# -*- coding: utf-8 -*-

# Copyright (c) 2020 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing a check for use of wildcard injection.
"""

#
# This is a modified version of the one found in the bandit package.
#
# Original Copyright 2014 Hewlett-Packard Development Company, L.P.
#
# SPDX-License-Identifier: Apache-2.0
#

from Security.SecurityDefaults import SecurityDefaults


def getChecks():
    """
    Public method to get a dictionary with checks handled by this module.
    
    @return dictionary containing checker lists containing checker function and
        list of codes
    @rtype dict
    """
    return {
        "Call": [
            (checkLinuxCommandsWildcardInjection, ("S609",)),
        ],
    }


def checkLinuxCommandsWildcardInjection(reportError, context, config):
    """
    Function to check for use of wildcard injection.
    
    @param reportError function to be used to report errors
    @type func
    @param context security context object
    @type SecurityContext
    @param config dictionary with configuration data
    @type dict
    """
    if config and "shell_injection_subprocess" in config:
        subProcessFunctionNames = config["shell_injection_subprocess"]
    else:
        subProcessFunctionNames = SecurityDefaults[
            "shell_injection_subprocess"]
    
    if config and "shell_injection_shell" in config:
        shellFunctionNames = config["shell_injection_shell"]
    else:
        shellFunctionNames = SecurityDefaults["shell_injection_shell"]
    
    vulnerableFunctions = ['chown', 'chmod', 'tar', 'rsync']
    if (
        context.callFunctionNameQual in shellFunctionNames or
        (context.callFunctionNameQual in subProcessFunctionNames and
         context.checkCallArgValue('shell', 'True'))
    ):
        if context.callArgsCount >= 1:
            callArgument = context.getCallArgAtPosition(0)
            argumentString = ''
            if isinstance(callArgument, list):
                for li in callArgument:
                    argumentString = argumentString + ' {0}'.format(li)
            elif isinstance(callArgument, str):
                argumentString = callArgument
            
            if argumentString != '':
                for vulnerableFunction in vulnerableFunctions:
                    if (
                        vulnerableFunction in argumentString and
                        '*' in argumentString
                    ):
                        lineNo = context.getLinenoForCallArg('shell')
                        if lineNo < 1:
                            lineNo = context.node.lineno
                        offset = context.getOffsetForCallArg('shell')
                        if offset < 0:
                            offset = context.node.col_offset
                        reportError(
                            lineNo - 1,
                            offset,
                            "S609",
                            "H",
                            "M",
                            context.callFunctionNameQual
                        )
