Remove pairing/bonding from the app

CLAUDE.md

@@ -61,11 +61,19 @@ merged/signed hex, no DFU zip (OTA is explicitly out of scope).
 
 ## App behavior to preserve
 
+- **No pairing/bonding:** `CONFIG_BT_SMP=n` — this sample has no encryption or bonding. A
+  real product handling sensitive data should set `CONFIG_BT_SMP=y` and use bonding
+  (`CONFIG_BT_BONDABLE=y`, the default) instead. Because of this, we can't use the
+  `CONFIG_BT_MDS_PERM_RW_ENCRYPT` option described in [Restricting Access to
+  MDS](https://docs.memfault.com/docs/mcu/mds#restricting-access-to-mds) — that requires a
+  bonded, encrypted link — so this app falls back to the custom `access_enable` callback
+  from that same doc (see MDS access control below).
 - **MDS access control:** register `bt_mds_cb` with an `access_enable` callback that gates
-  MDS access to the secured/connected gateway link (`CONFIG_BT_SMP=y` is required).
-- **Heartbeat-on-connect:** in `security_changed`, once the link is secured, call
-  `memfault_metrics_heartbeat_debug_trigger()` once so the device shows up in Memfault
-  immediately instead of waiting for the periodic timer.
+  MDS access to the first connected gateway link (tracked via `mds_conn` in `connected()`,
+  since there is no security level to check without `CONFIG_BT_SMP`).
+- **Heartbeat-on-connect:** in `connected()`, once the gateway link is captured as
+  `mds_conn`, call `memfault_metrics_heartbeat_debug_trigger()` once so the device shows up
+  in Memfault immediately instead of waiting for the periodic timer.
 - **Crash button (demo-only):** map an LBS button to a forced fault (e.g. `k_oops`) to
   demonstrate a coredump. Comment it clearly as demo-only.
 - Keep the LBS LED/button behavior so it remains a recognizable LBS device for the guide —

app/prj.conf

@@ -6,8 +6,11 @@
 CONFIG_BT=y
 CONFIG_BT_PERIPHERAL=y
 CONFIG_BT_SHELL=y
-# MDS access control needs a secured link
-CONFIG_BT_SMP=y
+# Encryption/pairing/bonding disabled for this sample. MDS access is instead
+# gated to the first connected gateway link (see mds_access_enable() in
+# main.c). A real product handling sensitive data should set CONFIG_BT_SMP=y
+# and use bonding (CONFIG_BT_BONDABLE=y, the default) instead.
+CONFIG_BT_SMP=n
 CONFIG_BT_DEVICE_NAME="Quickstart_Bluetooth"
 CONFIG_NCS_APPLICATION_BOOT_BANNER_STRING="Quickstart Bluetooth"
 CONFIG_BT_LBS=y

app/src/main.c

@@ -8,9 +8,10 @@
  * quickstart-bluetooth application.
  *
  * The peripheral_lbs button/LED base with Memfault observability over the
- * Memfault Diagnostic Service (MDS). The device serves Memfault chunks to a
- * secured gateway connection; the gateway performs the HTTPS upload. The device
- * never does on-device HTTP/TLS.
+ * Memfault Diagnostic Service (MDS). The device serves Memfault chunks to the
+ * first connected gateway; the gateway performs the HTTPS upload. The device
+ * never does on-device HTTP/TLS. No pairing/encryption (CONFIG_BT_SMP=n). A
+ * real product handling sensitive data should enable BT_SMP and bonding.
  *
  * Controls (nRF54L15 DK):
  *   Button 0  LBS button characteristic (standard LBS — central sees the press)
@@ -107,6 +108,17 @@ static void connected(struct bt_conn *conn, uint8_t err)
 
 	printk("Connected\n");
 	dk_set_led_on(CON_STATUS_LED);
+
+	/* No pairing/encryption in this sample (CONFIG_BT_SMP=n). The first
+	 * connected central is treated as the MDS-authorized gateway. Capture a
+	 * heartbeat immediately so the device (with its software/hardware
+	 * version and serial) appears in Memfault within seconds instead of
+	 * waiting for the periodic heartbeat timer.
+	 */
+	if (!mds_conn) {
+		mds_conn = conn;
+		memfault_metrics_heartbeat_debug_trigger();
+	}
 }
 
 static void disconnected(struct bt_conn *conn, uint8_t reason)
@@ -120,31 +132,6 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	}
 }
 
-static void security_changed(struct bt_conn *conn, bt_security_t level, enum bt_security_err err)
-{
-	char addr[BT_ADDR_LE_STR_LEN];
-
-	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
-
-	if (err) {
-		printk("Security failed: %s level %u err %d %s\n", addr, level, err,
-		       bt_security_err_to_str(err));
-		return;
-	}
-
-	printk("Security changed: %s level %u\n", addr, level);
-
-	/* Once the gateway link is secured, mark it as the MDS-authorized
-	 * connection and capture a heartbeat immediately so the device (with its
-	 * software/hardware version and serial) appears in Memfault within
-	 * seconds instead of waiting for the periodic heartbeat timer.
-	 */
-	if (level >= BT_SECURITY_L2 && !mds_conn) {
-		mds_conn = conn;
-		memfault_metrics_heartbeat_debug_trigger();
-	}
-}
-
 static void recycled_cb(void)
 {
 	advertising_start();
@@ -153,46 +140,10 @@ static void recycled_cb(void)
 BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
-	.security_changed = security_changed,
 	.recycled = recycled_cb,
 };
 
-static void pairing_complete(struct bt_conn *conn, bool bonded)
-{
-	char addr[BT_ADDR_LE_STR_LEN];
-
-	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
-	printk("Pairing completed: %s, bonded: %d\n", addr, bonded);
-}
-
-static void pairing_failed(struct bt_conn *conn, enum bt_security_err reason)
-{
-	char addr[BT_ADDR_LE_STR_LEN];
-
-	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
-	printk("Pairing failed conn: %s, reason %d %s\n", addr, reason,
-	       bt_security_err_to_str(reason));
-}
-
-static void auth_cancel(struct bt_conn *conn)
-{
-	char addr[BT_ADDR_LE_STR_LEN];
-
-	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
-	printk("Pairing cancelled: %s\n", addr);
-}
-
-/* Just-works pairing (no passkey entry) — the gateway initiates security. */
-static struct bt_conn_auth_cb conn_auth_callbacks = {
-	.cancel = auth_cancel,
-};
-
-static struct bt_conn_auth_info_cb conn_auth_info_callbacks = {
-	.pairing_complete = pairing_complete,
-	.pairing_failed = pairing_failed,
-};
-
-/* Gate MDS access to the secured gateway connection only. */
+/* Gate MDS access to the first connected gateway link only. */
 static bool mds_access_enable(struct bt_conn *conn)
 {
 	return (mds_conn && conn == mds_conn);
@@ -264,18 +215,6 @@ int main(void)
 		return 0;
 	}
 
-	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
-	if (err) {
-		printk("Failed to register authorization callbacks (err %d)\n", err);
-		return 0;
-	}
-
-	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
-	if (err) {
-		printk("Failed to register authorization info callbacks (err %d)\n", err);
-		return 0;
-	}
-
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
@@ -285,8 +224,8 @@ int main(void)
 	printk("Bluetooth initialized\n");
 
 #if defined(CONFIG_SETTINGS)
-	/* Loads the stored Memfault project key (memfault/project_key) and BT
-	 * bonds. The runtime key is applied here at boot, not live.
+	/* Loads the stored Memfault project key (memfault/project_key). The
+	 * runtime key is applied here at boot, not live.
 	 */
 	settings_load();
 

test/gateway/README.md

@@ -3,9 +3,9 @@
 A small Node.js gateway that acts as the phone/desktop side of the Memfault
 Diagnostic Service (MDS) path, so you can verify the `quickstart-bluetooth`
 firmware end-to-end **without the mobile app**. It connects to the DK over
-Bluetooth Low Energy, secures the link, drains Memfault chunks from the MDS
-data-export characteristic, and (optionally) forwards them to the Memfault
-cloud — exactly what the *nRF Connect for Desktop Quick Start* gateway does.
+Bluetooth Low Energy, drains Memfault chunks from the MDS data-export
+characteristic, and (optionally) forwards them to the Memfault cloud —
+exactly what the *nRF Connect for Desktop Quick Start* gateway does.
 
 It is a Node/[`@abandonware/noble`](https://github.com/abandonware/noble) port of
 Memfault's Web Bluetooth example, <https://github.com/memfault/web-ble-example>.
@@ -16,8 +16,8 @@ Memfault's Web Bluetooth example, <https://github.com/memfault/web-ble-example>.
 - **Node.js 18+** (uses the built-in `fetch`).
 - A `nrf54l15dk` flashed with this firmware and advertising as `Quickstart_Bluetooth`.
 - On first run, macOS will ask to grant your terminal **Bluetooth** permission
-  (System Settings → Privacy & Security → Bluetooth). The just-works pairing the
-  firmware uses is handled automatically by CoreBluetooth — no manual dialog.
+  (System Settings → Privacy & Security → Bluetooth). The firmware does not use
+  pairing/encryption, so there's no pairing dialog to handle.
 
 ## Install
 
@@ -37,8 +37,8 @@ npm run discover        # or: node discover.js
 
 ## Run the gateway
 
-**Dry run (default) — BLE only, no upload.** Connects, secures, and hexdumps the
-drained chunks so you can confirm streaming works without touching the cloud:
+**Dry run (default) — BLE only, no upload.** Connects and hexdumps the drained
+chunks so you can confirm streaming works without touching the cloud:
 
 ```sh
 npm run gateway         # or: node gateway.js
@@ -62,7 +62,7 @@ node gateway.js --upload
 
 ## Exercising a coredump
 
-1. Run the gateway once so the device is known/paired.
+1. Run the gateway once to confirm connectivity.
 2. Press **Button 2** on the DK (the demo crash → `k_oops`; on a `0`-labelled DK
    silkscreen this is the button labelled **`1`**). The device captures a
    RAM-backed coredump and reboots. Don't power-cycle — a RAM-backed coredump

test/gateway/gateway.js

@@ -9,7 +9,7 @@
  * Node port of memfault/web-ble-example's mds.js, using @abandonware/noble.
  * Upstream reference: https://github.com/memfault/web-ble-example
  *
- * Default: BLE-only dry run (connect, secure, drain chunks, hexdump) — NO upload.
+ * Default: BLE-only dry run (connect, drain chunks, hexdump) — NO upload.
  * Pass --upload to actually POST chunks to the Memfault data URI read from the device.
  *
  * Usage: node gateway.js [--upload] [--name Quickstart_Bluetooth] [--seconds 30]
@@ -126,8 +126,7 @@ async function run(peripheral) {
   );
   const byUuid = Object.fromEntries(characteristics.map((c) => [c.uuid, c]));
 
-  // First encrypted read triggers CoreBluetooth pairing/security.
-  log("Reading supported features (this triggers pairing if not yet secured)…");
+  log("Reading supported features…");
   const feat = await byUuid[CHAR.supportedFeatures].readAsync();
   log(`  SupportedFeatures: 0x${feat[0].toString(16)}`);