feat(agent-harness): secure the internal operations endpoint

apps/web/src/app/api/internal/agent-harness/operations/route.ts

@@ -0,0 +1,76 @@
+import { timingSafeEqual } from '@kilocode/encryption';
+import { TRPCError } from '@trpc/server';
+import { INTERNAL_API_SECRET } from '@/lib/config.server';
+import { executeHarnessOperation, harnessOperationFailure } from '@/lib/agent-harness/operations';
+
+export const maxDuration = 60;
+
+export async function POST(request: Request) {
+  const reply = (body: Awaited<ReturnType<typeof executeHarnessOperation>>, status = 200) => {
+    let json = JSON.stringify(body);
+    if (Buffer.byteLength(json, 'utf8') > 1024 * 1024) {
+      const failure = harnessOperationFailure(new TRPCError({ code: 'PAYLOAD_TOO_LARGE' }));
+      const result = 'result' in body ? body.result : undefined;
+      if (result && typeof result === 'object' && 'costMicrodollars' in result) {
+        // Keep the validated actual cost, even when cancellation races with the completed reply.
+        body = {
+          result: { status: 'failed', ...failure, costMicrodollars: result.costMicrodollars },
+        };
+      } else {
+        body = failure;
+        status = 400;
+      }
+      json = JSON.stringify(body);
+    }
+    return new Response(json, {
+      status,
+      headers: { 'content-type': 'application/json', 'cache-control': 'no-store' },
+    });
+  };
+  const service = request.headers.get('x-internal-api-key');
+  if (!INTERNAL_API_SECRET || !service || !timingSafeEqual(service, INTERNAL_API_SECRET))
+    return reply(harnessOperationFailure(new TRPCError({ code: 'UNAUTHORIZED' })), 401);
+  const token = request.headers.get('authorization')?.match(/^Bearer ([^\s]+)$/)?.[1];
+  if (!token) return reply(harnessOperationFailure(new TRPCError({ code: 'UNAUTHORIZED' })), 401);
+  let input: unknown;
+  const reader = request.body?.getReader();
+  try {
+    if (
+      request.headers.get('content-type')?.split(';')[0].trim().toLowerCase() !==
+        'application/json' ||
+      !reader
+    )
+      throw new TRPCError({ code: 'BAD_REQUEST' });
+    const chunks: Uint8Array[] = [];
+    let length = 0;
+    while (true) {
+      const { done, value } = await reader.read();
+      if (done) break;
+      length += value.byteLength;
+      if (length > 64 * 1024) throw new TRPCError({ code: 'PAYLOAD_TOO_LARGE' });
+      chunks.push(value);
+    }
+    input = JSON.parse(new TextDecoder('utf-8', { fatal: true }).decode(Buffer.concat(chunks)));
+  } catch (error) {
+    return reply(
+      harnessOperationFailure(
+        error instanceof TRPCError ? error : new TRPCError({ code: 'BAD_REQUEST' })
+      ),
+      400
+    );
+  } finally {
+    await reader?.cancel().catch(() => undefined);
+    reader?.releaseLock();
+  }
+  const result = await executeHarnessOperation(token, input, request.signal);
+  return reply(
+    result,
+    'error' in result
+      ? result.error.code === 'access_revoked'
+        ? 403
+        : result.error.retryable
+          ? 503
+          : 400
+      : 200
+  );
+}