@hclsoftware/secagent/src/Hooks/HookParser.js

IAST agent

//IASTIGNORE
/* eslint-disable no-new-wrappers */

/*
 * ****************************************************
 * Licensed Materials - Property of HCL.
 * (c) Copyright HCL Technologies Ltd. 2017, 2025.
 * Note to U.S. Government Users *Restricted Rights.
 * ****************************************************
 */

const HookRuleFactory = require('../Rules/HookRules/HookRuleFactory')
const BeforeRuleFactory = require('../Rules/BeforeRules/BeforeRuleFactory')
const hookRule = require('../Rules/HookRules/HookRule')
const HookValues = require('./HookValues')
const logger = require('../Logger/IastLogger').eventLog

const regularHooks = require('./Hooks')
const requireHooks = require('./RequireHooks')
const readOnlyHooks = require('./ReadOnlyHooks')
const TaintTracker = require('../TaintTracker')
const IastProperties = require('./IastProperties')

module.exports.loadHooks = () => {
    module.exports.hooksActive = false
    setRegularHooks()
    loadHooks(readOnlyHooks)
    loadHooks(requireHooks)
    module.exports.hooksActive = true
}

module.exports.hooksActive = true
const toActualHook = {}

/*
called at start up.
Populates an object with hook functions which are generated according to the hook list.
*/
function loadHooks(hooks) {
    for (const moduleName in hooks) {
        hooks[moduleName].forEach(hook => {
            const fullNames = getFullMethodName(moduleName, hook)
            for (const fullName of fullNames) {
                const methodName = fullName.substring(fullName.lastIndexOf('.') + 1)
                const hookFunction = parseHook(hook, methodName)
                toActualHook[fullName] = hookFunction
            }
        })
    }
}

/*
Given a module, it overrides the relevant original functions by appropriate hook functions which loaded at start up.
*/
module.exports.setRequireHook = (origModule, moduleName) => {
    const hooks = moduleName in requireHooks ? requireHooks[moduleName] : []
    hooks.forEach(hookObj => {
        // get hook function from cache:
        const fullNames = getFullMethodName(moduleName, hookObj)
        for (const fullName of fullNames) {
            const functionName = fullName.substring(fullName.lastIndexOf('.') + 1)
            const hookFunction = toActualHook[fullName]
            // need to fetch the hooked module in run time because it might be of different version in different requires:
            const hookedModule = getHookedModule(hookObj, origModule)
            if (hookedModule == null) { // module may not be present, e.g. fs.promises
              //logger.debug(`skipping undefined module ${origModule}, scope: ${JSON.stringify(hookObj.scopes)}`)
              return
            }
            const origFunction = hookedModule[functionName]
            if (origFunction != null) { // we may hook functions that do not exist in certain library versions
                setProxyOnFunction(hookedModule, moduleName, functionName, origFunction, hookFunction)
            }
            // else {
            //     logger.debug(`skipping undefined function ${moduleName}.${functionName}`)
            // }
        }
    })
}

function setRegularHooks() {
    for (const moduleName in regularHooks) {
        const baseModule = moduleName === 'global' ? global : require(moduleName)
        regularHooks[moduleName].forEach(hookObj => {
            const moduleObj = getHookedModule(hookObj, baseModule)
            if (moduleObj == null) { // module may not be present, e.g. fs.promises
              //logger.debug(`skipping undefined module ${baseModule}, scope: ${JSON.stringify(hookObj.scopes)}`)
              return
            }
            const functionNames = Array.isArray(hookObj.methodName) ? hookObj.methodName : [hookObj.methodName]
            for (const functionName of functionNames) {
                const hookFunction = parseHook(hookObj, functionName)
                const origFunction = moduleObj[functionName]
                if (origFunction != null) { // we may hook functions that do not exist in certain library versions
                    setProxyOnFunction(moduleObj, moduleName, functionName, origFunction, hookFunction)
                }
                // else {
                //   logger.debug(`skipping undefined function ${moduleName}.${functionName}`)
                // }
            }
        })
    }
}

/* This function is used for adding hooks by proxy. There are functions that we cannot override by our hook,
*  but with proxy because they contain additional properties that would be removed in the regular overriding way.
*/
function setProxyOnFunction(module, moduleName, functionName, origFunction, hookFunction) {
    // we store a flag for each function that indicates whether the function has already wrapped by a proxy, to prevent
    // a proxy chain, which might make the program crash.
    if (origFunction == null || (module[functionName] != null && module[functionName][IastProperties.property.FUNCTION_PROXY])) {
        return
    }
    module[functionName] = new Proxy(origFunction, {
        apply(target, thisArg, argArray) { // trap regular function call, e.g. Error(message)
            const that = thisArg == null || (!Buffer.isBuffer(thisArg)) && (!Array.isArray(thisArg) && thisArg.toString() === '[object global]') ? moduleName : thisArg
            return hookFunction(that, argArray, target)
        },

        construct(target, argArray, newTarget) { // trap constructor call, e.g. new Error(message)
            return hookFunction('global', argArray, target, newTarget)
        },
        get(target, p, receiver) {
            if (p === IastProperties.property.FUNCTION_PROXY) {
                return true;
            }
            return Reflect.get(target, p, receiver)
        }
    })
}

function getHookedModule(hookObj, baseModule) {
    let currentScope = baseModule
    const scopes = 'scopes' in hookObj ? hookObj.scopes : []
    scopes.forEach(scope => {
        if (currentScope != null) {
            currentScope = currentScope[scope]
        }
    })
    return currentScope
}

function getFullMethodName(moduleName, hook) {
    let fullNamesArray = []
    const namespace = 'scopes' in hook ? `${moduleName}.${hook.scopes.join('.')}` : `${moduleName}`
    if (Array.isArray(hook.methodName)) {
        fullNamesArray = hook.methodName.map(name => namespace + '.' + name)
    } else {
        fullNamesArray.push(namespace + '.' + hook.methodName)
    }
    return fullNamesArray
}

module.exports.getHookFunctionFor = (fullMethodName) => {
    return toActualHook[fullMethodName]
}

/*
This function Generates rules for required hook object.
It returns a function which would be called instead of the original method.
*/
function parseHook(hookObj, methodName) {
    const beforeRules = hookObj.beforeRules != null ? parseRules(hookObj.beforeRules, BeforeRuleFactory) : []
    const callbackRules = hookObj.callbackRules != null ? parseRules(hookObj.callbackRules, HookRuleFactory) : []
    const hookRules = hookObj.rules != null ? parseRules(hookObj.rules, HookRuleFactory) : []

    // this function would be called at run time instead of the original one:
    return function (that, origArgs, method, constructorProxy=null) {
        const hookValues = new HookValues(origArgs, that, method, methodName, hookObj.additionalInfo, callbackRules, constructorProxy)
        return doRules(hookObj, beforeRules, hookRules, hookValues)
    }
}

/*
Manages the hook execution:
1. executes before rules,
2 calls to the original method
3. executes the hook rules.
*/
function doRules(hookObj, beforeRules, hookRules, hookValues) {
        let thrownError
        try {
            beforeRules.forEach(rule => {
                try {
                    if (rule.runWhenInactive() || module.exports.hooksActive)
                    rule.doRule(hookValues)
                } catch (e) {
                    logger.error(e)
                }
            })

            if (hookValues.runOrigMethod) {
                try {
                if (hookValues.isConstructor) {
                    // hookValues.ret = new (Function.bind.apply(hookValues.origMethod, [null, ...hookValues.updatedArgs]))
                    hookValues.ret = Reflect.construct(hookValues.origMethod, hookValues.updatedArgs, hookValues.newTarget)
                }
                else {
                    hookValues.ret = hookValues.origMethod.apply(hookValues.updatedThat, hookValues.updatedArgs)
                }
                } catch (error) {
                    thrownError = error
                }
            }

            if (module.exports.hooksActive && shouldRunHookRules(hookObj, hookRules, hookValues)) {
                hookRules.forEach(rule => {
                    try {
                        rule.doHook(hookValues)
                    } catch (e) {
                        logger.error(e)
                    }
                })
            }
        } catch (e) {
                logger.error(e)
            }

        if (thrownError != null) {
            throw thrownError
        }
    return hookValues.ret
}

function shouldRunHookRules(hookObj, hookRules, hookValues) {
    if (hookRules.length === 0) {
        return false
    }
    if (hookObj.taintCondition != null) {
        return hookObj.taintCondition.some(p => isSpecifiedPositionTainted(p, hookValues))
    }
    return true
}

function isSpecifiedPositionTainted (position, hookValues) {
  if (position === 'args') {
    for (let i = 0; i < hookValues.args.length; i++) {
      if (TaintTracker.isObjectTainted(hookRule.getActualParam(i, hookValues))) return true
    }
    return false
  }
  return TaintTracker.isObjectTainted(hookRule.getActualParam(position, hookValues))
}

function parseRules(rulesObj, ruleFactory) {
    const rules = []
    for (const ruleObj of rulesObj) {
        rules.push(ruleFactory.createRule(ruleObj))
    }
    return rules
}