Bluetooth: BR: improve br_sufficient_key_size

lylezhu2012 · kartben · commit 2424bfd8699d · 2024-12-09T15:11:52.000+01:00
Currently, the minimum value of encryption key size is
`BT_HCI_ENCRYPTION_KEY_SIZE_MIN`.

Add a new Kconfig `BT_BR_MIN_ENC_KEY_SIZE`. It is used to set the
specific minimum encryption key size.
The default value is `BT_SMP_MIN_ENC_KEY_SIZE`. And it can be
configured if `BT_SMP_SC_ONLY` is not enabled.

Use `CONFIG_BT_BR_MIN_ENC_KEY_SIZE` as minimum encryption key size in
`br_sufficient_key_size`.

Signed-off-by: Lyle Zhu &lt;lyle.zhu@nxp.com&gt;
diff --git a/subsys/bluetooth/host/classic/Kconfig b/subsys/bluetooth/host/classic/Kconfig
@@ -18,6 +18,15 @@ config BT_CLASSIC
 	  This option enables Bluetooth BR/EDR support
 
 if BT_CLASSIC
+config BT_BR_MIN_ENC_KEY_SIZE
+	int
+	prompt "Minimum encryption key size accepted in octets" if !BT_SMP_SC_ONLY
+	default BT_SMP_MIN_ENC_KEY_SIZE
+	range 7 16
+	help
+	  This option sets the minimum encryption key size accepted during pairing
+	  for classic.
+
 config BT_MAX_SCO_CONN
 	int "Maximum number of simultaneous SCO connections"
 	default 1
diff --git a/subsys/bluetooth/host/classic/br.c b/subsys/bluetooth/host/classic/br.c
@@ -141,7 +141,7 @@ static bool br_sufficient_key_size(struct bt_conn *conn)
 		return key_size == BT_HCI_ENCRYPTION_KEY_SIZE_MAX;
 	}
 
-	return key_size >= BT_HCI_ENCRYPTION_KEY_SIZE_MIN;
+	return key_size >= CONFIG_BT_BR_MIN_ENC_KEY_SIZE;
 }
 
 bool bt_br_update_sec_level(struct bt_conn *conn)

Original file line number	Diff line number	Diff line change
`@@ -141,7 +141,7 @@ static bool br_sufficient_key_size(struct bt_conn *conn)`
`141`	`141`	`return key_size == BT_HCI_ENCRYPTION_KEY_SIZE_MAX;`
`142`	`142`	`}`
`143`	`143`
`144`		`- return key_size >= BT_HCI_ENCRYPTION_KEY_SIZE_MIN;`
	`144`	`+ return key_size >= CONFIG_BT_BR_MIN_ENC_KEY_SIZE;`
`145`	`145`	`}`
`146`	`146`
`147`	`147`	`bool bt_br_update_sec_level(struct bt_conn *conn)`