Checking Smart Contract Vulnerabilities in Blockchain-based Internet of Drones

Blockchain-based Internet of Drones (B-IoD) is a digital infrastructure that utilizes blockchain for the secure management and operation of drones. Through smart contracts (immutable on-chain programs), B-IoD can automate a variety of applications such as drone logistics, data analysis, and situation monitoring. In B-IoD systems, miners provide computing power to generate new blocks. This leads to contracts prone to blockchain-level vulnerabilities, where miners may control the transaction order and block information in new blocks to jeopardize system stability. Auditing blockchain-level vulnerabilities in contracts is a crucial problem. Existing methods employ symbolic execution to audit contracts. However, inaccurate execution modeling, such as memory and storage, leads existing methods to have inferior detection accuracy. For such, in this paper, we propose an effective static audit method for detecting blockchain-level vulnerabilities in smart contracts of B-IoD. Our method accurately models the executive data structure to capture contract state changes and uses symbolic execution to search for execution paths. We implement an automatic audit tool, ScAudit, which inputs Solidity source code and reports if the contract is vulnerable to blockchain-level vulnerabilities. We evaluate ScAudit on real-world contracts and compare it with existing tools. The experiment results show that ScAudit performs well and accurately detects blockchain-level vulnerabilities.