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  1. 12 3月, 2020 4 次提交
  3. 11 3月, 2020 3 次提交
  5. 08 3月, 2020 6 次提交
  7. 07 3月, 2020 1 次提交
  9. 04 3月, 2020 1 次提交
  11. 28 2月, 2020 6 次提交
  13. 20 2月, 2020 2 次提交
  15. 19 2月, 2020 1 次提交
  17. 18 2月, 2020 1 次提交
  19. 15 2月, 2020 1 次提交
  21. 14 2月, 2020 1 次提交
    • H
      Bluetooth: secure bluetooth stack from bluedump attack · cee5f20f
      由 Howard Chung 提交于 
      Attack scenario:
1. A Chromebook (let's call this device A) is paired to a legitimate
   Bluetooth classic device (e.g. a speaker) (let's call this device
   B).
2. A malicious device (let's call this device C) pretends to be the
   Bluetooth speaker by using the same BT address.
3. If device A is not currently connected to device B, device A will
   be ready to accept connection from device B in the background
   (technically, doing Page Scan).
4. Therefore, device C can initiate connection to device A
   (because device A is doing Page Scan) and device A will accept the
   connection because device A trusts device C's address which is the
   same as device B's address.
5. Device C won't be able to communicate at any high level Bluetooth
   profile with device A because device A enforces that device C is
   encrypted with their common Link Key, which device C doesn't have.
   But device C can initiate pairing with device A with just-works
   model without requiring user interaction (there is only pairing
   notification). After pairing, device A now trusts device C with a
   new different link key, common between device A and C.
6. From now on, device A trusts device C, so device C can at anytime
   connect to device A to do any kind of high-level hijacking, e.g.
   speaker hijack or mouse/keyboard hijack.

Since we don't know whether the repairing is legitimate or not,
leave the decision to user space if all the conditions below are met.
- the pairing is initialized by peer
- the authorization method is just-work
- host already had the link key to the peer
Signed-off-by: NHoward Chung <howardchung@google.com>
Acked-by: NJohan Hedberg <johan.hedberg@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
      cee5f20f
  23. 05 2月, 2020 2 次提交
  25. 30 1月, 2020 1 次提交
  27. 29 1月, 2020 1 次提交
    • M
      Bluetooth: Fix refcount use-after-free issue · 6c08fc89
      由 Manish Mandlik 提交于 
      There is no lock preventing both l2cap_sock_release() and
chan->ops->close() from running at the same time.

If we consider Thread A running l2cap_chan_timeout() and Thread B running
l2cap_sock_release(), expected behavior is:
  A::l2cap_chan_timeout()->l2cap_chan_close()->l2cap_sock_teardown_cb()
  A::l2cap_chan_timeout()->l2cap_sock_close_cb()->l2cap_sock_kill()
  B::l2cap_sock_release()->sock_orphan()
  B::l2cap_sock_release()->l2cap_sock_kill()

where,
sock_orphan() clears "sk->sk_socket" and l2cap_sock_teardown_cb() marks
socket as SOCK_ZAPPED.

In l2cap_sock_kill(), there is an "if-statement" that checks if both
sock_orphan() and sock_teardown() has been run i.e. sk->sk_socket is NULL
and socket is marked as SOCK_ZAPPED. Socket is killed if the condition is
satisfied.

In the race condition, following occurs:
  A::l2cap_chan_timeout()->l2cap_chan_close()->l2cap_sock_teardown_cb()
  B::l2cap_sock_release()->sock_orphan()
  B::l2cap_sock_release()->l2cap_sock_kill()
  A::l2cap_chan_timeout()->l2cap_sock_close_cb()->l2cap_sock_kill()

In this scenario, "if-statement" is true in both B::l2cap_sock_kill() and
A::l2cap_sock_kill() and we hit "refcount: underflow; use-after-free" bug.

Similar condition occurs at other places where teardown/sock_kill is
happening:
  l2cap_disconnect_rsp()->l2cap_chan_del()->l2cap_sock_teardown_cb()
  l2cap_disconnect_rsp()->l2cap_sock_close_cb()->l2cap_sock_kill()

  l2cap_conn_del()->l2cap_chan_del()->l2cap_sock_teardown_cb()
  l2cap_conn_del()->l2cap_sock_close_cb()->l2cap_sock_kill()

  l2cap_disconnect_req()->l2cap_chan_del()->l2cap_sock_teardown_cb()
  l2cap_disconnect_req()->l2cap_sock_close_cb()->l2cap_sock_kill()

  l2cap_sock_cleanup_listen()->l2cap_chan_close()->l2cap_sock_teardown_cb()
  l2cap_sock_cleanup_listen()->l2cap_sock_kill()

Protect teardown/sock_kill and orphan/sock_kill by adding hold_lock on
l2cap channel to ensure that the socket is killed only after marked as
zapped and orphan.
Signed-off-by: NManish Mandlik <mmandlik@google.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
      6c08fc89
  29. 28 1月, 2020 1 次提交
  31. 26 1月, 2020 1 次提交
  33. 25 1月, 2020 2 次提交
  35. 23 1月, 2020 2 次提交
  37. 16 1月, 2020 3 次提交