bluez: NULL pointer dereference in bluetooth-meshd org.bluez.mesh.Network1.Join

bluez: NULL pointer dereference in bluetooth-meshd org.bluez.mesh.Network1.Join

[Matthias Gerstner]

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Hi,

in the context of a review of the bluetooth-meshd D-Bus service [1] I
noticed a segmentation fault due to NULL pointer dereference. It can be
triggered in bluez version 5.51 via the following D-Bus call:

$ dbus-send --system --type=method_call --print-reply \
  --dest=org.bluez.mesh /org/bluez/mesh org.bluez.mesh.Network1.Join \
  objpath:/org/gnome/DisplayManager \
  array:byte:1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16

After the D-Bus timeout the bluetooth-meshd will crash with the
following backtrace:

    node_init_cb (node=0x0, agent=0x0) at mesh/mesh.c:359
    359                     reply = dbus_error(join_pending->msg, MESH_ERROR_FAILED,
    (gdb) bt
        user_data=0x5555555be170) at mesh/node.c:1760
        dbus=<optimized out>) at ell/dbus.c:216
        user_data=0x5555555a6e00) at ell/dbus.c:279
        user_data=0x5555555a7ef0) at ell/io.c:126
        at ell/main.c:642
        at mesh/main.c:205

The reason is probably that the `join_pending` data structure has
already been freed in a different function.

[1]: https://bugzilla.suse.com/show_bug.cgi?id=1151518

Cheers

Matthias

-- 
Matthias Gerstner <matthias.gerstner@suse.de>
Dipl.-Wirtsch.-Inf. (FH), Security Engineer
https://www.suse.com/security
Phone: +49 911 740 53 290
GPG Key ID: 0x14C405C971923553

SUSE Software Solutions Germany GmbH
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