t8n: sender/signature mismatch is accepted (JSON sender trusted over v/r/s)

[chfast]

Summary

evmone-t8n accepts transactions based on the JSON sender field without validating that (v,r,s) recovers to the same sender.

This creates a cross-client divergence with geth evm t8n: a tx signed by account A can be executed as account B in evmone-t8n if JSON sets sender=B.

Why this matters

In t8n/state-transition semantics, sender should be derived from signature and chain rules (or at least validated against provided sender).
Current behavior lets malformed tx JSON produce wrong state roots and acceptance/rejection results.

Reproducer

alloc.json

{
  "0x1111111111111111111111111111111111111111": {
    "code": "0x",
    "nonce": "0x0",
    "balance": "0xde0b6b3a7640000",
    "storage": {}
  }
}

env.json

{
  "currentCoinbase": "0x8888f1f195afa192cfee860698584c030f4c9db1",
  "currentNumber": "0x01",
  "currentTimestamp": "0x54c99069",
  "currentGasLimit": "0x2fefd8",
  "currentRandom": "0x0000000000000000000000000000000000000000000000000000000000000001",
  "parentBeaconBlockRoot": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "currentBaseFee": "0x1",
  "currentExcessBlobGas": "0x0",
  "withdrawals": []
}

txs.json

v,r,s below are from a tx signed by 0xa94f5374... (not by 0x1111...).

[
  {
    "to": "0x095E7BAea6a6c7c4c2DfeB977eFac326aF552d87",
    "input": "0x",
    "gas": "0x5208",
    "nonce": "0x0",
    "value": "0x0",
    "gasPrice": "0x1",
    "chainId": "0x1",
    "sender": "0x1111111111111111111111111111111111111111",
    "v": "0x26",
    "r": "0x62d32a1bac6b89021fce16cf51479a8b00f26523933afde1b62f7957ed1943a3",
    "s": "0x6f3941435cb48b0c649c1b0d707fc6878407f6287c9cd89c33c0048bd2710e45"
  }
]

Commands

evmone-t8n \
  --state.fork Cancun --state.reward 0 --state.chainid 1 \
  --input.alloc alloc.json --input.env env.json --input.txs txs.json \
  --output.basedir out-evmone --output.result out.json --output.alloc outAlloc.json

evm t8n \
  --state.fork Cancun --state.reward 0 --state.chainid 1 \
  --input.alloc alloc.json --input.env env.json --input.txs txs.json \
  --output.basedir out-geth --output.result out.json --output.alloc outAlloc.json

Observed

• evmone-t8n:
  • rejected: []
  • gasUsed: 0x5208
  • executes transaction and updates state.
• geth evm t8n:
  • rejects tx:
    • insufficient funds ... address 0xa94f5374... have 0 want 21000
  • gasUsed: 0x0
  • no executed tx in block result.

Suspected root cause

sender is loaded from JSON and used directly for state checks/execution:

• test/utils/statetest_loader.cpp
  • o.sender = load_if_exists<evmc::address>(j, "sender");
  • parses v/r/s but does not recover/validate sender from signature.
• test/state/state.cpp
  • validation and balance checks use tx.sender directly.

So (v,r,s) authenticity is effectively not enforced for tx sender in evmone-t8n.

Suggested fix direction

Recover sender from signature (per tx type / chain id / fork rules) and either:

1. Use recovered sender as authoritative, or
2. Reject when provided sender disagrees with recovered sender.

Also reject malformed signatures consistently with other clients.