When we initiate pairing through mgmt_pair_device the code has so far
been waiting for a successful HCI Encrypt Change event in order to
respond to the mgmt command. However, putting privacy into the play we
actually want the key distribution to be complete before replying so
that we can include the Identity Address in the mgmt response.

This patch updates the various hci_conn callbacks for LE in mgmt.c to
only respond in the case of failure, and adds a new mgmt_smp_complete
function that the SMP code will call once key distribution has been
completed.

Since the smp_chan_destroy function that's used to indicate completion
and clean up the SMP context can be called from various places,
including outside of smp.c, the easiest way to track failure vs success
is a new flag that we set once key distribution has been successfully
completed.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

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: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Since we want user space to see and use the LE Identity Address whenever
interfacing with the kernel it makes sense to track that instead of the
real address (the two will only be different in the case of an RPA).
This patch adds the necessary updates to when an LE connection gets
established and when receiving the Identity Address from a remote
device.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Now that each HCI device has its own AES crypto context we don't need
the one stored in the SMP data any more. This patch removes the variable
from struct smp_chan and updates the SMP code to use the per-hdev crypto
context.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When mgmt_unpair_device is called we should also remove any associated
IRKs. This patch adds a hci_remove_irk convenience function and ensures
that it's called when mgmt_unpair_device is called.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When we're the acceptors (peripheral/slave) of an SMP procedure and
we've completed distributing our keys we should only stick around
waiting for keys from the remote side if any of the initiator
distribution bits were actually set. This patch fixes the
smp_distribute_keys function to clear the SMP context when this
situation occurs.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

There is code (in mgmt.c) that depends on the hci_remove_ltk function to
fail if no match is found. This patch adds tracking of removed LTKs
(there can be up to two: one for master and another for slave) in the
hci_remove_ltk function and returns -ENOENT of no matches were found.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

There are many functions that never fail but still declare an integer
return value for no reason. This patch converts these functions to use a
void return value to avoid any confusion of whether they can fail or not.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When removing Long Term Keys we should also be checking that the given
address type (public vs random) matches. This patch updates the
hci_remove_ltk function to take an extra parameter and uses it for
address type matching.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

If we didn't request certain pieces of information during the key
distribution negotiation we should properly ignore those PDUs if the
peer incorrectly sends them. This includes the Encryption Information
and Master Identification PDUs if the EncKey bit was not set, and the
Identity Information and Identity Address Information PDUs if the IdKey
bit was not set.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This patch does the necessary changes to request the remote device to
distribute its IRK to us during the SMP pairing procedure. This includes
setting the right key distribution values in the pairing
request/response and handling of the two related SMP PDUs, i.e. Identity
Information and Identity Address Information.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This patch implements the Load IRKs command for the management
interface. The command is used to load the kernel with the initial set
of IRKs. It also sets a HCI_RPA_RESOLVING flag to indicate that we can
start requesting devices to distribute their IRK to us.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This patch adds the initial IRK storage and management functions to the
HCI core. This includes storing a list of IRKs per HCI device and the
ability to add, remove and lookup entries in that list.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Previously the crypto context has only been available for LE SMP
sessions, but now that we'll need to perform operations also during
discovery it makes sense to have this context part of the hci_dev
struct. Later, the context can be removed from the SMP context.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This patch adds a helper function to check whether a given IRK matches a
given Resolvable Private Address (RPA). The function will be needed for
implementing the rest of address resolving support.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This patch fixes a couple of unnecessary empty lines in the SMP code.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

For each received SMP PDU we need to check that we have enough data to
fit the specified size of the PDU. This patch adds the necessary checks
for each SMP PDU handler and ensures that buffer overflows do not occur
if to little data has been received.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Trying to setup HCI User Channel usage for LE only controllers without
a public address or configured static address will fail with an error
saying that no address is available.

In case of HCI User Channel the requirement for a valid address is not
needed. So allow skipping this extra validation step.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

When the setup of user channel fails, the index added event is not sent
and will cause issues with user interaction. This problem can be easily
triggered with a LE only controller without a public address. In that
case hci_dev_open() fails and that error case is not sending an event
saying that the controller is available for normal use again.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

The long term keys should only be stored when they belong to an
indentity address. The identity address can either be a public
address or a random static address.

For all other addresses (unresovable or resolvable) tell userspace
that the long term key is not persistent.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

The long term keys should be associated with an identity address. Valid
identity addresses are public addresses or static addresses. So only
allow these two as valid address information for long term keys.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

The skb truesize of a 12-byte payload with a 10-byte head/tail
reserve is 768 bytes. Consequently, even with 40 tx_credits, at
most 6 packets could be queued at any one time:

  40 tx_credits * 127-byte mtu < 768-byte truesize * 7

This error could also cause the tx queue to apparently stall if
credit flow control is disabled (where tx_credits is fixed at 5),
or if the receiver only granted a limited number of tx credits
(eg., less than 7).

Instead, track the outstanding number of queued packets not yet sent
in wmem_alloc and allow for a maximum of 40 queued packets. Report
the space avail for a single write() as the mtu * number of packets
left before reaching the maximum.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Compute the amount of space available for a single write()
within rfcomm_room(); clamp to 0 for negative values. Note
this patch does not change the result of the computation.

Report the amount of room returned in the debug printk.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The tty driver api design prefers no-fail writes if the driver
write_room() method has previously indicated space is available
to accept writes. Since this is trivially possible for the
RFCOMM tty driver, do so.

Introduce rfcomm_dlc_send_noerror(), which queues but does not
schedule the krfcomm thread if the dlc is not yet connected
(and thus does not error based on the connection state).
The mtu size test is also unnecessary since the caller already
chunks the written data into mtu size.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

If rfcomm_dlc_open() fails, set tty into error state which returns
-EIO from reads and writes.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

If RFCOMM tty device registration fails, cleanup by releasing
the tty_port reference to trigger rfcomm_dev destruction
(rather than open-coding it).

The dlc reference release is moved into rfcomm_dev_add(),
which ensures cleanup in both error paths -- ie., if
__rfcomm_dev_add() fails or if tty_port_register_device() fails.

Fixes releasing the module reference if device registration fails.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Move rfcomm_dev allocation and initialization into new function,
__rfcomm_dev_add(), to simplify resource release in error handling.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

At least two different race conditions exist with multiple concurrent
RFCOMMCREATEDEV and RFCOMMRELEASEDEV ioctls:
* Multiple concurrent RFCOMMCREATEDEVs with RFCOMM_REUSE_DLC can
  mistakenly share the same DLC.
* RFCOMMRELEASEDEV can destruct the rfcomm_dev still being
  constructed by RFCOMMCREATEDEV.

Introduce rfcomm_ioctl_mutex to serialize these add/remove operations.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Functions which search lists for matching id's are more
commonly named *_lookup, which is the convention in the
bluetooth core as well.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The RFCOMM tty device is parented to the acl link device when
the dlc state_change(BT_CONNECTED) notification is received.
However, if the dlc from the RFCOMM socket is being reused
(RFCOMM_REUSE_DLC is set), then the dlc may already be connected,
and no notification will occur.

Instead, always parent the RFCOMM tty device to the acl link
device at registration time. If the acl link device is not available
(eg, because the dlc is not connected) then the tty will remain
unparented until the BT_CONNECTED notification is received.

Fixes regression with ModemManager when the rfcomm device is
created with the flag RFCOMM_REUSE_DLC.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Accessing the results of hci_conn_hash_lookup_ba() is unsafe without
holding the hci_dev_lock() during the lookup. For example:

CPU 0                             | CPU 1
hci_conn_hash_lookup_ba           | hci_conn_del
  rcu_read_lock                   |   hci_conn_hash_del
  list_for_each_entry_rcu         |     list_del_rcu
    if (.....)                    |       synchronize_rcu
      rcu_read_unlock             |
                                  |   hci_conn_del_sysfs
                                  |   hci_dev_put
                                  |   hci_conn_put
                                  |     put_device (last reference)
                                  |       bt_link_release
                                  |         kfree(conn)
      return p  << just freed     |

Even if a hci_conn reference were taken (via hci_conn_get), would
not guarantee the lifetime of the sysfs device, but only safe
access to the in-memory structure.

Ensure the hci_conn device stays valid while the rfcomm device
is reparented; rename rfcomm_get_device() to rfcomm_reparent_device()
and perform the reparenting within the function while holding the
hci_dev_lock.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

If the RFCOMM session has not yet been started (ie., session is
still in BT_BOUND state) when a dlc is closed, directly close and
unlink the dlc rather than sending a DISC frame that is never
sent.

This allows the dlci to be immediately reused rather than waiting
for a 20 second timeout.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Prepare for directly closing dlc if the RFCOMM session has not
yet been started; refactor the dlc disconnect logic into a separate
local function, __rfcomm_dlc_disconn(). Retains functional
equivalence.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Prepare for directly closing dlc if the RFCOMM session has not
yet been started; refactor the deferred setup test for only those
dlc states to which the test applies. Retains functional
equivalence.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Merge conditional test for BT_LISTEN session state into following
switch statement (which is functionally equivalent).
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Only one session/channel combination may be in use at any one
time. However, the failure does not occur until the tty is
opened (in rfcomm_dlc_open()).

Because these settings are actually bound at rfcomm device
creation (via RFCOMMCREATEDEV ioctl), validate and fail before
creating the rfcomm tty device.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

RFCOMM tty device teardown can race with new tty device registration
for the same device id:

CPU 0                           | CPU 1
rfcomm_dev_add                  | rfcomm_dev_destruct
                                |   spin_lock
                                |   list_del   <== dev_id no longer used
                                |   spin_unlock
  spin_lock                     |     .
  [search rfcomm_dev_list]      |     .
  [dev_id not in use]           |     .
  [initialize new rfcomm_dev]   |     .
  spin_unlock                   |     .
                                |     .
  tty_port_register_device      |   tty_unregister_device

Don't remove rfcomm_dev from the device list until after tty device
unregistration has completed.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When RFCOMM_RELEASE_ONHUP is set, the rfcomm tty driver 'takes over'
the initial rfcomm_dev reference created by the RFCOMMCREATEDEV ioctl.
The assumption is that the rfcomm tty driver will release the
rfcomm_dev reference when the tty is freed (in rfcomm_tty_cleanup()).
However, if the tty is never opened, the 'take over' never occurs,
so when RFCOMMRELEASEDEV ioctl is called, the reference is not
released.

Track the state of the reference 'take over' so that the release
is guaranteed by either the RFCOMMRELEASEDEV ioctl or the rfcomm tty
driver.

Note that the synchronous hangup in rfcomm_release_dev() ensures
that rfcomm_tty_install() cannot race with the RFCOMMRELEASEDEV ioctl.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

No logic prevents an rfcomm_dev from being released multiple
times. For example, if the rfcomm_dev ref count is large due
to pending tx, then multiple RFCOMMRELEASEDEV ioctls may
mistakenly release the rfcomm_dev too many times. Note that
concurrent ioctls are not required to create this condition.

Introduce RFCOMM_DEV_RELEASED status bit which guarantees the
rfcomm_dev can only be released once.

NB: Since the flags are exported to userspace, introduce the status
field to track state for which userspace should not be aware.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When enumerating RFCOMM devices in the rfcomm_dev_list, holding
the rfcomm_dev_lock only guarantees the existence of the enumerated
rfcomm_dev in memory, and not safe access to its state. Testing
the device state (such as RFCOMM_TTY_RELEASED) does not guarantee
the device will remain in that state for the subsequent access
to the rfcomm_dev's fields, nor guarantee that teardown has not
commenced.

Obtain an rfcomm_dev reference for the duration of rfcomm_dev
access.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-By: NAlexander Holler <holler@ahsoftware.de>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>