Formalizing Stack Safety as a Security Property at Portland State University

Core Concepts

Stack safety is decomposed into integrity, confidentiality, and control-flow properties to ensure security in function activations.

Abstract

The content discusses the formalization of stack safety as a security property, proposing new concepts and properties to enhance protection mechanisms. It delves into the challenges of defining stack safety due to its protean nature and proposes a decomposition of stack safety into five distinct properties. The article validates these properties through testing and distinguishes between correct and incorrect implementations. It also explores the implications of various enforcement mechanisms on stack safety.

1. Introduction to Functions in High-Level Languages

• Functions manage local variables and information about callers.
• Call stack is fundamental for implementing functions.
• Attacks on the call stack are common in low-level attacks.

2. Proposal of New Formal Characterization of Stack Safety

• Decomposition of stack safety into integrity, confidentiality, and control-flow properties.
• Motivated by lazy enforcement mechanisms studied by Roessler and DeHon.

3. Validation of Properties Through Testing

• Use of property-based random testing to validate properties.
• Identification of broken variants using the proposed properties.

4. Framework and Assumptions for Security Semantics

• Definition of machine model, security semantics, and operations.
• Introduction of views, contexts, events, traces, variants, corrupted sets, and "on-return" assertions.

5. Core Properties Definitions

• Well-bracketed Control Flow (WBCF) ensures proper return after calls.
• Caller Integrity (CLRI) focuses on preserving sealed elements' values after calls.
• Caller Confidentiality (CLRC) protects against unauthorized access to caller's private state.

6. Formalization Details for Properties

• Detailed rules for each operation such as alloc, dealloc, call, return.

7. Events and Traces Abstraction

• Abstracting over observable events in the system.

8. Variants, Corrupted Sets, and "On-return" Assertions

• Defining variants for comparison between states.

9. Properties Criteria

• Defining criteria that must hold immediately after call steps for each property.

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Formalizing Stack Safety as a Security Property

by Sean Noble A... at arxiv.org 03-22-2024

https://arxiv.org/pdf/2105.00417.pdf

Deeper Inquiries

How can these formalized properties be practically implemented in real-world systems?

The formalized properties outlined in the context can be practically implemented in real-world systems by integrating them into the design and development process of software and hardware. Here are some steps to implement them:

Integration with Secure Coding Practices: Incorporate these properties as part of secure coding practices during software development. Developers should ensure that functions adhere to the defined integrity, confidentiality, and control-flow properties.

Security Testing: Develop test cases based on these properties to validate the correctness of implementations. Property-based testing tools like QuickChick can be utilized for this purpose.

Enforcement Mechanisms: Implement enforcement mechanisms at both software and hardware levels to ensure compliance with the defined security properties. This could involve using techniques like stack canaries, bounds checking, or capabilities.

Monitoring and Auditing: Regularly monitor system behavior against these properties and conduct audits to identify any deviations or vulnerabilities that may arise during runtime.

Documentation and Training: Document these security requirements clearly in system specifications, architecture documents, and developer guidelines. Provide training to developers on how to adhere to these security principles effectively.

What are potential limitations or drawbacks of this formal characterization approach?

While formalizing stack safety into specific security properties offers numerous benefits, there are also some limitations associated with this approach:

Complexity: The formalization process itself can be complex and time-consuming, requiring a deep understanding of both theoretical concepts and practical implementation details.

Resource Intensive: Implementing these formalized properties may require additional resources such as specialized tools for property-based testing or expertise in language-based security concepts.

Scalability Challenges: Adapting these formalizations across different architectures or languages might pose scalability challenges due to variations in implementation details.

4Interoperability Issues: Ensuring interoperability between different components within a system while maintaining adherence to the defined security properties could be challenging.
5Dynamic Environments: Real-world systems often operate in dynamic environments where changes occur frequently; ensuring continuous compliance with static security definitions may prove difficult.

How might advancements in hardware technology impact the enforcement mechanisms discussed?

Advancements in hardware technology have a significant impact on enforcing stack safety mechanisms:
1Hardware Acceleration: Hardware advancements enable dedicated accelerators for enforcing certain security mechanisms efficiently without impacting overall system performance significantly.
2Trusted Execution Environments (TEEs): Technologies like Intel SGX provide secure enclaves where critical operations related to stack safety can be executed securely without exposing sensitive data.
3Memory Protection Units (MPUs): Advanced MPUs offer more granular control over memory access rights which is crucial for implementing fine-grained stack protection mechanisms.
4Secure Boot Processes: Enhanced boot processes provided by modern CPUs help establish a chain of trust from bootloader onwards ensuring that only trusted code runs on the system thus enhancing overall system integrity.
5Side-Channel Attack Mitigation: Newer technologies focus on mitigating side-channel attacks through architectural enhancements which indirectly contribute towards better stack safety measures.
These advancements not only enhance existing enforcement mechanisms but also open up new possibilities for developing more robust solutions catering specifically towards ensuring stack safety within modern computing environments