def prefix(self, ast):
try:
prefix = ipaddr.IPNetwork(ast)
if not prefix.ip == prefix.network:
raise FailedSemantics('Not a valid IP address or prefix!')
except:
raise FailedSemantics('Not a valid IP address or prefix!')
return ast
def selector_name(self, ast):
# print("selector_name", ast)
if get_selector(ast.name) is None:
from grako.exceptions import FailedSemantics
e = FailedSemantics("\"%s\" is not a selector name" % ast.name)
e.pos = ast.parseinfo.pos
e.endpos = ast.parseinfo.endpos
raise e
return _SelectorName(ast.name)
def check_wspre(self, ast):
ctx = self._context
with self._state() as state:
wspre_off = state.peek_at("wspre_off")
if wspre_off is True:
raise FailedSemantics("wspre off")
return ast
def embedded_scheme_error(self, ast):
pinfo = ast.parseinfo
buf = pinfo.buffer
fname = buf.filename
line = buf.line_info(pinfo.pos).line
raise FailedSemantics(
"Error parsing embedded scheme (unbalanced parentheses?)")
def state_expr(self, ast):
if not self._protocol == "tcp":
raise FailedSemantics('Only TCP entries can be stateful')
if ast == "stateful":
return True
else:
return False
def regex(self, ast, *args):
pattern = ast
try:
re.compile(pattern, RE_FLAGS)
except (TypeError, re.error) as e:
raise FailedSemantics('regexp error: ' + str(e))
return pattern
def port_range(self, ast):
low = 0 if ast[0] == "-" else int(ast[0])
high = 65535 if ast[1] == "-" else int(ast[1])
if low > high:
raise FailedSemantics('First port cannot be higher than second \
port in a range expression')
sys.exit(2)
return [low, high]
def protocol_expr(self, ast):
if "icmp" in ast:
self._protocol = "icmp"
elif ast in ["tcp", "tcpudp", "udp", "any"]:
self._protocol = str(ast)
else:
raise FailedSemantics('No idea what protocol we are dealing with here')
return ast
def endpoint_tuple(self, ast):
# when port specifications are omitted any is assumed
if self._protocol not in ["tcp", "tcpudp", "udp"] and ast['l4'] is not None:
raise FailedSemantics('Cannot combine layer 4 information (ports) with ICMP protocol')
if not ast['l4']:
ast['l4'] = {}
ast['l4']['ports'] = ["any"]
return ast
def check_bol_skip(self, ast):
ctx = self._context
with self._state() as state:
bol_skip = state.get("bol_skip", None)
if bol_skip is None:
return
bol_skip_re = "".join(bol_skip)
if not ctx._buffer.matchre(bol_skip_re):
raise FailedSemantics("begin of line skip reject")
return ast
def check_ifnot(self, ast):
ctx = self._context
with self._state() as state:
ifnot_re = state.peek_at("ifnot")
if ifnot_re is None:
return
# FIXME: ctx._buffer vs ctx.buf (ModelContext)
if ctx._buffer.matchre(ifnot_re):
raise FailedSemantics("inline ifnot negative lookahead reject")
return ast
def check_no(self, ast):
ctx = self._context
with self._state() as state:
no_list = state.get_list("no")
if len(no_list) == 0:
return
# As the no list may use regex flags, we must check separately.
for item in no_list:
# FIXME: ctx._buffer vs ctx.buf (ModelContext)
if ctx._buffer.matchre(item):
raise FailedSemantics("inline negative lookahead reject")
return ast
def find_matches(self, session, models, results, ordered):
f = get_selector(self.name)
if f:
from ..objects import Objects
if isinstance(f, Objects):
results.combine(f)
else:
try:
f(session, models, results)
except Exception:
session.logger.report_exception(preface="Error executing selector '%s'" % self.name)
from grako.exceptions import FailedSemantics
raise FailedSemantics("error evaluating selector %s" % self.name)
def token(self, ast, *args):
token = eval_escapes(ast)
if not token:
raise FailedSemantics('empty token')
return grammars.Token(token)
def ul_marker(self, ast):
ctx = self._context
if ctx._state is not None:
if not ctx.buf.match("*" * ctx._state):
raise FailedSemantics("not at correct level")
return ast
def known_name(self, name):
if name not in self.rules:
raise FailedSemantics('rule "%s" not yet defined' % str(name))
return name
def new_name(self, name):
if name in self.rules:
raise FailedSemantics('rule "%s" already defined' % str(name))
return name
def NAME(self, ast):
if ast.lower() in self.keywords:
raise FailedSemantics("'{}' is a keyword.".format(ast))
return ast
def icmp_number(self, ast):
if 0 <= int(ast) < 255:
return int(ast)
else:
raise FailedSemantics('ICMP code/type must be between 0 and 255')
def port_number(self, ast):
if not 0 < ast < 2 ** 16:
raise FailedSemantics('Port number must be between 0 and 2^16')
return ast
def token(self, ast, *args):
token = ast
if not token:
raise FailedSemantics('empty token')
return grammars.Token(token)
def NAME(self, ast):
# type: (Any) -> _Result
if ast.lower() in self.keywords:
raise FailedSemantics("'{}' is a keyword.".format(ast))
return ast