class Fuzzer(object):
"""Take a valid network packet and fuzz the crap out of it
Fuzzing strategies:
- Random bytes
- Exhaustive (recursive)
- Fuzz vectors (known "dangerous" values"
"""
def __init__(self, context):
self.mh = MessageHelper(context)
def fuzz(self, valid_packet):
"""Generate fuzzed packets"""
i = 0
self.valid_packet = self.mh.unpack_request(valid_packet)[0]
# Just do a static number of permutations for now.
while i < 1000:
print '[i]', i
yield self.permute(self.valid_packet)
i += 1
def permute(self, packet):
"""Return a fuzzed packet"""
if packet.type == 'handshake':
packet_struct = get_struct('ClientInitHandShake')
else:
packet_struct = get_struct('ClientRequestHdr')
packet_struct += get_struct('Client' + packet.type[4:].title() +
'Request')
if packet.type == 'kXR_read':
packet_struct += get_struct('read_args')
# Remove 'type' field that we inserted for convenience
vars = packet._asdict()
del vars['type']
for field in packet_struct:
if field['fuzzable']:
vars[field['name']] = self.mutate(vars[field['name']],
field['type'])
return self.mh.build_message(packet_struct, vars)
def mutate(self, field, type):
if type == 'H':
return random.randint(0, 65535)
elif type == 'l':
return random.randint(-2147483648 + 1, 2147483647)
elif type == 'q':
return random.randint(-sys.maxint + 1, sys.maxint)
elif type in ('s', 'c'):
return os.urandom(len(field))
class Fuzzer(object):
"""Take a valid network packet and fuzz the crap out of it
Fuzzing strategies:
- Random bytes
- Exhaustive (recursive)
- Fuzz vectors (known "dangerous" values"
"""
def __init__(self, context):
self.mh = MessageHelper(context)
def fuzz(self, valid_packet):
"""Generate fuzzed packets"""
i = 0
self.valid_packet = self.mh.unpack_request(valid_packet)[0]
# Just do a static number of permutations for now.
while i < 1000:
print '[i]', i
yield self.permute(self.valid_packet)
i += 1
def permute(self, packet):
"""Return a fuzzed packet"""
if packet.type == 'handshake':
packet_struct = get_struct('ClientInitHandShake')
else:
packet_struct = get_struct('ClientRequestHdr')
packet_struct += get_struct('Client' + packet.type[4:].title() + 'Request')
if packet.type == 'kXR_read':
packet_struct += get_struct('read_args')
# Remove 'type' field that we inserted for convenience
vars = packet._asdict()
del vars['type']
for field in packet_struct:
if field['fuzzable']:
vars[field['name']] = self.mutate(vars[field['name']], field['type'])
return self.mh.build_message(packet_struct, vars)
def mutate(self, field, type):
if type == 'H':
return random.randint(0, 65535)
elif type == 'l':
return random.randint(-2147483648 + 1, 2147483647)
elif type == 'q':
return random.randint(-sys.maxint + 1, sys.maxint)
elif type in ('s', 'c'):
return os.urandom(len(field))
