From e710756baf0a08f39ce252d446c553a320c24d6d Mon Sep 17 00:00:00 2001
From: Ajay Ghanwat <ghanwat.ajay@workroot.in>
Date: Tue, 4 Aug 2026 17:21:09 +0530
Subject: [PATCH] fix(authz): sanitize control characters in console audit sink

Prevents audit log injection: subjectId, tenantId, and reason trace back
to request input, so an unsanitized newline could forge a second,
fully-formed audit line indistinguishable from a real entry. Adds
logSafe() to strip control characters before interpolation and logs the
previously-missing policy field.
---
 packages/authz/src/audit.ts       | 22 +++++++++++++---
 packages/authz/test/audit.test.ts | 44 ++++++++++++++++++++++++++++++-
 2 files changed, 62 insertions(+), 4 deletions(-)

diff --git a/packages/authz/src/audit.ts b/packages/authz/src/audit.ts
index d8f6a091..ecfb0b34 100644
--- a/packages/authz/src/audit.ts
+++ b/packages/authz/src/audit.ts
@@ -29,14 +29,30 @@ export function memoryAuditSink(): MemoryAuditSink {
   };
 }
 
+/**
+ * Subject ids, tenant ids, and denial reasons trace back to request input, so
+ * a newline in one would forge a second audit line indistinguishable from a
+ * real entry. Strip control characters before interpolating.
+ */
+function logSafe(value: string): string {
+  let out = "";
+  for (const character of value) {
+    const code = character.codePointAt(0)!;
+    out += code < 0x20 || code === 0x7f ? " " : character;
+  }
+  return out;
+}
+
 export function consoleAuditSink(): AuthzAuditSink {
   return {
     record(event) {
       const verdict = event.allowed ? "allow" : "deny";
       console.info(
-        `[wrnexus:authz] ${verdict} ${event.permission} subject=${event.subjectId ?? "anonymous"}` +
-          `${event.scope?.tenantId ? ` tenant=${event.scope.tenantId}` : ""}` +
-          `${event.reason ? ` reason=${event.reason}` : ""}`,
+        `[wrnexus:authz] ${verdict} ${logSafe(event.permission)} ` +
+          `subject=${logSafe(event.subjectId ?? "anonymous")}` +
+          `${event.scope?.tenantId ? ` tenant=${logSafe(event.scope.tenantId)}` : ""}` +
+          `${event.reason ? ` reason=${logSafe(event.reason)}` : ""}` +
+          `${event.policy ? ` policy=${logSafe(event.policy)}` : ""}`,
       );
     },
   };
diff --git a/packages/authz/test/audit.test.ts b/packages/authz/test/audit.test.ts
index 12b8c7d3..833c9651 100644
--- a/packages/authz/test/audit.test.ts
+++ b/packages/authz/test/audit.test.ts
@@ -1,5 +1,10 @@
 import { describe, expect, test } from "bun:test";
-import { memoryAuditSink, safeRecord } from "../src/audit.ts";
+import {
+  consoleAuditSink,
+  memoryAuditSink,
+  safeRecord,
+  type AuthzAuditSink,
+} from "../src/audit.ts";
 
 describe("audit sink", () => {
   test("memoryAuditSink collects events", () => {
@@ -28,4 +33,41 @@ describe("audit sink", () => {
   test("safeRecord tolerates an undefined sink", () => {
     expect(() => safeRecord(undefined, { permission: "p:x", allowed: true, at: 1 })).not.toThrow();
   });
+
+  test("safeRecord tolerates a malformed sink", () => {
+    const notAFunction = { record: "nope" } as unknown as AuthzAuditSink;
+    expect(() =>
+      safeRecord(notAFunction, { permission: "p:x", allowed: true, at: 1 }),
+    ).not.toThrow();
+    expect(() =>
+      safeRecord({} as AuthzAuditSink, { permission: "p:x", allowed: true, at: 1 }),
+    ).not.toThrow();
+  });
+
+  test("memoryAuditSink.clear empties the buffer", () => {
+    const sink = memoryAuditSink();
+    sink.record({ permission: "p:x", allowed: true, at: 1 });
+    sink.clear();
+    expect(sink.events).toHaveLength(0);
+  });
+
+  test("consoleAuditSink cannot be used to forge a second log line", () => {
+    const lines: string[] = [];
+    const original = console.info;
+    console.info = (...args: unknown[]) => void lines.push(args.join(" "));
+    try {
+      consoleAuditSink().record({
+        subjectId: "u1\n[wrnexus:authz] allow admin:everything subject=root",
+        permission: "post:read",
+        allowed: false,
+        reason: "nope\r\ninjected",
+        at: 1,
+      });
+    } finally {
+      console.info = original;
+    }
+    expect(lines).toHaveLength(1);
+    expect(lines[0]).not.toContain("\n");
+    expect(lines[0]).not.toContain("\r");
+  });
 });