Bluetooth: Add debug setting for changing minimum encryption key size

For testing and qualification purposes it is useful to allow changing
the minimum encryption key size value that the host stack is going to
enforce. This adds a new debugfs setting min_encrypt_key_size to achieve
this functionality.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index ded574b32c2089c2140397a30d985ff7c1c550f0..ffc95b382eb56cac8b32ec2c022eb3a9e19159ad 100644 (file)
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -278,6 +278,7 @@ struct hci_dev {
        __u16           conn_info_min_age;
        __u16           conn_info_max_age;
        __u16           auth_payload_timeout;
+       __u8            min_enc_key_size;
        __u8            ssp_debug_mode;
        __u8            hw_error_code;
        __u32           clock;

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index b9585e7d9d2e9492b0d495ae58b8da9029bce6b7..04bc79359a1736b28e83f0eb88828ceefd430f25 100644 (file)
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -3202,6 +3202,7 @@ struct hci_dev *hci_alloc_dev(void)
        hdev->conn_info_min_age = DEFAULT_CONN_INFO_MIN_AGE;
        hdev->conn_info_max_age = DEFAULT_CONN_INFO_MAX_AGE;
        hdev->auth_payload_timeout = DEFAULT_AUTH_PAYLOAD_TIMEOUT;
+       hdev->min_enc_key_size = HCI_MIN_ENC_KEY_SIZE;
 
        mutex_init(&hdev->lock);
        mutex_init(&hdev->req_lock);

diff --git a/net/bluetooth/hci_debugfs.c b/net/bluetooth/hci_debugfs.c
index bb67f4a5479a2c79d724956c883d80e2a0c93345..402e2cc54044acc3ec7243915a177affdb004c14 100644 (file)
--- a/net/bluetooth/hci_debugfs.c
+++ b/net/bluetooth/hci_debugfs.c
@@ -433,6 +433,35 @@ static int auto_accept_delay_set(void *data, u64 val)
        return 0;
 }
 
+static int min_encrypt_key_size_set(void *data, u64 val)
+{
+       struct hci_dev *hdev = data;
+
+       if (val < 1 || val > 16)
+               return -EINVAL;
+
+       hci_dev_lock(hdev);
+       hdev->min_enc_key_size = val;
+       hci_dev_unlock(hdev);
+
+       return 0;
+}
+
+static int min_encrypt_key_size_get(void *data, u64 *val)
+{
+       struct hci_dev *hdev = data;
+
+       hci_dev_lock(hdev);
+       *val = hdev->min_enc_key_size;
+       hci_dev_unlock(hdev);
+
+       return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(min_encrypt_key_size_fops,
+                       min_encrypt_key_size_get,
+                       min_encrypt_key_size_set, "%llu\n");
+
 static int auto_accept_delay_get(void *data, u64 *val)
 {
        struct hci_dev *hdev = data;
@@ -545,6 +574,8 @@ void hci_debugfs_create_bredr(struct hci_dev *hdev)
        if (lmp_ssp_capable(hdev)) {
                debugfs_create_file("ssp_debug_mode", 0444, hdev->debugfs,
                                    hdev, &ssp_debug_mode_fops);
+               debugfs_create_file("min_encrypt_key_size", 0644, hdev->debugfs,
+                                   hdev, &min_encrypt_key_size_fops);
                debugfs_create_file("auto_accept_delay", 0644, hdev->debugfs,
                                    hdev, &auto_accept_delay_fops);
        }

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index cc506fe99b4d7e092eefd90f9ea41bce9297dfca..dfc1edb168b78b2ed43575cdd6087c45b75a0f82 100644 (file)
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1361,7 +1361,7 @@ static bool l2cap_check_enc_key_size(struct hci_conn *hcon)
         * actually encrypted before enforcing a key size.
         */
        return (!test_bit(HCI_CONN_ENCRYPT, &hcon->flags) ||
-               hcon->enc_key_size >= HCI_MIN_ENC_KEY_SIZE);
+               hcon->enc_key_size >= hcon->hdev->min_enc_key_size);
 }
 
 static void l2cap_do_start(struct l2cap_chan *chan)