From feb38e2ccdac2d60709f09a8457a7a01a0ba97bf Mon Sep 17 00:00:00 2001
From: Xudong Zheng <7pkvm5aw@slicealias.com>
Date: Tue, 21 Jan 2025 00:52:01 -0500
Subject: [PATCH] fix(ble): enforce maximum length for dynamic device name

---
 app/Kconfig   | 5 +++++
 app/src/ble.c | 4 +++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/app/Kconfig b/app/Kconfig
index 5fc03822a02..c1d88a584f7 100644
--- a/app/Kconfig
+++ b/app/Kconfig
@@ -238,6 +238,11 @@ config BT_PERIPHERAL_PREF_LATENCY
 config BT_PERIPHERAL_PREF_TIMEOUT
     default 400
 
+# The device name should be 16 characters or less so it fits within the
+# advertising data.
+config BT_DEVICE_NAME_MAX
+    default 16
+
 endif # ZMK_BLE
 
 endmenu # Output Types
diff --git a/app/src/ble.c b/app/src/ble.c
index 02d8901b982..7176bd0a67c 100644
--- a/app/src/ble.c
+++ b/app/src/ble.c
@@ -66,7 +66,9 @@ static uint8_t active_profile;
 #define DEVICE_NAME CONFIG_BT_DEVICE_NAME
 #define DEVICE_NAME_LEN (sizeof(DEVICE_NAME) - 1)
 
-BUILD_ASSERT(DEVICE_NAME_LEN <= 16, "ERROR: BLE device name is too long. Max length: 16");
+BUILD_ASSERT(
+    DEVICE_NAME_LEN <= CONFIG_BT_DEVICE_NAME_MAX,
+    "ERROR: BLE device name is too long. Max length: " STRINGIFY(CONFIG_BT_DEVICE_NAME_MAX));
 
 static struct bt_data zmk_ble_ad[] = {
     BT_DATA_BYTES(BT_DATA_GAP_APPEARANCE, 0xC1, 0x03),