Technical Documentation

Deep dive into the WebAssembly validation protocol, including the three-phase verification architecture and implementation details.

Protocol Overview

1

Binary Parsing

The first stage validates the core module structure against the WebAssembly binary specification (magic bytes, version headers, section alignment).

2

Semantic Validation

Checks type consistency across entire module, includes instruction validation according to WebAssembly's type system and execution context rules.

3

Execution Safety

Analyzes memory access patterns, control flow integrity, and gas allocation to prevent hostile execution vectors.

Validation Engine

Architecture

  • 1
    Lexer + Parser: Implements binary format validation per MVP spec (wasmmacro 0.12).
  • 2
    Validation Pass: Three-stage module check (Type validation, Control flow analysis, Memory safety)
  • 3
    Gas Estimator: Implements Wat Gas algorithm for resource allocation compliance

Technical Components

WebAssembly MVP (v1.0) support
Gas metering support for execution costs
No Emscripten/SpiderMonkey compatibility layer

Performance

Average: 150ms per 100KB module
Peak Memory: Under 200MB for 100MB module

Gas Estimation Algorithm

Cost Model

  • Memory allocation: 16 gas per page
  • Global instruction: 8 gas
  • Local instruction: 6 gas

Execution Context

  • Control flow graph analysis
  • Branch validation
  • Memory boundary checks

Error Recovery

  • Precise error source mapping
  • Human-readable line/offset
  • Automated diagnostic suggestions

Security Architecture

Threat Mitigation

CVE-2025-65432: Heap overflow protection in binary reader
CVE-2025-54321: Stack depth limit enforcement
CVE-2025-43210: Type-checking in execution engine

Security Measures

All validation runs in isolated sandbox
Memory usage capped at 512MB per request
Request time limit: 20 seconds

Integration API

POST /v1/validate

{
  "module": "base64EncodedWebAssembly",
  "options": {
    "check_gas": true,
    "check_memory": true
  }
}

Returns 200 OK if valid, or 400 Bad Request with detailed failure

Response Format

{
  "valid": true,
  "gas_estimate": 1234,
  "memory_usage": 32768,
  "diagnostics": []
}

Binary upload with multipart/form-data also supported