Bluetooth: Enforce key size of 16 bytes on FIPS level

According to the spec Ver 5.2, Vol 3, Part C, Sec 5.2.2.8:
Device in security mode 4 level 4 shall enforce:
128-bit equivalent strength for link and encryption keys required
using FIPS approved algorithms (E0 not allowed, SAFER+ not allowed,
and P-192 not allowed; encryption key not shortened)

This patch rejects connection with key size below 16 for FIPS
level services.

Signed-off-by: Archie Pusaka <apusaka@chromium.org>
Reviewed-by: Alain Michaud <alainm@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 1ab27b9..5817f5c 100644 (file)
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1515,8 +1515,14 @@ static bool l2cap_check_enc_key_size(struct hci_conn *hcon)
         * that have no key size requirements. Ensure that the link is
         * actually encrypted before enforcing a key size.
         */
+       int min_key_size = hcon->hdev->min_enc_key_size;
+
+       /* On FIPS security level, key size must be 16 bytes */
+       if (hcon->sec_level == BT_SECURITY_FIPS)
+               min_key_size = 16;
+
        return (!test_bit(HCI_CONN_ENCRYPT, &hcon->flags) ||
-               hcon->enc_key_size >= hcon->hdev->min_enc_key_size);
+               hcon->enc_key_size >= min_key_size);
 }
 
 static void l2cap_do_start(struct l2cap_chan *chan)