeaconRoot
transactionsRoot     0x6c533608b1915b1cdee26aab0f74acd509d37ad99c950fb61e50154751e02f4e
receiptsRoot         0xf39d1001ac70825f2ff1c341efd025b7fbc98812723830f392779f7758f70b8b
sha3Uncles           0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347
size                 722
stateRoot            0x14dcf7f26a6d706785ede826ae68953b0c42c2286ececf260bd1ac0534c0a181
timestamp            1697749500 (Thu, 19 Oct 2023 21:05:00 +0000)
withdrawalsRoot
totalDifficulty      282997
blobGasUsed
excessBlobGas
requestsHash
transactions:        [
	0x1f22baba6174ded8c15abbb20ac9ad21088b26981d789d8783bd1caf1472537d
]

Synced to the latest finalized block:

2. PR title

Your PR title must follow conventional commits (as we are doing squash merge for each PR), so it must start with one of the following types:

build: Changes that affect the build system or external dependencies (example scopes: yarn, eslint, typescript)
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docs: Documentation-only changes
feat: A new feature
fix: A bug fix
perf: A code change that improves performance
refactor: A code change that doesn't fix a bug, or add a feature, or improves performance
style: Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc)
test: Adding missing tests or correcting existing tests

3. Deployment tag versioning

Has the version in params/version.go been updated?

This PR doesn't involve a new deployment, git tag, docker image tag, and it doesn't affect traces
Yes

4. Breaking change label

Does this PR have the breaking-change label?

This PR is not a breaking change
Yes

coderabbitai · 2025-05-29T07:40:22Z

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semgrep-app · 2025-05-29T07:41:46Z

Semgrep found 1 ssc-089edcd4-740d-452f-b7f4-23e72908be35 finding:

rollup/missing_header_fields/export-headers-toolkit/go.mod
- L14 - Triage

Risk: Affected versions of github.com/btcsuite/btcd are vulnerable to Always-Incorrect Control Flow Implementation. The btcd Bitcoin client did not correctly re-implement Bitcoin Core's "FindAndDelete()" functionality. This logic is consensus-critical: the difference in behavior with the other Bitcoin clients can lead to btcd clients accepting an invalid Bitcoin block (or rejecting a valid one).

Fix: Upgrade this library to at least version 0.24.2-beta.rc1 at go-ethereum/rollup/missing_header_fields/export-headers-toolkit/go.mod:14.

Reference(s): GHSA-27vh-h6mc-q6g8, CVE-2024-38365

…port reset of syncing pipeline

cmd/utils/flags.go

rollup/missing_header_fields/manager.go

rollup/missing_header_fields/manager_test.go

rollup/missing_header_fields/reader.go

rollup/missing_header_fields/reader_test.go

…ng header fields file

georgehao · 2025-06-19T09:46:19Z

core/blockchain.go

@@ -1880,15 +1880,17 @@ func (bc *BlockChain) BuildAndWriteBlock(parentBlock *types.Block, header *types

 	header.ParentHash = parentBlock.Hash()

+	// sanitize base fee
+	if header.BaseFee != nil && header.BaseFee.Cmp(common.Big0) == 0 {


What's the reason to reset the header's BaseFee?

it's due to differences in serialization and therefore the block hash. big.Int == 0 is serialized while big.Int == nil is not. during testing it became clear that this needs to be done so the block hashes will end up matching

georgehao · 2025-06-19T10:05:07Z

eth/backend.go

+				return nil, fmt.Errorf("cannot create missing header fields manager: %w", err)
+			}
+
+			eth.syncingPipeline, err = da_syncer.NewSyncingPipeline(context.Background(), eth.blockchain, chainConfig, eth.chainDb, l1Client, stack.Config().L1DeploymentBlock, config.DA, missingHeaderFieldsManager)


Why not init missingHeaderFieldsManager inside the SyncingPipeline?

there's too many dependencies (and implicit behavior) so that imo it's more fitting to do it when setting up the node

georgehao · 2025-06-19T10:12:50Z

rollup/missing_header_fields/export-headers-toolkit/go.mod

@@ -2,17 +2,19 @@ module github.com/scroll-tech/go-ethereum/export-headers-toolkit

 go 1.22

+replace github.com/scroll-tech/go-ethereum => ../../..


No it's so this separate submodule uses the correct version of the l2geth code base. Since the export toolkit from #903 is only used separately to export block headers once this should be ok

georgehao · 2025-06-19T10:40:31Z

eth/backend.go

+	downloadURL, err := url.Parse(stack.Config().DAMissingHeaderFieldsBaseURL)
+	if err != nil {
+		return nil, fmt.Errorf("invalid DAMissingHeaderFieldsBaseURL: %w", err)
+	}
+	downloadURL.Path = path.Join(downloadURL.Path, chainConfig.ChainID.String()+".bin")


How about:

downloadUrl := stack.Config().DAMissingHeaderFieldsBaseURL + "/" + chainConfig.ChainID.String()+".bin"

Since the flag is a user input I think the correct way is sanitizing the flag properly with url.Parse and subsequently using path.Join to join as this will remove any duplicate / and so forth when concatenating the different url segments

georgehao · 2025-06-19T10:43:25Z

rollup/missing_header_fields/manager.go

+
+func (m *Manager) GetMissingHeaderFields(headerNum uint64) (difficulty uint64, stateRoot common.Hash, coinbase common.Address, nonce types.BlockNonce, extraData []byte, err error) {
+	// lazy initialization: if the reader is not initialized this is the first time we read from the file
+	if m.reader == nil {


how about using sync.Once

the missing header fields manager is not suitable for concurrent usage. therefore I just used this simple nil check. It's been tested and verified to work on Sepolia and Mainnet

georgehao · 2025-06-19T11:28:29Z

another question: who upload the https://scroll-block-missing-metadata.s3.us-west-2.amazonaws.com/xxx.bin, blob_uploader?

jonastheis · 2025-07-08T06:25:16Z

another question: who upload the https://scroll-block-missing-metadata.s3.us-west-2.amazonaws.com/xxx.bin, blob_uploader?

This is uploaded by us by utilizing the toolkit from #903. It's a one time operation and as you can see in this PR the hash of the data is added to the genesis.

Thegaram · 2025-07-08T18:58:25Z

cmd/utils/flags.go

@@ -898,6 +898,12 @@ var (
 		Name:  "da.sync",
 		Usage: "Enable node syncing from DA",
 	}
+	DAMissingHeaderFieldsBaseURLFlag = cli.StringFlag{
+		Name:  "da.missingheaderfields.baseurl",


nitpick, but something like "block data hint" sounds nicer.

Thegaram · 2025-07-08T18:59:26Z

core/blockchain.go

@@ -1880,15 +1880,17 @@ func (bc *BlockChain) BuildAndWriteBlock(parentBlock *types.Block, header *types

 	header.ParentHash = parentBlock.Hash()

+	// sanitize base fee
+	if header.BaseFee != nil && header.BaseFee.Cmp(common.Big0) == 0 {


Will this break if we set base fee to 0? Or that is already invalid?

Thegaram · 2025-07-08T19:00:08Z

core/blockchain.go

@@ -1901,7 +1903,11 @@ func (bc *BlockChain) BuildAndWriteBlock(parentBlock *types.Block, header *types

 	// finalize and assemble block as fullBlock: replicates consensus.FinalizeAndAssemble()
 	header.GasUsed = gasUsed
-	header.Root = statedb.IntermediateRoot(bc.chainConfig.IsEIP158(header.Number))
+
+	// state root might be set from partial header. If it is not set, we calculate it.


It is set for pre-Euclid zktrie roots, right?

Thegaram · 2025-07-08T19:06:06Z

rollup/missing_header_fields/manager.go

+	computedChecksum := h.Sum(nil)
+	if !bytes.Equal(computedChecksum, m.expectedChecksum[:]) {
+		return fmt.Errorf("expectedChecksum mismatch, expected %x, got %x", m.expectedChecksum, computedChecksum)
+	}


If there's a partially downloaded file, or some random file, will we be stuck here? Should we remove the file and download again?

Thegaram · 2025-07-08T19:06:16Z

rollup/missing_header_fields/manager.go

+}
+func (m *Manager) Close() error {


Suggested change

}

func (m *Manager) Close() error {

}

func (m *Manager) Close() error {

Thegaram · 2025-07-08T19:08:15Z

rollup/missing_header_fields/manager.go

+		return fmt.Errorf("failed to create download request: %v", err)
+	}
+
+	resp, err := http.DefaultClient.Do(req)


I wonder if we can run into the previous "download hangs" issue. It would be nice to time out if we don't receive any data (but if we do, then `timeoutDownload is suitable).

Thegaram · 2025-07-08T19:08:54Z

rollup/missing_header_fields/manager.go

+}
+
+func (m *Manager) GetMissingHeaderFields(headerNum uint64) (difficulty uint64, stateRoot common.Hash, coinbase common.Address, nonce types.BlockNonce, extraData []byte, err error) {
+	// lazy initialization: if the reader is not initialized this is the first time we read from the file


So lazy init means that on devnets, new networks, etc. this is never called, right?

implement missing header fields reader and manager

4561826

jonastheis added the bump-version label May 29, 2025

jonastheis changed the base branch from develop to jt/export-headers-toolkit May 29, 2025 07:40

chore: auto version bump [bot]

a47ccd8

jonastheis added 3 commits May 29, 2025 12:00

increase download timeout

5774441

sanitize BaseFee when executing blocks from DA

66f0aef

initialize and pass missing header manager to DA syncing pipeline

7a48a92

jonastheis mentioned this pull request May 29, 2025

fix: blockhash mismatch #913

Closed

13 tasks

jonastheis added 8 commits May 29, 2025 19:43

Merge branch 'jt/export-headers-toolkit' into fix-blockhash-mismatch

30d5a46

add state root to deduplicated header

2ef390e

overwrite state root if given via missing header file

de651d9

Merge branch 'jt/export-headers-toolkit' into fix-blockhash-mismatch

3e33a8a

fix test

7d8bb01

set correct links and missing header file hashes

b90e909

allow reading of previous headers by resetting file and buffer to sup…

51d5c7d

…port reset of syncing pipeline

Merge branch 'jt/export-headers-toolkit' into fix-blockhash-mismatch

eaad65b

jonastheis requested review from Thegaram and colinlyguo June 2, 2025 10:58

colinlyguo reviewed Jun 4, 2025

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cmd/utils/flags.go Outdated Show resolved Hide resolved

rollup/missing_header_fields/manager.go Show resolved Hide resolved

rollup/missing_header_fields/manager_test.go Outdated Show resolved Hide resolved

rollup/missing_header_fields/reader.go Outdated Show resolved Hide resolved

colinlyguo reviewed Jun 4, 2025

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rollup/missing_header_fields/reader_test.go Show resolved Hide resolved

jonastheis added 8 commits June 5, 2025 08:48

address review comments

2ee9190

Merge branch 'jt/export-headers-toolkit' into fix-blockhash-mismatch

56cc282

Merge branch 'jt/export-headers-toolkit' into fix-blockhash-mismatch

8e4a635

add coinbase and nonce field to missing header reader

ed1f352

replace missing header reader in toolkit with actual implementation

32b8209

update sync from DA pipeline to include coinbase and nonce from missi…

b54c25f

…ng header fields file

update sha256 hashes for missing header fields files

3b78f62

lint

cc23f6d

address review comments

0559042

jonastheis requested a review from colinlyguo June 18, 2025 10:31

colinlyguo approved these changes Jun 18, 2025

View reviewed changes

georgehao reviewed Jun 19, 2025

View reviewed changes

Thegaram approved these changes Jul 8, 2025

View reviewed changes

		@@ -2,17 +2,19 @@ module github.com/scroll-tech/go-ethereum/export-headers-toolkit

		go 1.22

		replace github.com/scroll-tech/go-ethereum => ../../..

fix(l1 follower, rollup verifier): blockhash mismatch #1192

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fix(l1 follower, rollup verifier): blockhash mismatch #1192

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1. Purpose or design rationale of this PR

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3. Deployment tag versioning

4. Breaking change label

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