Sigvex
SolanaRemediation1 min read

Cross-Contract Consistency Remediation

How to fix cross-account state consistency issues.

svmaccess-control

Cross-Contract Consistency Remediation

Overview

Related Detector: Cross-Contract Consistency

Partial multi-account updates create exploitable inconsistencies. The fix is to validate all preconditions before any writes, then commit all updates together.

// Validate everything first
require!(a.balance >= amount, Insufficient);
require!(b.balance.checked_add(amount).is_some(), Overflow);
// Then commit all writes
a.balance -= amount;
b.balance += amount;

Common Mistakes

Mistake: Writing Between Validations

a.balance -= amount;
a.serialize(data_a)?;  // Written
require!(b.can_receive(amount), CannotReceive);  // May fail
b.balance += amount;  // Never reached

Validate all preconditions before any state mutations.

References