Bluetooth: use inclusive language in SMP

This patch replaces some non-inclusive terms based on the appropriate
language mapping table compiled by the Bluetooth SIG:
https://specificationrefs.bluetooth.com/language-mapping/Appropriate_Language_Mapping_Table.pdf

Specifically, these terms are replaced:
master -> initiator
slave -> responder

Signed-off-by: Archie Pusaka <apusaka@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Bluetooth: Move force_bredr_smp debugfs into hci_debugfs_create_bredr

Avoid multiple attempts to create the debugfs entry, force_bredr_smp,
by moving it from the SMP registration to the BR/EDR controller init
section. hci_debugfs_create_bredr is only called when HCI_SETUP and
HCI_CONFIG is not set.

Signed-off-by: Claire Chang <tientzu@chromium.org>
Reviewed-by: Alain Michaud <alainm@chromium.org>
Reviewed-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Bluetooth: SMP: fix crash in unpairing

In case unpair_device() was called through mgmt interface at the same time
when pairing was in progress, Bluetooth kernel module crash was seen.

[ 600.351225] general protection fault: 0000 [#1] SMP PTI
[ 600.351235] CPU: 1 PID: 11096 Comm: btmgmt Tainted: G OE 4.19.0-rc1+ #1
[ 600.351238] Hardware name: Dell Inc. Latitude E5440/08RCYC, BIOS A18 05/14/2017
[ 600.351272] RIP: 0010:smp_chan_destroy.isra.10+0xce/0x2c0 [bluetooth]
[ 600.351276] Code: c0 0f 84 b4 01 00 00 80 78 28 04 0f 84 53 01 00 00 4d 85 ed 0f 85 ab 00 00 00 48 8b 08 48 8b 50 08 be 10 00 00 00 48 89 51 08 <48> 89 0a 48 b9 00 02 00 00 00 00 ad de 48 89 48 08 48 8b 83 00 01
[ 600.351279] RSP: 0018:ffffa9be839b3b50 EFLAGS: 00010246
[ 600.351282] RAX: ffff9c999ac565a0 RBX: ffff9c9996e98c00 RCX: ffff9c999aa28b60
[ 600.351285] RDX: dead000000000200 RSI: 0000000000000010 RDI: ffff9c999e403500
[ 600.351287] RBP: ffffa9be839b3b70 R08: 0000000000000000 R09: ffffffff92a25c00
[ 600.351290] R10: ffffa9be839b3ae8 R11: 0000000000000001 R12: ffff9c995375b800
[ 600.351292] R13: 0000000000000000 R14: ffff9c99619a5000 R15: ffff9c9962a01c00
[ 600.351295] FS: 00007fb2be27c700(0000) GS:ffff9c999e880000(0000) knlGS:0000000000000000
[ 600.351298] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 600.351300] CR2: 00007fb2bdadbad0 CR3: 000000041c328001 CR4: 00000000001606e0
[ 600.351302] Call Trace:
[ 600.351325] smp_failure+0x4f/0x70 [bluetooth]
[ 600.351345] smp_cancel_pairing+0x74/0x80 [bluetooth]
[ 600.351370] unpair_device+0x1c1/0x330 [bluetooth]
[ 600.351399] hci_sock_sendmsg+0x960/0x9f0 [bluetooth]
[ 600.351409] ? apparmor_socket_sendmsg+0x1e/0x20
[ 600.351417] sock_sendmsg+0x3e/0x50
[ 600.351422] sock_write_iter+0x85/0xf0
[ 600.351429] do_iter_readv_writev+0x12b/0x1b0
[ 600.351434] do_iter_write+0x87/0x1a0
[ 600.351439] vfs_writev+0x98/0x110
[ 600.351443] ? ep_poll+0x16d/0x3d0
[ 600.351447] ? ep_modify+0x73/0x170
[ 600.351451] do_writev+0x61/0xf0
[ 600.351455] ? do_writev+0x61/0xf0
[ 600.351460] __x64_sys_writev+0x1c/0x20
[ 600.351465] do_syscall_64+0x5a/0x110
[ 600.351471] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 600.351474] RIP: 0033:0x7fb2bdb62fe0
[ 600.351477] Code: 73 01 c3 48 8b 0d b8 6e 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 69 c7 2c 00 00 75 10 b8 14 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 de 80 01 00 48 89 04 24
[ 600.351479] RSP: 002b:00007ffe062cb8f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
[ 600.351484] RAX: ffffffffffffffda RBX: 000000000255b3d0 RCX: 00007fb2bdb62fe0
[ 600.351487] RDX: 0000000000000001 RSI: 00007ffe062cb920 RDI: 0000000000000004
[ 600.351490] RBP: 00007ffe062cb920 R08: 000000000255bd80 R09: 0000000000000000
[ 600.351494] R10: 0000000000000353 R11: 0000000000000246 R12: 0000000000000001
[ 600.351497] R13: 00007ffe062cbbe0 R14: 0000000000000000 R15: 0000000000000000
[ 600.351501] Modules linked in: algif_hash algif_skcipher af_alg cmac ipt_MASQUERADE nf_conntrack_netlink nfnetlink xfrm_user xfrm_algo iptable_nat nf_nat_ipv4 xt_addrtype iptable_filter ip_tables xt_conntrack x_tables nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c br_netfilter bridge stp llc overlay arc4 nls_iso8859_1 dm_crypt intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp dell_laptop kvm_intel crct10dif_pclmul dell_smm_hwmon crc32_pclmul ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper intel_cstate intel_rapl_perf uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_common videodev media hid_multitouch input_leds joydev serio_raw dell_wmi snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic dell_smbios dcdbas sparse_keymap
[ 600.351569] snd_hda_intel btusb snd_hda_codec btrtl btbcm btintel snd_hda_core bluetooth(OE) snd_hwdep snd_pcm iwlmvm ecdh_generic wmi_bmof dell_wmi_descriptor snd_seq_midi mac80211 snd_seq_midi_event lpc_ich iwlwifi snd_rawmidi snd_seq snd_seq_device snd_timer cfg80211 snd soundcore mei_me mei dell_rbtn dell_smo8800 mac_hid parport_pc ppdev lp parport autofs4 hid_generic usbhid hid i915 nouveau kvmgt vfio_mdev mdev vfio_iommu_type1 vfio kvm irqbypass i2c_algo_bit ttm drm_kms_helper syscopyarea sysfillrect sysimgblt mxm_wmi psmouse ahci sdhci_pci cqhci libahci fb_sys_fops sdhci drm e1000e video wmi
[ 600.351637] ---[ end trace e49e9f1df09c94fb ]---
[ 600.351664] RIP: 0010:smp_chan_destroy.isra.10+0xce/0x2c0 [bluetooth]
[ 600.351666] Code: c0 0f 84 b4 01 00 00 80 78 28 04 0f 84 53 01 00 00 4d 85 ed 0f 85 ab 00 00 00 48 8b 08 48 8b 50 08 be 10 00 00 00 48 89 51 08 <48> 89 0a 48 b9 00 02 00 00 00 00 ad de 48 89 48 08 48 8b 83 00 01
[ 600.351669] RSP: 0018:ffffa9be839b3b50 EFLAGS: 00010246
[ 600.351672] RAX: ffff9c999ac565a0 RBX: ffff9c9996e98c00 RCX: ffff9c999aa28b60
[ 600.351674] RDX: dead000000000200 RSI: 0000000000000010 RDI: ffff9c999e403500
[ 600.351676] RBP: ffffa9be839b3b70 R08: 0000000000000000 R09: ffffffff92a25c00
[ 600.351679] R10: ffffa9be839b3ae8 R11: 0000000000000001 R12: ffff9c995375b800
[ 600.351681] R13: 0000000000000000 R14: ffff9c99619a5000 R15: ffff9c9962a01c00
[ 600.351684] FS: 00007fb2be27c700(0000) GS:ffff9c999e880000(0000) knlGS:0000000000000000
[ 600.351686] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 600.351689] CR2: 00007fb2bdadbad0 CR3: 000000041c328001 CR4: 00000000001606e0

Crash happened because list_del_rcu() was called twice for smp->ltk. This
was possible if unpair_device was called right after ltk was generated
but before keys were distributed.

In this commit smp_cancel_pairing was refactored to cancel pairing if it
is in progress and otherwise just removes keys. Once keys are removed from
rcu list, pointers to smp context's keys are set to NULL to make sure
removed list items are not accessed later.

This commit also adjusts the functionality of mgmt unpair_device() little
bit. Previously pairing was canceled only if pairing was in state that
keys were already generated. With this commit unpair_device() cancels
pairing already in earlier states.

Bug was found by fuzzing kernel SMP implementation using Synopsys
Defensics.

Reported-by: Pekka Oikarainen <pekka.oikarainen@synopsys.com>
Signed-off-by: Matias Karhumaa <matias.karhumaa@gmail.com>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

Bluetooth: SMP: Add support for H7 crypto function and CT2 auth flag

Bluetooth 5.0 introduces a new H7 key generation function that's used
when both sides of the pairing set the CT2 authentication flag to 1.

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

Bluetooth: Fix crash in SMP when unpairing

When unpairing the keys stored in hci_dev are removed. If SMP is
ongoing the SMP context will also have references to these keys, so
removing them from the hci_dev lists will make the pointers invalid.
This can result in the following type of crashes:

BUG: unable to handle kernel paging request at 6b6b6b6b
IP: [<c11f26be>] __list_del_entry+0x44/0x71
*pde = 00000000
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Modules linked in: hci_uart btqca btusb btintel btbcm btrtl hci_vhci rfcomm bluetooth_6lowpan bluetooth
CPU: 0 PID: 723 Comm: kworker/u5:0 Not tainted 4.3.0-rc3+ #1379
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.1-20150318_183358- 04/01/2014
Workqueue: hci0 hci_rx_work [bluetooth]
task: f19da940 ti: f1a94000 task.ti: f1a94000
EIP: 0060:[<c11f26be>] EFLAGS: 00010202 CPU: 0
EIP is at __list_del_entry+0x44/0x71
EAX: c0088d20 EBX: f30fcac0 ECX: 6b6b6b6b EDX: 6b6b6b6b
ESI: f4b60000 EDI: c0088d20 EBP: f1a95d90 ESP: f1a95d8c
DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
CR0: 8005003b CR2: 6b6b6b6b CR3: 319e5000 CR4: 00000690
Stack:
f30fcac0 f1a95db0 f82dc3e1 f1bfc000 00000000 c106524f f1bfc000 f30fd020
f1a95dc0 f1a95dd0 f82dcbdb f1a95de0 f82dcbdb 00000067 f1bfc000 f30fd020
f1a95de0 f1a95df0 f82d1126 00000067 f82d1126 00000006 f30fd020 f1bfc000
Call Trace:
[<f82dc3e1>] smp_chan_destroy+0x192/0x240 [bluetooth]
[<c106524f>] ? trace_hardirqs_on_caller+0x14e/0x169
[<f82dcbdb>] smp_teardown_cb+0x47/0x64 [bluetooth]
[<f82dcbdb>] ? smp_teardown_cb+0x47/0x64 [bluetooth]
[<f82d1126>] l2cap_chan_del+0x5d/0x14d [bluetooth]
[<f82d1126>] ? l2cap_chan_del+0x5d/0x14d [bluetooth]
[<f82d40ef>] l2cap_conn_del+0x109/0x17b [bluetooth]
[<f82d40ef>] ? l2cap_conn_del+0x109/0x17b [bluetooth]
[<f82c0205>] ? hci_event_packet+0x5b1/0x2092 [bluetooth]
[<f82d41aa>] l2cap_disconn_cfm+0x49/0x50 [bluetooth]
[<f82d41aa>] ? l2cap_disconn_cfm+0x49/0x50 [bluetooth]
[<f82c0228>] hci_event_packet+0x5d4/0x2092 [bluetooth]
[<c1332c16>] ? skb_release_data+0x6a/0x95
[<f82ce5d4>] ? hci_send_to_monitor+0xe7/0xf4 [bluetooth]
[<c1409708>] ? _raw_spin_unlock_irqrestore+0x44/0x57
[<f82b3bb0>] hci_rx_work+0xf1/0x28b [bluetooth]
[<f82b3bb0>] ? hci_rx_work+0xf1/0x28b [bluetooth]
[<c10635a0>] ? __lock_is_held+0x2e/0x44
[<c104772e>] process_one_work+0x232/0x432
[<c1071ddc>] ? rcu_read_lock_sched_held+0x50/0x5a
[<c104772e>] ? process_one_work+0x232/0x432
[<c1047d48>] worker_thread+0x1b8/0x255
[<c1047b90>] ? rescuer_thread+0x23c/0x23c
[<c104bb71>] kthread+0x91/0x96
[<c14096a7>] ? _raw_spin_unlock_irq+0x27/0x44
[<c1409d61>] ret_from_kernel_thread+0x21/0x30
[<c104bae0>] ? kthread_parkme+0x1e/0x1e

To solve the issue, introduce a new smp_cancel_pairing() API that can
be used to clean up the SMP state before touching the hci_dev lists.

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

Bluetooth: Add function for generating LE SC out-of-band data

This patch adds a smp_generate_oob function that allows to create
local out-of-band data that can be used for pairing and also provides
the confirmation and random value.

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

Bluetooth: Add skeleton for SMP self-tests

This patch adds the initial skeleton and kernel config option for SMP
self-tests.

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

Bluetooth: Fix missing const declarations in SMP functions

Several SMP functions take read-only data. This patch fixes the
declaration of these parameters to use the const specifier as
appropriate.

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

Bluetooth: Set the correct security level for SC LTKs

When the looked-up LTK is one generated by Secure Connections pairing
the security level it gives is BT_SECURITY_FIPS. This patch updates the
LTK request event handler to correctly set this level.

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

Bluetooth: Add mgmt support for LE Secure Connections LTK types

We need a dedicated LTK type for LTK resulting from a Secure Connections
based SMP pairing. This patch adds a new define for it and ensures that
both the New LTK event as well as the Load LTKs command supports it.

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

Bluetooth: Add basic SMP defines for LE Secure Connections

This patch adds basic SMP defines for commands, error codes and PDU
definitions for the LE Secure Connections feature.

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

Bluetooth: Add key preference parameter to smp_sufficient_security

So far smp_sufficient_security() has returned false if we're encrypted
with an STK but do have an LTK available. However, for the sake of LE
CoC servers we do want to let the incoming connection through even
though we're only encrypted with the STK.

This patch adds a key preference parameter to smp_sufficient_security()
with two possible values (enum used instead of bool for readability).

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

Bluetooth: Add smp_ltk_sec_level() helper function

There are several places that need to determine the security level that
an LTK can provide. This patch adds a convenience function for this to
help make the code more readable.

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

Bluetooth: Add strict checks for allowed SMP PDUs

SMP defines quite clearly when certain PDUs are to be expected/allowed
and when not, but doesn't have any explicit request/response definition.
So far the code has relied on each PDU handler to behave correctly if
receiving PDUs at an unexpected moment, however this requires many
different checks and is prone to errors.

This patch introduces a generic way to keep track of allowed PDUs and
thereby reduces the responsibility & load on individual command
handlers. The tracking is implemented using a simple bit-mask where each
opcode maps to its own bit. If the bit is set the corresponding PDU is
allow and if the bit is not set the PDU is not allowed.

As a simple example, when we send the Pairing Request we'd set the bit
for Pairing Response, and when we receive the Pairing Response we'd
clear the bit for Pairing Response.

Since the disallowed PDU rejection is now done in a single central place
we need to be a bit careful of which action makes most sense to all
cases. Previously some, such as Security Request, have been simply
ignored whereas others have caused an explicit disconnect.

The only PDU rejection action that keeps good interoperability and can
be used for all the applicable use cases is to drop the data. This may
raise some concerns of us now being more lenient for misbehaving (and
potentially malicious) devices, but the policy of simply dropping data
has been a successful one for many years e.g. in L2CAP (where this is
the *only* policy for such cases - we never request disconnection in
l2cap_core.c because of bad data). Furthermore, we cannot prevent
connected devices from creating the SMP context (through a Security or
Pairing Request), and once the context exists looking up the
corresponding bit for the received opcode and deciding to reject it is
essentially an equally lightweight operation as the kind of rejection
that l2cap_core.c already successfully does.

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

Bluetooth: Make smp_chan_destroy() private to smp.c

There are no external users of smp_chan_destroy() so make it private to
smp.c. The patch also moves the function higher up in the c-file in
order to avoid forward declarations.

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

Bluetooth: Use L2CAP resume callback to call smp_distribute_keys

There's no need to export the smp_distribute_keys() function since the
resume callback is called in the same scenario. This patch makes the
smp_notify_keys function private (at the same time moving it higher up
in smp.c to avoid forward declarations) and adds a resume callback for
SMP to call it from there instead.

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

Bluetooth: Convert SMP to use l2cap_chan infrastructure

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>

Bluetooth: Make AES crypto context private to SMP

Now that we have per-adapter SMP data thanks to the root SMP L2CAP
channel we can take advantage of it and attach the AES crypto context
(only used for SMP) to it. This means that the smp_irk_matches() and
smp_generate_rpa() function can be converted to internally handle the
AES context.

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

Bluetooth: Move SMP (de)initialization to smp.c

As preparation for moving SMP to use l2cap_chan infrastructure we need
to move the (de)initialization functions to smp.c (where they'll
eventually need access to the local L2CAP channel callbacks).

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

Bluetooth: Remove HCI prefix from SMP LTK defines

The LTK type has really nothing to do with HCI so it makes more sense to
have these in smp.h than hci.h. This patch moves the defines to smp.h
and removes the HCI_ prefix in the same go.

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

Bluetooth: Make SMP context private to smp.c

There are no users of the smp_chan struct outside of smp.c so move it
away from smp.h. The addition of the l2cap.h include to hci_core.c,
hci_conn.c and mgmt.c is something that should have been there already
previously to avoid warnings of undeclared struct l2cap_conn, but the
compiler warning was apparently shadowed away by the mention of
l2cap_conn in the struct smp_chan definition.

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

Bluetooth: Add support for SMP Invalid Parameters error code

The Invalid Parameters error code is used to indicate that the command
length is invalid or that a parameter is outside of the specified range.
This error code wasn't clearly specified in the Bluetooth 4.0
specification but since 4.1 this has been fixed.

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

Bluetooth: Remove LTK re-encryption procedure

Due to several devices being unable to handle this procedure reliably
(resulting in forced disconnections before pairing completes) it's
better to remove it altogether.

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

Bluetooth: Add SMP flag to track which side is the initiator

For remotely initiated just-works pairings we want to show the user a
confirmation dialog for the pairing. However, we can only know which
side was the initiator by tracking which side sends the first Security
Request or Pairing Request PDU. This patch adds a new SMP flag to
indicate whether our side was the initiator for the pairing.

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

Bluetooth: Increase SMP re-encryption delay to 500ms

In some cases the current 250ms delay is not enough for the remote to
receive the keys, as can be witnessed by the following log:

> ACL Data RX: Handle 64 flags 0x02 dlen 21 [hci1] 231.414217
SMP: Signing Information (0x0a) len 16
Signature key: 555bb66b7ab3abc9d5c287c97fe6eb29
< ACL Data TX: Handle 64 flags 0x00 dlen 21 [hci1] 231.414414
SMP: Encryption Information (0x06) len 16
Long term key: 2a7cdc233c9a4b1f3ed31dd9843fea29
< ACL Data TX: Handle 64 flags 0x00 dlen 15 [hci1] 231.414466
SMP: Master Identification (0x07) len 10
EDIV: 0xeccc
Rand: 0x322e0ef50bd9308a
< ACL Data TX: Handle 64 flags 0x00 dlen 21 [hci1] 231.414505
SMP: Signing Information (0x0a) len 16
Signature key: bbda1b2076e2325aa66fbcdd5388f745
> HCI Event: Number of Completed Packets (0x13) plen 5 [hci1] 231.483130
Num handles: 1
Handle: 64
Count: 2
< HCI Command: LE Start Encryption (0x08|0x0019) plen 28 [hci1] 231.664211
Handle: 64
Random number: 0x5052ad2b75fed54b
Encrypted diversifier: 0xb7c2
Long term key: a336ede66711b49a84bde9b41426692e
> HCI Event: Command Status (0x0f) plen 4 [hci1] 231.666937
LE Start Encryption (0x08|0x0019) ncmd 1
Status: Success (0x00)
> HCI Event: Number of Completed Packets (0x13) plen 5 [hci1] 231.712646
Num handles: 1
Handle: 64
Count: 1
> HCI Event: Disconnect Complete (0x05) plen 4 [hci1] 232.562587
Status: Success (0x00)
Handle: 64
Reason: Remote User Terminated Connection (0x13)

As can be seen, the last key (Signing Information) is sent at 231.414505
but the completed packets event for it comes only at 231.712646,
i.e. roughly 298ms later.

To have a better margin of error this patch increases the delay to
500ms.

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

Bluetooth: Add support for handling signature resolving keys

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

Bluetooth: Delay LTK encryption to let remote receive all keys

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

Bluetooth: Re-encrypt link after receiving an LTK

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

Bluetooth: Use __le64 type for LE random numbers

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

Bluetooth: Remove unneeded "force" parameter from smp_distribute_keys()

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

Bluetooth: Add SMP function for generating RPAs

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

Bluetooth: Track SMP keys in the SMP context

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

Bluetooth: Wait for SMP key distribution completion when pairing

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

Bluetooth: Remove SMP data specific crypto context

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

Bluetooth: Enable support for remote IRK distribution

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

Bluetooth: Add smp_irk_matches helper function

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

Bluetooth: Fix minor whitespace issues in SMP code

This patch fixes a couple of unnecessary empty lines in the SMP code.

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

Bluetooth: Add smp_sufficient_security helper function

This function is needed both by the smp_conn_security function as well
as upcoming code to check for the security requirements when receiving
an L2CAP connect request over LE.

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

Bluetooth: Move smp.h header file into net/bluetooth/

The smp.h header file is only used internally by the bluetooth.ko
module and is not a public API. So make it local to the core
Bluetooth module.

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