def interpret(self):
'''interpret a line (first call Parser.getline())
Returns 0 on success, 1 on error
'''
if not self.keyword:
stderr('%s: no keyword set; invalid parser state' % self)
self.errors += 1
return 1
if not self.ifdef_stack[0]:
if not self.keyword in ('ifdef', 'ifndef', 'else', 'endif'):
debug("%s: skipping %s" % (self, self.keyword))
return 0
# get the parser function
try:
func = getattr(self, 'parse_%s' % self.keyword)
except AttributeError:
stderr("%s: unknown keyword '%s'" % (self, self.keyword))
self.errors += 1
return 1
try:
func()
except ParseError as parse_error:
parse_error.perror()
self.errors += 1
return 1
return 0
def parse_end(self):
arr = self.arr
if len(arr) > 2:
raise ParseError("%s: syntax error, 'end' takes only one "
"argument" % self)
if arr[1] == 'verbatim':
if not self.in_verbatim:
raise ParseError("%s: 'end' can not be used here" % self)
debug('end verbatim')
self.in_verbatim = False
bytecode_end_verbatim = firewater.globals.BYTECODE.pop()
bytecode = firewater.bytecode.ByteCode()
bytecode.set_verbatim(self.filename, self.lineno,
self.verbatim_text)
firewater.globals.BYTECODE.append(bytecode)
firewater.globals.BYTECODE.append(bytecode_end_verbatim)
else:
raise ParseError("%s: unknown argument '%s' to 'end'" %
(self, arr[1]))
def getline(self):
'''read statement from input file
Upon return, self.keyword should be set, as well as other members
Returns True when OK, False on EOF
'''
self.full_line = None
self.line = ''
self.comment = None
self.arr = None
self.keyword = None
while True:
# read lines from the input file
# variable tmp_line is used to be able to
# do multi-line reads (backslash terminated)
tmp_line = self.file.readline()
if not tmp_line:
return False
self.lineno += 1
if self.in_verbatim:
# copy verbatim until the statement 'end verbatim'
# is reached
verbatim_line = tmp_line.strip()
arr = verbatim_line.lower().split()
# it is tested with an array so that both spaces
# and tabs work
# note that this shadows the 'end' keyword, but
# only when in verbatim mode
if not (len(arr) == 2 and arr[0] == 'end' and
arr[1] == 'verbatim'):
debug('verbatim line == [%s]' % verbatim_line)
self.verbatim_text.append(verbatim_line)
continue
n = tmp_line.find('#')
if n >= 0:
self.comment = ' ' + tmp_line[n:].strip()
tmp_line = tmp_line[:n] # strip comment
else:
self.comment = ''
tmp_line = tmp_line.strip()
if not tmp_line:
continue
if tmp_line[-1] == '\\':
tmp_line = tmp_line[:-1].strip()
self.line = self.line + ' ' + tmp_line
continue
self.line = self.line + ' ' + tmp_line
self.full_line = self.line + self.comment
self.arr = self.line.split()
self.keyword = self.arr[0].lower()
break
return True
def read_input_file(filename):
'''read a (included) input file
Returns 0 on success, or error count on errors
'''
errors = 0
parser = Parser()
try:
parser.open(filename)
except IOError as err:
stderr('failed to open %s: %s' % (filename, err.strerror))
return 1
while parser.getline():
parser.insert_comment_line()
parser.interpret()
if len(parser.ifdef_stack) > 1:
ParseError("%s: missing 'endif' statement" % parser).perror()
errors += 1
parser.close()
errors = errors + parser.errors
debug('errors == %d' % errors)
return errors
def parse_define(self):
arr = self.arr
if len(arr) != 2:
raise ParseError("%s: syntax error, 'define' takes only one "
"argument: a symbol to define" % self)
debug('parser: define "%s"' % arr[1])
firewater.globals.DEFINES.append(arr[1])
def parse_verbatim(self):
arr = self.arr
if len(arr) > 1:
raise ParseError("%s: syntax error, 'verbatim' does not take "
"any arguments" % self)
debug('in verbatim')
self.in_verbatim = True
self.verbatim_text = []
def parse_interface(self):
arr = self.arr
if len(arr) < 3:
raise ParseError("%s: '%s' requires at least 2 arguments: "
"the interface alias and the real interface "
"name" % (self, self.keyword))
alias = arr[1]
if alias == 'any':
raise ParseError("%s: 'any' is a reserved word" % self)
iface_list = ' '.join(arr[2:])
iface_list = iface_list.split(',')
elem = self.missing_comma(iface_list)
if elem is not None:
raise ParseError("%s: missing comma after '%s'" % (self, elem))
if alias in iface_list:
raise ParseError("%s: interface %s references back to itself" %
(self, alias))
if firewater.globals.INTERFACES.has_key(alias):
raise ParseError("%s: redefinition of interface %s" % (self,
alias))
# expand the list by filling in any previously defined aliases
new_iface_list = []
while len(iface_list) > 0:
iface = iface_list.pop(0)
if firewater.globals.INTERFACES.has_key(iface):
iface_list.extend(firewater.globals.INTERFACES[iface])
else:
# treat as real system interface name
if not iface in new_iface_list:
new_iface_list.append(iface)
debug('new interface: %s:%s' % (alias, new_iface_list))
firewater.globals.INTERFACES[alias] = new_iface_list
all_ifaces = firewater.globals.INTERFACES['all']
for iface in new_iface_list:
if not iface in all_ifaces:
all_ifaces.append(iface)
def parse_include(self):
arr = self.arr
if len(arr) <= 1:
raise ParseError("%s: 'include' requires a filename argument" %
self)
include_file = ' '.join(arr[1:])
debug('include %s' % include_file)
try:
# recursively read the given parse file
if read_input_file(include_file) > 0:
raise ParseError("%s: error in included file %s" %
(self, include_file))
except IOError:
raise ParseError("%s: failed to read file '%s'" % (self,
include_file))
def parse_chain(self):
arr = self.arr
if len(arr) < 2:
raise ParseError("%s: syntax error" % self)
chain = arr[1]
if not chain in ('incoming', 'outgoing', 'forwarding'):
raise ParseError("%s: syntax error: unknown chain '%s'" % (self,
chain))
if len(arr) == 5:
if arr[2] != 'default' or arr[3] != 'policy':
raise ParseError("%s: syntax error" % self)
policy = arr[4]
debug('policy == %s' % policy)
if not policy in ('allow', 'deny', 'accept', 'drop'):
raise ParseError("%s: syntax error: unknown policy '%s'" %
(self, policy))
# allow for common aliases to be used here
if policy == 'accept':
policy = 'allow'
if policy == 'drop':
policy = 'deny'
debug('set chain %s policy %s' % (chain, policy))
# emit default policy setting code
bytecode = firewater.bytecode.ByteCode()
bytecode.set_policy(self.filename, self.lineno, chain, policy)
firewater.globals.BYTECODE.append(bytecode)
else:
if len(arr) == 2:
# change the current chain
debug('set current chain %s' % chain)
bytecode = firewater.bytecode.ByteCode()
bytecode.set_chain(self.filename, self.lineno, chain)
firewater.globals.BYTECODE.append(bytecode)
else:
raise ParseError("%s: syntax error" % self)
def _parse_rule(self):
'''parse a rule
rule syntax:
allow|deny|reject [<proto>] [from <source> [port <service>]] \
[to <dest> [port <service>]] \
[on [interface|iface] <iface> [interface]]
'''
arr = self.arr
allow = arr.pop(0)
if len(arr) < 1:
raise ParseError("%s: syntax error, premature end of line" % self)
proto = None
if arr[0] in firewater.globals.KNOWN_PROTOCOLS:
proto = arr.pop(0)
if len(arr) <= 1:
raise ParseError("%s: syntax error, premature end of line" % self)
# the line can be parsed using tokens
source_addr = None
source_port = None
dest_addr = None
dest_port = None
interface = None
while len(arr) > 0:
token = arr.pop(0)
if len(arr) < 1:
raise ParseError("%s: syntax error, premature end of line" %
self)
if token == 'from':
if source_addr is not None:
raise ParseError("%s: syntax error ('from' is used "
"multiple times)" % self)
source_addr = arr.pop(0)
if len(arr) > 0:
# check for source port
if arr[0] == 'port':
arr.pop(0)
if len(arr) < 1:
raise ParseError("%s: syntax error, premature "
"end of line" % self)
source_port = arr.pop(0)
continue
elif token == 'to':
if dest_addr is not None:
raise ParseError("%s: syntax error ('to' is used "
"multiple times)" % self)
dest_addr = arr.pop(0)
if len(arr) > 0:
# check for dest port
if arr[0] == 'port':
arr.pop(0)
if len(arr) < 1:
raise ParseError("%s: syntax error, premature "
"end of line" % self)
dest_port = arr.pop(0)
continue
elif token == 'on':
if interface is not None:
raise ParseError("%s: syntax error ('on' is used "
"multiple times)" % self)
if arr[0] in ('interface', 'iface'):
arr.pop(0)
if len(arr) < 1:
raise ParseError("%s: syntax error, premature "
"end of line" % self)
interface = arr.pop(0)
if len(arr) > 0 and arr[0] in ('interface', 'iface'):
arr.pop(0)
continue
else:
raise ParseError("%s: syntax error, unknown token '%s'" %
(self, token))
debug('rule {')
debug(' %s proto %s' % (allow, proto))
debug(' source (%s, %s)' % (source_addr, source_port))
debug(' dest (%s, %s)' % (dest_addr, dest_port))
debug(' iface %s' % interface)
debug('}')
sources = self._parse_rule_address(source_addr)
source_port = self._parse_rule_service(source_port)
destinations = self._parse_rule_address(dest_addr)
dest_port = self._parse_rule_service(dest_port)
ifaces = self._parse_rule_interfaces(interface)
debug('rule got {')
debug(' sources: ' + str(sources))
debug(' port: ' + str(source_port))
debug(' destinations: ' + str(destinations))
debug(' port: ' + str(dest_port))
debug(' ifaces: ' + str(ifaces))
debug('}')
if not proto and (source_port.port > 0 or dest_port.port > 0):
if source_port.port > 0 and source_port.proto:
proto = source_port.proto
if dest_port.port > 0 and dest_port.proto:
proto = dest_port.proto
if not proto:
raise ParseError("%s: missing protocol" % self)
# save the rule in globals.BYTECODE[]
# the output statements are generated later,
# if there were no parse errors
for src in sources:
for dest in destinations:
if not ifaces:
debug('%s: %s %s %s eq %s %s eq %s' % (self, allow, proto,
src, source_port,
dest, dest_port))
bytecode = firewater.bytecode.ByteCode()
bytecode.set_rule(self.filename, self.lineno, allow,
proto, src, source_port,
dest, dest_port, None)
firewater.globals.BYTECODE.append(bytecode)
else:
for iface in ifaces:
debug('%s: %s %s %s eq %s %s eq %s on %s' %
(self, allow, proto, src, source_port,
dest, dest_port, iface))
bytecode = firewater.bytecode.ByteCode()
bytecode.set_rule(self.filename, self.lineno, allow,
proto, src, source_port,
dest, dest_port, iface)
firewater.globals.BYTECODE.append(bytecode)
def parse_service(self):
arr = self.arr
if len(arr) < 3:
raise ParseError("%s: '%s' requires at least 2 arguments: "
"the service alias and at least 1 property" %
(self, arr[0]))
alias = arr[1]
if alias == 'any':
raise ParseError("%s: 'any' is a reserved word" % self)
if firewater.globals.SERVICES.has_key(alias):
raise ParseError("%s: redefinition of service %s" % (self, alias))
obj = firewater.service.ServiceObject(alias)
if arr[2] in firewater.globals.KNOWN_PROTOCOLS:
obj.proto = arr.pop(2)
if len(arr) < 3:
raise ParseError("%s: missing service or port number" % self)
# parse port range or number, or alias, or service name
m = REGEX_PORT_RANGE.match(arr[2])
if m is not None:
# it's a port range
port_range = arr[2]
obj.port = int(m.groups()[0])
if obj.port < 0 or obj.port > 65535:
raise ParseError("%s: invalid port range '%s'" %
(self, port_range))
obj.endport = int(m.groups()[1])
if obj.endport < 0 or obj.endport > 65535:
raise ParseError("%s: invalid port range '%s'" %
(self, port_range))
else:
m = REGEX_NUMERIC.match(arr[2])
if m is not None:
# it's a single port number
obj.port = int(arr[2])
if obj.port < 0 or obj.port > 65535:
raise ParseError("%s: invalid port number '%d'" %
(self, obj.port))
else:
# it's a string
if arr[2] == alias:
raise ParseError("%s: service %s references back to "
"itself" % self)
if firewater.globals.SERVICES.has_key(arr[2]):
obj2 = firewater.globals.SERVICES[arr[2]]
# copy the other service object
if not obj.proto:
obj.proto = obj2.proto
obj.port = obj2.port
obj.endport = obj2.endport
obj.iface = obj2.iface
else:
# treat as system service name
obj.port = firewater.service.servbyname(arr[2])
if obj.port is None:
raise ParseError("%s: no such service '%s'" %
(self, arr[2]))
if len(arr) > 3:
if arr[3] in ('iface', 'interface'):
if len(arr) == 5:
# interface-specific service
iface = arr[4]
if firewater.globals.INTERFACES.has_key(iface):
obj.iface = firewater.globals.INTERFACES[iface]
else:
# treat as real system interface
obj.iface = []
obj.iface.append(arr[4])
else:
raise ParseError("%s: too many arguments to '%s'" %
(self, arr[0]))
debug('new service: %s:%s' % (alias, obj))
firewater.globals.SERVICES[alias] = obj
def parse_group(self):
arr = self.arr
if len(arr) < 3:
raise ParseError("%s: 'group' requires at least 2 arguments: "
"the group alias and at least 1 member" % self)
alias = arr[1]
if alias == 'any':
raise ParseError("%s: 'any' is a reserved word" % self)
group_list = ','.join(arr[2:])
group_list = group_list.replace(' ', '')
group_list = group_list.replace(',,', ',')
group_list = group_list.split(',')
elem = self.missing_comma(group_list)
if elem is not None:
raise ParseError("%s: missing comma after '%s'" % (self, elem))
if alias in group_list:
raise ParseError("%s: range %s references back to itself" %
(self, alias))
# note that group are stored in the same way as groups
if firewater.globals.HOSTS.has_key(alias):
raise ParseError("%s: redefinition of range or group %s" %
(self, alias))
# expand the list by filling in any previously defined aliases
new_group_list = []
while len(group_list) > 0:
group = group_list.pop(0)
if firewater.globals.HOSTS.has_key(group):
group_list.extend(firewater.globals.HOSTS[group])
else:
# treat as IP address or fqdn
if group.find(':') > -1:
# treat as IPv6 address
pass
elif group.find('/') > -1:
# treat as network range
a = group.split('/')
if len(a) != 2:
raise ParseError("%s: invalid address range '%s'" %
(self, group))
if not _is_ipv4_address(a[0]):
raise ParseError("%s: invalid address range '%s'" %
(self, group))
try:
bits = int(a[1])
except ValueError:
raise ParseError("%s: invalid address range '%s'" %
(self, group))
if bits < 0 or bits > 32:
raise ParseError("%s: invalid address range '%s'" %
(self, group))
else:
# treat as fqdn, so resolve the address
addrs = firewater.resolv.resolv(group)
if addrs is None: # error
raise ParseError("%s: failed to resolve '%s'" %
(self, group))
for addr in addrs:
if not addr in new_group_list:
new_group_list.append(addr)
continue
if not group in new_group_list:
new_group_list.append(group)
debug('new group: %s:%s' % (alias, new_group_list))
firewater.globals.HOSTS[alias] = new_group_list
def parse_range(self):
arr = self.arr
if len(arr) < 3:
raise ParseError("%s: '%s' requires at least 2 arguments: "
"the range alias and the address range" %
(self, arr[0]))
alias = arr[1]
if alias == 'any':
raise ParseError("%s: 'any' is a reserved word" % self)
ranges_list = ' '.join(arr[2:])
ranges_list = ranges_list.replace(' ', '')
ranges_list = ranges_list.replace(',,', ',')
ranges_list = ranges_list.split(',')
elem = self.missing_comma(ranges_list)
if elem is not None:
raise ParseError("%s: missing comma after '%s'" % (self, elem))
if alias in ranges_list:
raise ParseError("%s: %s %s references back to itself" %
(self, arr[0], alias))
# note that ranges are stored in the same way as hosts
if firewater.globals.HOSTS.has_key(alias):
raise ParseError("%s: redefinition of %s or host %s" %
(self, arr[0], alias))
# expand the list by filling in any previously defined aliases
new_ranges_list = []
while len(ranges_list) > 0:
# 'range' is a Python keyword ...
# so I use 'host' instead (confusing huh?)
host = ranges_list.pop(0)
if firewater.globals.HOSTS.has_key(host):
ranges_list.extend(firewater.globals.HOSTS[host])
else:
# treat as IP address or fqdn
if host.find(':') > -1:
# treat as IPv6 address
pass
elif host.find('/') > -1:
# treat as network range
a = host.split('/')
if len(a) != 2:
raise ParseError("%s: invalid address range '%s'" %
(self, host))
if not _is_ipv4_address(a[0]):
raise ParseError("%s: invalid address range '%s'" %
(self, host))
try:
bits = int(a[1])
except ValueError:
raise ParseError("%s: invalid address range '%s'" %
(self, host))
if bits < 0 or bits > 32:
raise ParseError("%s: invalid address range '%s'" %
(self, host))
else:
raise ParseError("%s: invalid address range '%s'" %
(self, host))
if not host in new_ranges_list:
new_ranges_list.append(host)
debug('new %s: %s:%s' % (arr[0], alias, new_ranges_list))
firewater.globals.HOSTS[alias] = new_ranges_list
def parse_host(self):
arr = self.arr
if len(arr) < 3:
raise ParseError("%s: 'host' requires at least 2 arguments: "
"the host alias and the IP address or fqdn" %
self)
alias = arr[1]
if alias == 'any':
raise ParseError("%s: 'any' is a reserved word" % self)
host_list = ' '.join(arr[2:])
host_list = host_list.replace(' ', '')
host_list = host_list.replace(',,', ',')
host_list = host_list.split(',')
elem = self.missing_comma(host_list)
if elem is not None:
raise ParseError("%s: missing comma after '%s'" % (self, elem))
if alias in host_list:
raise ParseError("%s: host %s references back to itself" %
(self, alias))
if firewater.globals.HOSTS.has_key(alias):
raise ParseError("%s: redefinition of host %s" % (self, alias))
# expand the list by filling in any previously defined aliases
new_host_list = []
while len(host_list) > 0:
host = host_list.pop(0)
if firewater.globals.HOSTS.has_key(host):
host_list.extend(firewater.globals.HOSTS[host])
else:
# treat as IP address or fqdn
if host.find(':') > -1:
# treat as IPv6 address
pass
elif host.find('/') > -1:
# treat as network range
a = host.split('/')
if len(a) != 2:
raise ParseError("%s: invalid host address '%s'" %
(self, host))
if not _is_ipv4_address(a[0]):
raise ParseError("%s: invalid host address '%s'" %
(self, host))
if a[1] != '32':
raise ParseError("%s: invalid host address '%s'" %
(self, host))
elif _is_ipv4_address(host):
# treat as IPv4 address
pass
else:
# treat as fqdn, so resolve the address
addrs = firewater.resolv.resolv(host)
if addrs is None: # error
raise ParseError("%s: failed to resolve '%s'" %
(self, host))
for addr in addrs:
if not addr in new_host_list:
new_host_list.append(addr)
continue
if not host in new_host_list:
new_host_list.append(host)
debug('new host: %s:%s' % (alias, new_host_list))
firewater.globals.HOSTS[alias] = new_host_list
