HTTP API Authorization

# METADATA
# title: Hierarchical Authorization
# description: Context-aware authorization based on organizational hierarchy
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

# Define organizational hierarchy
subordinates := {
    "alice": [],
    "charlie": [],
    "bob": ["alice"],
    "betty": ["charlie"]
}

default allow := false

# METADATA
# title: Allow authorized requests
# description: Permits requests based on hierarchical manager-subordinate relationships
# entrypoint: true
# custom:
#   severity: HIGH
# Allow users to get their own salaries
allow if {
    input.method == "GET"
    input.path == ["finance", "salary", input.user]
}

# Allow managers to get their subordinates' salaries
allow if {
    some username
    input.method == "GET"
    input.path = ["finance", "salary", username]
    username in subordinates[input.user]
}

{
    "method": "GET",
    "path": ["finance", "salary", "alice"],
    "user": "bob"
}

# METADATA
# title: JWT-Based Access Control
# description: Validates JWT tokens and extracts claims for authorization decisions
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow JWT-authenticated requests
# description: Permits requests when JWT token claims match authorization requirements
# entrypoint: true
# custom:
#   severity: HIGH
# Allow users to get their own salaries
allow if {
    some username
    input.method == "GET"
    input.path = ["finance", "salary", username]
    token.payload.user == username
    user_owns_token
}

# Allow managers to get their subordinates' salaries
allow if {
    some username
    input.method == "GET"
    input.path = ["finance", "salary", username]
    username in token.payload.subordinates
    user_owns_token
}

# Allow HR members to get anyone's salary
allow if {
    input.method == "GET"
    input.path = ["finance", "salary", _]
    token.payload.hr == true
    user_owns_token
}

# Ensure that the token was issued to the user supplying it
user_owns_token if {
    input.user == token.payload.azp
}

# Helper to get the token payload
token := {"payload": payload} if {
    [header, payload, signature] := io.jwt.decode(input.token)
}

{
    "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
    "method": "GET",
    "path": ["finance", "salary", "alice"],
    "user": "alice"
}

# METADATA
# title: Method-Based Permissions
# description: Restricts HTTP methods based on user read/write/admin permissions
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

import data.users

default allow := false

# METADATA
# title: Allow method-based access
# description: Permits requests when user has the required permission for the HTTP method
# entrypoint: true
# custom:
#   severity: HIGH
# Allow GET requests for users with read permission
allow if {
    input.method == "GET"
    "read" in users[input.user].permissions
}

# Allow POST, PUT, PATCH for users with write permission
allow if {
    input.method in {"POST", "PUT", "PATCH"}
    "write" in users[input.user].permissions
}

# Allow DELETE for users with admin permission
allow if {
    input.method == "DELETE"
    "admin" in users[input.user].permissions
}

{
    "alice": {"permissions": ["read", "write"]},
    "bob": {"permissions": ["read"]},
    "admin": {"permissions": ["read", "write", "admin"]}
}

{
    "method": "DELETE",
    "user": "alice"
}

# METADATA
# title: Path-Based Authorization
# description: Controls access based on API path patterns using glob matching
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

import data.api_permissions

default allow := false

# METADATA
# title: Allow path-matched requests
# description: Permits requests when the user has a matching path pattern permission
# entrypoint: true
# custom:
#   severity: HIGH
# Check if user has permission for the requested path
allow if {
    some pattern in api_permissions[input.user]
    glob.match(pattern, ["/"], concat("/", input.path))
}

{
    "alice": ["/api/users/*", "/api/reports/personal/*"],
    "bob": ["/api/*/read", "/api/public/*"],
    "admin": ["/api/**"]
}

{
    "user": "alice",
    "path": ["api", "users", "123"]
}

# METADATA
# title: OAuth2 Token Validation
# description: Validates OAuth2 access tokens by checking scopes, expiration, and issuer
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow OAuth2-authenticated requests
# description: Permits requests when the OAuth2 token is valid and has the required scope
# entrypoint: true
# custom:
#   severity: HIGH
# Allow access if token has required scope and is valid
allow if {
    token_valid
    has_required_scope
}

# Validate token expiration and issuer
token_valid if {
    token.payload.exp > time.now_ns() / 1000000000
    token.payload.iss == "https://auth.example.com"
}

# Check if token has required scope for the endpoint
has_required_scope if {
    required_scope := endpoint_scopes[concat("/", input.path)]
    required_scope in token.payload.scope
}

# Map endpoints to required OAuth2 scopes
endpoint_scopes := {
    "/api/users": "users:read",
    "/api/users/create": "users:write",
    "/api/admin": "admin:access"
}

# Decode JWT token
token := {"payload": payload} if {
    [header, payload, signature] := io.jwt.decode(input.token)
}

{
    "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczovL2F1dGguZXhhbXBsZS5jb20iLCJleHAiOjk5OTk5OTk5OTksInNjb3BlIjpbInVzZXJzOnJlYWQiXX0...",
    "path": ["api", "users"]
}

# METADATA
# title: OpenID Connect Integration
# description: Integrates with OIDC providers by validating ID tokens and user profiles
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow OIDC-authenticated requests
# description: Permits requests when the OIDC ID token is valid and user domain is allowed
# entrypoint: true
# custom:
#   severity: HIGH
# Allow access if OIDC token is valid
allow if {
    oidc_token_valid
    user_has_access
}

# Validate OIDC ID token
oidc_token_valid if {
    # Token not expired
    token.payload.exp > time.now_ns() / 1000000000

    # Token issued by trusted provider
    token.payload.iss == "https://accounts.google.com"

    # Token audience matches our application
    token.payload.aud == "our-app-client-id"

    # Email verified
    token.payload.email_verified == true
}

# Check if user's email domain has access
user_has_access if {
    email := token.payload.email
    domain := split(email, "@")[1]
    domain in allowed_domains
}

allowed_domains := {"example.com", "partner.com"}

# Decode ID token
token := {"payload": payload} if {
    [header, payload, signature] := io.jwt.decode(input.id_token)
}

{
    "id_token": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczovL2FjY291bnRzLmdvb2dsZS5jb20iLCJhdWQiOiJvdXItYXBwLWNsaWVudC1pZCIsImV4cCI6OTk5OTk5OTk5OSwiZW1haWwiOiJ1c2VyQGV4YW1wbGUuY29tIiwiZW1haWxfdmVyaWZpZWQiOnRydWV9..."
}

# METADATA
# title: API Key Authentication
# description: Validates API keys and enforces key-specific permissions and rate limits
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

import data.api_keys

default allow := false

# METADATA
# title: Allow API key-authenticated requests
# description: Permits requests when the API key is valid and has matching path permission
# entrypoint: true
# custom:
#   severity: HIGH
# Allow access if API key is valid and has permission
allow if {
    api_key_valid
    api_key_has_permission
}

# Validate API key exists and is active
api_key_valid if {
    key := api_keys[input.api_key]
    key.active == true
    key.expires > time.now_ns()
}

# Check if API key has permission for the endpoint
api_key_has_permission if {
    key := api_keys[input.api_key]
    endpoint := concat("/", input.path)
    some path in key.allowed_paths
    glob.match(path, ["/"], endpoint)
}

{
    "sk_live_abc123": {
        "active": true,
        "expires": 9999999999000000000,
        "allowed_paths": ["/api/v1/*", "/webhooks/*"],
        "rate_limit": 1000
    },
    "sk_test_xyz789": {
        "active": true,
        "expires": 9999999999000000000,
        "allowed_paths": ["/api/v1/test/*"],
        "rate_limit": 100
    }
}

{
    "api_key": "sk_live_abc123",
    "path": ["api", "v1", "users"]
}

# METADATA
# title: Rate Limiting Policies
# description: Enforces rate limits based on user identity or IP address to prevent abuse
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

import data.rate_limits

default allow := false

# METADATA
# title: Allow rate-limited requests
# description: Permits requests when the user and IP are within their rate limits
# entrypoint: true
# custom:
#   severity: MEDIUM
# Allow access if within rate limit
allow if {
    not rate_limit_exceeded
}

# Check if user has exceeded their rate limit
rate_limit_exceeded if {
    limit := user_rate_limit
    count := rate_limits.user_requests[input.user]
    count >= limit
}

# Check if IP has exceeded rate limit
rate_limit_exceeded if {
    limit := ip_rate_limit
    count := rate_limits.ip_requests[input.source_ip]
    count >= limit
}

# Get user-specific rate limit
user_rate_limit := limit if {
    import data.users
    limit := users[input.user].rate_limit
} else := 100  # Default limit

# IP-based rate limit (stricter)
ip_rate_limit := 50

{
    "user_requests": {
        "alice": 95,
        "bob": 150
    },
    "ip_requests": {
        "192.168.1.100": 45,
        "192.168.1.101": 60
    }
}

{
    "user": "bob",
    "source_ip": "192.168.1.100"
}

# METADATA
# title: API Versioning Policies
# description: Enforces different authorization rules based on API version
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow version-appropriate requests
# description: Permits requests based on API version-specific authentication requirements
# entrypoint: true
# custom:
#   severity: LOW
# API v1 - Legacy, requires basic auth
allow if {
    input.path[0] == "api"
    input.path[1] == "v1"
    input.auth_type == "basic"
    valid_basic_auth
}

# API v2 - Modern, requires JWT
allow if {
    input.path[0] == "api"
    input.path[1] == "v2"
    input.auth_type == "bearer"
    valid_jwt_token
}

# API v3 - Future, requires OAuth2 with specific scopes
allow if {
    input.path[0] == "api"
    input.path[1] == "v3"
    input.auth_type == "bearer"
    valid_oauth2_token
    has_required_scope_v3
}

valid_basic_auth if {
    # Basic validation logic
    input.credentials != ""
}

valid_jwt_token if {
    token := {"payload": payload} | [_, payload, _] := io.jwt.decode(input.token)
    token.payload.exp > time.now_ns() / 1000000000
}

valid_oauth2_token if {
    valid_jwt_token
}

has_required_scope_v3 if {
    token := {"payload": payload} | [_, payload, _] := io.jwt.decode(input.token)
    "api:v3:access" in token.payload.scopes
}

{
    "path": ["api", "v2", "users"],
    "auth_type": "bearer",
    "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjk5OTk5OTk5OTl9..."
}

# METADATA
# title: CORS Policy Enforcement
# description: Enforces Cross-Origin Resource Sharing policies by validating origin headers
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow CORS-compliant requests
# description: Permits requests from same-origin or allowed cross-origin sources
# entrypoint: true
# custom:
#   severity: MEDIUM
# Allow same-origin requests
allow if {
    input.method in {"GET", "POST", "PUT", "DELETE"}
    not input.headers["origin"]
}

# Allow CORS requests from allowed origins
allow if {
    input.method in {"GET", "POST", "PUT", "DELETE"}
    origin := input.headers["origin"]
    origin in allowed_origins
}

# Allow preflight requests from allowed origins
allow if {
    input.method == "OPTIONS"
    origin := input.headers["origin"]
    origin in allowed_origins
}

# Define allowed origins
allowed_origins := {
    "https://app.example.com",
    "https://staging.example.com",
    "https://admin.example.com"
}

# Additional check for credentials
deny contains "CORS credentials not allowed" if {
    input.headers["origin"]
    input.headers["origin"] not in allowed_origins
    input.headers["access-control-allow-credentials"] == "true"
}

{
    "method": "POST",
    "headers": {
        "origin": "https://app.example.com",
        "content-type": "application/json"
    }
}

# METADATA
# title: Request Body Validation
# description: Validates request body structure and content before allowing API access
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow requests with valid body
# description: Permits requests when the request body passes structural and content validation
# entrypoint: true
# custom:
#   severity: MEDIUM
# Allow POST requests with valid body
allow if {
    input.method == "POST"
    input.path == ["api", "users"]
    valid_user_creation_body
}

# Validate user creation request body
valid_user_creation_body if {
    body := input.body

    # Required fields present
    body.email
    body.username
    body.password

    # Field validation
    count(body.password) >= 8
    contains(body.email, "@")
    count(body.username) >= 3

    # No prohibited fields
    not body.is_admin
    not body.role
}

# Allow PUT requests with valid update body
allow if {
    input.method == "PUT"
    input.path = ["api", "users", user_id]
    valid_user_update_body
    input.user == user_id  # Can only update own profile
}

valid_user_update_body if {
    body := input.body

    # Only allowed fields
    allowed_fields := {"email", "display_name", "bio"}
    body_fields := {field | body[field]}
    body_fields - allowed_fields == set()
}

{
    "method": "POST",
    "path": ["api", "users"],
    "body": {
        "email": "user@example.com",
        "username": "newuser",
        "password": "securepass123"
    }
}

# METADATA
# title: Response Filtering
# description: Filters response data based on user permissions, removing sensitive fields
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

import data.users

# METADATA
# title: Allowed response fields
# description: Determines which fields can be included in the response based on user role
# entrypoint: true
# custom:
#   severity: MEDIUM
# Determine which fields can be included in response
allowed_response_fields contains field if {
    input.method == "GET"
    input.path = ["api", "users", user_id]

    # Public fields always allowed
    field in public_fields
}

allowed_response_fields contains field if {
    input.method == "GET"
    input.path = ["api", "users", user_id]

    # Private fields only for the user themselves
    user_id == input.user
    field in private_fields
}

allowed_response_fields contains field if {
    input.method == "GET"
    input.path = ["api", "users", user_id]

    # Admin fields only for admins
    users[input.user].role == "admin"
    field in admin_fields
}

public_fields := {"username", "display_name", "avatar"}
private_fields := {"email", "phone", "bio"}
admin_fields := {"created_at", "last_login", "ip_address", "status"}

# Generate filtered response
filtered_response := {field: value |
    some field, value in input.response
    field in allowed_response_fields
}

{
    "method": "GET",
    "path": ["api", "users", "alice"],
    "user": "bob",
    "response": {
        "username": "alice",
        "email": "alice@example.com",
        "display_name": "Alice Smith",
        "created_at": "2023-01-01"
    }
}

# METADATA
# title: Tenant Isolation
# description: Enforces tenant isolation to prevent cross-tenant data access in SaaS applications
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

import data.tenants

default allow := false

# METADATA
# title: Allow tenant-scoped requests
# description: Permits requests when the user belongs to the requested tenant
# entrypoint: true
# custom:
#   severity: HIGH
# Allow access if user belongs to the tenant
allow if {
    user_tenant_id := user_tenant[input.user]
    requested_tenant_id := extract_tenant_from_path
    user_tenant_id == requested_tenant_id
}

# Extract tenant ID from request path
extract_tenant_from_path := tenant_id if {
    input.path[0] == "tenants"
    tenant_id := input.path[1]
}

# Get user's tenant
user_tenant[user] := tenant_id if {
    some tenant_id, tenant in tenants
    user in tenant.users
}

# Platform admins can access any tenant
allow if {
    input.user in platform_admins
}

platform_admins := {"platform_admin", "support_admin"}

{
    "tenant_a": {
        "users": ["alice", "bob"],
        "name": "Company A"
    },
    "tenant_b": {
        "users": ["charlie", "david"],
        "name": "Company B"
    }
}

{
    "user": "alice",
    "path": ["tenants", "tenant_a", "resources", "123"]
}

# METADATA
# title: Time-Window Based Access
# description: Restricts API access to specific time windows such as business hours
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow time-restricted requests
# description: Permits requests during business hours and outside maintenance windows
# entrypoint: true
# custom:
#   severity: MEDIUM
# Allow access during business hours
allow if {
    is_business_hours
    not is_maintenance_window
}

# Allow admin access anytime
allow if {
    input.user in admins
}

# Check if current time is within business hours
is_business_hours if {
    [hour, minute, second] := time.clock(time.now_ns())
    hour >= 9
    hour < 17
}

# Check if current time is within maintenance window
is_maintenance_window if {
    [year, month, day] := time.date(time.now_ns())
    [hour, minute, second] := time.clock(time.now_ns())

    # Maintenance every Sunday 2-4 AM
    day_of_week := time.weekday(time.now_ns())
    day_of_week == "Sunday"
    hour >= 2
    hour < 4
}

admins := {"admin", "ops_team"}

{
    "user": "alice"
}

# METADATA
# title: IP Allowlist/Denylist
# description: Controls API access based on source IP addresses using allowlists and denylists
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow IP-validated requests
# description: Permits requests from allowlisted IPs that are not on the denylist
# entrypoint: true
# custom:
#   severity: HIGH
# Allow if IP is in allowlist and not in denylist
allow if {
    ip_allowed
    not ip_denied
}

# Check if IP is in allowlist (using CIDR ranges)
ip_allowed if {
    some cidr in ip_allowlist
    net.cidr_contains(cidr, input.source_ip)
}

# Check if IP is explicitly denied
ip_denied if {
    input.source_ip in ip_denylist
}

# Internal network ranges
ip_allowlist := [
    "10.0.0.0/8",
    "172.16.0.0/12",
    "192.168.0.0/16"
]

# Known malicious IPs
ip_denylist := {
    "192.168.1.100",
    "10.0.0.50"
}

# Allow specific public IPs for partners
allow if {
    input.source_ip in partner_ips
    input.path[0] == "api"
    input.path[1] == "partner"
}

partner_ips := {
    "203.0.113.10",
    "198.51.100.20"
}

{
    "source_ip": "10.0.0.25",
    "path": ["api", "internal", "resources"]
}

# METADATA
# title: User Agent Restrictions
# description: Restricts API access based on User-Agent headers to prevent scraping
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow approved user agent requests
# description: Permits requests from approved user agents and client applications
# entrypoint: true
# custom:
#   severity: MEDIUM
# Allow requests from approved user agents
allow if {
    user_agent := input.headers["user-agent"]
    is_approved_user_agent(user_agent)
}

# Check if user agent is approved
is_approved_user_agent(ua) if {
    # Official mobile app
    contains(ua, "MyApp-iOS")
}

is_approved_user_agent(ua) if {
    # Official Android app
    contains(ua, "MyApp-Android")
}

is_approved_user_agent(ua) if {
    # Web browser access
    some allowed in approved_browsers
    contains(ua, allowed)
}

# Block known bots and scrapers
deny contains "Bot/scraper not allowed" if {
    user_agent := input.headers["user-agent"]
    some blocked in blocked_patterns
    contains(lower(user_agent), blocked)
}

approved_browsers := {
    "Chrome",
    "Firefox",
    "Safari",
    "Edge"
}

blocked_patterns := {
    "bot",
    "crawler",
    "scraper",
    "spider"
}

{
    "headers": {
        "user-agent": "MyApp-iOS/1.2.3 (iPhone; iOS 15.0)"
    }
}

# METADATA
# title: Content-Type Validation
# description: Validates that requests have appropriate Content-Type headers for the endpoint
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow content-type validated requests
# description: Permits requests with correct Content-Type headers for the target endpoint
# entrypoint: true
# custom:
#   severity: LOW
# Allow GET requests (no content-type required)
allow if {
    input.method == "GET"
}

# Allow POST/PUT with correct content type
allow if {
    input.method in {"POST", "PUT", "PATCH"}
    valid_content_type
}

# Validate content type for the endpoint
valid_content_type if {
    content_type := input.headers["content-type"]
    endpoint := concat("/", input.path)
    required := required_content_types[endpoint]
    startswith(content_type, required)
}

# Map endpoints to required content types
required_content_types := {
    "/api/users": "application/json",
    "/api/upload": "multipart/form-data",
    "/api/webhook": "application/json",
    "/api/import": "text/csv"
}

# Deny specific dangerous content types
deny contains "Dangerous content type" if {
    content_type := input.headers["content-type"]
    some dangerous in dangerous_content_types
    contains(content_type, dangerous)
}

dangerous_content_types := {
    "application/x-www-form-urlencoded",  # If not expected
    "text/html"  # Prevent XSS injection
}

{
    "method": "POST",
    "path": ["api", "users"],
    "headers": {
        "content-type": "application/json; charset=utf-8"
    }
}

# METADATA
# title: Query Parameter Validation
# description: Validates query parameters to prevent injection attacks and enforce business rules
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow parameter-validated requests
# description: Permits requests with valid query parameters and no injection risk
# entrypoint: true
# custom:
#   severity: MEDIUM
# Allow requests with valid query parameters
allow if {
    valid_query_params
    not has_injection_risk
}

# Validate query parameters for the endpoint
valid_query_params if {
    endpoint := concat("/", input.path)
    endpoint == "/api/users"
    validate_users_query_params
}

# Validate parameters for /api/users endpoint
validate_users_query_params if {
    params := input.query_params

    # Limit parameter must be a reasonable number
    limit := to_number(params.limit)
    limit > 0
    limit <= 100

    # Offset must be non-negative
    offset := to_number(params.offset)
    offset >= 0

    # Sort field must be allowed
    params.sort in allowed_sort_fields
}

# Check for SQL injection patterns
has_injection_risk if {
    some param, value in input.query_params
    some pattern in injection_patterns
    contains(lower(value), pattern)
}

allowed_sort_fields := {
    "created_at",
    "username",
    "email"
}

injection_patterns := {
    "union select",
    "drop table",
    "--",
    "/*",
    "xp_",
    "exec"
}

{
    "path": ["api", "users"],
    "query_params": {
        "limit": "50",
        "offset": "0",
        "sort": "username"
    }
}

# METADATA
# title: HTTP Header Requirements
# description: Enforces required HTTP headers for security and tracking purposes
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow header-validated requests
# description: Permits requests that include all required headers with valid values
# entrypoint: true
# custom:
#   severity: MEDIUM
# Allow requests with all required headers
allow if {
    has_required_headers
    valid_header_values
}

# Check if all required headers are present
has_required_headers if {
    every header in required_headers {
        input.headers[header]
    }
}

# Validate header values
valid_header_values if {
    # API version header
    api_version := input.headers["x-api-version"]
    api_version in supported_api_versions

    # Request ID for tracing
    request_id := input.headers["x-request-id"]
    count(request_id) > 0

    # Content Security Policy compliance
    not input.headers["x-frame-options"]
    not input.headers["x-xss-protection"]
}

# Security headers check
deny contains "Missing security headers" if {
    input.path[0] == "admin"
    some header in security_headers
    not input.headers[header]
}

required_headers := {
    "x-api-version",
    "x-request-id"
}

supported_api_versions := {"v1", "v2", "v3"}

security_headers := {
    "x-csrf-token",
    "authorization"
}

{
    "path": ["api", "resources"],
    "headers": {
        "x-api-version": "v2",
        "x-request-id": "req-abc-123-xyz",
        "authorization": "Bearer token123"
    }
}

# METADATA
# title: Comprehensive Multi-Factor Authorization
# description: Combines multiple authorization factors including identity, JWT, roles, IP, and time
# authors:
# - API Security Team <api-security@example.com>
# custom:
#   category: http-authorization
package httpapi.authz

import rego.v1

default allow := false

# METADATA
# title: Allow multi-factor authorized requests
# description: Permits requests that pass authentication, authorization, and blocking checks
# entrypoint: true
# custom:
#   severity: HIGH
# Main authorization decision combining multiple factors
allow if {
    authenticated
    authorized
    not blocked
}

# Authentication: Valid JWT token
authenticated if {
    token_valid
    token_not_expired
    token_signature_valid
}

token_valid if {
    [header, payload, signature] := io.jwt.decode(input.token)
    payload.iss == "https://auth.example.com"
    payload.aud == "api.example.com"
}

token_not_expired if {
    [_, payload, _] := io.jwt.decode(input.token)
    payload.exp > time.now_ns() / 1000000000
}

token_signature_valid if {
    # In production, verify signature with public key
    io.jwt.verify_rs256(input.token, input.public_key)
}

# Authorization: Role-based and attribute-based checks
authorized if {
    has_required_role
    has_path_permission
    within_rate_limit
}

has_required_role if {
    [_, payload, _] := io.jwt.decode(input.token)
    required_role := endpoint_roles[concat("/", input.path)]
    required_role in payload.roles
}

has_path_permission if {
    [_, payload, _] := io.jwt.decode(input.token)
    user_level := payload.level
    endpoint_level := endpoint_levels[concat("/", input.path)]
    user_level >= endpoint_level
}

within_rate_limit if {
    import data.rate_limits
    [_, payload, _] := io.jwt.decode(input.token)
    user_id := payload.sub
    current_requests := rate_limits[user_id]
    current_requests < 1000
}

# Blocking conditions
blocked if {
    ip_blocked
}

blocked if {
    outside_business_hours
    not emergency_access
}

ip_blocked if {
    some blocked_ip in blocked_ips
    input.source_ip == blocked_ip
}

outside_business_hours if {
    [hour, _, _] := time.clock(time.now_ns())
    hour < 9
    hour >= 18
}

emergency_access if {
    [_, payload, _] := io.jwt.decode(input.token)
    "emergency" in payload.roles
}

# Configuration data
endpoint_roles := {
    "/api/users": "user",
    "/api/admin": "admin",
    "/api/reports": "analyst"
}

endpoint_levels := {
    "/api/users": 1,
    "/api/admin": 5,
    "/api/reports": 3
}

blocked_ips := {
    "192.168.1.100",
    "10.0.0.50"
}

{
    "token": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczovL2F1dGguZXhhbXBsZS5jb20iLCJhdWQiOiJhcGkuZXhhbXBsZS5jb20iLCJleHAiOjk5OTk5OTk5OTksInN1YiI6InVzZXIxMjMiLCJyb2xlcyI6WyJ1c2VyIiwiYW5hbHlzdCJdLCJsZXZlbCI6M30...",
    "path": ["api", "reports"],
    "source_ip": "10.0.1.50",
    "public_key": "-----BEGIN PUBLIC KEY-----\n..."
}

{
    "user": "alice",
    "method": "GET",
    "path": ["api", "v1", "resources", "123"],
    "headers": {
        "authorization": "Bearer token...",
        "content-type": "application/json",
        "user-agent": "MyApp/1.0"
    },
    "query_params": {
        "limit": "10",
        "offset": "0"
    },
    "body": {},
    "source_ip": "192.168.1.50",
    "token": "eyJhbGci...",
    "timestamp": 1234567890
}

# Python example
import requests

input_dict = {
    "input": {
        "user": request.user,
        "method": request.method,
        "path": request.path.strip("/").split("/"),
        "headers": dict(request.headers),
        "source_ip": request.remote_addr
    }
}

response = requests.post(
    "http://opa:8181/v1/data/httpapi/authz",
    json=input_dict
)

if response.json().get("result", {}).get("allow"):
    # Request authorized
    pass
else:
    # Request denied
    return 403