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authorelijah <elijah@riseup.net>2014-07-09 16:30:25 -0700
committerTomás Touceda <chiiph@leap.se>2014-07-21 12:03:30 -0300
commitd08a6963e2789eb869735785ff018ee9b670441c (patch)
tree35ff924bad7858909e93e6a4c03237707de19e7c
parent21952b073e15fe7ba75b65dc66df693ea16a0205 (diff)
firewall stop: try to be much more robust in stopping the firewall whenever we can
-rwxr-xr-xpkg/linux/bitmask-root142
1 files changed, 103 insertions, 39 deletions
diff --git a/pkg/linux/bitmask-root b/pkg/linux/bitmask-root
index 5367a31c..3ffd0eee 100755
--- a/pkg/linux/bitmask-root
+++ b/pkg/linux/bitmask-root
@@ -150,7 +150,7 @@ def is_valid_address(value):
socket.inet_aton(value)
return True
except Exception:
- print("%s: ERROR: MALFORMED IP: %s!" % (SCRIPT, value))
+ log("%s: ERROR: MALFORMED IP: %s!" % (SCRIPT, value))
return False
@@ -348,7 +348,7 @@ class Daemon(object):
if os.path.exists(self.pidfile):
os.remove(self.pidfile)
else:
- print(str(err))
+ log(str(err))
sys.exit(1)
def restart(self):
@@ -376,23 +376,24 @@ def run(command, *args, **options):
`detach`: If True, run in detached process.
`input`: If True, open command for writing stream to, returning the Popen
object.
+ `throw`: If True, raise an exception if there is an error instead of bailing.
"""
parts = [command]
parts.extend(args)
- if TEST or DEBUG:
- print("%s run: %s " (SCRIPT, " ".join(parts)))
+ debug("%s run: %s " % (SCRIPT, " ".join(parts)))
_check = options.get("check", True)
_detach = options.get("detach", False)
_input = options.get("input", False)
_exitcode = options.get("exitcode", False)
+ _throw = options.get("throw", False)
- if not _check or _detach or _input:
+ if not (_check or _throw) or _detach or _input:
if _input:
return subprocess.Popen(parts, stdin=subprocess.PIPE)
else:
- # XXX ok with return None ??
subprocess.Popen(parts)
+ return None
else:
try:
devnull = open('/dev/null', 'w')
@@ -402,24 +403,49 @@ def run(command, *args, **options):
if DEBUG:
logger.exception(exc)
if _exitcode:
+ debug("ERROR: Could not run %s: %s" % (exc.cmd, exc.output),
+ exception=exc)
return exc.returncode
+ elif _throw:
+ raise exc
else:
bail("ERROR: Could not run %s: %s" % (exc.cmd, exc.output),
exception=exc)
-def bail(msg=None, exception=None):
+def log(msg=None, exception=None, priority=syslog.LOG_INFO):
"""
- Abnormal exit.
+ print and log warning message or exception.
:param msg: optional error message.
:type msg: str
+ :param msg: optional exception.
+ :type msg: Exception
+ :param msg: syslog level
+ :type msg: one of LOG_EMERG, LOG_ALERT, LOG_CRIT, LOG_ERR,
+ LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG
"""
if msg is not None:
print("%s: %s" % (SCRIPT, msg))
- syslog.syslog(syslog.LOG_ERR, msg)
+ syslog.syslog(priority, msg)
if exception is not None:
- traceback.print_exc()
+ if TEST or DEBUG:
+ traceback.print_exc()
+ syslog.syslog(priority, traceback.format_exc())
+
+def debug(msg=None, exception=None):
+ """
+ Just like log, but is skipped unless DEBUG. Use syslog.LOG_INFO
+ even for debug messages (we don't want to miss them).
+ """
+ if TEST or DEBUG:
+ log(msg, exception)
+
+def bail(msg=None, exception=None):
+ """
+ abnormal exit. like log(), but exits with error status code.
+ """
+ log(msg, exception)
exit(1)
##
@@ -457,21 +483,21 @@ def parse_openvpn_flags(args):
if required_params:
flag_params = flag[1:]
if len(flag_params) != len(required_params):
- print("%s: ERROR: not enough params for %s" %
+ log("%s: ERROR: not enough params for %s" %
(SCRIPT, flag_name))
return None
for param, param_type in zip(flag_params, required_params):
if PARAM_FORMATS[param_type](param):
result.append(param)
else:
- print("%s: ERROR: Bad argument %s" %
+ log("%s: ERROR: Bad argument %s" %
(SCRIPT, param))
return None
else:
- print("WARNING: unrecognized openvpn flag %s" % flag_name)
+ log("WARNING: unrecognized openvpn flag %s" % flag_name)
return result
except Exception as exc:
- print("%s: ERROR PARSING FLAGS: %s" % (SCRIPT, exc))
+ log("%s: ERROR PARSING FLAGS: %s" % (SCRIPT, exc))
if DEBUG:
logger.exception(exc)
return None
@@ -490,8 +516,8 @@ def openvpn_start(args):
OPENVPN = get_openvpn_bin()
flags = [OPENVPN] + FIXED_FLAGS + openvpn_flags
if DEBUG:
- print("%s: running openvpn with flags:" % (SCRIPT,))
- print(flags)
+ log("%s: running openvpn with flags:" % (SCRIPT,))
+ log(flags)
# note: first argument to command is ignored, but customarily set to
# the command.
os.execv(OPENVPN, flags)
@@ -584,7 +610,7 @@ class NameserverRestorer(Daemon):
if os.path.isfile(RESOLVCONF):
run(RESOLVCONF, "-d", "bitmask")
else:
- print("%s: ERROR: package openresolv "
+ log("%s: ERROR: package openresolv "
"or resolvconf not installed." %
(SCRIPT,))
@@ -703,29 +729,49 @@ def ip6tables(*args, **options):
"""
run_iptable_with_check(IP6TABLES, *args, **options)
+#
+# NOTE: these tests to see if a chain exists might incorrectly return false.
+# This happens when there is an error in calling `iptables --list bitmask`.
+#
+# For this reason, when stopping the firewall, we do not trust the
+# output of ipvx_chain_exists() but instead always attempt to delete
+# the chain.
+#
-def ipv4_chain_exists(table):
+def ipv4_chain_exists(chain):
"""
Check if a given chain exists.
- :param table: the table to check against
- :type table: str
+ :param chain: the chain to check against
+ :type chain: str
:rtype: bool
"""
- code = run(IPTABLES, "--list", table, "--numeric", exitcode=True)
- return code == 0
+ code = run(IPTABLES, "--list", chain, "--numeric", exitcode=True)
+ if code == 0:
+ return True
+ elif code == 1:
+ return False
+ else:
+ log("ERROR: Could not determine state of iptable chain")
+ return False
-def ipv6_chain_exists(table):
+def ipv6_chain_exists(chain):
"""
Check if a given chain exists.
- :param table: the table to check against
- :type table: str
+ :param chain: the chain to check against
+ :type chain: str
:rtype: bool
"""
- code = run(IP6TABLES, "--list", table, "--numeric", exitcode=True)
- return code == 0
+ code = run(IP6TABLES, "--list", chain, "--numeric", exitcode=True)
+ if code == 0:
+ return True
+ elif code == 1:
+ return False
+ else:
+ log("ERROR: Could not determine state of iptable chain")
+ return False
def firewall_start(args):
@@ -812,15 +858,34 @@ def firewall_start(args):
def firewall_stop():
"""
- Stop the firewall.
+ Stop the firewall. Because we really really always want the firewall to be
+ stopped if at all possible, this function is cautious and contains a lot of
+ trys and excepts.
+
+ If there were any problems, we raise an exception at the end. This allows the calling code
+ to retry stopping the firewall. Stopping the firewall can fail if iptables is being run by
+ another process (only one iptables command can be run at a time).
"""
- iptables("--delete", "OUTPUT", "--jump", BITMASK_CHAIN)
- if ipv4_chain_exists(BITMASK_CHAIN):
- ip4tables("--flush", BITMASK_CHAIN)
- ip4tables("--delete-chain", BITMASK_CHAIN)
- if ipv6_chain_exists(BITMASK_CHAIN):
- ip6tables("--flush", BITMASK_CHAIN)
- ip6tables("--delete-chain", BITMASK_CHAIN)
+ ok = True
+ try:
+ iptables("--wait", "--delete", "OUTPUT", "--jump", BITMASK_CHAIN, throw=True)
+ except subprocess.CalledProcessError as exc:
+ log("INFO: not able to remove bitmask firewall from OUTPUT chain (maybe it is already removed?)", exc)
+ ok = False
+ try:
+ ip4tables("--flush", BITMASK_CHAIN, throw=True)
+ ip4tables("--delete-chain", BITMASK_CHAIN, throw=True)
+ except subprocess.CalledProcessError as exc:
+ log("INFO: not able to flush and delete bitmask ipv4 firewall chain (maybe it is already destroyed?)", exc)
+ ok = False
+ try:
+ ip6tables("--flush", BITMASK_CHAIN, throw=True)
+ ip6tables("--delete-chain", BITMASK_CHAIN, throw=True)
+ except subprocess.CalledProcessError as exc:
+ log("INFO: not able to flush and delete bitmask ipv6 firewall chain (maybe it is already destroyed?)", exc)
+ ok = False
+ if not ok:
+ raise Exception("firewall might still be left up. Please try `firewall stop` again.")
##
## MAIN
@@ -874,7 +939,7 @@ def main():
elif command == "firewall_isup":
if ipv4_chain_exists(BITMASK_CHAIN):
- print("%s: INFO: bitmask firewall is up" % (SCRIPT,))
+ log("%s: INFO: bitmask firewall is up" % (SCRIPT,))
else:
bail("INFO: bitmask firewall is down")
@@ -884,8 +949,7 @@ def main():
bail("ERROR: No such command")
if __name__ == "__main__":
- if DEBUG:
- logger.debug(" ".join(sys.argv))
+ debug(" ".join(sys.argv))
main()
- print("%s: done" % (SCRIPT,))
+ log("%s: done" % (SCRIPT,))
exit(0)