Commit Graph

18 Commits

Author SHA1 Message Date
Dan Carpenter
04a329133b Bluetooth: delete a stray unlock
commit df66499a1fab340c167250a5743931dc50d5f0fa upstream.

We used to take a lock in amp_physical_cfm() but then we moved it to
the caller function.  Unfortunately the unlock on this error path was
overlooked so it leads to a double unlock.

Fixes: a514b17fab51 ("Bluetooth: Refactor locking in amp_physical_cfm")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-07 13:24:53 +02:00
Mattijs Korpershoek
05f2d8bc5d Bluetooth: hci_core: fix init for HCI_USER_CHANNEL
[ Upstream commit eb8c101e28496888a0dcfe16ab86a1bee369e820 ]

During the setup() stage, HCI device drivers expect the chip to
acknowledge its setup() completion via vendor specific frames.

If userspace opens() such HCI device in HCI_USER_CHANNEL [1] mode,
the vendor specific frames are never tranmitted to the driver, as
they are filtered in hci_rx_work().

Allow HCI devices which operate in HCI_USER_CHANNEL mode to receive
frames if the HCI device is is HCI_INIT state.

[1] https://www.spinics.net/lists/linux-bluetooth/msg37345.html

Fixes: 23500189d7e0 ("Bluetooth: Introduce new HCI socket channel for user operation")
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-07 13:20:46 +02:00
Luiz Augusto von Dentz
45e7dbec1c Bluetooth: L2CAP: Detect if remote is not able to use the whole MPS
[ Upstream commit a5c3021bb62b970713550db3f7fd08aa70665d7e ]

If the remote is not able to fully utilize the MPS choosen recalculate
the credits based on the actual amount it is sending that way it can
still send packets of MTU size without credits dropping to 0.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-07 12:29:42 +02:00
Marcel Holtmann
fcc3dbb04e Revert "Bluetooth: validate BLE connection interval updates"
[ Upstream commit 68d19d7d995759b96169da5aac313363f92a9075 ]

This reverts commit c49a8682fc5d298d44e8d911f4fa14690ea9485e.

There are devices which require low connection intervals for usable operation
including keyboards and mice. Forcing a static connection interval for
these types of devices has an impact in latency and causes a regression.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-07 07:35:58 +02:00
Szymon Janc
6f2446b3e4 Bluetooth: Add SMP workaround Microsoft Surface Precision Mouse bug
commit 1d87b88ba26eabd4745e158ecfd87c93a9b51dc2 upstream.

Microsoft Surface Precision Mouse provides bogus identity address when
pairing. It connects with Static Random address but provides Public
Address in SMP Identity Address Information PDU. Address has same
value but type is different. Workaround this by dropping IRK if ID
address discrepancy is detected.

> HCI Event: LE Meta Event (0x3e) plen 19
      LE Connection Complete (0x01)
        Status: Success (0x00)
        Handle: 75
        Role: Master (0x00)
        Peer address type: Random (0x01)
        Peer address: E0:52:33:93:3B:21 (Static)
        Connection interval: 50.00 msec (0x0028)
        Connection latency: 0 (0x0000)
        Supervision timeout: 420 msec (0x002a)
        Master clock accuracy: 0x00

....

> ACL Data RX: Handle 75 flags 0x02 dlen 12
      SMP: Identity Address Information (0x09) len 7
        Address type: Public (0x00)
        Address: E0:52:33:93:3B:21

Signed-off-by: Szymon Janc <szymon.janc@codecoup.pl>
Tested-by: Maarten Fonville <maarten.fonville@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199461
Cc: stable@vger.kernel.org
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-06 20:04:59 +02:00
csonsino
1db4851e10 Bluetooth: validate BLE connection interval updates
[ Upstream commit c49a8682fc5d298d44e8d911f4fa14690ea9485e ]

Problem: The Linux Bluetooth stack yields complete control over the BLE
connection interval to the remote device.

The Linux Bluetooth stack provides access to the BLE connection interval
min and max values through /sys/kernel/debug/bluetooth/hci0/
conn_min_interval and /sys/kernel/debug/bluetooth/hci0/conn_max_interval.
These values are used for initial BLE connections, but the remote device
has the ability to request a connection parameter update. In the event
that the remote side requests to change the connection interval, the Linux
kernel currently only validates that the desired value is within the
acceptable range in the Bluetooth specification (6 - 3200, corresponding to
7.5ms - 4000ms). There is currently no validation that the desired value
requested by the remote device is within the min/max limits specified in
the conn_min_interval/conn_max_interval configurations. This essentially
leads to Linux yielding complete control over the connection interval to
the remote device.

The proposed patch adds a verification step to the connection parameter
update mechanism, ensuring that the desired value is within the min/max
bounds of the current connection. If the desired value is outside of the
current connection min/max values, then the connection parameter update
request is rejected and the negative response is returned to the remote
device. Recall that the initial connection is established using the local
conn_min_interval/conn_max_interval values, so this allows the Linux
administrator to retain control over the BLE connection interval.

The one downside that I see is that the current default Linux values for
conn_min_interval and conn_max_interval typically correspond to 30ms and
50ms respectively. If this change were accepted, then it is feasible that
some devices would no longer be able to negotiate to their desired
connection interval values. This might be remedied by setting the default
Linux conn_min_interval and conn_max_interval values to the widest
supported range (6 - 3200 / 7.5ms - 4000ms). This could lead to the same
behavior as the current implementation, where the remote device could
request to change the connection interval value to any value that is
permitted by the Bluetooth specification, and Linux would accept the
desired value.

Signed-off-by: Carey Sonsino <csonsino@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-06 19:55:43 +02:00
Matias Karhumaa
84d9ed3476 Bluetooth: Check state in l2cap_disconnect_rsp
[ Upstream commit 28261da8a26f4915aa257d12d506c6ba179d961f ]

Because of both sides doing L2CAP disconnection at the same time, it
was possible to receive L2CAP Disconnection Response with CID that was
already freed. That caused problems if CID was already reused and L2CAP
Connection Request with same CID was sent out. Before this patch kernel
deleted channel context regardless of the state of the channel.

Example where leftover Disconnection Response (frame #402) causes local
device to delete L2CAP channel which was not yet connected. This in
turn confuses remote device's stack because same CID is re-used without
properly disconnecting.

Btmon capture before patch:
** snip **
> ACL Data RX: Handle 43 flags 0x02 dlen 8                #394 [hci1] 10.748949
      Channel: 65 len 4 [PSM 3 mode 0] {chan 2}
      RFCOMM: Disconnect (DISC) (0x43)
         Address: 0x03 cr 1 dlci 0x00
         Control: 0x53 poll/final 1
         Length: 0
         FCS: 0xfd
< ACL Data TX: Handle 43 flags 0x00 dlen 8                #395 [hci1] 10.749062
      Channel: 65 len 4 [PSM 3 mode 0] {chan 2}
      RFCOMM: Unnumbered Ack (UA) (0x63)
         Address: 0x03 cr 1 dlci 0x00
         Control: 0x73 poll/final 1
         Length: 0
         FCS: 0xd7
< ACL Data TX: Handle 43 flags 0x00 dlen 12               #396 [hci1] 10.749073
      L2CAP: Disconnection Request (0x06) ident 17 len 4
        Destination CID: 65
        Source CID: 65
> HCI Event: Number of Completed Packets (0x13) plen 5    #397 [hci1] 10.752391
        Num handles: 1
        Handle: 43
        Count: 1
> HCI Event: Number of Completed Packets (0x13) plen 5    #398 [hci1] 10.753394
        Num handles: 1
        Handle: 43
        Count: 1
> ACL Data RX: Handle 43 flags 0x02 dlen 12               #399 [hci1] 10.756499
      L2CAP: Disconnection Request (0x06) ident 26 len 4
        Destination CID: 65
        Source CID: 65
< ACL Data TX: Handle 43 flags 0x00 dlen 12               #400 [hci1] 10.756548
      L2CAP: Disconnection Response (0x07) ident 26 len 4
        Destination CID: 65
        Source CID: 65
< ACL Data TX: Handle 43 flags 0x00 dlen 12               #401 [hci1] 10.757459
      L2CAP: Connection Request (0x02) ident 18 len 4
        PSM: 1 (0x0001)
        Source CID: 65
> ACL Data RX: Handle 43 flags 0x02 dlen 12               #402 [hci1] 10.759148
      L2CAP: Disconnection Response (0x07) ident 17 len 4
        Destination CID: 65
        Source CID: 65
= bluetoothd: 00:1E:AB:4C:56:54: error updating services: Input/o..   10.759447
> HCI Event: Number of Completed Packets (0x13) plen 5    #403 [hci1] 10.759386
        Num handles: 1
        Handle: 43
        Count: 1
> ACL Data RX: Handle 43 flags 0x02 dlen 12               #404 [hci1] 10.760397
      L2CAP: Connection Request (0x02) ident 27 len 4
        PSM: 3 (0x0003)
        Source CID: 65
< ACL Data TX: Handle 43 flags 0x00 dlen 16               #405 [hci1] 10.760441
      L2CAP: Connection Response (0x03) ident 27 len 8
        Destination CID: 65
        Source CID: 65
        Result: Connection successful (0x0000)
        Status: No further information available (0x0000)
< ACL Data TX: Handle 43 flags 0x00 dlen 27               #406 [hci1] 10.760449
      L2CAP: Configure Request (0x04) ident 19 len 19
        Destination CID: 65
        Flags: 0x0000
        Option: Maximum Transmission Unit (0x01) [mandatory]
          MTU: 1013
        Option: Retransmission and Flow Control (0x04) [mandatory]
          Mode: Basic (0x00)
          TX window size: 0
          Max transmit: 0
          Retransmission timeout: 0
          Monitor timeout: 0
          Maximum PDU size: 0
> HCI Event: Number of Completed Packets (0x13) plen 5    #407 [hci1] 10.761399
        Num handles: 1
        Handle: 43
        Count: 1
> ACL Data RX: Handle 43 flags 0x02 dlen 16               #408 [hci1] 10.762942
      L2CAP: Connection Response (0x03) ident 18 len 8
        Destination CID: 66
        Source CID: 65
        Result: Connection successful (0x0000)
        Status: No further information available (0x0000)
*snip*

Similar case after the patch:
*snip*
> ACL Data RX: Handle 43 flags 0x02 dlen 8            #22702 [hci0] 1664.411056
      Channel: 65 len 4 [PSM 3 mode 0] {chan 3}
      RFCOMM: Disconnect (DISC) (0x43)
         Address: 0x03 cr 1 dlci 0x00
         Control: 0x53 poll/final 1
         Length: 0
         FCS: 0xfd
< ACL Data TX: Handle 43 flags 0x00 dlen 8            #22703 [hci0] 1664.411136
      Channel: 65 len 4 [PSM 3 mode 0] {chan 3}
      RFCOMM: Unnumbered Ack (UA) (0x63)
         Address: 0x03 cr 1 dlci 0x00
         Control: 0x73 poll/final 1
         Length: 0
         FCS: 0xd7
< ACL Data TX: Handle 43 flags 0x00 dlen 12           #22704 [hci0] 1664.411143
      L2CAP: Disconnection Request (0x06) ident 11 len 4
        Destination CID: 65
        Source CID: 65
> HCI Event: Number of Completed Pac.. (0x13) plen 5  #22705 [hci0] 1664.414009
        Num handles: 1
        Handle: 43
        Count: 1
> HCI Event: Number of Completed Pac.. (0x13) plen 5  #22706 [hci0] 1664.415007
        Num handles: 1
        Handle: 43
        Count: 1
> ACL Data RX: Handle 43 flags 0x02 dlen 12           #22707 [hci0] 1664.418674
      L2CAP: Disconnection Request (0x06) ident 17 len 4
        Destination CID: 65
        Source CID: 65
< ACL Data TX: Handle 43 flags 0x00 dlen 12           #22708 [hci0] 1664.418762
      L2CAP: Disconnection Response (0x07) ident 17 len 4
        Destination CID: 65
        Source CID: 65
< ACL Data TX: Handle 43 flags 0x00 dlen 12           #22709 [hci0] 1664.421073
      L2CAP: Connection Request (0x02) ident 12 len 4
        PSM: 1 (0x0001)
        Source CID: 65
> ACL Data RX: Handle 43 flags 0x02 dlen 12           #22710 [hci0] 1664.421371
      L2CAP: Disconnection Response (0x07) ident 11 len 4
        Destination CID: 65
        Source CID: 65
> HCI Event: Number of Completed Pac.. (0x13) plen 5  #22711 [hci0] 1664.424082
        Num handles: 1
        Handle: 43
        Count: 1
> HCI Event: Number of Completed Pac.. (0x13) plen 5  #22712 [hci0] 1664.425040
        Num handles: 1
        Handle: 43
        Count: 1
> ACL Data RX: Handle 43 flags 0x02 dlen 12           #22713 [hci0] 1664.426103
      L2CAP: Connection Request (0x02) ident 18 len 4
        PSM: 3 (0x0003)
        Source CID: 65
< ACL Data TX: Handle 43 flags 0x00 dlen 16           #22714 [hci0] 1664.426186
      L2CAP: Connection Response (0x03) ident 18 len 8
        Destination CID: 66
        Source CID: 65
        Result: Connection successful (0x0000)
        Status: No further information available (0x0000)
< ACL Data TX: Handle 43 flags 0x00 dlen 27           #22715 [hci0] 1664.426196
      L2CAP: Configure Request (0x04) ident 13 len 19
        Destination CID: 65
        Flags: 0x0000
        Option: Maximum Transmission Unit (0x01) [mandatory]
          MTU: 1013
        Option: Retransmission and Flow Control (0x04) [mandatory]
          Mode: Basic (0x00)
          TX window size: 0
          Max transmit: 0
          Retransmission timeout: 0
          Monitor timeout: 0
          Maximum PDU size: 0
> ACL Data RX: Handle 43 flags 0x02 dlen 16           #22716 [hci0] 1664.428804
      L2CAP: Connection Response (0x03) ident 12 len 8
        Destination CID: 66
        Source CID: 65
        Result: Connection successful (0x0000)
        Status: No further information available (0x0000)
*snip*

Fix is to check that channel is in state BT_DISCONN before deleting the
channel.

This bug was found while fuzzing Bluez's OBEX implementation using
Synopsys Defensics.

Reported-by: Matti Kamunen <matti.kamunen@synopsys.com>
Reported-by: Ari Timonen <ari.timonen@synopsys.com>
Signed-off-by: Matias Karhumaa <matias.karhumaa@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-06 19:55:41 +02:00
Josua Mayer
2f20994a73 Bluetooth: 6lowpan: search for destination address in all peers
[ Upstream commit b188b03270b7f8568fc714101ce82fbf5e811c5a ]

Handle overlooked case where the target address is assigned to a peer
and neither route nor gateway exist.

For one peer, no checks are performed to see if it is meant to receive
packets for a given address.

As soon as there is a second peer however, checks are performed
to deal with routes and gateways for handling complex setups with
multiple hops to a target address.
This logic assumed that no route and no gateway imply that the
destination address can not be reached, which is false in case of a
direct peer.

Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Tested-by: Michael Scott <mike@foundries.io>
Signed-off-by: Josua Mayer <josua.mayer@jm0.eu>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-06 19:55:39 +02:00
Matias Karhumaa
791b8f12e4 Bluetooth: Fix faulty expression for minimum encryption key size check
commit eca94432934fe5f141d084f2e36ee2c0e614cc04 upstream.

Fix minimum encryption key size check so that HCI_MIN_ENC_KEY_SIZE is
also allowed as stated in the comment.

This bug caused connection problems with devices having maximum
encryption key size of 7 octets (56-bit).

Fixes: 693cd8ce3f88 ("Bluetooth: Fix regression with minimum encryption key size alignment")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203997
Signed-off-by: Matias Karhumaa <matias.karhumaa@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-06 19:17:37 +02:00
Marcel Holtmann
838a7e80bf Bluetooth: Fix regression with minimum encryption key size alignment
commit 693cd8ce3f882524a5d06f7800dd8492411877b3 upstream.

When trying to align the minimum encryption key size requirement for
Bluetooth connections, it turns out doing this in a central location in
the HCI connection handling code is not possible.

Original Bluetooth version up to 2.0 used a security model where the
L2CAP service would enforce authentication and encryption.  Starting
with Bluetooth 2.1 and Secure Simple Pairing that model has changed into
that the connection initiator is responsible for providing an encrypted
ACL link before any L2CAP communication can happen.

Now connecting Bluetooth 2.1 or later devices with Bluetooth 2.0 and
before devices are causing a regression.  The encryption key size check
needs to be moved out of the HCI connection handling into the L2CAP
channel setup.

To achieve this, the current check inside hci_conn_security() has been
moved into l2cap_check_enc_key_size() helper function and then called
from four decisions point inside L2CAP to cover all combinations of
Secure Simple Pairing enabled devices and device using legacy pairing
and legacy service security model.

Fixes: d5bb334a8e17 ("Bluetooth: Align minimum encryption key size for LE and BR/EDR connections")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203643
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-06 19:16:54 +02:00
Marcel Holtmann
bf7688aca6 Bluetooth: Align minimum encryption key size for LE and BR/EDR connections
commit d5bb334a8e171b262e48f378bd2096c0ea458265 upstream.

The minimum encryption key size for LE connections is 56 bits and to
align LE with BR/EDR, enforce 56 bits of minimum encryption key size for
BR/EDR connections as well.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-06 19:16:52 +02:00
Greg Kroah-Hartman
61232d87e8 Revert "Bluetooth: Align minimum encryption key size for LE and BR/EDR connections"
This reverts commit d016dc1bd29a2cfb0707fc6fb290ccd21f3b139c which is
commit d5bb334a8e171b262e48f378bd2096c0ea458265 upstream.

Lots of people have reported issues with this patch, and as there does
not seem to be a fix going into Linus's kernel tree any time soon,
revert the commit in the stable trees so as to get people's machines
working properly again.

Reported-by: Vasily Khoruzhick <anarsoul@gmail.com>
Reported-by: Hans de Goede <hdegoede@redhat.com>
Cc: Jeremy Cline <jeremy@jcline.org>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-06 19:02:48 +02:00
Marcel Holtmann
9ac1c34ea1 Bluetooth: Align minimum encryption key size for LE and BR/EDR connections
commit d5bb334a8e171b262e48f378bd2096c0ea458265 upstream.

The minimum encryption key size for LE connections is 56 bits and to
align LE with BR/EDR, enforce 56 bits of minimum encryption key size for
BR/EDR connections as well.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-06 16:43:10 +02:00
Young Xiao
cacf770e56 Bluetooth: hidp: fix buffer overflow
commit a1616a5ac99ede5d605047a9012481ce7ff18b16 upstream.

Struct ca is copied from userspace. It is not checked whether the "name"
field is NULL terminated, which allows local users to obtain potentially
sensitive information from kernel stack memory, via a HIDPCONNADD command.

This vulnerability is similar to CVE-2011-1079.

Signed-off-by: Young Xiao <YangX92@hotmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-06 16:43:08 +02:00
Myungho Jung
2fb7619b57 Bluetooth: Fix decrementing reference count twice in releasing socket
commit e20a2e9c42c9e4002d9e338d74e7819e88d77162 upstream.

When releasing socket, it is possible to enter hci_sock_release() and
hci_sock_dev_event(HCI_DEV_UNREG) at the same time in different thread.
The reference count of hdev should be decremented only once from one of
them but if storing hdev to local variable in hci_sock_release() before
detached from socket and setting to NULL in hci_sock_dev_event(),
hci_dev_put(hdev) is unexpectedly called twice. This is resolved by
referencing hdev from socket after bt_sock_unlink() in
hci_sock_release().

Reported-by: syzbot+fdc00003f4efff43bc5b@syzkaller.appspotmail.com
Signed-off-by: Myungho Jung <mhjungk@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Zubin Mithra <zsm@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-06 14:19:03 +02:00
Marcel Holtmann
d8d647faea Bluetooth: Verify that l2cap_get_conf_opt provides large enough buffer
commit 7c9cbd0b5e38a1672fcd137894ace3b042dfbf69 upstream.

The function l2cap_get_conf_opt will return L2CAP_CONF_OPT_SIZE + opt->len
as length value. The opt->len however is in control over the remote user
and can be used by an attacker to gain access beyond the bounds of the
actual packet.

To prevent any potential leak of heap memory, it is enough to check that
the resulting len calculation after calling l2cap_get_conf_opt is not
below zero. A well formed packet will always return >= 0 here and will
end with the length value being zero after the last option has been
parsed. In case of malformed packets messing with the opt->len field the
length value will become negative. If that is the case, then just abort
and ignore the option.

In case an attacker uses a too short opt->len value, then garbage will
be parsed, but that is protected by the unknown option handling and also
the option parameter size checks.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-06 11:46:01 +02:00
Marcel Holtmann
665a139065 Bluetooth: Check L2CAP option sizes returned from l2cap_get_conf_opt
commit af3d5d1c87664a4f150fcf3534c6567cb19909b0 upstream.

When doing option parsing for standard type values of 1, 2 or 4 octets,
the value is converted directly into a variable instead of a pointer. To
avoid being tricked into being a pointer, check that for these option
types that sizes actually match. In L2CAP every option is fixed size and
thus it is prudent anyway to ensure that the remote side sends us the
right option size along with option paramters.

If the option size is not matching the option type, then that option is
silently ignored. It is a protocol violation and instead of trying to
give the remote attacker any further hints just pretend that option is
not present and proceed with the default values. Implementation
following the specification and its qualification procedures will always
use the correct size and thus not being impacted here.

To keep the code readable and consistent accross all options, a few
cosmetic changes were also required.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-06 11:45:59 +02:00
prashantpaddune
3bca37f224 A750FXXU4CTBC 2020-03-27 21:51:54 +05:30