Bluetooth: Fix append max 11 bytes of name to scan rsp data

Append maximum of 10 + 1 bytes of name to scan response data.
Complete name is appended only if exists and is <= 10 characters.
Else append short name if exists or shorten complete name if not.
This makes sure name is consistent across multiple advertising
instances.

Signed-off-by: Michał Narajowski <michal.narajowski@codecoup.pl>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 17 insertions, 9 deletions

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 736038085feb..1fba2a03f8ae 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -6017,7 +6017,15 @@ static int read_adv_features(struct sock *sk, struct hci_dev *hdev,
         return err;
 }
 
-static u8 tlv_data_max_len(u32 adv_flags, bool is_adv_data)
+static u8 calculate_name_len(struct hci_dev *hdev)
+{
+        u8 buf[HCI_MAX_SHORT_NAME_LENGTH + 3];
+
+        return append_local_name(hdev, buf, 0);
+}
+
+static u8 tlv_data_max_len(struct hci_dev *hdev, u32 adv_flags,
+                           bool is_adv_data)
 {
         u8 max_len = HCI_MAX_AD_LENGTH;
 
@@ -6030,9 +6038,8 @@ static u8 tlv_data_max_len(u32 adv_flags, bool is_adv_data)
                 if (adv_flags & MGMT_ADV_FLAG_TX_POWER)
                         max_len -= 3;
         } else {
-                /* at least 1 byte of name should fit in */
                 if (adv_flags & MGMT_ADV_FLAG_LOCAL_NAME)
-                        max_len -= 3;
+                        max_len -= calculate_name_len(hdev);
 
                 if (adv_flags & (MGMT_ADV_FLAG_APPEARANCE))
                         max_len -= 4;
@@ -6063,12 +6070,13 @@ static bool appearance_managed(u32 adv_flags)
         return adv_flags & MGMT_ADV_FLAG_APPEARANCE;
 }
 
-static bool tlv_data_is_valid(u32 adv_flags, u8 *data, u8 len, bool is_adv_data)
+static bool tlv_data_is_valid(struct hci_dev *hdev, u32 adv_flags, u8 *data,
+                              u8 len, bool is_adv_data)
 {
         int i, cur_len;
         u8 max_len;
 
-        max_len = tlv_data_max_len(adv_flags, is_adv_data);
+        max_len = tlv_data_max_len(hdev, adv_flags, is_adv_data);
 
         if (len > max_len)
                 return false;
@@ -6215,8 +6223,8 @@ static int add_advertising(struct sock *sk, struct hci_dev *hdev,
                 goto unlock;
         }
 
-        if (!tlv_data_is_valid(flags, cp->data, cp->adv_data_len, true) ||
-            !tlv_data_is_valid(flags, cp->data + cp->adv_data_len,
+        if (!tlv_data_is_valid(hdev, flags, cp->data, cp->adv_data_len, true) ||
+            !tlv_data_is_valid(hdev, flags, cp->data + cp->adv_data_len,
                                cp->scan_rsp_len, false)) {
                 err = mgmt_cmd_status(sk, hdev->id, MGMT_OP_ADD_ADVERTISING,
                                       MGMT_STATUS_INVALID_PARAMS);
@@ -6429,8 +6437,8 @@ static int get_adv_size_info(struct sock *sk, struct hci_dev *hdev,
 
         rp.instance = cp->instance;
         rp.flags = cp->flags;
-        rp.max_adv_data_len = tlv_data_max_len(flags, true);
-        rp.max_scan_rsp_len = tlv_data_max_len(flags, false);
+        rp.max_adv_data_len = tlv_data_max_len(hdev, flags, true);
+        rp.max_scan_rsp_len = tlv_data_max_len(hdev, flags, false);
 
         err = mgmt_cmd_complete(sk, hdev->id, MGMT_OP_GET_ADV_SIZE_INFO,
                                 MGMT_STATUS_SUCCESS, &rp, sizeof(rp));