fix(transaction): make Verify recover-and-compare, fail-closed#15
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ety001 wants to merge 1 commit into
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fix(transaction): make Verify recover-and-compare, fail-closed#15ety001 wants to merge 1 commit into
ety001 wants to merge 1 commit into
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SignedTransaction.Verify iterated over an empty slice instead of tx.Signatures, so the verification loop body never executed and the method unconditionally returned (true, nil) for any input — including transactions with no signatures, garbage signatures, or signatures over a tampered digest. Rewrite Verify to recover each signer's public key from the compact (recoverable) signature via ecdsa.RecoverCompact and compare it to the expected pubkey. This matches the codebase's existing verified path (wif.PublicKey.VerifySha256). Sign() emits compact signatures, so the previous DER-based ecdsa.ParseSignature approach in the audit fix suggestion could never have worked even with correct iteration. Verify is now fail-closed: empty signatures, pubkey/signature count mismatch, malformed hex, bad compact-signature format, recovery failure, and key mismatch all return (false, non-nil error). Add TestTransaction_VerifyNegativeCases covering tampered digest, empty signatures, wrong pubkey, and malformed signature, plus a baseline sanity check. Refs: steem-audit/projects/steemutil/audit-reports/2026-07-code-scan.md (finding [中])
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Summary
Fixes the [中] signature verification bypass finding in
steem-audit/projects/steemutil/audit-reports/2026-07-code-scan.md.SignedTransaction.Verifybuilt an empty slice and iterated over that instead oftx.Signatures, so the loop body never ran and the method returned(true, nil)for any input — no signatures, garbage signatures, signatures over a tampered digest, all passed.Fix
Rewrite as recover-and-compare: recover each signer's pubkey from the compact signature via
ecdsa.RecoverCompactand compare to the expected key. This is the same verified mechanism already used inwif.PublicKey.VerifySha256.Verify is now fail-closed: empty sigs, count mismatch, malformed hex, bad compact format, recovery failure, key mismatch →
(false, error).Test
TestTransaction_SignAndVerifystill passes (positive path).TestTransaction_VerifyNegativeCases: tampered digest, empty signatures, wrong pubkey, malformed signature (all returnfalse), plus a baseline sanity check.Refs: steem-audit/projects/steemutil/audit-reports/2026-07-code-scan.md