LibreFang Security Architecture

pub enum Capability {
    // Filesystem
    FileRead(String),       // Glob pattern, e.g. "/data/*"
    FileWrite(String),

    // Network
    NetConnect(String),     // Host:port pattern, e.g. "*.openai.com:443"
    NetListen(u16),

    // Tools
    ToolInvoke(String),     // Specific tool ID
    ToolAll,                // All tools (dangerous)

    // LLM
    LlmQuery(String),
    LlmMaxTokens(u64),

    // Agent interaction
    AgentSpawn,
    AgentMessage(String),
    AgentKill(String),

    // Memory
    MemoryRead(String),
    MemoryWrite(String),

    // Shell
    ShellExec(String),
    EnvRead(String),

    // OFP Wire Protocol
    OfpDiscover,
    OfpConnect(String),
    OfpAdvertise,

    // Economic
    EconSpend(f64),
    EconEarn,
    EconTransfer(String),
}

fn check_capability(
    capabilities: &[Capability],
    required: &Capability,
) -> Result<(), serde_json::Value> {
    for granted in capabilities {
        if capability_matches(granted, required) {
            return Ok(());
        }
    }
    Err(json!({"error": format!("Capability denied: {required:?}")}))
}

pub fn validate_capability_inheritance(
    parent_caps: &[Capability],
    child_caps: &[Capability],
) -> Result<(), String> {
    for child_cap in child_caps {
        let is_covered = parent_caps
            .iter()
            .any(|parent_cap| capability_matches(parent_cap, child_cap));
        if !is_covered {
            return Err(format!(
                "Privilege escalation denied: child requests {:?} \
                 but parent does not have a matching grant",
                child_cap
            ));
        }
    }
    Ok(())
}

// SandboxConfig defaults
pub fuel_limit: u64,  // Default: 1_000_000

// Applied at execution time
if config.fuel_limit > 0 {
    store.set_fuel(config.fuel_limit)?;
}

let fuel_remaining = store.get_fuel().unwrap_or(0);
let fuel_consumed = config.fuel_limit.saturating_sub(fuel_remaining);

store.set_epoch_deadline(1);
let engine_clone = engine.clone();
let timeout = config.timeout_secs.unwrap_or(30);
let _watchdog = std::thread::spawn(move || {
    std::thread::sleep(std::time::Duration::from_secs(timeout));
    engine_clone.increment_epoch();
});

pub struct SandboxConfig {
    pub fuel_limit: u64,           // Default: 1_000_000
    pub max_memory_bytes: usize,   // Default: 16 MB
    pub capabilities: Vec<Capability>,
    pub timeout_secs: Option<u64>, // Default: 30 seconds
}

pub enum SandboxError {
    Compilation(String),
    Instantiation(String),
    Execution(String),
    FuelExhausted,         // Trap::OutOfFuel
    AbiError(String),
}

pub enum AuditAction {
    ToolInvoke,
    CapabilityCheck,
    AgentSpawn,
    AgentKill,
    AgentMessage,
    MemoryAccess,
    FileAccess,
    NetworkAccess,
    ShellExec,
    AuthAttempt,
    WireConnect,
    ConfigChange,
}

pub struct AuditEntry {
    pub seq: u64,          // Monotonically increasing sequence number
    pub timestamp: String, // ISO-8601
    pub agent_id: String,
    pub action: AuditAction,
    pub detail: String,    // e.g. tool name, file path
    pub outcome: String,   // "ok", "denied", error message
    pub prev_hash: String, // SHA-256 of previous entry (or 64 zeros)
    pub hash: String,      // SHA-256 of this entry + prev_hash
}

fn compute_entry_hash(
    seq: u64, timestamp: &str, agent_id: &str,
    action: &AuditAction, detail: &str,
    outcome: &str, prev_hash: &str,
) -> String {
    let mut hasher = Sha256::new();
    hasher.update(seq.to_string().as_bytes());
    hasher.update(timestamp.as_bytes());
    hasher.update(agent_id.as_bytes());
    hasher.update(action.to_string().as_bytes());
    hasher.update(detail.as_bytes());
    hasher.update(outcome.as_bytes());
    hasher.update(prev_hash.as_bytes());
    hex::encode(hasher.finalize())
}

pub fn verify_integrity(&self) -> Result<(), String> {
    let entries = self.entries.lock().unwrap_or_else(|e| e.into_inner());
    let mut expected_prev = "0".repeat(64);  // Genesis sentinel

    for entry in entries.iter() {
        if entry.prev_hash != expected_prev {
            return Err(format!(
                "chain break at seq {}: expected prev_hash {} but found {}",
                entry.seq, expected_prev, entry.prev_hash
            ));
        }
        let recomputed = compute_entry_hash(/* ... */);
        if recomputed != entry.hash {
            return Err(format!(
                "hash mismatch at seq {}: expected {} but found {}",
                entry.seq, recomputed, entry.hash
            ));
        }
        expected_prev = entry.hash.clone();
    }
    Ok(())
}

pub enum TaintLabel {
    ExternalNetwork,  // Data from external network requests
    UserInput,        // Direct user input
    Pii,              // Personally identifiable information
    Secret,           // API keys, tokens, passwords
    UntrustedAgent,   // Data from sandboxed/untrusted agents
}

pub struct TaintedValue {
    pub value: String,              // The payload
    pub labels: HashSet<TaintLabel>, // Attached taint labels
    pub source: String,             // Human-readable origin
}

pub struct TaintViolation {
    pub label: TaintLabel,    // The offending label
    pub sink_name: String,    // "shell_exec", "net_fetch", etc.
    pub source: String,       // Where the tainted value came from
}

tainted.declassify(&TaintLabel::ExternalNetwork);
tainted.declassify(&TaintLabel::UserInput);
// After declassification, value can flow to shell_exec
assert!(tainted.check_sink(&TaintSink::shell_exec()).is_ok());

let mut combined = TaintedValue::new(/* ... */);
combined.merge_taint(&other_value);
// combined.labels is now the union of both

pub struct SignedManifest {
    pub manifest: String,           // Raw TOML content
    pub content_hash: String,       // Hex SHA-256 of manifest
    pub signature: Vec<u8>,         // Ed25519 signature (64 bytes)
    pub signer_public_key: Vec<u8>, // Ed25519 public key (32 bytes)
    pub signer_id: String,          // Human-readable signer ID
}

let signing_key = SigningKey::generate(&mut OsRng);
let signed = SignedManifest::sign(manifest_toml, &signing_key, "admin@org.com");

pub fn sign(manifest: impl Into<String>, signing_key: &SigningKey, signer_id: impl Into<String>) -> Self {
    let manifest = manifest.into();
    let content_hash = hash_manifest(&manifest);  // SHA-256
    let signature = signing_key.sign(content_hash.as_bytes());
    let verifying_key = signing_key.verifying_key();
    Self {
        manifest,
        content_hash,
        signature: signature.to_bytes().to_vec(),
        signer_public_key: verifying_key.to_bytes().to_vec(),
        signer_id: signer_id.into(),
    }
}

pub fn verify(&self) -> Result<(), String> {
    let recomputed = hash_manifest(&self.manifest);
    if recomputed != self.content_hash {
        return Err("content hash mismatch: ...");
    }
    let verifying_key = VerifyingKey::from_bytes(&pk_bytes)?;
    let signature = Signature::from_bytes(&sig_bytes);
    verifying_key.verify(self.content_hash.as_bytes(), &signature)
        .map_err(|e| format!("signature verification failed: {}", e))
}

if !url.starts_with("http://") && !url.starts_with("https://") {
    return Err(json!({"error": "Only http:// and https:// URLs are allowed"}));
}

let socket_addr = format!("{hostname}:{port}");
if let Ok(addrs) = socket_addr.to_socket_addrs() {
    for addr in addrs {
        let ip = addr.ip();
        if ip.is_loopback() || ip.is_unspecified() || is_private_ip(&ip) {
            return Err(json!({"error": format!(
                "SSRF blocked: {hostname} resolves to private IP {ip}"
            )}));
        }
    }
}

fn is_private_ip(ip: &std::net::IpAddr) -> bool {
    match ip {
        IpAddr::V4(v4) => {
            let octets = v4.octets();
            matches!(
                octets,
                [10, ..] | [172, 16..=31, ..] | [192, 168, ..] | [169, 254, ..]
            )
        }
        IpAddr::V6(v6) => {
            let segments = v6.segments();
            (segments[0] & 0xfe00) == 0xfc00 || (segments[0] & 0xffc0) == 0xfe80
        }
    }
}

https://api.openai.com/v1/chat  ->  api.openai.com:443
http://localhost:8080/api       ->  localhost:8080
http://example.com              ->  example.com:80

// On Drop, the inner String's buffer is overwritten with zeros
let key = Zeroizing::new("sk-secret-key".to_string());
// Use key transparently via Deref
client.post(url).header("authorization", format!("Bearer {}", &*key));
// When key goes out of scope, memory is zeroed

fn resolve_api_key(env_var: &str) -> Option<Zeroizing<String>> {
    std::env::var(env_var).ok().filter(|k| !k.is_empty()).map(Zeroizing::new)
}

if config.shared_secret.is_empty() {
    return Err(WireError::HandshakeFailed(
        "OFP requires shared_secret. Set [network] shared_secret in config.toml".into(),
    ));
}

type HmacSha256 = Hmac<Sha256>;

fn hmac_sign(secret: &str, data: &[u8]) -> String {
    let mut mac = HmacSha256::new_from_slice(secret.as_bytes())
        .expect("HMAC accepts any key size");
    mac.update(data);
    hex::encode(mac.finalize().into_bytes())
}

fn hmac_verify(secret: &str, data: &[u8], signature: &str) -> bool {
    let expected = hmac_sign(secret, data);
    subtle::ConstantTimeEq::ct_eq(expected.as_bytes(), signature.as_bytes()).into()
}

pub async fn security_headers(request: Request<Body>, next: Next) -> Response<Body> {
    let mut response = next.run(request).await;
    let headers = response.headers_mut();
    headers.insert("x-content-type-options", "nosniff".parse().unwrap());
    headers.insert("x-frame-options", "DENY".parse().unwrap());
    headers.insert("x-xss-protection", "1; mode=block".parse().unwrap());
    headers.insert("content-security-policy", /* CSP policy */);
    headers.insert("referrer-policy", "strict-origin-when-cross-origin".parse().unwrap());
    headers.insert("cache-control", "no-store, no-cache, must-revalidate".parse().unwrap());
    response
}

pub fn create_rate_limiter() -> Arc<KeyedRateLimiter> {
    Arc::new(RateLimiter::keyed(Quota::per_minute(NonZeroU32::new(500).unwrap())))
}

pub fn operation_cost(method: &str, path: &str) -> NonZeroU32 {
    match (method, path) {
        (_, "/api/health")                            => 1,
        ("GET", "/api/status")                        => 1,
        ("GET", "/api/version")                       => 1,
        ("GET", "/api/tools")                         => 1,
        ("GET", "/api/agents")                        => 2,
        ("GET", "/api/skills")                        => 2,
        ("GET", "/api/peers")                         => 2,
        ("GET", "/api/config")                        => 2,
        ("GET", "/api/usage")                         => 3,
        ("GET", p) if p.starts_with("/api/audit")     => 5,
        ("GET", p) if p.starts_with("/api/marketplace")=> 10,
        ("POST", "/api/agents")                       => 50,
        ("POST", p) if p.contains("/message")         => 30,
        ("POST", p) if p.contains("/run")             => 100,
        ("POST", "/api/skills/install")               => 50,
        ("POST", "/api/skills/uninstall")             => 10,
        ("POST", "/api/migrate")                      => 100,
        ("PUT", p) if p.contains("/update")           => 10,
        _                                             => 5,
    }
}

pub async fn gcra_rate_limit(
    State(limiter): State<Arc<KeyedRateLimiter>>,
    request: Request<Body>,
    next: Next,
) -> Response<Body> {
    let ip = /* extract from ConnectInfo, default 127.0.0.1 */;
    let cost = operation_cost(&method, &path);

    if limiter.check_key_n(&ip, cost).is_err() {
        tracing::warn!(ip, cost, path, "GCRA rate limit exceeded");
        return Response::builder()
            .status(StatusCode::TOO_MANY_REQUESTS)
            .header("retry-after", "60")
            .body(/* JSON error */)
            .unwrap_or_default();
    }
    next.run(request).await
}

pub type KeyedRateLimiter = RateLimiter<IpAddr, DashMapStateStore<IpAddr>, DefaultClock>;

fn safe_resolve_path(path: &str) -> Result<std::path::PathBuf, serde_json::Value> {
    let p = Path::new(path);

    // Phase 1: Reject any path with ".." components
    for component in p.components() {
        if matches!(component, Component::ParentDir) {
            return Err(json!({"error": "Path traversal denied: '..' components forbidden"}));
        }
    }

    // Phase 2: Canonicalize to resolve symlinks and normalize
    std::fs::canonicalize(p)
        .map_err(|e| json!({"error": format!("Cannot resolve path: {e}")}))
}

fn safe_resolve_parent(path: &str) -> Result<std::path::PathBuf, serde_json::Value> {
    let p = Path::new(path);

    // Phase 1: Reject ".." in any component
    for component in p.components() {
        if matches!(component, Component::ParentDir) {
            return Err(json!({"error": "Path traversal denied: '..' components forbidden"}));
        }
    }

    // Phase 2: Canonicalize the parent directory
    let parent = p.parent().filter(|par| !par.as_os_str().is_empty())
        .ok_or_else(|| json!({"error": "Invalid path: no parent directory"}))?;
    let canonical_parent = std::fs::canonicalize(parent)?;

    // Phase 3: Belt-and-suspenders check on filename
    let file_name = p.file_name()
        .ok_or_else(|| json!({"error": "Invalid path: no file name"}))?;
    if file_name.to_string_lossy().contains("..") {
        return Err(json!({"error": "Path traversal denied in file name"}));
    }

    Ok(canonical_parent.join(file_name))
}

pub fn sandbox_command(cmd: &mut tokio::process::Command, allowed_env_vars: &[String]) {
    cmd.env_clear();  // Remove ALL inherited env vars

    // Re-add platform-independent safe vars
    for var in SAFE_ENV_VARS {
        if let Ok(val) = std::env::var(var) {
            cmd.env(var, val);
        }
    }

    // Re-add Windows-specific safe vars (on Windows)
    #[cfg(windows)]
    for var in SAFE_ENV_VARS_WINDOWS { /* ... */ }

    // Re-add caller-specified allowed vars
    for var in allowed_env_vars { /* ... */ }
}

pub const SAFE_ENV_VARS: &[&str] = &[
    "PATH", "HOME", "TMPDIR", "TMP", "TEMP", "LANG", "LC_ALL", "TERM",
];

pub const SAFE_ENV_VARS_WINDOWS: &[&str] = &[
    "USERPROFILE", "SYSTEMROOT", "APPDATA", "LOCALAPPDATA",
    "COMSPEC", "WINDIR", "PATHEXT",
];

pub fn validate_executable_path(path: &str) -> Result<(), String> {
    let p = Path::new(path);
    for component in p.components() {
        if let std::path::Component::ParentDir = component {
            return Err(format!(
                "executable path '{}' contains '..' component which is not allowed",
                path
            ));
        }
    }
    Ok(())
}

"ignore previous instructions", "ignore all previous",
"disregard previous", "forget your instructions",
"you are now", "new instructions:", "system prompt override",
"ignore the above", "do not follow", "override system"

"send to http", "send to https", "post to http", "post to https",
"exfiltrate", "forward all", "send all data",
"base64 encode and send", "upload to"

"rm -rf", "chmod ", "sudo "

pub fn verify_checksum(data: &[u8], expected_sha256: &str) -> bool {
    let actual = Self::sha256_hex(data);
    actual == expected_sha256.to_lowercase()
}

pub struct SkillWarning {
    pub severity: WarningSeverity,  // Info, Warning, Critical
    pub message: String,
}

pub struct LoopGuardConfig {
    pub warn_threshold: u32,         // Default: 3
    pub block_threshold: u32,        // Default: 5
    pub global_circuit_breaker: u32, // Default: 30
}

pub fn check(&mut self, tool_name: &str, params: &serde_json::Value) -> LoopGuardVerdict {
    self.total_calls += 1;

    // Global circuit breaker
    if self.total_calls > self.config.global_circuit_breaker {
        return LoopGuardVerdict::CircuitBreak(/* ... */);
    }

    let hash = Self::compute_hash(tool_name, params);
    let count = self.call_counts.entry(hash).or_insert(0);
    *count += 1;

    if *count >= self.config.block_threshold {
        LoopGuardVerdict::Block(/* ... */)
    } else if *count >= self.config.warn_threshold {
        LoopGuardVerdict::Warn(/* ... */)
    } else {
        LoopGuardVerdict::Allow
    }
}

fn compute_hash(tool_name: &str, params: &serde_json::Value) -> String {
    let mut hasher = Sha256::new();
    hasher.update(tool_name.as_bytes());
    hasher.update(b"|");
    let params_str = serde_json::to_string(params).unwrap_or_default();
    hasher.update(params_str.as_bytes());
    hex::encode(hasher.finalize())
}

pub fn validate_and_repair(messages: &[Message]) -> Vec<Message>

fn merge_content(dst: &mut MessageContent, src: MessageContent) {
    let dst_blocks = content_to_blocks(std::mem::replace(dst, MessageContent::Text(String::new())));
    let src_blocks = content_to_blocks(src);
    let mut combined = dst_blocks;
    combined.extend(src_blocks);
    *dst = MessageContent::Blocks(combined);
}

{
    "status": "ok",
    "version": "0.1.0"
}

{
    "status": "ok",
    "version": "0.1.0",
    "uptime_seconds": 3600,
    "panic_count": 0,
    "restart_count": 2,
    "agent_count": 15,
    "database": "connected",
    "config_warnings": []
}

if api_key.is_empty() {
    let is_loopback = request.extensions()
        .get::<ConnectInfo<SocketAddr>>()
        .map(|ci| ci.0.ip().is_loopback())
        .unwrap_or(false);
    if !is_loopback {
        return Response::builder()
            .status(StatusCode::FORBIDDEN)
            .body(/* "No API key configured. Remote access denied." */)
            ...;
    }
}

# API Authentication
api_key = "your-secret-api-key"  # Empty = localhost-only mode

# OFP Wire Protocol
[network]
shared_secret = "your-pre-shared-key"  # Required for OFP

# WASM Sandbox
[sandbox]
fuel_limit = 1000000       # CPU instruction budget per execution
timeout_secs = 30          # Wall-clock timeout per execution
max_memory_bytes = 16777216 # 16 MB max WASM memory

# Rate Limiting
# 500 tokens/minute/IP (not currently configurable via config.toml)

# Web Search SSRF Protection
[web]
# SSRF protection is always on and cannot be disabled

[agent]
name = "my-agent"

[[capabilities]]
type = "FileRead"
value = "/data/*"

[[capabilities]]
type = "NetConnect"
value = "*.openai.com:443"

[[capabilities]]
type = "ToolInvoke"
value = "web_search"

[[capabilities]]
type = "LlmMaxTokens"
value = 4096

sandbox_command(&mut cmd, &["MY_CUSTOM_VAR".to_string()]);