Re: [PATCH] Bluetooth: Fix SMP authentication requirement when initiator

[Johan Hedberg <johan.hedberg@gmail.com>]

On Tue, Jul 29, 2014, johan.hedberg@gmail.com wrote:
> Even if we're not pairable (the HCI_PAIRABLE flag is unset) we should
> still allow initiating pairing with bonding. This patch adds a missing
> check for SMP_FLAG_INITIATOR to build_pairing_cmd() and ensures this
> flag is properly set before calling the function.
> 
> Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
> ---
>  net/bluetooth/smp.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
> index a7c344b4acbc..7e914477721a 100644
> --- a/net/bluetooth/smp.c
> +++ b/net/bluetooth/smp.c
> @@ -307,7 +307,8 @@ static void build_pairing_cmd(struct l2cap_conn *conn,
>  	struct hci_dev *hdev = hcon->hdev;
>  	u8 local_dist = 0, remote_dist = 0;
>  
> -	if (test_bit(HCI_PAIRABLE, &conn->hcon->hdev->dev_flags)) {
> +	if (test_bit(HCI_PAIRABLE, &conn->hcon->hdev->dev_flags) ||
> +	    test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
>  		local_dist = SMP_DIST_ENC_KEY | SMP_DIST_SIGN;
>  		remote_dist = SMP_DIST_ENC_KEY | SMP_DIST_SIGN;
>  		authreq |= SMP_AUTH_BONDING;
> @@ -985,6 +986,8 @@ int smp_conn_security(struct hci_conn *hcon, __u8 sec_level)
>  	    hcon->pending_sec_level > BT_SECURITY_MEDIUM)
>  		authreq |= SMP_AUTH_MITM;
>  
> +	set_bit(SMP_FLAG_INITIATOR, &smp->flags);
> +
>  	if (hcon->role == HCI_ROLE_MASTER) {
>  		struct smp_cmd_pairing cp;
>  
> @@ -999,8 +1002,6 @@ int smp_conn_security(struct hci_conn *hcon, __u8 sec_level)
>  		smp_send_cmd(conn, SMP_CMD_SECURITY_REQ, sizeof(cp), &cp);
>  	}
>  
> -	set_bit(SMP_FLAG_INITIATOR, &smp->flags);
> -
>  	return 0;
>  }

Hold on with this patch for a bit. There are some SM test cases that
require us to be able to initiate no-bonding pairing (e.g.
TP/JW/BV-01-C). So we have to retain somehow the capability of doing
this.

A simple solution would be to revert bluez.git back to always enabling
pairable and then forget about this kernel patch.

Johan