From df5a862beb84145dfc8434efde7d7fee783199cf Mon Sep 17 00:00:00 2001
From: sarthurdev <965089+sarthurdev@users.noreply.github.com>
Date: Thu, 13 Jan 2022 12:58:37 +0100
Subject: firewall: T4178: Use lowercase for TCP flags and add an validator

---
 src/conf_mode/firewall.py     |  3 +++
 src/conf_mode/policy-route.py | 10 +++++-----
 src/validators/tcp-flag       | 19 +++++++++++++++++++
 3 files changed, 27 insertions(+), 5 deletions(-)
 create mode 100755 src/validators/tcp-flag

(limited to 'src')

diff --git a/src/conf_mode/firewall.py b/src/conf_mode/firewall.py
index 7b491a325..853470fd8 100755
--- a/src/conf_mode/firewall.py
+++ b/src/conf_mode/firewall.py
@@ -142,6 +142,9 @@ def verify_rule(firewall, rule_conf, ipv6):
         if not {'count', 'time'} <= set(rule_conf['recent']):
             raise ConfigError('Recent "count" and "time" values must be defined')
 
+    if dict_search_args(rule_conf, 'tcp', 'flags') and dict_search_args(rule_conf, 'protocol') != 'tcp':
+        raise ConfigError('Protocol must be tcp when specifying tcp flags')
+
     for side in ['destination', 'source']:
         if side in rule_conf:
             side_conf = rule_conf[side]
diff --git a/src/conf_mode/policy-route.py b/src/conf_mode/policy-route.py
index c5904309f..30597ef4e 100755
--- a/src/conf_mode/policy-route.py
+++ b/src/conf_mode/policy-route.py
@@ -76,7 +76,7 @@ def get_config(config=None):
 
     return policy
 
-def verify_rule(policy, rule_conf, ipv6):
+def verify_rule(policy, name, rule_conf, ipv6):
     icmp = 'icmp' if not ipv6 else 'icmpv6'
     if icmp in rule_conf:
         icmp_defined = False
@@ -93,14 +93,14 @@ def verify_rule(policy, rule_conf, ipv6):
 
         if icmp_defined and 'protocol' not in rule_conf or rule_conf['protocol'] != icmp:
             raise ConfigError(f'{name} rule {rule_id}: ICMP type/code or type-name can only be defined if protocol is ICMP')
+
     if 'set' in rule_conf:
         if 'tcp_mss' in rule_conf['set']:
             tcp_flags = dict_search_args(rule_conf, 'tcp', 'flags')
             if not tcp_flags or 'SYN' not in tcp_flags.split(","):
                 raise ConfigError(f'{name} rule {rule_id}: TCP SYN flag must be set to modify TCP-MSS')
-    if 'tcp' in rule_conf:
-        if 'flags' in rule_conf['tcp']:
-            if 'protocol' not in rule_conf or rule_conf['protocol'] != 'tcp':
+
+    if dict_search_args(rule_conf, 'tcp', 'flags') and dict_search_args(rule_conf, 'protocol') != 'tcp':
                 raise ConfigError(f'{name} rule {rule_id}: TCP flags can only be set if protocol is set to TCP')
 
     for side in ['destination', 'source']:
@@ -138,7 +138,7 @@ def verify(policy):
             for name, pol_conf in policy[route].items():
                 if 'rule' in pol_conf:
                     for rule_id, rule_conf in pol_conf['rule'].items():
-                        verify_rule(policy, rule_conf, ipv6)
+                        verify_rule(policy, name, rule_conf, ipv6)
 
     for ifname, if_policy in policy['interfaces'].items():
         name = dict_search_args(if_policy, 'route')
diff --git a/src/validators/tcp-flag b/src/validators/tcp-flag
new file mode 100755
index 000000000..86ebec189
--- /dev/null
+++ b/src/validators/tcp-flag
@@ -0,0 +1,19 @@
+#!/usr/bin/python3
+
+import sys
+import re
+
+if __name__ == '__main__':
+    if len(sys.argv)>1:
+        flags = sys.argv[1].split(",")
+
+        for flag in flags:
+            if flag and flag[0] == '!':
+                flag = flag[1:]
+            if flag.lower() not in ['syn', 'ack', 'rst', 'fin', 'urg', 'psh']:
+                print(f'Error: {flag} is not a valid TCP flag')
+                sys.exit(1)
+    else:
+        sys.exit(2)
+
+    sys.exit(0)
-- 
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