From 7a18c719df1b3f2515baff8bdecc8784f1d935b1 Mon Sep 17 00:00:00 2001 From: Nicolas Fort Date: Wed, 24 Jul 2024 14:15:34 +0000 Subject: T4072: firewall: improve error handling when firewall configuration is wrong. Use nft -c option to check temporary file, and use output provided by nftables to parse the error if possible, or print it as it is if it's an unknown error --- src/conf_mode/firewall.py | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) (limited to 'src/conf_mode') diff --git a/src/conf_mode/firewall.py b/src/conf_mode/firewall.py index 352d5cbb1..77218cc77 100755 --- a/src/conf_mode/firewall.py +++ b/src/conf_mode/firewall.py @@ -36,6 +36,7 @@ from vyos.utils.process import cmd from vyos.utils.process import rc_cmd from vyos import ConfigError from vyos import airbag +from subprocess import run as subp_run airbag.enable() @@ -495,8 +496,53 @@ def generate(firewall): render(sysctl_file, 'firewall/sysctl-firewall.conf.j2', firewall) return None +def parse_firewall_error(output): + # Define the regex patterns to extract the error message and the comment + error_pattern = re.compile(r'Error:\s*(.*?)\n') + comment_pattern = re.compile(r'comment\s+"([^"]+)"') + error_output = [] + + # Find all error messages in the output + error_matches = error_pattern.findall(output) + # Find all comment matches in the output + comment_matches = comment_pattern.findall(output) + + if not error_matches or not comment_matches: + raise ConfigError(f'Unknown firewall error detected: {output}') + + error_output.append('Fail to apply firewall') + # Loop over the matches and process them + for error_message, comment in zip(error_matches, comment_matches): + # Parse the comment + parsed_entries = comment.split('-') + family = 'bridge' if parsed_entries[0] == 'bri' else parsed_entries[0] + if parsed_entries[1] == 'NAM': + chain = 'name' + elif parsed_entries[1] == 'FWD': + chain = 'forward' + elif parsed_entries[1] == 'INP': + chain = 'input' + elif parsed_entries[1] == 'OUT': + chain = 'output' + elif parsed_entries[1] == 'PRE': + chain = 'prerouting' + error_output.append(f'Error found on: firewall {family} {chain} {parsed_entries[2]} rule {parsed_entries[3]}') + error_output.append(f'\tError message: {error_message.strip()}') + + raise ConfigError('\n'.join(error_output)) + def apply(firewall): + # Use nft -c option to check current configuration file + completed_process = subp_run(['nft', '-c', '--file', nftables_conf], capture_output=True) + install_result = completed_process.returncode + if install_result == 1: + # We need to handle firewall error + output = completed_process.stderr + parse_firewall_error(output.decode()) + + # No error detected during check, we can apply the new configuration install_result, output = rc_cmd(f'nft --file {nftables_conf}') + # Double check just in case if install_result == 1: raise ConfigError(f'Failed to apply firewall: {output}') -- cgit v1.2.3