Memory-Safety Challenge Considered Solved? An In-Depth Study with All Rust CVEs

Abstract

Rust is an emerging programing language that aims at preventing memory-safety bugs without sacrificing much efficiency. The property is very attractive to developers, and many projects start using the language. However, can Rust achieve the memorysafety promise? This paper studies the question by surveying the bug reports collected from two public datasets, Advisorydb and Trophy-cases, which contain all existing CVEs (common vulnerability and exposures) of Rust. We manually analyze each bug and extract their memory-safety issues and culprits. Our results show that buffer overflow and dangling pointers are still the major memory-safety issues in Rust, and most culprits are related to unsafe Rust. Such security issues reveal that the security cost of Rust to support unsafe functions is high. To elaborate, the culprits of buffer overflow bugs in Rust are very similar to those in C/C++, which generally involve both logical errors and arbitrary pointer operations that are allowed only by unsafe Rust. However, the culprits of dangling pointers in Rust have unique patterns, especially those related to the vulnerability of Rust's borrow checker and lifetime checker. Based on these findings, we further suggest two directions to improve the resilience of Rust against dangling pointers, including recommending the best practice of some APIs to program developers, as well as approaches to enhancing the borrow checker and lifetime checker. Our work intends to raise more concerns regarding the memory-safety promise of Rust and facilitates the maturity of the language.

SafeDrop: Detecting Memory Deallocation Bugs of Rust Programs via Static Data-Flow Analysis

“…To answer RQ1, we collect a dataset with all 11 existing related CVEs for evaluation [29], including three use-after-free, three double free, and four invalid memory access bugs due to uninitialized memory. These CVEs are from 10 different Rust crates.…”

“…Due to these advantages, many real-world projects start to embrace Rust, such as Servo [2] and TockOS [20]. Although the feedback of Rust's effectiveness in preventing memory-safety bug is positive, there still exist a considerable amount of such bugs in real-world projects [9,24,29].…”