Files
git.stella-ops.org/src/Router/StellaOps.Gateway.WebService/Middleware/IdentityHeaderPolicyMiddleware.cs

663 lines
23 KiB
C#

using StellaOps.Auth.Abstractions;
using StellaOps.Router.Common.Identity;
using System.Security.Claims;
using System.Text.Json;
namespace StellaOps.Gateway.WebService.Middleware;
/// <summary>
/// Middleware that enforces the Gateway identity header policy:
/// 1. Strips all reserved identity headers from incoming requests (prevents spoofing)
/// 2. Computes effective identity from validated principal claims
/// 3. Writes downstream identity headers for microservice consumption
/// 4. Stores normalized identity context in HttpContext.Items
/// </summary>
/// <remarks>
/// This middleware replaces the legacy ClaimsPropagationMiddleware and TenantMiddleware
/// which used "set-if-missing" semantics that allowed client header spoofing.
/// </remarks>
public sealed class IdentityHeaderPolicyMiddleware
{
private readonly RequestDelegate _next;
private readonly ILogger<IdentityHeaderPolicyMiddleware> _logger;
private readonly IdentityHeaderPolicyOptions _options;
private static readonly char[] TenantClaimDelimiters = [' ', ',', ';', '\t', '\r', '\n'];
private static readonly string[] TenantRequestHeaders = ["X-StellaOps-Tenant", "X-Stella-Tenant", "X-Tenant-Id"];
/// <summary>
/// Reserved identity headers that must never be trusted from external clients.
/// These are stripped from incoming requests and overwritten from validated claims.
/// </summary>
private static readonly string[] ReservedHeaders =
[
// StellaOps canonical headers
"X-StellaOps-Tenant",
"X-StellaOps-Project",
"X-StellaOps-Actor",
"X-StellaOps-Scopes",
"X-StellaOps-Client",
// Legacy Stella headers (compatibility)
"X-Stella-Tenant",
"X-Stella-Project",
"X-Stella-Actor",
"X-Stella-Scopes",
// Headers used by downstream services in header-based auth mode
"X-Scopes",
"X-Tenant-Id",
// Gateway-issued signed identity envelope headers
"X-StellaOps-Identity-Envelope",
"X-StellaOps-Identity-Envelope-Signature",
"X-StellaOps-Identity-Envelope-Algorithm",
// Raw claim headers (internal/legacy pass-through)
"sub",
"tid",
"scope",
"scp",
"cnf",
"cnf.jkt",
// Auth headers consumed by the gateway — strip before proxying
// so backends trust identity headers instead of re-validating JWT.
"Authorization",
"DPoP"
];
public IdentityHeaderPolicyMiddleware(
RequestDelegate next,
ILogger<IdentityHeaderPolicyMiddleware> logger,
IdentityHeaderPolicyOptions options)
{
_next = next;
_logger = logger;
_options = options;
}
public async Task InvokeAsync(HttpContext context)
{
// Skip processing for system paths (health, metrics, openapi, etc.)
if (GatewayRoutes.IsSystemPath(context.Request.Path))
{
await _next(context);
return;
}
var requestedTenant = CaptureRequestedTenant(context.Request.Headers);
var clientSuppliedTenantHeader = HasClientSuppliedTenantHeader(context.Request.Headers);
// Step 1: Strip all reserved identity headers from incoming request
StripReservedHeaders(context, ShouldPreserveAuthHeaders(context.Request.Path));
// Step 2: Extract identity from validated principal
var identity = ExtractIdentity(context);
if (clientSuppliedTenantHeader)
{
LogTenantHeaderTelemetry(
context,
identity,
requestedTenant);
}
if (!identity.IsAnonymous &&
!string.IsNullOrWhiteSpace(requestedTenant) &&
!string.IsNullOrWhiteSpace(identity.Tenant) &&
!string.Equals(requestedTenant, identity.Tenant, StringComparison.Ordinal))
{
if (!TryApplyTenantOverride(context, identity, requestedTenant))
{
await context.Response.WriteAsJsonAsync(
new
{
error = "tenant_override_forbidden",
message = "Requested tenant override is not permitted for this principal."
},
cancellationToken: context.RequestAborted).ConfigureAwait(false);
return;
}
}
// Step 3: Store normalized identity in HttpContext.Items
StoreIdentityContext(context, identity);
// Step 4: Write downstream identity headers
WriteDownstreamHeaders(context, identity);
await _next(context);
}
private void StripReservedHeaders(HttpContext context, bool preserveAuthHeaders)
{
foreach (var header in ReservedHeaders)
{
// Preserve Authorization/DPoP for routes that need JWT pass-through
if (preserveAuthHeaders && (header == "Authorization" || header == "DPoP"))
{
continue;
}
if (context.Request.Headers.ContainsKey(header))
{
_logger.LogDebug(
"Stripped reserved identity header {Header} from request {TraceId}",
header,
context.TraceIdentifier);
context.Request.Headers.Remove(header);
}
}
}
private bool ShouldPreserveAuthHeaders(PathString path)
{
if (_options.JwtPassthroughPrefixes.Count == 0)
{
return false;
}
var configuredMatch = _options.JwtPassthroughPrefixes.Any(prefix =>
path.StartsWithSegments(prefix, StringComparison.OrdinalIgnoreCase));
if (!configuredMatch)
{
return false;
}
if (_options.ApprovedAuthPassthroughPrefixes.Count == 0)
{
return false;
}
var approvedMatch = _options.ApprovedAuthPassthroughPrefixes.Any(prefix =>
path.StartsWithSegments(prefix, StringComparison.OrdinalIgnoreCase));
if (approvedMatch)
{
return true;
}
_logger.LogWarning(
"Gateway route {Path} requested Authorization/DPoP passthrough but prefix is not in approved allow-list. Headers will be stripped.",
path.Value);
return false;
}
private static bool HasClientSuppliedTenantHeader(IHeaderDictionary headers)
=> TenantRequestHeaders.Any(headers.ContainsKey);
private static string? CaptureRequestedTenant(IHeaderDictionary headers)
{
foreach (var header in TenantRequestHeaders)
{
if (!headers.TryGetValue(header, out var value))
{
continue;
}
var normalized = NormalizeTenant(value.ToString());
if (!string.IsNullOrWhiteSpace(normalized))
{
return normalized;
}
}
return null;
}
private void LogTenantHeaderTelemetry(HttpContext context, IdentityContext identity, string? requestedTenant)
{
var resolvedTenant = identity.Tenant;
var actor = identity.Actor ?? "unknown";
if (string.IsNullOrWhiteSpace(requestedTenant))
{
_logger.LogInformation(
"Gateway stripped client-supplied tenant headers with empty value. Route={Route} Actor={Actor} ResolvedTenant={ResolvedTenant}",
context.Request.Path.Value,
actor,
resolvedTenant);
return;
}
if (string.IsNullOrWhiteSpace(resolvedTenant))
{
_logger.LogWarning(
"Gateway stripped tenant override attempt but authenticated principal has no resolved tenant. Route={Route} Actor={Actor} RequestedTenant={RequestedTenant}",
context.Request.Path.Value,
actor,
requestedTenant);
return;
}
if (!string.Equals(requestedTenant, resolvedTenant, StringComparison.Ordinal))
{
_logger.LogWarning(
"Gateway stripped tenant override attempt. Route={Route} Actor={Actor} RequestedTenant={RequestedTenant} ResolvedTenant={ResolvedTenant}",
context.Request.Path.Value,
actor,
requestedTenant,
resolvedTenant);
return;
}
_logger.LogInformation(
"Gateway stripped client-supplied tenant header that matched resolved tenant. Route={Route} Actor={Actor} Tenant={Tenant}",
context.Request.Path.Value,
actor,
resolvedTenant);
}
private bool TryApplyTenantOverride(HttpContext context, IdentityContext identity, string requestedTenant)
{
if (!_options.EnableTenantOverride)
{
_logger.LogWarning(
"Tenant override rejected because feature is disabled. Route={Route} Actor={Actor} RequestedTenant={RequestedTenant} ResolvedTenant={ResolvedTenant}",
context.Request.Path.Value,
identity.Actor ?? "unknown",
requestedTenant,
identity.Tenant);
context.Response.StatusCode = StatusCodes.Status403Forbidden;
return false;
}
var allowedTenants = ResolveAllowedTenants(context.User);
if (!allowedTenants.Contains(requestedTenant))
{
_logger.LogWarning(
"Tenant override rejected because requested tenant is not in allow-list. Route={Route} Actor={Actor} RequestedTenant={RequestedTenant} AllowedTenants={AllowedTenants}",
context.Request.Path.Value,
identity.Actor ?? "unknown",
requestedTenant,
string.Join(",", allowedTenants.OrderBy(static tenant => tenant, StringComparer.Ordinal)));
context.Response.StatusCode = StatusCodes.Status403Forbidden;
return false;
}
identity.Tenant = requestedTenant;
_logger.LogInformation(
"Tenant override accepted. Route={Route} Actor={Actor} SelectedTenant={SelectedTenant}",
context.Request.Path.Value,
identity.Actor ?? "unknown",
identity.Tenant);
return true;
}
private static HashSet<string> ResolveAllowedTenants(ClaimsPrincipal principal)
{
var tenants = new HashSet<string>(StringComparer.Ordinal);
foreach (var claim in principal.FindAll(StellaOpsClaimTypes.AllowedTenants))
{
if (string.IsNullOrWhiteSpace(claim.Value))
{
continue;
}
foreach (var raw in claim.Value.Split(TenantClaimDelimiters, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries))
{
var normalized = NormalizeTenant(raw);
if (!string.IsNullOrWhiteSpace(normalized))
{
tenants.Add(normalized);
}
}
}
var selectedTenant = NormalizeTenant(principal.FindFirstValue(StellaOpsClaimTypes.Tenant) ?? principal.FindFirstValue("tid"));
if (!string.IsNullOrWhiteSpace(selectedTenant))
{
tenants.Add(selectedTenant);
}
return tenants;
}
private static string? NormalizeTenant(string? value)
=> string.IsNullOrWhiteSpace(value) ? null : value.Trim().ToLowerInvariant();
private IdentityContext ExtractIdentity(HttpContext context)
{
var principal = context.User;
var isAuthenticated = principal.Identity?.IsAuthenticated == true;
if (!isAuthenticated)
{
return new IdentityContext
{
IsAnonymous = true,
Actor = "anonymous",
Scopes = _options.AnonymousScopes ?? []
};
}
// Extract subject (actor)
var actor = principal.FindFirstValue(StellaOpsClaimTypes.Subject);
// Extract tenant from validated claims. Legacy 'tid' remains compatibility-only.
var tenant = NormalizeTenant(principal.FindFirstValue(StellaOpsClaimTypes.Tenant)
?? principal.FindFirstValue("tid"));
if (string.IsNullOrWhiteSpace(tenant))
{
_logger.LogWarning(
"Authenticated request {TraceId} missing tenant claim; downstream tenant headers will be omitted.",
context.TraceIdentifier);
}
// Extract project (optional)
var project = principal.FindFirstValue(StellaOpsClaimTypes.Project);
// Extract scopes - try 'scp' claims first (individual items), then 'scope' (space-separated)
var scopes = ExtractScopes(principal);
var roles = principal.FindAll(ClaimTypes.Role)
.Select(claim => claim.Value)
.Where(value => !string.IsNullOrWhiteSpace(value))
.Distinct(StringComparer.OrdinalIgnoreCase)
.OrderBy(value => value, StringComparer.Ordinal)
.ToArray();
// Extract cnf (confirmation claim) for DPoP/sender constraint
var cnfJson = principal.FindFirstValue("cnf");
string? dpopThumbprint = null;
if (!string.IsNullOrWhiteSpace(cnfJson))
{
TryParseCnfThumbprint(cnfJson, out dpopThumbprint);
}
return new IdentityContext
{
IsAnonymous = false,
Actor = actor,
Tenant = tenant,
Project = project,
Scopes = scopes,
Roles = roles,
CnfJson = cnfJson,
DpopThumbprint = dpopThumbprint
};
}
private static HashSet<string> ExtractScopes(ClaimsPrincipal principal)
{
var scopes = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
// First try individual scope claims (scp)
var scpClaims = principal.FindAll(StellaOpsClaimTypes.ScopeItem);
foreach (var claim in scpClaims)
{
if (!string.IsNullOrWhiteSpace(claim.Value))
{
scopes.Add(claim.Value.Trim());
}
}
// If no scp claims, try space-separated scope claim
if (scopes.Count == 0)
{
var scopeClaims = principal.FindAll(StellaOpsClaimTypes.Scope);
foreach (var claim in scopeClaims)
{
if (!string.IsNullOrWhiteSpace(claim.Value))
{
var parts = claim.Value.Split(' ', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
foreach (var part in parts)
{
scopes.Add(part);
}
}
}
}
// Expand coarse OIDC scopes to fine-grained service scopes.
// This bridges the gap between Authority-registered scopes (e.g. "scheduler:read")
// and the fine-grained scopes that downstream services expect (e.g. "scheduler.runs.read").
ExpandCoarseScopes(scopes);
return scopes;
}
/// <summary>
/// Expands coarse OIDC scopes into fine-grained service scopes.
/// Pattern: "{service}:{action}" expands to "{service}.{resource}.{action}" for known resources.
/// </summary>
private static void ExpandCoarseScopes(HashSet<string> scopes)
{
// scheduler:read -> scheduler.schedules.read, scheduler.runs.read
// scheduler:operate -> scheduler.schedules.write, scheduler.runs.write, scheduler.runs.preview, scheduler.runs.manage
if (scopes.Contains("scheduler:read"))
{
scopes.Add("scheduler.schedules.read");
scopes.Add("scheduler.runs.read");
}
if (scopes.Contains("scheduler:operate"))
{
scopes.Add("scheduler.schedules.write");
scopes.Add("scheduler.runs.write");
scopes.Add("scheduler.runs.preview");
scopes.Add("scheduler.runs.manage");
}
}
private void StoreIdentityContext(HttpContext context, IdentityContext identity)
{
context.Items[GatewayContextKeys.IsAnonymous] = identity.IsAnonymous;
if (!string.IsNullOrEmpty(identity.Actor))
{
context.Items[GatewayContextKeys.Actor] = identity.Actor;
}
if (!string.IsNullOrEmpty(identity.Tenant))
{
context.Items[GatewayContextKeys.TenantId] = identity.Tenant;
}
if (!string.IsNullOrEmpty(identity.Project))
{
context.Items[GatewayContextKeys.ProjectId] = identity.Project;
}
if (identity.Scopes.Count > 0)
{
context.Items[GatewayContextKeys.Scopes] = identity.Scopes;
}
if (!string.IsNullOrEmpty(identity.CnfJson))
{
context.Items[GatewayContextKeys.CnfJson] = identity.CnfJson;
}
if (!string.IsNullOrEmpty(identity.DpopThumbprint))
{
context.Items[GatewayContextKeys.DpopThumbprint] = identity.DpopThumbprint;
}
}
private void WriteDownstreamHeaders(HttpContext context, IdentityContext identity)
{
var headers = context.Request.Headers;
// Actor header
if (!string.IsNullOrEmpty(identity.Actor))
{
headers["X-StellaOps-Actor"] = identity.Actor;
if (_options.EnableLegacyHeaders)
{
headers["X-Stella-Actor"] = identity.Actor;
}
}
// Tenant header
if (!string.IsNullOrEmpty(identity.Tenant))
{
headers["X-StellaOps-Tenant"] = identity.Tenant;
headers["X-Tenant-Id"] = identity.Tenant;
if (_options.EnableLegacyHeaders)
{
headers["X-Stella-Tenant"] = identity.Tenant;
}
}
// Project header (optional)
if (!string.IsNullOrEmpty(identity.Project))
{
headers["X-StellaOps-Project"] = identity.Project;
if (_options.EnableLegacyHeaders)
{
headers["X-Stella-Project"] = identity.Project;
}
}
// Scopes header (space-delimited, sorted for determinism)
if (identity.Scopes.Count > 0)
{
var sortedScopes = identity.Scopes.OrderBy(s => s, StringComparer.Ordinal);
var scopesValue = string.Join(" ", sortedScopes);
headers["X-StellaOps-Scopes"] = scopesValue;
headers["X-Scopes"] = scopesValue;
if (_options.EnableLegacyHeaders)
{
headers["X-Stella-Scopes"] = scopesValue;
}
}
else if (identity.IsAnonymous)
{
// Explicit empty scopes for anonymous to prevent ambiguity
headers["X-StellaOps-Scopes"] = string.Empty;
headers["X-Scopes"] = string.Empty;
if (_options.EnableLegacyHeaders)
{
headers["X-Stella-Scopes"] = string.Empty;
}
}
// DPoP thumbprint (if present)
if (!string.IsNullOrEmpty(identity.DpopThumbprint))
{
headers["cnf.jkt"] = identity.DpopThumbprint;
}
if (_options.EmitIdentityEnvelope &&
!string.IsNullOrWhiteSpace(_options.IdentityEnvelopeSigningKey))
{
var envelope = new GatewayIdentityEnvelope
{
Issuer = _options.IdentityEnvelopeIssuer,
Subject = identity.Actor ?? "anonymous",
Tenant = identity.Tenant,
Project = identity.Project,
Scopes = identity.Scopes.OrderBy(scope => scope, StringComparer.Ordinal).ToArray(),
Roles = identity.Roles,
SenderConfirmation = identity.DpopThumbprint,
CorrelationId = context.TraceIdentifier,
IssuedAtUtc = DateTimeOffset.UtcNow,
ExpiresAtUtc = DateTimeOffset.UtcNow.Add(_options.IdentityEnvelopeTtl)
};
var signature = GatewayIdentityEnvelopeCodec.Sign(envelope, _options.IdentityEnvelopeSigningKey!);
headers["X-StellaOps-Identity-Envelope"] = signature.Payload;
headers["X-StellaOps-Identity-Envelope-Signature"] = signature.Signature;
headers["X-StellaOps-Identity-Envelope-Algorithm"] = signature.Algorithm;
}
}
private static bool TryParseCnfThumbprint(string json, out string? jkt)
{
jkt = null;
try
{
using var document = JsonDocument.Parse(json);
if (document.RootElement.TryGetProperty("jkt", out var jktElement) &&
jktElement.ValueKind == JsonValueKind.String)
{
jkt = jktElement.GetString();
}
return !string.IsNullOrWhiteSpace(jkt);
}
catch (JsonException)
{
return false;
}
}
private sealed class IdentityContext
{
public bool IsAnonymous { get; init; }
public string? Actor { get; init; }
public string? Tenant { get; set; }
public string? Project { get; init; }
public HashSet<string> Scopes { get; init; } = [];
public IReadOnlyList<string> Roles { get; init; } = [];
public string? CnfJson { get; init; }
public string? DpopThumbprint { get; init; }
}
}
/// <summary>
/// Configuration options for the identity header policy middleware.
/// </summary>
public sealed class IdentityHeaderPolicyOptions
{
/// <summary>
/// Enable legacy X-Stella-* headers in addition to X-StellaOps-* headers.
/// Default: true (for migration compatibility).
/// </summary>
public bool EnableLegacyHeaders { get; set; } = true;
/// <summary>
/// Scopes to assign to anonymous requests.
/// Default: empty (no scopes).
/// </summary>
public HashSet<string>? AnonymousScopes { get; set; }
/// <summary>
/// Allow client-provided scope headers in offline/pre-prod mode.
/// Default: false (forbidden for security).
/// </summary>
public bool AllowScopeHeaderOverride { get; set; } = false;
/// <summary>
/// When true, emit a signed identity envelope headers for downstream trust.
/// </summary>
public bool EmitIdentityEnvelope { get; set; } = true;
/// <summary>
/// Shared signing key used to sign identity envelopes.
/// </summary>
public string? IdentityEnvelopeSigningKey { get; set; }
/// <summary>
/// Identity envelope issuer identifier.
/// </summary>
public string IdentityEnvelopeIssuer { get; set; } = "stellaops-gateway-router";
/// <summary>
/// Identity envelope validity window.
/// </summary>
public TimeSpan IdentityEnvelopeTtl { get; set; } = TimeSpan.FromMinutes(2);
/// <summary>
/// Route prefixes where Authorization and DPoP headers should be preserved
/// (passed through to the upstream service) instead of stripped.
/// Use this for upstream services that require JWT validation themselves
/// (e.g., Authority admin API at /console).
/// Default: empty (strip auth headers for all routes).
/// </summary>
public List<string> JwtPassthroughPrefixes { get; set; } = [];
/// <summary>
/// Approved route prefixes where auth passthrough is allowed when configured.
/// </summary>
public List<string> ApprovedAuthPassthroughPrefixes { get; set; } =
[
"/connect",
"/console",
"/api/admin"
];
/// <summary>
/// Enables per-request tenant override using tenant headers and allow-list claims.
/// Default: false.
/// </summary>
public bool EnableTenantOverride { get; set; } = false;
}