fix(blob clients): nil pointer with unexpected blob client response #1195

jonastheis · 2025-06-05T09:05:01Z

1. Purpose or design rationale of this PR

This PR fixes an issue where the blob client API delivers an unexpected response that is not checked for length before accessed.

WARN [06-05|06:46:37.665] BlobClients: failed to get blob by versioned hash from BlobClient err="beacon node request failed, status: 404 Not Found, body: {\"code\":404,\"message\":\"NOT_FOUND: no blobs stored for block 0xb2946d447a0dc81b6bcfe3119df4e05087126770b886092a2792992890f880b0\",\"stacktraces\":[]}" blob client pos in BlobClients=1
panic: runtime error: slice bounds out of range [2:0]
goroutine 88 [running]:
github.com/scroll-tech/go-ethereum/rollup/da_syncer/blob_client.(*BlobScanClient).GetBlobByVersionedHashAndBlockTime(0xc02bb31bc0, {0x1cea5a0, 0xc01a40a320}, {0x1, 0xb9, 0x1f, 0xc, 0xf6, 0x95, 0xa0, ...}, ...)
	github.com/scroll-tech/go-ethereum/rollup/da_syncer/blob_client/blob_scan_client.go:67 +0xde5
github.com/scroll-tech/go-ethereum/rollup/da_syncer/blob_client.(*BlobClients).GetBlobByVersionedHashAndBlockTime(0xc027f489a0, {0x1cea5a0, 0xc01a40a320}, {0x1, 0xb9, 0x1f, 0xc, 0xf6, 0x95, 0xa0, ...}, ...)
	github.com/scroll-tech/go-ethereum/rollup/da_syncer/blob_client/blob_client.go:41 +0x182
github.com/scroll-tech/go-ethereum/rollup/da_syncer/da.NewCommitBatchDAV1({0x1cea5a0, 0xc01a40a320}, {0x1cf6f78, 0xc000028558}, {0x1ce01e0?, 0xc027f489a0}, {0x1cf7df0, 0x29d3500}, 0xc02c2925b0, {0xc0303600a4, ...}, ...)
	github.com/scroll-tech/go-ethereum/rollup/da_syncer/da/commitV1.go:45 +0x1e9

2. PR title

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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

Summary by CodeRabbit

Bug Fixes
- Improved validation for blob data responses to prevent errors when handling invalid or empty data.
Chores
- Updated the patch version number.

coderabbitai · 2025-06-05T09:05:09Z

Walkthrough

The patch updates the patch version constant in the versioning parameters and introduces validation checks in two blob client modules to ensure blob data fields have a minimum length before decoding. These checks prevent errors when handling insufficient or invalid blob data in JSON responses.

Changes

File(s)	Change Summary
params/version.go	Incremented `VersionPatch` constant from 51 to 52.
rollup/da_syncer/blob_client/blob_scan_client.go, rollup/da_syncer/blob_client/block_native_client.go	Added validation to check blob data length before decoding; returns error if data is too short.

Sequence Diagram(s)

sequenceDiagram
    participant Client
    participant BlobClient
    participant JSONResponse

    Client->>BlobClient: Request blob data
    BlobClient->>JSONResponse: Decode JSON response
    JSONResponse-->>BlobClient: Return BlobResp struct
    BlobClient->>BlobClient: Check if Data length >= 2
    alt Data too short
        BlobClient-->>Client: Return error (data too short)
    else Data valid
        BlobClient->>BlobClient: Decode hex string
        BlobClient-->>Client: Return decoded data
    end

Suggested reviewers

Thegaram

Poem

A patch hops in, from fifty-one to two,
With checks on blobs—no short data gets through!
If your hex is too tiny, an error you'll see,
For robust code is as sweet as can be.
🐇✨ Version up, and bugs adieu!

📜 Recent review details

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📥 Commits

Reviewing files that changed from the base of the PR and between cdd77c1 and 6f24e3a.

📒 Files selected for processing (3)

params/version.go (1 hunks)
rollup/da_syncer/blob_client/blob_scan_client.go (1 hunks)
rollup/da_syncer/blob_client/block_native_client.go (1 hunks)

🧰 Additional context used

🧬 Code Graph Analysis (1)

rollup/da_syncer/blob_client/block_native_client.go (1)

crypto/kzg4844/kzg4844.go (1)

Blob (31-31)

⏰ Context from checks skipped due to timeout of 90000ms (1)

GitHub Check: Analyze (go)

🔇 Additional comments (3)

params/version.go (1)

27-27: LGTM! Appropriate version bump for bug fix.

The patch version increment aligns with the bug fix addressing nil pointer panics in blob client modules. This follows proper semantic versioning practices.

rollup/da_syncer/blob_client/block_native_client.go (1)

63-66: Excellent fix for the nil pointer panic issue!

This validation check effectively prevents the slice bounds out of range panic that was occurring when result.Blob.Data[2:] was accessed on strings shorter than 2 characters. The error message is informative and includes debugging context.

rollup/da_syncer/blob_client/blob_scan_client.go (1)

68-71: Consistent and effective validation implementation!

This validation check mirrors the fix in block_native_client.go, ensuring consistent handling of short blob data across both client implementations. The check prevents slice bounds panic when accessing result.Data[2:] and provides clear error messaging.

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colinlyguo

lgtm.

fix nil pointer with unexpected blob client response

80b8599

jonastheis added the bump-version label Jun 5, 2025

jonastheis requested review from Thegaram and colinlyguo June 5, 2025 09:05

chore: auto version bump [bot]

6f24e3a

colinlyguo approved these changes Jun 5, 2025

View reviewed changes

Thegaram approved these changes Jun 5, 2025

View reviewed changes

Thegaram merged commit 7fbc35d into develop Jun 5, 2025
4 checks passed

Thegaram deleted the fix/blob-client-nil-pointr branch June 5, 2025 09:20

colinlyguo mentioned this pull request Jun 18, 2025

feat(rollup-relayer): support codecv8 scroll-tech/scroll#1681

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fix(blob clients): nil pointer with unexpected blob client response #1195

fix(blob clients): nil pointer with unexpected blob client response #1195

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jonastheis commented Jun 5, 2025 •

edited by Thegaram

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fix(blob clients): nil pointer with unexpected blob client response #1195

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1. Purpose or design rationale of this PR

2. PR title

3. Deployment tag versioning

4. Breaking change label

Summary by CodeRabbit

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jonastheis commented Jun 5, 2025 •

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