Bluetooth: Add support for using the crypto subsystem
This will allow using the crypto subsystem for encrypting data. As SMP
(Security Manager Protocol) is implemented almost entirely on the host
side and the crypto module already implements the needed methods
(AES-128), it makes sense to use it.
There's now a new module option to enable/disable SMP support.
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Signed-off-by: Anderson Briglia <anderson.briglia@openbossa.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index f3d530f..e35fd4b 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -177,6 +177,8 @@
__u16 init_last_cmd;
+ struct crypto_blkcipher *tfm;
+
struct inquiry_cache inq_cache;
struct hci_conn_hash conn_hash;
struct list_head blacklist;
diff --git a/net/bluetooth/Kconfig b/net/bluetooth/Kconfig
index 6ae5ec5..f495dea 100644
--- a/net/bluetooth/Kconfig
+++ b/net/bluetooth/Kconfig
@@ -22,6 +22,7 @@
BNEP Module (Bluetooth Network Encapsulation Protocol)
CMTP Module (CAPI Message Transport Protocol)
HIDP Module (Human Interface Device Protocol)
+ SMP Module (Security Manager Protocol)
Say Y here to compile Bluetooth support into the kernel or say M to
compile it as module (bluetooth).
@@ -36,11 +37,18 @@
config BT_L2CAP
bool "L2CAP protocol support"
select CRC16
+ select CRYPTO
+ select CRYPTO_BLKCIPHER
+ select CRYPTO_AES
+ select CRYPTO_ECB
help
L2CAP (Logical Link Control and Adaptation Protocol) provides
connection oriented and connection-less data transport. L2CAP
support is required for most Bluetooth applications.
+ Also included is support for SMP (Security Manager Protocol) which
+ is the security layer on top of LE (Low Energy) links.
+
config BT_SCO
bool "SCO links support"
help
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index e14e8a1..f62ca19 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -42,6 +42,7 @@
#include <linux/notifier.h>
#include <linux/rfkill.h>
#include <linux/timer.h>
+#include <linux/crypto.h>
#include <net/sock.h>
#include <asm/system.h>
@@ -59,6 +60,8 @@
static DEFINE_RWLOCK(hci_task_lock);
+static int enable_smp;
+
/* HCI device list */
LIST_HEAD(hci_dev_list);
DEFINE_RWLOCK(hci_dev_list_lock);
@@ -1274,6 +1277,14 @@
return 0;
}
+static struct crypto_blkcipher *alloc_cypher(void)
+{
+ if (enable_smp)
+ return crypto_alloc_blkcipher("ecb(aes)", 0, CRYPTO_ALG_ASYNC);
+
+ return ERR_PTR(-ENOTSUPP);
+}
+
/* Register HCI device */
int hci_register_dev(struct hci_dev *hdev)
{
@@ -1358,6 +1369,11 @@
if (!hdev->workqueue)
goto nomem;
+ hdev->tfm = alloc_cypher();
+ if (IS_ERR(hdev->tfm))
+ BT_INFO("Failed to load transform for ecb(aes): %ld",
+ PTR_ERR(hdev->tfm));
+
hci_register_sysfs(hdev);
hdev->rfkill = rfkill_alloc(hdev->name, &hdev->dev,
@@ -1406,6 +1422,9 @@
!test_bit(HCI_SETUP, &hdev->flags))
mgmt_index_removed(hdev->id);
+ if (!IS_ERR(hdev->tfm))
+ crypto_free_blkcipher(hdev->tfm);
+
hci_notify(hdev, HCI_DEV_UNREG);
if (hdev->rfkill) {
@@ -2242,3 +2261,6 @@
}
}
}
+
+module_param(enable_smp, bool, 0644);
+MODULE_PARM_DESC(enable_smp, "Enable SMP support (LE only)");
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 2240e96..aa20bee 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -154,9 +154,13 @@
int smp_conn_security(struct l2cap_conn *conn, __u8 sec_level)
{
+ struct hci_conn *hcon = conn->hcon;
__u8 authreq;
- BT_DBG("conn %p hcon %p level 0x%2.2x", conn, conn->hcon, sec_level);
+ BT_DBG("conn %p hcon %p level 0x%2.2x", conn, hcon, sec_level);
+
+ if (IS_ERR(hcon->hdev->tfm))
+ return 1;
switch (sec_level) {
case BT_SECURITY_MEDIUM:
@@ -174,7 +178,7 @@
return 1;
}
- if (conn->hcon->link_mode & HCI_LM_MASTER) {
+ if (hcon->link_mode & HCI_LM_MASTER) {
struct smp_cmd_pairing cp;
cp.io_capability = 0x00;
cp.oob_flag = 0x00;
@@ -198,6 +202,12 @@
__u8 reason;
int err = 0;
+ if (IS_ERR(conn->hcon->hdev->tfm)) {
+ err = PTR_ERR(conn->hcon->hdev->tfm);
+ reason = SMP_PAIRING_NOTSUPP;
+ goto done;
+ }
+
skb_pull(skb, sizeof(code));
switch (code) {
@@ -233,10 +243,14 @@
BT_DBG("Unknown command code 0x%2.2x", code);
reason = SMP_CMD_NOTSUPP;
+ err = -EOPNOTSUPP;
+ goto done;
+ }
+
+done:
+ if (reason)
smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(reason),
&reason);
- err = -EOPNOTSUPP;
- }
kfree_skb(skb);
return err;