From 7883746bc663150e8acd7a57397fc889698b0b33 Mon Sep 17 00:00:00 2001 From: Johan Hedberg Date: Wed, 11 Nov 2015 21:47:12 +0200 Subject: [PATCH] Bluetooth: Fix l2cap_chan leak in SMP The L2CAP core expects channel implementations to manage the reference returned by the new_connection callback. With sockets this is already handled with each channel being tied to the corresponding socket. With SMP however there's no context to tie the pointer to in the smp_new_conn_cb function. The function can also not just drop the reference since it's the only one at that point. For fixed channels (like SMP) the code path inside the L2CAP core from new_connection() to ready() is short and straight-forwards. The crucial difference is that in ready() the implementation has access to the l2cap_conn that SMP needs associate its l2cap_chan. Instead of taking a new reference in smp_ready_cb() we can simply assume to already own the reference created in smp_new_conn_cb(), i.e. there is no need to call l2cap_chan_hold(). Signed-off-by: Johan Hedberg Signed-off-by: Marcel Holtmann Cc: stable@vger.kernel.org # 3.19+ --- net/bluetooth/smp.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c index c91353841e40..ffed8a1d4f27 100644 --- a/net/bluetooth/smp.c +++ b/net/bluetooth/smp.c @@ -3027,8 +3027,13 @@ static void smp_ready_cb(struct l2cap_chan *chan) BT_DBG("chan %p", chan); + /* No need to call l2cap_chan_hold() here since we already own + * the reference taken in smp_new_conn_cb(). This is just the + * first time that we tie it to a specific pointer. The code in + * l2cap_core.c ensures that there's no risk this function wont + * get called if smp_new_conn_cb was previously called. + */ conn->smp = chan; - l2cap_chan_hold(chan); if (hcon->type == ACL_LINK && test_bit(HCI_CONN_ENCRYPT, &hcon->flags)) bredr_pairing(chan);