Ops: Add script to test lockout with spoofed X-Forwarded-For headers

scripts/test_lockout.sh

@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+#
+# Test reactbin's login rate limiter and demonstrate the XFF injection bypass.
+#
+# Phase 1: Send 6 bad login attempts in quick succession.
+#   Attempts 1-5 should return 401 (invalid credentials).
+#   Attempt 6 should return 429 (rate limited) — the limiter blocks after
+#   max_failures=5 within the window.
+#
+# Phase 2: Send a 7th bad attempt with a spoofed X-Forwarded-For header
+#   pointing at a different IP. If the lockout keys correctly on the trusted
+#   client IP, this should still return 429 (same client, still locked).
+#   If reactbin trusts client-supplied XFF blindly, this would return 401
+#   instead — the spoof would make the request look like a different client
+#   that hasn't accumulated failures.
+#
+# Interpretation:
+#   - 429 on attempt 7  → lockout is correctly identifying the client
+#   - 401 on attempt 7  → XFF injection succeeded; server treated us as a
+#                          new client because we set a fake XFF
+#
+# Note: this script is ONLY useful when run against the public origin path
+# where XFF spoofing is potentially possible. It does not exercise the
+# Cloudflare-proxied path because Cloudflare strips/replaces XFF before
+# forwarding to origin.
+
+set -u
+
+URL="${URL:-https://reactbin.juggalol.com/api/v1/auth/token}"
+SPOOFED_IP="${SPOOFED_IP:-198.51.100.99}"  # TEST-NET-2, never routed
+USERNAME="${USERNAME:-not-a-real-user}"
+PASSWORD="${PASSWORD:-not-a-real-password}"
+
+# JSON body for a bad login. Username/password chosen to be obviously fake;
+# adjust if your auth provider has its own validation that would 400 instead
+# of 401 on these values.
+BODY=$(printf '{"username":"%s","password":"%s"}' "$USERNAME" "$PASSWORD")
+
+echo "Target: $URL"
+echo "Body:   $BODY"
+echo
+
+echo "=== Phase 1: 6 bad logins from real client IP ==="
+for i in 1 2 3 4 5 6; do
+    code=$(curl -sS -o /dev/null -w '%{http_code}' \
+        -X POST \
+        -H 'Content-Type: application/json' \
+        --data "$BODY" \
+        "$URL")
+    echo "Attempt $i: HTTP $code"
+done
+
+echo
+echo "=== Phase 2: 7th attempt with spoofed X-Forwarded-For ==="
+echo "Setting X-Forwarded-For: $SPOOFED_IP"
+code=$(curl -sS -o /dev/null -w '%{http_code}' \
+    -X POST \
+    -H 'Content-Type: application/json' \
+    -H "X-Forwarded-For: $SPOOFED_IP" \
+    --data "$BODY" \
+    "$URL")
+echo "Attempt 7: HTTP $code"
+
+echo
+echo "Interpretation:"
+echo "  Attempt 7 = 429  → lockout correctly tracks real client; XFF spoof ineffective"
+echo "  Attempt 7 = 401  → XFF spoof succeeded; server believed the fake client IP"