gsm0408_rcv_cc: guard against NULL subscriber

Check conn->subscr against NULL.

gsm0408_rcv_cc() dereferences many conn members without checking presence: the
bts and lchan members may be expected to be NULL in the ongoing MSC split and
3G developments.

But the conn->subscr is initially NULL, so an MS sending a CC message before
something like a LU or CM Service Request will result in a segfault. Prevent
that.

Note: the upcoming VLR will be more restrictive on what messages are processed,
this is a "backport" to the situation on current master.

Change-Id: If067db7cc0dd3210d9eb1da15be6b637795a3ecf

0 files changed, 0 insertions, 0 deletions