#!/usr/bin/env node

/*
This script takes the output of npm audit --json from stdin
and writes a filtered version to stdout.
The filtered version will have the entries listed in `AUDIT_ALLOW_LIST` removed.
Specifically, each property of `vulnerabilities` in the input is matched by name in the allow list.

Sample output of `npm audit --json` (NPM v6):

{
  "actions": [
    {
      "action": "review",
      "module": "trim-newlines",
      "resolves": [
        {
          "id": 1753,
          "path": "lerna>@lerna/publish>@lerna/version>@lerna/conventional-commits>conventional-changelog-core>get-pkg-repo>meow>trim-newlines",
          "dev": true,
          "optional": false,
          "bundled": false
        }
      ]
    }
  ],
  // Other properties ...
}


The reason we have this script is that there may be low-severity or unexploitable vulnerabilities
that have not yet been fixed in newer versions of the package.

Note: if we update to NPM v7, we will have to change this script because the `npm audit` output will be different.
See commit 935647112d96fa5cf82e61314f7135376d24f291 in https://github.com/actions/toolkit/pull/846.
*/

'use strict'
const fs = require('fs')

const USAGE = "Usage: npm audit --json | scripts/audit-allow-list"

// To add entires to the allow list:
//   - Run `npm audit --json`
//   - Copy `path` from each `actions[k].resolves` you want to allow
//   - Fill in the `advisoryUrl` and `justification` (these are just for documentation)
const AUDIT_ALLOW_LIST = [
  {
    path: "lerna>@lerna/publish>@lerna/version>@lerna/conventional-commits>conventional-changelog-core>get-pkg-repo>meow>trim-newlines",
    advisoryUrl: "https://www.npmjs.com/advisories/1753",
    justification: "dependency of lerna (dev only); low severity"
  },
  {
    path: "lerna>@lerna/version>@lerna/conventional-commits>conventional-changelog-core>get-pkg-repo>meow>trim-newlines",
    advisoryUrl: "https://www.npmjs.com/advisories/1753",
    justification: "dependency of lerna (dev only); low severity"
  },
  {
    path: "lerna>@lerna/version>@lerna/github-client>git-url-parse>git-up>parse-url",
    advisoryUrl: "https://github.com/advisories/GHSA-j9fq-vwqv-2fm2",
    justification: "dependency of lerna; moderate severity"
  },
  {
    path: "lerna>@lerna/publish>@lerna/version>@lerna/github-client>git-url-parse>git-up>parse-url",
    advisoryUrl: "https://github.com/advisories/GHSA-j9fq-vwqv-2fm2",
    justification: "dependency of lerna; moderate severity"
  }
]

/**
 * @param audits - JavaScript object matching the schema of `npm audit --json`
 * @param allowedPaths - List of dependency paths to exclude from the audit
*/
function filterVulnerabilities(audits, allowedPaths) {
  const vulnerabilities = audits.actions.flatMap(x => x.resolves)
  return vulnerabilities.filter(x => !allowedPaths.includes(x.path))
}

const input = fs.readFileSync("/dev/stdin", "utf-8")
if (input === "") {
  console.error(USAGE)
  process.exit(1)
}

const audits = JSON.parse(input)
const allowedPaths = AUDIT_ALLOW_LIST.map(x => x.path)
// This function assumes `audits` has the right structure.
// Just let the error terminate the process if the input doesn't match the schema.
const remainingVulnerabilities = filterVulnerabilities(audits, allowedPaths)

// `npm audit` will return exit code 1 if it finds vulnerabilities.
// This script should do the same.
const numVulnerabilities = remainingVulnerabilities.length
if (numVulnerabilities > 0) {
  const pluralized = numVulnerabilities === 1 ? "y" : "ies"
  console.log(`Found ${numVulnerabilities} unrecognized vulnerabilit${pluralized} from \`npm audit\`:`)
  console.log(JSON.stringify(remainingVulnerabilities, null, 2))
  process.exit(1)
}