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path: root/net/bluetooth/l2cap.c
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2009-11-16Bluetooth: Fix regression with L2CAP configuration in Basic ModeGustavo F. Padovan
Basic Mode is the default mode of operation of a L2CAP entity. In this case the RFC (Retransmission and Flow Control) configuration option should not be used at all. Normally remote L2CAP implementation should just ignore this option, but it can cause various side effects with other Bluetooth stacks that are not capable of handling unknown options. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-11-16Bluetooth: Select Basic Mode as default for SOCK_SEQPACKETGustavo F. Padovan
The default mode for SOCK_SEQPACKET is Basic Mode. So when no mode has been specified, Basic Mode shall be used. This is important for current application to keep working as expected and not cause a regression. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-10-19bluetooth: static lock key fixDave Young
When shutdown ppp connection, lockdep waring about non-static key will happen, it is caused by the lock is not initialized properly at that time. Fix with tuning the lock/skb_queue_head init order [ 94.339261] INFO: trying to register non-static key. [ 94.342509] the code is fine but needs lockdep annotation. [ 94.342509] turning off the locking correctness validator. [ 94.342509] Pid: 0, comm: swapper Not tainted 2.6.31-mm1 #2 [ 94.342509] Call Trace: [ 94.342509] [<c0248fbe>] register_lock_class+0x58/0x241 [ 94.342509] [<c024b5df>] ? __lock_acquire+0xb57/0xb73 [ 94.342509] [<c024ab34>] __lock_acquire+0xac/0xb73 [ 94.342509] [<c024b7fa>] ? lock_release_non_nested+0x17b/0x1de [ 94.342509] [<c024b662>] lock_acquire+0x67/0x84 [ 94.342509] [<c04cd1eb>] ? skb_dequeue+0x15/0x41 [ 94.342509] [<c054a857>] _spin_lock_irqsave+0x2f/0x3f [ 94.342509] [<c04cd1eb>] ? skb_dequeue+0x15/0x41 [ 94.342509] [<c04cd1eb>] skb_dequeue+0x15/0x41 [ 94.342509] [<c054a648>] ? _read_unlock+0x1d/0x20 [ 94.342509] [<c04cd641>] skb_queue_purge+0x14/0x1b [ 94.342509] [<fab94fdc>] l2cap_recv_frame+0xea1/0x115a [l2cap] [ 94.342509] [<c024b5df>] ? __lock_acquire+0xb57/0xb73 [ 94.342509] [<c0249c04>] ? mark_lock+0x1e/0x1c7 [ 94.342509] [<f8364963>] ? hci_rx_task+0xd2/0x1bc [bluetooth] [ 94.342509] [<fab95346>] l2cap_recv_acldata+0xb1/0x1c6 [l2cap] [ 94.342509] [<f8364997>] hci_rx_task+0x106/0x1bc [bluetooth] [ 94.342509] [<fab95295>] ? l2cap_recv_acldata+0x0/0x1c6 [l2cap] [ 94.342509] [<c02302c4>] tasklet_action+0x69/0xc1 [ 94.342509] [<c022fbef>] __do_softirq+0x94/0x11e [ 94.342509] [<c022fcaf>] do_softirq+0x36/0x5a [ 94.342509] [<c022fe14>] irq_exit+0x35/0x68 [ 94.342509] [<c0204ced>] do_IRQ+0x72/0x89 [ 94.342509] [<c02038ee>] common_interrupt+0x2e/0x34 [ 94.342509] [<c024007b>] ? pm_qos_add_requirement+0x63/0x9d [ 94.342509] [<c038e8a5>] ? acpi_idle_enter_bm+0x209/0x238 [ 94.342509] [<c049d238>] cpuidle_idle_call+0x5c/0x94 [ 94.342509] [<c02023f8>] cpu_idle+0x4e/0x6f [ 94.342509] [<c0534153>] rest_init+0x53/0x55 [ 94.342509] [<c0781894>] start_kernel+0x2f0/0x2f5 [ 94.342509] [<c0781091>] i386_start_kernel+0x91/0x96 Reported-by: Oliver Hartkopp <oliver@hartkopp.net> Signed-off-by: Dave Young <hidave.darkstar@gmail.com> Tested-by: Oliver Hartkopp <oliver@hartkopp.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-09-30net: Make setsockopt() optlen be unsigned.David S. Miller
This provides safety against negative optlen at the type level instead of depending upon (sometimes non-trivial) checks against this sprinkled all over the the place, in each and every implementation. Based upon work done by Arjan van de Ven and feedback from Linus Torvalds. Signed-off-by: David S. Miller <davem@davemloft.net>
2009-08-26Bluetooth: Add support for L2CAP 'Send RRorRNR' actionGustavo F. Padovan
When called, 'Send RRorRNR' should send a RNR frame if local device is busy or a RR frame otherwise. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-26Bluetooth: Handle L2CAP case when the remote receiver is busyGustavo F. Padovan
Implement all issues related to RemoteBusy in the RECV state table. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-26Bluetooth: Acknowledge L2CAP packets when receiving RR-frames (F-bit=1)Gustavo F. Padovan
Implement the Recv ReqSeqAndFBit event when a RR frame with F bit set is received. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-24Bluetooth: Use proper *_unaligned_le{16,32} helpers for L2CAPGustavo F. Padovan
Simplify more conversions to the right endian with the proper helpers. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-24Bluetooth: Add locking scheme to L2CAP timeout callbacksGustavo F. Padovan
Avoid race conditions when accessing the L2CAP socket from within the timeout handlers. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Full support for receiving L2CAP SREJ framesGustavo F. Padovan
Support for receiving of SREJ frames as specified by the state table. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Add support for L2CAP SREJ exceptionGustavo F. Padovan
When L2CAP loses an I-frame we send a SREJ frame to the transmitter side requesting the lost packet. This patch implement all Recv I-frame events on SREJ_SENT state table except the ones that deal with SendRej (the REJ exception at receiver side is yet not implemented). Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Add support for FCS option to L2CAPGustavo F. Padovan
Implement CRC16 check for L2CAP packets. FCS is used by Streaming Mode and Enhanced Retransmission Mode and is a extra check for the packet content. Using CRC16 is the default, L2CAP won't use FCS only when both side send a "No FCS" request. Initially based on a patch from Nathan Holstein <nathan@lampreynetworks.com> Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Enable Streaming Mode for L2CAPGustavo F. Padovan
Streaming Mode is helpful for the Bluetooth streaming based profiles, such as A2DP. It doesn't have any error control or flow control. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Add support for Retransmission and Monitor TimersGustavo F. Padovan
L2CAP uses retransmission and monitor timers to inquiry the other side about unacked I-frames. After sending each I-frame we (re)start the retransmission timer. If it expires, we start a monitor timer that send a S-frame with P bit set and wait for S-frame with F bit set. If monitor timer expires, try again, at a maximum of L2CAP_DEFAULT_MAX_TX. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Initial support for retransmission of packets with REJ framesGustavo F. Padovan
When receiving an I-frame with unexpected txSeq, receiver side start the recovery procedure by sending a REJ S-frame to the transmitter side. So the transmitter can re-send the lost I-frame. This patch just adds a basic support for retransmission, it doesn't mean that ERTM now has full support for packet retransmission. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Add support for Segmentation and Reassembly of SDUsGustavo F. Padovan
ERTM should use Segmentation and Reassembly to break down a SDU in many PDUs on sending data to the other side. On sending packets we queue all 'segments' until end of segmentation and just the add them to the queue for sending. On receiving we create a new SKB with the SDU reassembled. Initially based on a patch from Nathan Holstein <nathan@lampreynetworks.com> Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Add initial support for ERTM packets transfersGustavo F. Padovan
This patch adds support for ERTM transfers, without retransmission, with txWindow up to 63 and with acknowledgement of packets received. Now the packets are queued before call l2cap_do_send(), so packets couldn't be sent at the time we call l2cap_sock_sendmsg(). They will be sent in an asynchronous way on later calls of l2cap_ertm_send(). Besides if an error occurs on calling l2cap_do_send() we disconnect the channel. Initially based on a patch from Nathan Holstein <nathan@lampreynetworks.com> Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Create separate l2cap_send_disconn_req() functionGustavo F. Padovan
The code for sending a disconnect request was repeated several times within L2CAP source code. So move this into its own function. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Add configuration support for ERTM and Streaming modeGustavo F. Padovan
Add support to config_req and config_rsp to configure ERTM and Streaming mode. If the remote device specifies ERTM or Streaming mode, then the same mode is proposed. Otherwise ERTM or Basic mode is used. And in case of a state 2 device, the remote device should propose the same mode. If not, then the channel gets disconnected. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Add L2CAP RFC option if ERTM is enabledMarcel Holtmann
When trying to establish a connection with Enhanced Retransmission mode enabled, the RFC option needs to be added to the configuration. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Allow setting of L2CAP ERTM via socket optionMarcel Holtmann
To enable Enhanced Retransmission mode it needs to be set via a socket option. A different mode can be set on a socket, but on listen() and connect() the mode is checked and ERTM is only allowed if it is enabled via the module parameter. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-08-22Bluetooth: Add module option to enable L2CAP ERTM supportMarcel Holtmann
Since the Enhanced Retransmission mode for L2CAP is still under heavy development disable it by default and provide a module option to enable it manually for testing. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-06-08Bluetooth: Remove pointless endian conversion helpersMarcel Holtmann
The Bluetooth source uses some endian conversion helpers, that in the end translate to kernel standard routines. So remove this obfuscation since it is fully pointless. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-06-08Bluetooth: Add basic constants for L2CAP ERTM support and use themMarcel Holtmann
This adds the basic constants required to add support for L2CAP Enhanced Retransmission feature. Based on a patch from Nathan Holstein <nathan@lampreynetworks.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-06-08Bluetooth: Fix errors and warnings in L2CAP reported by checkpatch.plGustavo F. Padovan
This patch fixes the errors without changing the l2cap.o binary: text data bss dec hex filename 18059 568 0 18627 48c3 l2cap.o.after 18059 568 0 18627 48c3 l2cap.o.before Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-06-08Bluetooth: Remove unnecessary variable initializationMarcel Holtmann
The initial value of err is not used until it is set to -ENOMEM. So just remove the initialization completely. Based on a patch from Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-06-08Bluetooth: Use macro for L2CAP hint mask on receiving config requestGustavo F. Padovan
Using the L2CAP_CONF_HINT macro is easier to understand than using a hardcoded 0x80 value. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-06-08Bluetooth: Use macros for L2CAP channel identifiersGustavo F. Padovan
Use macros instead of hardcoded numbers to make the L2CAP source code more readable. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Remove some pointless conditionals before kfree_skb()Wei Yongjun
Remove some pointless conditionals before kfree_skb(). Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Permit BT_SECURITY also for L2CAP raw socketsMarcel Holtmann
Userspace pairing code can be simplified if it doesn't have to fall back to using L2CAP_LM in the case of L2CAP raw sockets. This patch allows the BT_SECURITY socket option to be used for these sockets. Signed-off-by: Johan Hedberg <johan.hedberg@nokia.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Disallow usage of L2CAP CID setting for nowMarcel Holtmann
In the future the L2CAP layer will have full support for fixed channels and right now it already can export the channel assignment, but for the functions bind() and connect() the usage of only CID 0 is allowed. This allows an easy detection if the kernel supports fixed channels or not, because otherwise it would impossible for application to tell. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Fix authentication requirements for L2CAP security checkMarcel Holtmann
The L2CAP layer can trigger the authentication via an ACL connection or later on to increase the security level. When increasing the security level it didn't use the same authentication requirements when triggering a new ACL connection. Make sure that exactly the same authentication requirements are used. The only exception here are the L2CAP raw sockets which are only used for dedicated bonding. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Ask upper layers for HCI disconnect reasonMarcel Holtmann
Some of the qualification tests demand that in case of failures in L2CAP the HCI disconnect should indicate a reason why L2CAP fails. This is a bluntly layer violation since multiple L2CAP connections could be using the same ACL and thus forcing a disconnect reason is not a good idea. To comply with the Bluetooth test specification, the disconnect reason is now stored in the L2CAP connection structure and every time a new L2CAP channel is added it will set back to its default. So only in the case where the L2CAP channel with the disconnect reason is really the last one, it will propagated to the HCI layer. The HCI layer has been extended with a disconnect indication that allows it to ask upper layers for a disconnect reason. The upper layer must not support this callback and in that case it will nicely default to the existing behavior. If an upper layer like L2CAP can provide a disconnect reason that one will be used to disconnect the ACL or SCO link. No modification to the ACL disconnect timeout have been made. So in case of Linux to Linux connection the initiator will disconnect the ACL link before the acceptor side can signal the specific disconnect reason. That is perfectly fine since Linux doesn't make use of this value anyway. The L2CAP layer has a perfect valid error code for rejecting connection due to a security violation. It is unclear why the Bluetooth specification insists on having specific HCI disconnect reason. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Add CID field to L2CAP socket address structureMarcel Holtmann
In preparation for L2CAP fixed channel support, the CID value of a L2CAP connection needs to be accessible via the socket interface. The CID is the connection identifier and exists as source and destination value. So extend the L2CAP socket address structure with this field and change getsockname() and getpeername() to fill it in. The bind() and connect() functions have been modified to handle L2CAP socket address structures of variable sizes. This makes them future proof if additional fields need to be added. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Request L2CAP fixed channel list if availableMarcel Holtmann
If the extended features mask indicates support for fixed channels, request the list of available fixed channels. This also enables the fixed channel features bit so remote implementations can request information about it. Currently only the signal channel will be listed. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Don't enforce authentication for L2CAP PSM 1 and 3Marcel Holtmann
The recommendation for the L2CAP PSM 1 (SDP) is to not use any kind of authentication or encryption. So don't trigger authentication for incoming and outgoing SDP connections. For L2CAP PSM 3 (RFCOMM) there is no clear requirement, but with Bluetooth 2.1 the initiator is required to enable authentication and encryption first and this gets enforced. So there is no need to trigger an additional authentication step. The RFCOMM service security will make sure that a secure enough link key is present. When the encryption gets enabled after the SDP connection setup, then switch the security level from SDP to low security. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Fix double L2CAP connection requestMarcel Holtmann
If the remote L2CAP server uses authentication pending stage and encryption is enabled it can happen that a L2CAP connection request is sent twice due to a race condition in the connection state machine. When the remote side indicates any kind of connection pending, then track this state and skip sending of L2CAP commands for this period. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Fix race condition with L2CAP information requestMarcel Holtmann
When two L2CAP connections are requested quickly after the ACL link has been established there exists a window for a race condition where a connection request is sent before the information response has been received. Any connection request should only be sent after an exchange of the extended features mask has been finished. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Use general bonding whenever possibleMarcel Holtmann
When receiving incoming connection to specific services, always use general bonding. This ensures that the link key gets stored and can be used for further authentications. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Don't check encryption for L2CAP raw socketsMarcel Holtmann
For L2CAP sockets with medium and high security requirement a missing encryption will enforce the closing of the link. For the L2CAP raw sockets this is not needed, so skip that check. This fixes a crash when pairing Bluetooth 2.0 (and earlier) devices since the L2CAP state machine got confused and then locked up the whole system. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Update version numbersMarcel Holtmann
With the support for the enhanced security model and the support for deferring connection setup, it is a good idea to increase various version numbers. This is purely cosmetic and has no effect on the behavior, but can be really helpful when debugging problems in different kernel versions. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Restrict application of socket optionsMarcel Holtmann
The new socket options should only be evaluated for SOL_BLUETOOTH level and not for every other level. Previously this causes some minor issues when detecting if a kernel with certain features is available. Also restrict BT_SECURITY to SOCK_SEQPACKET for L2CAP and SOCK_STREAM for the RFCOMM protocol. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Disconnect L2CAP connections without encryptionMarcel Holtmann
For L2CAP connections with high security setting, the link will be immediately dropped when the encryption gets disabled. For L2CAP connections with medium security there will be grace period where the remote device has the chance to re-enable encryption. If it doesn't happen then the link will also be disconnected. The requirement for the grace period with medium security comes from Bluetooth 2.0 and earlier devices that require role switching. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Replace L2CAP link mode with security levelMarcel Holtmann
Change the L2CAP internals to use the new security levels and remove the link mode details. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Add enhanced security model for Simple PairingMarcel Holtmann
The current security model is based around the flags AUTH, ENCRYPT and SECURE. Starting with support for the Bluetooth 2.1 specification this is no longer sufficient. The different security levels are now defined as SDP, LOW, MEDIUM and SECURE. Previously it was possible to set each security independently, but this actually doesn't make a lot of sense. For Bluetooth the encryption depends on a previous successful authentication. Also you can only update your existing link key if you successfully created at least one before. And of course the update of link keys without having proper encryption in place is a security issue. The new security levels from the Bluetooth 2.1 specification are now used internally. All old settings are mapped to the new values and this way it ensures that old applications still work. The only limitation is that it is no longer possible to set authentication without also enabling encryption. No application should have done this anyway since this is actually a security issue. Without encryption the integrity of the authentication can't be guaranteed. As default for a new L2CAP or RFCOMM connection, the LOW security level is used. The only exception here are the service discovery sessions on PSM 1 where SDP level is used. To have similar security strength as with a Bluetooth 2.0 and before combination key, the MEDIUM level should be used. This is according to the Bluetooth specification. The MEDIUM level will not require any kind of man-in-the-middle (MITM) protection. Only the HIGH security level will require this. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Add support for deferring L2CAP connection setupMarcel Holtmann
In order to decide if listening L2CAP sockets should be accept()ed the BD_ADDR of the remote device needs to be known. This patch adds a socket option which defines a timeout for deferring the actual connection setup. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2009-02-27Bluetooth: Preparation for usage of SOL_BLUETOOTHMarcel Holtmann
The socket option levels SOL_L2CAP, SOL_RFOMM and SOL_SCO are currently in use by various Bluetooth applications. Going forward the common option level SOL_BLUETOOTH should be used. This patch prepares the clean split of the old and new option levels while keeping everything backward compatibility. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2008-11-30Bluetooth: Enable per-module dynamic debug messagesMarcel Holtmann
With the introduction of CONFIG_DYNAMIC_PRINTK_DEBUG it is possible to allow debugging without having to recompile the kernel. This patch turns all BT_DBG() calls into pr_debug() to support dynamic debug messages. As a side effect all CONFIG_BT_*_DEBUG statements are now removed and some broken debug entries have been fixed. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2008-09-09[Bluetooth] Reject L2CAP connections on an insecure ACL linkMarcel Holtmann
The Security Mode 4 of the Bluetooth 2.1 specification has strict authentication and encryption requirements. It is the initiators job to create a secure ACL link. However in case of malicious devices, the acceptor has to make sure that the ACL is encrypted before allowing any kind of L2CAP connection. The only exception here is the PSM 1 for the service discovery protocol, because that is allowed to run on an insecure ACL link. Previously it was enough to reject a L2CAP connection during the connection setup phase, but with Bluetooth 2.1 it is forbidden to do any L2CAP protocol exchange on an insecure link (except SDP). The new hci_conn_check_link_mode() function can be used to check the integrity of an ACL link. This functions also takes care of the cases where Security Mode 4 is disabled or one of the devices is based on an older specification. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2008-09-09[Bluetooth] Enforce correct authentication requirementsMarcel Holtmann
With the introduction of Security Mode 4 and Simple Pairing from the Bluetooth 2.1 specification it became mandatory that the initiator requires authentication and encryption before any L2CAP channel can be established. The only exception here is PSM 1 for the service discovery protocol (SDP). It is meant to be used without any encryption since it contains only public information. This is how Bluetooth 2.0 and before handle connections on PSM 1. For Bluetooth 2.1 devices the pairing procedure differentiates between no bonding, general bonding and dedicated bonding. The L2CAP layer wrongly uses always general bonding when creating new connections, but it should not do this for SDP connections. In this case the authentication requirement should be no bonding and the just-works model should be used, but in case of non-SDP connection it is required to use general bonding. If the new connection requires man-in-the-middle (MITM) protection, it also first wrongly creates an unauthenticated link key and then later on requests an upgrade to an authenticated link key to provide full MITM protection. With Simple Pairing the link key generation is an expensive operation (compared to Bluetooth 2.0 and before) and doing this twice during a connection setup causes a noticeable delay when establishing a new connection. This should be avoided to not regress from the expected Bluetooth 2.0 connection times. The authentication requirements are known up-front and so enforce them. To fulfill these requirements the hci_connect() function has been extended with an authentication requirement parameter that will be stored inside the connection information and can be retrieved by userspace at any time. This allows the correct IO capabilities exchange and results in the expected behavior. Signed-off-by: Marcel Holtmann <marcel@holtmann.org>