sec-design.md

Okay, let's create a design document for the Solana project, focusing on aspects relevant for threat modeling.

BUSINESS POSTURE

Solana is a high-performance blockchain designed to support scalable, decentralized applications (dApps) and marketplaces. Its primary business goals are:

• Provide a fast and low-cost platform for developers to build and deploy dApps.
• Achieve global scalability to support a large number of transactions and users.
• Maintain a high level of security and decentralization to ensure the integrity of the network and user assets.
• Foster a vibrant ecosystem of developers, validators, and users.
• Become a leading blockchain platform for DeFi, NFTs, and other Web3 applications.

Business priorities:

• Network uptime and stability.
• Transaction throughput and latency.
• Security of user funds and data.
• Developer adoption and ecosystem growth.
• Resistance to censorship and attacks.

Most important business risks:

• Critical vulnerabilities in the core blockchain code leading to network halts, loss of funds, or data breaches.
• Concentration of validator power, leading to potential censorship or manipulation of the network.
• Scalability bottlenecks that limit the growth and adoption of the platform.
• Competition from other high-performance blockchains.
• Regulatory uncertainty and potential legal challenges.
• Lack of adoption by developers and users.

SECURITY POSTURE

Existing security controls (based on reviewing the repository and general knowledge of blockchain security):

• security control: Cryptographic signatures for transaction authorization and account management. (Implemented in core Solana codebase, transaction processing logic).
• security control: Proof-of-History (PoH) as a verifiable delay function to provide a global, synchronized clock. (Implemented in core consensus mechanism).
• security control: Proof-of-Stake (PoS) consensus mechanism with slashing for malicious validator behavior. (Implemented in core consensus mechanism).
• security control: Gulf Stream, a mempool-less transaction forwarding protocol. (Implemented in transaction processing).
• security control: Sealevel, a parallel smart contracts runtime. (Implemented in runtime environment).
• security control: Pipeline VM for transaction processing optimization. (Implemented in runtime environment).
• security control: Cloudbreak, a horizontally scalable accounts database. (Implemented in data storage layer).
• security control: Turbine, a block propagation protocol. (Implemented in networking layer).
• security control: Regular security audits and bug bounty programs. (Mentioned in documentation and community resources).
• security control: Use of Rust, a memory-safe programming language, for core development. (Evident in codebase).
• security control: Formal verification of critical components (mentioned in some documentation, extent unclear).

Accepted risks:

• accepted risk: Complexity of the codebase increases the risk of undiscovered vulnerabilities.
• accepted risk: Reliance on a relatively new consensus mechanism (PoH + PoS) introduces potential risks.
• accepted risk: Rapid development and innovation may introduce new security challenges.
• accepted risk: Potential for 51% attacks, although mitigated by PoS and slashing.
• accepted risk: Dependence on the security of underlying hardware and infrastructure.
• accepted risk: Potential for smart contract vulnerabilities in dApps built on Solana.

Recommended security controls:

• Implement a comprehensive fuzzing framework for continuous testing of various components.
• Enhance formal verification efforts, particularly for consensus-critical code.
• Develop a robust incident response plan to address potential security breaches.
• Strengthen supply chain security for dependencies and build processes.
• Provide more detailed security documentation and guidelines for developers building on Solana.

Security Requirements:

• Authentication:

  • All transactions must be cryptographically signed by the authorized account holder.
  • Validators must authenticate themselves using cryptographic keys.
  • Multi-factor authentication should be supported for user accounts (where applicable, e.g., wallets).

• Authorization:

  • Access control mechanisms must be in place to restrict access to sensitive data and functions.
  • Smart contracts should implement appropriate authorization checks to prevent unauthorized access.
  • Validators should have limited privileges based on their stake.

• Input Validation:

  • All inputs to the system (transactions, smart contract calls, etc.) must be rigorously validated to prevent malformed data or malicious payloads.
  • Input validation should be performed at multiple layers (network, runtime, smart contract).

• Cryptography:

  • Use strong, well-vetted cryptographic algorithms for all security-critical operations (signatures, encryption, hashing).
  • Key management practices must be secure and follow industry best practices.
  • Regularly review and update cryptographic libraries to address any discovered vulnerabilities.

DESIGN

C4 CONTEXT

graph LR
    User["User (e.g., Wallet, dApp)"] -- "Interacts with" --> Solana["Solana Blockchain"]
    Solana -- "Uses" --> ExternalSystem["External Systems (e.g., Oracles, Bridges)"]
    Solana -- "Validates transactions" --> Validator["Validator Nodes"]

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Context Diagram Element Descriptions:

• Element:

  • Name: User (e.g., Wallet, dApp)
  • Type: Person
  • Description: Represents an end-user interacting with the Solana blockchain, either directly through a wallet or indirectly via a decentralized application.
  • Responsibilities:
    • Initiate transactions.
    • Manage accounts and keys.
    • Interact with smart contracts.
  • Security controls:
    • Cryptographic signatures for transaction authorization.
    • Secure key storage and management (responsibility of the wallet/dApp).
    • (Potentially) Multi-factor authentication.

• Element:

  • Name: Solana Blockchain
  • Type: Software System
  • Description: The core Solana blockchain platform, providing a distributed ledger and smart contract execution environment.
  • Responsibilities:
    • Process transactions.
    • Maintain consensus.
    • Execute smart contracts.
    • Store data.
  • Security controls:
    • Proof-of-History (PoH).
    • Proof-of-Stake (PoS).
    • Gulf Stream.
    • Sealevel.
    • Pipeline VM.
    • Cloudbreak.
    • Turbine.

• Element:

  • Name: External Systems (e.g., Oracles, Bridges)
  • Type: Software System
  • Description: External systems that interact with the Solana blockchain, such as oracles providing real-world data or bridges connecting to other blockchains.
  • Responsibilities:
    • Provide data feeds to smart contracts.
    • Facilitate cross-chain communication.
  • Security controls:
    • Depend on the specific external system.
    • Should be carefully vetted and audited.

• Element:

  • Name: Validator Nodes
  • Type: Software System
  • Description: Nodes in the network that participate in consensus and validate transactions.
  • Responsibilities:
    • Validate transactions.
    • Produce blocks.
    • Maintain the integrity of the blockchain.
  • Security controls:
    • Proof-of-Stake (PoS) with slashing.
    • Secure communication protocols.
    • Regular security audits.

C4 CONTAINER

graph LR
    User["User (e.g., Wallet, dApp)"] -- "Sends transactions" --> RPC["RPC API"]
    RPC -- "Forwards transactions" --> TVU["Transaction Validation Unit (TVU)"]
    TVU -- "Validates & forwards" --> TPU["Transaction Processing Unit (TPU)"]
    TPU -- "Executes transactions" --> Runtime["Runtime Environment (Sealevel)"]
    Runtime -- "Reads/Writes" --> AccountsDB["Accounts Database (Cloudbreak)"]
    TPU -- "Propagates blocks" --> BlockEngine["Block Engine"]
    BlockEngine -- "Consensus" --> Consensus["Consensus Mechanism (PoH + PoS)"]
    Consensus -- "Network communication" --> Networking["Networking Layer (Turbine)"]
    Validator["Validator Nodes"] -- "Network communication" --> Networking

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Container Diagram Element Descriptions:

• Element:

  • Name: User (e.g., Wallet, dApp)
  • Type: Person
  • Description: Same as in the Context Diagram.
  • Responsibilities: Same as in the Context Diagram.
  • Security controls: Same as in the Context Diagram.

• Element:

  • Name: RPC API
  • Type: Container (API)
  • Description: Provides an interface for users and applications to interact with the Solana blockchain.
  • Responsibilities:
    • Receive and validate incoming requests.
    • Forward transactions to the TVU.
    • Provide data querying capabilities.
  • Security controls:
    • Input validation.
    • Rate limiting.
    • Authentication (if applicable).

• Element:

  • Name: Transaction Validation Unit (TVU)
  • Type: Container (Software Component)
  • Description: Validates transactions before they are processed.
  • Responsibilities:
    • Verify signatures.
    • Check account balances.
    • Prevent double-spending.
  • Security controls:
    • Cryptographic signature verification.
    • Input validation.

• Element:

  • Name: Transaction Processing Unit (TPU)
  • Type: Container (Software Component)
  • Description: Processes validated transactions and executes smart contracts.
  • Responsibilities:
    • Execute smart contract code.
    • Update account states.
    • Forward transactions to the block engine.
  • Security controls:
    • Sandboxing of smart contract execution.
    • Resource limits.

• Element:

  • Name: Runtime Environment (Sealevel)
  • Type: Container (Runtime)
  • Description: The parallel smart contracts runtime environment.
  • Responsibilities:
    • Execute smart contracts in parallel.
    • Manage account states.
  • Security controls:
    • Parallel execution with conflict detection.
    • Memory safety (Rust).

• Element:

  • Name: Accounts Database (Cloudbreak)
  • Type: Container (Database)
  • Description: Horizontally scalable database for storing account data.
  • Responsibilities:
    • Store account balances, program data, and other state information.
    • Provide fast access to account data.
  • Security controls:
    • Data encryption (if applicable).
    • Access control.

• Element:

  • Name: Block Engine
  • Type: Container (Software Component)
  • Description: Assembles validated transactions into blocks.
  • Responsibilities:
    • Order transactions.
    • Create block headers.
    • Propagate blocks to the network.
  • Security controls:
    • Timestamping (PoH).

• Element:

  • Name: Consensus Mechanism (PoH + PoS)
  • Type: Container (Software Component)
  • Description: The core consensus mechanism that ensures agreement on the state of the blockchain.
  • Responsibilities:
    • Validate blocks.
    • Reach consensus on the next block.
    • Handle forks.
  • Security controls:
    • Proof-of-History (PoH).
    • Proof-of-Stake (PoS) with slashing.

• Element:

  • Name: Networking Layer (Turbine)
  • Type: Container (Network Protocol)
  • Description: Handles communication between nodes in the network.
  • Responsibilities:
    • Propagate blocks and transactions.
    • Maintain connections with other nodes.
  • Security controls:
    • Secure communication protocols (e.g., TLS).
    • DoS protection.

• Element:

  • Name: Validator Nodes
  • Type: Software System
  • Description: Same as in the Context Diagram.
  • Responsibilities: Same as in the Context Diagram.
  • Security controls: Same as in the Context Diagram.

DEPLOYMENT

Solana validators can be deployed in various configurations, ranging from individual setups to large-scale deployments across multiple data centers. Here are some possible deployment solutions:

1. Single Validator Node: A single machine running the Solana validator software. Suitable for testing or small-scale participation.
2. Multi-Validator Setup: Multiple validator nodes running on separate machines, potentially in different locations. Increases resilience and decentralization.
3. Cloud-Based Deployment: Utilizing cloud providers (AWS, GCP, Azure, etc.) to deploy validator nodes. Offers scalability and ease of management.
4. Data Center Deployment: Deploying validator nodes in dedicated data centers for maximum control and performance.
5. Hybrid Deployment: Combining cloud-based and on-premise deployments for a balance of flexibility and control.

We will describe the Cloud-Based Deployment using AWS as an example:

graph LR
    Internet["Internet"] -- "Traffic" --> LB["Load Balancer (e.g., AWS ALB)"]
    LB -- "Distributes traffic" --> ASG["Auto Scaling Group (ASG)"]
    ASG -- "Manages instances" --> EC2["EC2 Instances (Validator Nodes)"]
    EC2 -- "Accesses" --> EBS["EBS Volumes (Storage)"]
    EC2 -- "Communicates with" --> VPC["Virtual Private Cloud (VPC)"]
    VPC -- "Connects to" --> IGW["Internet Gateway (IGW)"]
    S3["S3 Bucket (for backups)"]

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Deployment Diagram Element Descriptions:

• Element:

  • Name: Internet
  • Type: External Entity
  • Description: The global network.
  • Responsibilities:
    • Route traffic to the Solana network.
  • Security controls:
    • Standard internet security protocols.

• Element:

  • Name: Load Balancer (e.g., AWS ALB)
  • Type: Infrastructure Node (Load Balancer)
  • Description: Distributes incoming traffic across multiple validator nodes.
  • Responsibilities:
    • Handle incoming connections.
    • Distribute traffic based on load and health checks.
  • Security controls:
    • SSL/TLS termination.
    • DDoS protection (e.g., AWS Shield).
    • Web Application Firewall (WAF) integration.

• Element:

  • Name: Auto Scaling Group (ASG)
  • Type: Infrastructure Node (Auto Scaling Group)
  • Description: Manages the scaling of validator nodes based on demand.
  • Responsibilities:
    • Launch and terminate EC2 instances as needed.
    • Maintain a desired number of running instances.
  • Security controls:
    • IAM roles and policies.
    • Security groups.

• Element:

  • Name: EC2 Instances (Validator Nodes)
  • Type: Infrastructure Node (Virtual Machine)
  • Description: Virtual machines running the Solana validator software.
  • Responsibilities:
    • Run the Solana validator software.
    • Participate in consensus.
    • Process transactions.
  • Security controls:
    • Security groups.
    • IAM roles and policies.
    • Regular patching and updates.
    • Intrusion detection systems (IDS).

• Element:

  • Name: EBS Volumes (Storage)
  • Type: Infrastructure Node (Storage)
  • Description: Persistent storage for validator data.
  • Responsibilities:
    • Store the Solana blockchain data.
  • Security controls:
    • Encryption at rest.
    • Regular backups.

• Element:

  • Name: Virtual Private Cloud (VPC)
  • Type: Infrastructure Node (Network)
  • Description: A logically isolated section of the AWS cloud.
  • Responsibilities:
    • Provide a private network for the validator nodes.
  • Security controls:
    • Network Access Control Lists (NACLs).
    • Security groups.
    • VPC flow logs.

• Element:

  • Name: Internet Gateway (IGW)
  • Type: Infrastructure Node (Gateway)
  • Description: Enables communication between the VPC and the internet.
  • Responsibilities:
    • Route traffic between the VPC and the internet.
  • Security controls:
    • Security groups.

• Element:

  • Name: S3 Bucket (for backups)
  • Type: Infrastructure Node (Storage)
  • Description: Object storage for backups of validator data.
  • Responsibilities:
    • Store backups of validator data.
  • Security controls:
    • Encryption at rest.
    • Access control policies.
    • Versioning.

BUILD

Solana's build process is primarily managed through GitHub Actions, as evidenced by the .github/workflows directory in the repository. The build process involves multiple stages, including building, testing, and packaging the software.

graph LR
    Developer["Developer"] -- "Pushes code" --> GitHub["GitHub Repository"]
    GitHub -- "Triggers workflow" --> Workflow["GitHub Actions Workflow"]
    Workflow -- "Builds software" --> Build["Build Stage (Rust, Cargo)"]
    Build -- "Runs tests" --> Test["Test Stage (Unit, Integration, etc.)"]
    Test -- "Performs security checks" --> SecurityChecks["Security Checks (SAST, Linters)"]
    SecurityChecks -- "Analyzes code" --> CodeAnalysis["Code Analysis Tools (Clippy, etc.)"]
    Test -- "If successful" --> Package["Package Stage (Create binaries, Docker images)"]
    Package -- "Publishes artifacts" --> Artifacts["Build Artifacts (Binaries, Docker Images)"]

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Build Process Security Controls:

• security control: Use of Rust and Cargo for building the software, providing memory safety and dependency management.
• security control: Automated build process using GitHub Actions, ensuring consistency and reproducibility.
• security control: Unit and integration tests to verify the correctness of the code.
• security control: Security checks, including static analysis (SAST) using tools like Clippy, to identify potential vulnerabilities.
• security control: Dependency analysis to identify and manage vulnerable dependencies.
• security control: Code signing (potentially, not explicitly mentioned in the repository).
• security control: Containerization (Docker) for packaging and deployment, providing isolation and consistency.

RISK ASSESSMENT

Critical Business Processes:

• Transaction processing: Ensuring that transactions are processed quickly, reliably, and securely.
• Consensus: Maintaining agreement on the state of the blockchain among validator nodes.
• Smart contract execution: Providing a secure and reliable environment for executing smart contracts.
• Data storage: Storing blockchain data securely and reliably.
• Network communication: Ensuring secure and efficient communication between nodes.

Data to Protect and Sensitivity:

• Account balances: Highly sensitive, representing the value held by users.
• Transaction data: Sensitive, revealing information about user activity and potentially private data.
• Smart contract code: Sensitive, as vulnerabilities can lead to loss of funds or data breaches.
• Private keys: Extremely sensitive, providing control over accounts and funds. (Managed by users/wallets, not directly by the Solana blockchain itself).
• Validator keys: Extremely sensitive, as compromise can lead to network disruption or manipulation.
• Network metadata: Moderately sensitive, potentially revealing information about network topology and validator identities.

QUESTIONS & ASSUMPTIONS

Questions:

• What is the specific threat model used by the Solana Foundation for ongoing security assessments?
• What are the detailed procedures for handling security incidents and vulnerabilities?
• What are the specific criteria for selecting and onboarding validators?
• What is the extent of formal verification applied to the codebase?
• What are the plans for addressing potential long-term scalability challenges?
• What specific measures are in place to prevent and mitigate DDoS attacks?
• What is the process for auditing and approving external systems (oracles, bridges) that interact with the Solana blockchain?
• How is the supply chain security of dependencies managed and monitored?

Assumptions:

• BUSINESS POSTURE: The Solana Foundation prioritizes security and is committed to addressing vulnerabilities promptly.
• BUSINESS POSTURE: The Solana community actively participates in security discussions and bug reporting.
• SECURITY POSTURE: Regular security audits are conducted by reputable third-party firms.
• SECURITY POSTURE: The development team follows secure coding practices.
• DESIGN: The core components of Solana are designed with security in mind.
• DESIGN: The deployment infrastructure for validators is secured according to industry best practices.
• DESIGN: The build process includes automated security checks.
• DESIGN: Validators are responsible for securing their own infrastructure.