If a sudden disconnection happens the l2cap_conn pointer may already
have been cleaned up by the time hci_conn_security gets called,
resulting in the following oops if we don't have a proper NULL check:

BUG: unable to handle kernel NULL pointer dereference at 000000c8
IP: [<c132e2ed>] smp_conn_security+0x26/0x151
*pde = 00000000
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
CPU: 1 PID: 673 Comm: memcheck-x86-li Not tainted 3.14.0-rc2+ #437
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
task: f0ef0520 ti: f0d6a000 task.ti: f0d6a000
EIP: 0060:[<c132e2ed>] EFLAGS: 00010246 CPU: 1
EIP is at smp_conn_security+0x26/0x151
EAX: f0ec1770 EBX: f0ec1770 ECX: 00000002 EDX: 00000002
ESI: 00000002 EDI: 00000000 EBP: f0d6bdc0 ESP: f0d6bda0
 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
CR0: 80050033 CR2: 000000c8 CR3: 30f0f000 CR4: 00000690
Stack:
 f4f55000 00000002 f0d6bdcc c1097a2b c1319f40 f0ec1770 00000002 f0d6bdd0
 f0d6bde8 c1312a82 f0d6bdfc c1312a82 c1319f84 00000008 f4d81c20 f0e5fd86
 f0ec1770 f0d6bdfc f0d6be28 c131be3b c131bdc1 f0d25270 c131be3b 00000008
Call Trace:
 [<c1097a2b>] ? __kmalloc+0x118/0x128
 [<c1319f40>] ? mgmt_pending_add+0x49/0x9b
 [<c1312a82>] hci_conn_security+0x4a/0x1dd
 [<c1312a82>] ? hci_conn_security+0x4a/0x1dd
 [<c1319f84>] ? mgmt_pending_add+0x8d/0x9b
 [<c131be3b>] pair_device+0x1e1/0x206
 [<c131bdc1>] ? pair_device+0x167/0x206
 [<c131be3b>] ? pair_device+0x1e1/0x206
 [<c131ed44>] mgmt_control+0x275/0x2d6
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

We need to ensure that we do not send events to user space with the
identity address if we have not yet notified user space of the IRK. The
code was previously trying to handle this for the mgmt_pair_device
response (which worked well enough) but this is not the only connection
related event that might be sent to user space before pairing is
successful: another important event is Device Disconnected.

The issue can actually be solved more simply than the solution
previously used for mgmt_pair_device. Since we do have the identity
address tracked as part of the remote IRK struct we can just copy it
over from there to the hci_conn struct once we've for real sent the mgmt
event for the new IRK.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The passkey_notify and user_confirm functions in mgmt.c were expecting
different endianess for the passkey, leading to a big endian bug and
sparse warning in recently added SMP code. This patch converts both
functions to expect host endianess and do the conversion to little
endian only when assigning to the mgmt event struct.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When performing SMP pairing with MITM protection one side needs to
enter the passkey while the other side displays to the user what needs
to be entered. Nowhere in the SMP specification does it say that the
displaying side needs to any kind of confirmation of the passkey, even
though a code comment in smp.c implies this.

This patch removes the misleading comment and converts the code to use
the passkey notification mgmt event instead of the passkey confirmation
mgmt event.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This is a trivial coding style simplification by instead of having an
extra early return to instead revert the if condition and do the single
needed queue_work() call there.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The pairing process initiated through mgmt sets the conn->auth_type
value regardless of BR/EDR or LE pairing. This value will contain the
MITM flag if the local IO capability allows it. When sending the SMP
pairing request we should check the value and ensure that the MITM bit
gets correctly set in the bonding flags.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The SMP specification is written with the assumption that both key
information, plaintextData and encryptedData follow the same little
endian byte ordering as the rest of SMP.

Since the kernel crypto routines expect big endian data the code has had
to do various byte swapping tricks to make the behavior as expected,
however the swapping has been scattered all around the place.

This patch centralizes the byte order swapping into the smp_e function
by making its public interface match what the other SMP functions expect
as per specification. The benefit is vastly simplified calls to smp_e.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

To make it possible to (correctly) pass data declared as const as the
src parameter to the swap56 and swap128 functions declare this parameter
also as const.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

When performing pairing using SMP the remote may clear any key
distribution bits it wants in its pairing response. We must therefore
update our local variable accordingly, otherwise we might get stuck
waiting for keys that will never come.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The use of __constant_<foo> has been unnecessary for quite awhile now.

Make these uses consistent with the rest of the kernel.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

In case the pairable option has been disabled, the pairing procedure
does not create keys for bonding. This means that these generated keys
should not be stored persistently.

For LTK and CSRK this is important to tell userspace to not store these
new keys. They will be available for the lifetime of the device, but
after the next power cycle they should not be used anymore.

Inform userspace to actually store the keys persistently only if both
sides request bonding.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

The connection signature resolving key (CSRK) is used for attribute
protocol signed write procedures. This change generates a new local
key during pairing and requests the peer key as well.

Newly generated key and received key will be provided to userspace
using the New Signature Resolving Key management event.

The Master CSRK can be used for verification of remote signed write
PDUs and the Slave CSRK can be used for sending signed write PDUs
to the remote device.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

Some devices may refuse to re-encrypt with the LTK if they haven't
received all our keys yet. This patch adds a 250ms delay before
attempting re-encryption with the LTK.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

It's not strictly speaking required to re-encrypt a link once we receive
an LTK since the connection is already encrypted with the STK. However,
re-encrypting with the LTK allows us to verify that we've received an
LTK that actually works.

This patch updates the SMP code to request encrypting with the LTK in
case we're in master role and waits until the key refresh complete event
before notifying user space of the distributed keys.

A new flag is also added for the SMP context to ensure that we
re-encryption only once in case of multiple calls to smp_distribute_keys.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Now that we have nicely tracked values of the initiator and responder
address information we can pass that directly to the smp_c1 function
without worrying e.g. about who initiated the connection. This patch
updates the two places in smp.c to use the new variables.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

If SMP fails we should not leave any keys (LTKs or IRKs) hanging around
the internal lists. This patch adds the necessary code to
smp_chan_destroy to remove any keys we may have in case of pairing
failure.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The random numbers in Bluetooth Low Energy are 64-bit numbers and should
also be little endian since the HCI specification is little endian.

Change the whole Low Energy pairing to use __le64 instead of a byte
array.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

Now that to-be-received keys are properly tracked we no-longer need the
"force" parameter to smp_distribute_keys(). It was essentially acting as
an indicator whether all keys have been received, but now it's just
redundant together with smp->remote_key_dist.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Now that smp->remote_key_dist is tracking the keys we're still waiting
for we can use it to simplify the logic for checking whether we're done
with key distribution or not. At the same time the reliance on the
"force" parameter of smp_distribute_keys goes away and it can completely
be removed in a subsequent patch.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

To make is easier to track which keys we've received and which ones
we're still waiting for simply clear the corresponding key bits from
smp->remote_key_dist as they get received. This will allow us to
simplify the code for checking for SMP completion in subsequent patches.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The Core Specification (4.1) leaves room for sending an SMP Identity
Address Information PDU with an all-zeros BD_ADDR value. This
essentially means that we would not have an Identity Address for the
device and the only means of identifying it would be the IRK value
itself.

Due to lack of any known implementations behaving like this it's best to
keep our implementation as simple as possible as far as handling such
situations is concerned. This patch updates the Identity Address
Information handler function to simply ignore the IRK received from such
a device.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

We need a function in smp.c to generate Resolvable Random Addresses in
order to support privacy. The local RPA will need to be generated before
advertising, scanning or connecting and regenerated at periodic
intervals. This patch adds the necessary function for RPA generation.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

The SMP Identity Address Information PDU should contain our Identity
Address. This patch updates the code to copy the correct values from the
hci_conn object.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This code adds a HCI_PRIVACY flag to track whether Privacy support is
enabled (meaning we have a local IRK) and makes sure the IRK is
distributed during SMP key distribution in case this flag is set.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This patch a couple of helper variables to the smp_distribute_keys
function in order to avoid long chains of dereferences and thereby help
readability.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This patch adds the necessary helper function to send the New IRK mgmt
event and makes sure that the function is called at when SMP key
distribution has completed. The event is sent before the New LTK event
so user space knows which remote device to associate with the keys.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This patch moves the SMP Long Term Key notification over mgmt from the
hci_add_ltk function to smp.c when both sides have completed their key
distribution. This way we are also able to update the identity address
into the mgmt_new_ltk event.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

As preparation to do mgmt notification in a single place at the end of
the key distribution, store the keys that need to be notified within the
SMP context.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

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 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>

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 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>

If LTK distribution happens in both directions we will have two LTKs for
the same remote device: one which is used when we're connecting as
master and another when we're connecting as slave. When looking up LTKs
from the locally stored list we shouldn't blindly return the first match
but also consider which type of key is in question. If we do not do this
we may end up selecting an incorrect encryption key for a connection.

This patch fixes the issue by always specifying to the LTK lookup
functions whether we're looking for a master or a slave key.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

So far we've only been requesting the LTK to be distributed to the
master (initiator) of pairing, which is usually enough since it's the
master that will establish future connections and initiate encryption.
However, in the case that both devices support switching to the opposing
role (which seems to be increasingly common) pairing will have to
performed again since the "new" master will not have all information.

As there is no real harm in it, this patch updates the code to always
try distributing the LTK also to the slave device, thereby enabling role
switches for future connections.
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>
Acked-by: NVinicius Gomes <vcgomes@gmail.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>