There are several actions that smp_conn_security() might make that do
not require a valid SMP context (conn->smp pointer). One of these
actions is to encrypt the link with an existing LTK. If the SMP
context wasn't initialized properly we should still allow the
independent actions to be done, i.e. the check for the context should
only be done at the last possible moment.

Reported-by: Chuck Ebbert <cebbert.lkml@gmail.com>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org # 4.0+

The l2cap_conn->smp pointer may be NULL for various valid reasons where SMP has
failed to initialize properly. One such scenario is when crypto support is
missing, another when the adapter has been powered on through a legacy method.
The smp_conn_security() function should have the appropriate check for this
situation to avoid NULL pointer dereferences.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org # 4.0+

When pairing over SMP over BR/EDR the generated LTK has by default the
same key size as the BR/EDR Link Key. Make sure we don't set our
Pairing Request/Response max value to anything higher than that.

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

This patch adds a debugfs control to set a different minimum LE
encryption key size. This is useful for testing that implementation of
the encryption key size handling is behaving correctly (e.g. that we
get appropriate 'Encryption Key Size' error responses when necessary).

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

This patch adds a debugfs control to set a different maximum LE
encryption key size. This is useful for testing that implementation of
the encryption key size handling is behaving correctly.

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

When we notify user space of a new LTK or distribute an LTK to the
remote peer the value passed should be the shortened version so that
it's easy to compare values in various traces. The core spec also sets
the requirements for the shortening/masking as:

"The masking shall be done after generation and before being
distributed, used or stored."

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

The encryption key size for LTKs is supposed to be applied only at the
moment of encryption. When generating a Link Key (using LE SC) from
the LTK the full non-shortened value should be used. This patch
modifies the code to always keep the full value around and only apply
the key size when passing the value to HCI.

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

To help debug legacy SMP crypto functions add debug logs of the
various values involved.

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

When SMP selftest is enabled, then besides printing the result into the
kernel message buffer, also create a debugfs file that allows retrieving
the same information.

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

We're getting very close to the maximum possible size of bt_skb_cb. To
prepare to shrink the struct with the help of a union this patch moves
all L2CAP related variables into the l2cap_ctrl struct. To later add
other 'ctrl' structs the L2CAP one is renamed simple 'l2cap' instead
of 'control'.

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