Define types for C calls in netlink_lib

Previously this was not done, which meant all arguments were
assumed to be ints. As long as we didn't get any large pointer
addresses this worked fine, but for some reason the addition of
threading to oslo.privsep triggered larger addresses that were then
truncated. This caused segfaults in the underlying C library because
we were passing it invalid pointers.

This change sets argument and return types for all of the calls
that are used in the module.

Change-Id: I9dbbb01eac8cf7cded7794f8ba69797d6357eeec
Closes-Bug: 1810518
This commit is contained in:
Ben Nemec 2019-01-08 23:59:10 +00:00
parent 15c782b5a1
commit c6d358d4c6
1 changed files with 36 additions and 1 deletions

View File

@ -49,9 +49,44 @@ from neutron.privileged.agent.linux import netlink_constants as nl_constants
LOG = logging.getLogger(__name__)
nfct = ctypes.CDLL(util.find_library('netfilter_conntrack'))
nfct_lib = util.find_library('netfilter_conntrack')
nfct = ctypes.CDLL(nfct_lib)
libc = ctypes.CDLL(util.find_library('libc.so.6'))
# In unit tests the actual nfct library may not be installed, and since we
# don't make actual calls to it we don't want to add a hard dependency.
if nfct_lib:
# It's important that the types be defined properly on all of the functions
# we call from nfct, otherwise pointers can be truncated and cause
# segfaults.
nfct.nfct_set_attr.argtypes = [ctypes.c_void_p,
ctypes.c_int,
ctypes.c_void_p]
nfct.nfct_set_attr_u8.argtypes = [ctypes.c_void_p,
ctypes.c_int,
ctypes.c_uint8]
nfct.nfct_set_attr_u16.argtypes = [ctypes.c_void_p,
ctypes.c_int,
ctypes.c_uint16]
nfct.nfct_snprintf.argtypes = [ctypes.c_char_p,
ctypes.c_uint,
ctypes.c_void_p,
ctypes.c_uint,
ctypes.c_uint,
ctypes.c_uint]
nfct.nfct_new.restype = ctypes.c_void_p
nfct.nfct_destroy.argtypes = [ctypes.c_void_p]
nfct.nfct_query.argtypes = [ctypes.c_void_p,
ctypes.c_int,
ctypes.c_void_p]
nfct.nfct_callback_register.argtypes = [ctypes.c_void_p,
ctypes.c_int,
ctypes.c_void_p,
ctypes.c_void_p]
nfct.nfct_open.restype = ctypes.c_void_p
nfct.nfct_close.argtypes = [ctypes.c_void_p]
IP_VERSIONS = [constants.IP_VERSION_4, constants.IP_VERSION_6]
DATA_CALLBACK = None