Re: [PATCH v1] Bluetooth: Fix incorrect ssp mode bit for non ssp devices

Jaganath Kanakkassery <jaganath.k@xxxxxxxxxxx> · Tue, 09 Apr 2013 10:45:15 +0530

Hi Marcel,

--------------------------------------------------
From: "Marcel Holtmann" <marcel@xxxxxxxxxxxx>
Sent: Tuesday, April 09, 2013 10:24 AM
To: "Jaganath Kanakkassery" <jaganath.k@xxxxxxxxxxx>
Cc: <linux-bluetooth@xxxxxxxxxxxxxxx>
Subject: Re: [PATCH v1] Bluetooth: Fix incorrect ssp mode bit for non ssp 
devices

Hi Jaganath,

Some devices send extended inquiry response where as it wont
support ssp in remote extended features. So when we recieve eir,
we set ssp bit in conn flag which we are not clearing in
remote ext features event. So eventually ssp in conn flag will be
incorrectly set.

actually it is not allowed to use send EIR data when SSP is disabled. That 
is not a Bluetooth 2.1 compliant device that you are having here. Can you 
please list the faulty device in the commit message.


It's a desktop software called MecApp and I have seen same behavior with
most of the 2.1 dongles when I use this software.
http://www.mecel.se/products/bluetooth/downloads/MecApp_download
So I will add software name (MecApp) in the commit message?

In hci_remote_ext_features_evt(), if ssp is not supported then
we should clear HCI_CONN_SSP_ENABLED in conn flag since it might
have set while initiating acl connection using eir.

hcidump log
----------

< HCI Command: LE Set Scan Parameters (0x08|0x000b) plen 7
   type 0x01 (active)
   interval 11.250ms window 11.250ms
   own address: 0x00 (Public) policy: All
HCI Event: Command Complete (0x0e) plen 4
   LE Set Scan Parameters (0x08|0x000b) ncmd 1
   status 0x00
< HCI Command: LE Set Scan Enable (0x08|0x000c) plen 2
   value 0x01 (scanning enabled)
   filter duplicates 0x01 (enabled)
HCI Event: Command Complete (0x0e) plen 4
   LE Set Scan Enable (0x08|0x000c) ncmd 1
   status 0x00
< HCI Command: LE Set Scan Enable (0x08|0x000c) plen 2
   value 0x00 (scanning disabled)
   filter duplicates 0x00 (disabled)
HCI Event: Command Complete (0x0e) plen 4
   LE Set Scan Enable (0x08|0x000c) ncmd 1
   status 0x00
< HCI Command: Inquiry (0x01|0x0001) plen 5
   lap 0x9e8b33 len 4 num 0
HCI Event: Command Status (0x0f) plen 4
   Inquiry (0x01|0x0001) status 0x00 ncmd 1
HCI Event: Extended Inquiry Result (0x2f) plen 255
   bdaddr 00:1B:DC:05:B5:25 mode 1 clkoffset 0x3263 class 0x3c0000 
rssi -77
   Unknown type 0x42 with 8 bytes data
   Unknown type 0x1e with 2 bytes data
HCI Event: Inquiry Complete (0x01) plen 1
   status 0x00

< HCI Command: Create Connection (0x01|0x0005) plen 13
   bdaddr 00:1B:DC:05:B5:25 ptype 0xcc18 rswitch 0x01 clkoffset 0x0000
   Packet type: DM1 DM3 DM5 DH1 DH3 DH5
HCI Event: Command Status (0x0f) plen 4
   Create Connection (0x01|0x0005) status 0x00 ncmd 1
HCI Event: Connect Complete (0x03) plen 11
   status 0x00 handle 12 bdaddr 00:1B:DC:05:B5:25 type ACL encrypt 0x00
< HCI Command: Read Remote Supported Features (0x01|0x001b) plen 2
   handle 12
HCI Event: Command Status (0x0f) plen 4
   Read Remote Supported Features (0x01|0x001b) status 0x00 ncmd 1
HCI Event: Read Remote Supported Features (0x0b) plen 11
   status 0x00 handle 12
   Features: 0xff 0xff 0x8f 0x7e 0xd8 0x1f 0x5b 0x87
< HCI Command: Read Remote Extended Features (0x01|0x001c) plen 3
   handle 12 page 1
HCI Event: Command Status (0x0f) plen 4
   Read Remote Extended Features (0x01|0x001c) status 0x00 ncmd 1
HCI Event: Page Scan Repetition Mode Change (0x20) plen 7
   bdaddr 00:1B:DC:05:B5:25 mode 1
HCI Event: Max Slots Change (0x1b) plen 3
   handle 12 slots 5
HCI Event: Read Remote Extended Features (0x23) plen 13
   status 0x00 handle 12 page 1 max 0
   Features: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
< HCI Command: Remote Name Request (0x01|0x0019) plen 10
   bdaddr 00:1B:DC:05:B5:25 mode 2 clkoffset 0x0000
HCI Event: Command Status (0x0f) plen 4
   Remote Name Request (0x01|0x0019) status 0x00 ncmd 1
HCI Event: Remote Name Req Complete (0x07) plen 255
   status 0x00 bdaddr 00:1B:DC:05:B5:25 name 'Bluetooth PTS Radio v4'
< HCI Command: Authentication Requested (0x01|0x0011) plen 2
   handle 12
HCI Event: Command Status (0x0f) plen 4
   Authentication Requested (0x01|0x0011) status 0x00 ncmd 1
HCI Event: Link Key Request (0x17) plen 6
   bdaddr 00:1B:DC:05:B5:25
< HCI Command: Link Key Request Negative Reply (0x01|0x000c) plen 6
   bdaddr 00:1B:DC:05:B5:25
HCI Event: Command Complete (0x0e) plen 10
   Link Key Request Negative Reply (0x01|0x000c) ncmd 1
   status 0x00 bdaddr 00:1B:DC:05:B5:25
HCI Event: PIN Code Request (0x16) plen 6
   bdaddr 00:1B:DC:05:B5:25

Signed-off-by: Jaganath Kanakkassery <jaganath.k@xxxxxxxxxxx>
---
net/bluetooth/hci_event.c |    2 ++
1 file changed, 2 insertions(+)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 0a2b128..d0b1706 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -2935,6 +2935,8 @@ static void hci_remote_ext_features_evt(struct 
hci_dev *hdev,

if (ev->features[0] & LMP_HOST_SSP)
set_bit(HCI_CONN_SSP_ENABLED, &conn->flags);
+ else
+ clear_bit(HCI_CONN_SSP_ENABLED, &conn->flags);

You need to add a comment here on why this is done like this. As explained 
above you are working around not allowed behavior. The clear should not be 
needed.


Ok.

Thanks,
Jaganath 

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