Build System Security

Cypheron Core’s build system implements comprehensive security measures to safely compile potentially untrusted C vendor code while maintaining security guarantees.

For complete technical details, see Architecture Documentation.

Build Security Pipeline

┌─────────────────────────────────────────────────────────────┐
│                    BUILD SECURITY PIPELINE                  │
├─────────────────────────────────────────────────────────────┤
│ 1. Pre-Build Security Checks                                │
│    ├─ Vendor code integrity verification                    │
│    ├─ Build dependency validation                           │
│    └─ Toolchain security verification                       │
├─────────────────────────────────────────────────────────────┤
│ 2. Secure Compilation Phase                                 │  
│    ├─ Security-hardened compiler flags                      │
│    ├─ Platform-specific optimizations                       │
│    └─ Stack protection enablement                           │
├─────────────────────────────────────────────────────────────┤
│ 3. FFI Binding Generation                                   │
│    ├─ API surface minimization                              │
│    ├─ Function allowlisting                                 │
│    └─ Type safety enforcement                               │
└─────────────────────────────────────────────────────────────┘

Vendor Code Integrity

Verification Process

# Automated integrity verification
find vendor/ -name "*.c" -o -name "*.h" | xargs sha256sum > SHA256SUMS
sha256sum -c SHA256SUMS

Security Properties

• Tamper Detection: Any modification to vendor code detected immediately
• Reproducible Builds: Consistent verification across environments
• Build Failure on Mismatch: Compilation halts if integrity check fails
• Version Control Integration: Checksum files tracked in git

Vendor Sources

Secure Compilation

Security-Hardened Compiler Flags

Stack Protection:

#![allow(unused)]
fn main() {
cc.flag("-fstack-protector-strong");      // Stack canary protection
cc.flag("-D_FORTIFY_SOURCE=2");           // Buffer overflow detection
}

Control Flow Integrity:

#![allow(unused)]
fn main() {
#[cfg(target_os = "linux")]
cc.flag("-fcf-protection=full");          // Intel CET support

#[cfg(target_os = "windows")]
cc.flag("/guard:cf");                     // Windows CFG
}

Memory Safety Hardening:

#![allow(unused)]
fn main() {
cc.flag("-fPIE");                         // Position Independent Executable
cc.flag("-Wl,-z,relro");                  // Read-only relocations  
cc.flag("-Wl,-z,now");                    // Immediate symbol resolution
}

Platform-Specific Security

Linux Security Features:

#![allow(unused)]
fn main() {
cc.flag("-fstack-clash-protection");     // Stack clash protection
cc.flag("-fcf-protection=full");         // Control Flow Integrity
cc.flag("-mshstk");                      // Shadow stack (Intel CET)
}

Windows Security Features:

#![allow(unused)]
fn main() {
cc.flag("/GS");                         // Stack buffer security check
cc.flag("/guard:cf");                   // Control Flow Guard
cc.flag("/DYNAMICBASE");                // ASLR support
}

FFI Binding Security

API Surface Minimization

Function Allowlisting:

#![allow(unused)]
fn main() {
let allowed_functions = vec![
    "crypto_kem_keypair",
    "crypto_kem_enc",
    "crypto_kem_dec",
    "crypto_sign_keypair", 
    "crypto_sign",
    "crypto_sign_open",
    // Only essential cryptographic functions exposed
];
}

Type Restriction:

#![allow(unused)]
fn main() {
bindgen_builder
    .allowlist_type("crypto_.*")
    .blocklist_type("internal_.*")           // Block internal details
    .opaque_type("rng_state")               // Opaque sensitive structures
}

Security Through Isolation

Symbol Visibility Control:

#![allow(unused)]
fn main() {
cc.flag("-fvisibility=hidden");              // Hide symbols by default
cc.define("CRYPTO_API", "extern");           // Explicit API marking

// Platform-specific symbol control
#[cfg(target_os = "windows")]
cc.define("CRYPTO_EXPORT", "__declspec(dllexport)");

#[cfg(unix)]  
cc.define("CRYPTO_EXPORT", "__attribute__((visibility(\"default\")))");
}

Static Linking Security:

#![allow(unused)]
fn main() {
cc.static_flag(true);                        // Force static linking
cc.shared_flag(false);                       // Prevent DLL injection
cc.flag("-static-libgcc");                   // Static runtime linking
}

Build Reproducibility

Deterministic Compilation

#![allow(unused)]
fn main() {
cc.flag("-frandom-seed=0");                  // Reproducible randomization
cc.env("SOURCE_DATE_EPOCH", "1609459200");  // Reproducible timestamps
cc.flag("-fdebug-prefix-map=/build=.");     // Reproducible debug paths
}

Build Audit Trail

#![allow(unused)]
fn main() {
println!("cargo:warning=Building with security flags: {:?}", security_flags);
println!("cargo:warning=Target architecture: {}", target_arch());
println!("cargo:warning=Compiler version: {}", compiler_version());
}

Development Build Commands

Standard Build

cargo build                    # Debug build with all security checks
cargo build --release          # Optimized build with security hardening

Security Validation

cargo clippy                   # Static analysis and security lints
cargo test                     # Comprehensive test suite
cargo audit                    # Dependency security audit

Platform-Specific Builds

# Linux with maximum security features
RUSTFLAGS="-C target-cpu=native" cargo build --release

# Windows with enhanced security
cargo build --target x86_64-pc-windows-msvc --release

# macOS with Apple Silicon optimizations  
cargo build --target aarch64-apple-darwin --release

Continuous Integration Security

Security Validation Pipeline

1. Vendor Integrity Check: Verify all C code checksums
2. Compiler Security Audit: Validate security flags applied
3. Binary Analysis: Static analysis of generated binaries
4. Symbol Analysis: Verify minimal symbol exposure
5. Runtime Security Testing: Validate security features

Security Regression Prevention

• All security flags tracked in version control
• Build failures on missing security features
• Automated security flag regression detection
• Platform-specific security feature validation

For complete build system architecture including dependency management and security validation, see the full Architecture Documentation.