Bluetooth Core Specification v5.2, Vol. 3, Part A, section 1.4, table
1.1:
'Start Fragments always either begin with the first octet of the Basic
L2CAP header of a PDU or they have a length of zero (see [Vol 2] Part
B, Section 6.6.2).'
Apparently this was changed by the following errata:
https://www.bluetooth.org/tse/errata_view.cfm?errata_id=10216
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Only sockets will have the chan->data set to an actual sk, channels
like A2MP would have its own data which would likely cause a crash when
calling sk_filter, in order to fix this a new callback has been
introduced so channels can implement their own filtering if necessary.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This uses the DEFER_SETUP flag to group channels with
L2CAP_CREDIT_BASED_CONNECTION_REQ.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This adds a callback to read the socket pid.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This should make it safe to have the code upstream without affecting
stable systems since there are a few details not sort out with ECRED
mode e.g: how to initiate multiple connections at once.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This adds the initial code for Enhanced Credit Based Mode which
introduces a new socket mode called L2CAP_MODE_EXT_FLOWCTL, which for
the most part work the same as L2CAP_MODE_LE_FLOWCTL but uses different
PDUs to setup the connections and also works over BR/EDR.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This introduces the definitions for the new L2CAP mode called Enhanced
Credit Based Mode.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Add the result values specific to L2CAP LE credit based connections
and change the old result values wherever they were used.
Signed-off-by: Mallikarjun Phulari <mallikarjun.phulari@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Give enough rx credits for a full packet instead of using an arbitrary
number which may not be enough depending on the MTU and MPS which can
cause interruptions while waiting for more credits, also remove
debugfs entry for l2cap_le_max_credits.
With these changes the credits are restored after each SDU is received
instead of using fixed threshold, this way it is garanteed that there
will always be enough credits to send a packet without waiting more
credits to arrive.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This ensures the MPS can fit in a single HCI fragment so each
segment don't have to be reassembled at HCI level, in addition to
that also remove the debugfs entry to configure the MPS.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Fix issue found during L2CAP qualification test TP/LE/CFC/BV-20-C.
Signed-off-by: Marcin Kraglak <marcin.kraglak@tieto.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Having proper defines makes the code a bit readable, it also avoids
duplicating hard-coded values since these are also needed when
auto-allocating PSM values (in a subsequent patch).
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The core spec defines specific response codes for situations when the
received CID is incorrect. Add the defines for these and return them
as appropriate from the LE Connect Request handler function.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Add a timeout to prevent the do while loop running in an
infinite loop. This ensures that the channel will be
instructed to close within 10 seconds so prevents
l2cap_sock_shutdown() getting stuck forever.
Returns -ENOLINK when the timeout is reached. The channel
will be subequently closed and not all data will be ACK'ed.
Signed-off-by: Dean Jenkins <Dean_Jenkins@mentor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Use msecs_to_jiffies() instead of using HZ so that it
is easier to specify the time in milliseconds.
Also add a #define L2CAP_WAIT_ACK_POLL_PERIOD to specify the 200ms
polling period so that it is defined in a single place.
Signed-off-by: Dean Jenkins <Dean_Jenkins@mentor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The Internet Protocol Support Profile a.k.a BT 6LoWPAN specification
is ready so PSM value for it is now known.
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Just use copy_from_iter(). That's what this method is trying to do
in all cases, in a very convoluted fashion.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Note that the code _using_ ->msg_iter at that point will be very
unhappy with anything other than unshifted iovec-backed iov_iter.
We still need to convert users to proper primitives.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
it'll die soon enough - now that kvec-backed iov_iter works regardless
of set_fs(), both instances will become copy_from_iter() as soon as
we introduce ->msg_iter...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This patch adds the very basic code for creating and destroying SMP
L2CAP channels for BR/EDR connections.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
To pave the way for future fixed channels to be added easily we should
track both the local and remote mask on a per-L2CAP connection (struct
l2cap_conn) basis. So far the code has used a global variable in a racy
way which anyway needs fixing.
This patch renames the existing conn->fixed_chan_mask that tracked
the remote mask to conn->remote_fixed_chan and adds a new variable
conn->local_fixed_chan to track the local mask. Since the HS support
info is now available in the local mask we can remove the
conn->hs_enabled variable.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
By default lockdep considers all L2CAP channels equal. This would mean
that we get warnings if a channel is locked when another one's lock is
tried to be acquired in the same thread. This kind of inter-channel
locking dependencies exist in the form of parent-child channels as well
as any channel wishing to elevate the security by requesting procedures
on the SMP channel.
To eliminate the chance for these lockdep warnings we introduce a
nesting level for each channel and use that when acquiring the channel
lock. For now there exists the earlier mentioned three identified
categories: SMP, "normal" channels and parent channels (i.e. those in
BT_LISTEN state). The nesting level is defined as atomic_t since we need
access to it before the lock is actually acquired.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The identity address update of all channels for an l2cap_conn needs to
take the lock for each channel, i.e. it's safest to do this by a
separate workqueue callback.
Previously this was partially solved by moving the entire SMP key
distribution behind a workqueue. However, if we want SMP context locking
to be correct and safe we should always use the l2cap_chan lock when
accessing it, meaning even smp_distribute_keys needs to take that lock
which would once again create a dead lock when updating the identity
address.
The simplest way to solve this is to have l2cap_conn manage the deferred
work which is what this patch does. A subsequent patch will remove the
now unnecessary SMP key distribution work struct.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Now that there are no more users of the l2cap_conn_shutdown API (since
smp.c switched to using hci_disconnect) we can simply remove it along
with all of it's l2cap_conn variables.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
It's natural to have *_get() functions that increment the reference
count of an object to return the object type itself. This way it's
simple to make a copy of the object pointer and increase the reference
count in a single step. This patch updates two such get() functions,
namely hci_conn_get() and l2cap_conn_get(), and updates the users to
take advantage of the new API.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Now that SMP has been converted to use fixed channels we've got a bit of
a problem with the hci_conn reference counting. So far the L2CAP code
has kept a reference for each L2CAP channel that was notified of the
connection. With SMP however this would mean that the connection is
never dropped even though there are no other users of it. Furthermore,
SMP already does its own hci_conn reference counting internally,
starting from a security or pairing request and ending with the key
distribution.
This patch makes L2CAP fixed channels default to the L2CAP core not
keeping a hci_conn reference for them. A new FLAG_HOLD_HCI_CONN flag is
added so that L2CAP users can declare an exception to this rule and hold
a reference even for their fixed channels. One such exception is the
L2CAP socket layer which does want a reference for each socket (e.g. an
ATT socket which uses a fixed channel).
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Now that there are no-longer any users for l2cap_conn->security_timer we
can go ahead and simply remove it. The patch makes initialization of the
conn->info_timer unconditional since it's better not to leave any
l2cap_conn data structures uninitialized no matter what the underlying
transport.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Since we no-longer do special handling of SMP within l2cap_core.c we
don't have any code for calling l2cap_conn_del() when smp.c doesn't like
the data it gets. At the same time we cannot simply export
l2cap_conn_del() since it will try to lock the channels it calls into
whereas we already hold the lock in the smp.c l2cap_chan callbacks (i.e.
it'd lead to a deadlock).
This patch adds a new l2cap_conn_shutdown() API which is very similar to
l2cap_conn_del() except that it defers the call to l2cap_conn_del()
through a workqueue, thereby making it safe to use it from an L2CAP
channel callback.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Now that we have all the necessary pieces in place we can fully convert
SMP to use the L2CAP channel infrastructure. This patch adds the
necessary callbacks and removes the now unneeded conn->smp_chan pointer.
One notable behavioral change in this patch comes from the following
code snippet:
- case L2CAP_CID_SMP:
- if (smp_sig_channel(conn, skb))
- l2cap_conn_del(conn->hcon, EACCES);
This piece of code was essentially forcing a disconnection if garbage
SMP data was received. The l2cap_conn_del() function is private to
l2cap_conn.c so we don't have access to it anymore when using the L2CAP
channel callbacks. Therefore, the behavior of the new code is simply to
return errors in the recv() callback (which is simply the old
smp_sig_channel()), but no disconnection will occur.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This patch creates the initial SMP L2CAP channels and a skeleton for
their callbacks. There is one per-adapter channel created upon adapter
registration, and then one channel per-connection created through the
new_connection callback. The channels are registered with the reserved
CID 0x1f for now in order to not conflict with existing SMP
functionality. Once everything is in place the value can be changed to
what it should be, i.e. L2CAP_CID_SMP.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
In preparation for converting SMP to use l2cap_chan it's useful to add a
few more callback helpers so that smp.c won't need to define all of its
own.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The LE ATT socket uses a special trick where it temporarily sets
BT_CONFIG state for the duration of a security level elevation. In order
to not require special hacks for going back to BT_CONNECTED state in the
l2cap_core.c code the most reasonable place to resume the state is the
resume callback. This patch adds a new flag to track the pending
security level change and ensures that the state is set back to
BT_CONNECTED in the resume callback in case the flag is set.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
We're interested in whether an authentication request is because of a
remote or local action. So far hci_conn_security() has been used both
for incoming and outgoing actions (e.g. RFCOMM or L2CAP connect
requests) so without some modifications it cannot know which peer is
responsible for requesting authentication.
This patch adds a new "bool initiator" parameter to hci_conn_security()
to indicate which side is responsible for the request and updates the
current users to pass this information correspondingly.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The spinlock protecting the L2CAP ident number can be converted into
a mutex since the whole processing is run in a workqueue. So instead
of using a spinlock, just use a mutex here.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The list of L2CAP fixed channels increased with newer versions of the
specification. This just updates the constants for it.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Create a CoC dynamically instead of one fixed channel for communication
to peer devices.
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
The highly optimized TX path for L2CAP channels and its fragmentation
within the HCI ACL packets requires to copy data from user provided
IO vectors and also kernel provided memory buffers.
This patch allows channel clients to provide a memcpy_fromiovec callback
to keep this optimized behavior, but adapt it to kernel vs user memory
for the TX path. For all kernel internal L2CAP channels, a default
implementation is provided that can be referenced.
In case of A2MP, this fixes a long-standing issue with wrongly accessing
kernel memory as user memory.
This patch originally by Marcel Holtmann.
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
When allocating the L2CAP SKB for transmission, provide the upper layers
with a clear distinction on what is the header and what is the body
portion of the SKB.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The SKB for L2CAP sockets are all allocated in a central callback
in the socket support. Instead of having to pass around the socket
priority all the time, assign it to skb->priority when actually
allocating the SKB.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The struct l2cap_ops field should not allow any modifications and thus
it is better declared as const.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
When we receive a remote identity address during SMP key distribution we
should ensure that any associated L2CAP channel instances get their
address information correspondingly updated (so that e.g. doing
getpeername on associated sockets returns the correct address).
This patch adds a new L2CAP core function l2cap_conn_update_id_addr()
which is used to iterate through all L2CAP channels associated with a
connection and update their address information.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Now that the LE L2CAP Connection Oriented Channel support has undergone a
decent amount of testing we can make it officially supported. This patch
removes the enable_lecoc module parameter which was previously needed to
enable support for LE L2CAP CoC.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
There's no reason why A2MP should need or deserve its on channel type.
Instead we should be able to group all fixed CID users under a single
channel type and reuse as much code as possible for them. Where CID
specific exceptions are needed the chan-scid value can be used.
This patch renames the current A2MP channel type to a generic one and
thereby paves the way to allow converting ATT and SMP (and any future
fixed channel protocols) to use the new channel type.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This patch adds a queue for incoming L2CAP data that's received before
l2cap_connect_cfm is called and processes the data once
l2cap_connect_cfm is called. This way we ensure that we have e.g. all
remote features before processing L2CAP signaling data (which is very
important for making the correct security decisions).
The processing of the pending rx data needs to be done through
queue_work since unlike l2cap_recv_acldata, l2cap_connect_cfm is called
with the hci_dev lock held which could cause potential deadlocks.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
With the introduction of security level 4, the L2CAP sockets need to
be made aware of this new level. This change ensures that the pairing
requirements are set correctly for these connections.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This is initial version of
http://tools.ietf.org/html/draft-ietf-6lo-btle-00
By default the 6LoWPAN support is not activated and user
needs to tweak /sys/kernel/debug/bluetooth/hci0/6lowpan
file.
The kernel needs IPv6 support before 6LoWPAN is usable.
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Luiz Augusto von Dentz