feat: scrub substring values with their hash (#44)

* feat: scrub mac address from objects

* chore: define the SQL scrubber

* chore: make scrubber generic

* chore: fix some sql scrubber thingies

src/scrubber.test.ts

@@ -430,3 +430,53 @@ test('getScrubberSql', () => {
   expect(scrubber.getScrubberSql('pw')).toMatchInlineSnapshot(`"'notsecret'"`)
   expect(scrubber.getScrubberSql('name')).toMatchInlineSnapshot(`"'Jane Doe'"`)
 })
+
+test('saltedHashSubstringScrubber should scrub substring values', () => {
+  const data = {
+    Data: [
+      { id: '01' },
+      { id: 'ab02cd' },
+      { id: 'ab03cd', foo: '03' },
+      { id: 'ab04cd', foo: 'ab04cd' },
+      { id: '01\n02\n03' },
+    ],
+  }
+
+  const result = scrub(data, {
+    fields: {
+      'id,foo': {
+        scrubber: 'saltedHashSubstringScrubber',
+        params: {
+          regex: ['\\d\\d'],
+          initializationVector: 'initializationVector',
+        },
+      },
+    },
+  })
+
+  expect(result).toMatchInlineSnapshot(`
+{
+  "Data": [
+    {
+      "id": "42bb960e91b4abf82bd6bdcc8e49cb405678ba5655a1cdc0210a4089cf2980f9",
+    },
+    {
+      "id": "ab5365d6a9320a362fe52dbd54a20bc58eaa775d548e20dccf58d761882201381acd",
+    },
+    {
+      "foo": "bb722ef61aa727e4a61aab72132badd39388204e9c6d8653c90a313a581bd622",
+      "id": "abbb722ef61aa727e4a61aab72132badd39388204e9c6d8653c90a313a581bd622cd",
+    },
+    {
+      "foo": "ab67fe825923d446fa7cd7711e66345232ab15a4bdc1cc9590b975353be70ad616cd",
+      "id": "ab67fe825923d446fa7cd7711e66345232ab15a4bdc1cc9590b975353be70ad616cd",
+    },
+    {
+      "id": "42bb960e91b4abf82bd6bdcc8e49cb405678ba5655a1cdc0210a4089cf2980f9
+5365d6a9320a362fe52dbd54a20bc58eaa775d548e20dccf58d761882201381a
+bb722ef61aa727e4a61aab72132badd39388204e9c6d8653c90a313a581bd622",
+    },
+  ],
+}
+`)
+})

src/scrubbers.test.ts

@@ -1,3 +1,4 @@
+import { _stringMapEntries } from '@naturalcycles/js-lib'
 import { nanoid } from '@naturalcycles/nodejs-lib'
 import {
   bcryptStringScrubber,
@@ -7,6 +8,7 @@ import {
   charsFromRightScrubberSQL,
   isoDateStringScrubber,
   isoDateStringScrubberSQL,
+  saltedHashSubstringScrubber,
   preserveOriginalScrubber,
   preserveOriginalScrubberSQL,
   randomEmailInContentScrubber,
@@ -25,6 +27,8 @@ import {
   undefinedScrubberSQL,
   unixTimestampScrubber,
   unixTimestampScrubberSQL,
+  defaultScrubbers,
+  defaultScrubbersSQL,
 } from './scrubbers'
 
 const bryptStr1 = '$2a$12$HYNzBb8XYOZZeRwZDiVux.orKNqkSVAoXBDc9Gw7nSxr8rcZupbRK'
@@ -434,3 +438,76 @@ test('bcryptStringScrubberSQL', () => {
     bcryptStringScrubberSQL({ replacements: '$2a$10$:$2a$10$456,$2a$12$:$2a$12$123' }),
   ).toMatchSnapshot()
 })
+
+describe('saltedHashSubstringScrubber', () => {
+  const initializationVector = nanoid()
+
+  test('should scrub the matching substring with a hash', () => {
+    const result = saltedHashSubstringScrubber('foo|00:00:00:00:00:00|bar', {
+      regex: '00:00:00:00:00:00',
+      initializationVector,
+    })
+
+    expect(result).toMatch(/foo\|.{64}\|bar/)
+    expect(result).not.toContain('00:00:00:00:00:00')
+  })
+
+  test('should scrub the same value with the same hash', () => {
+    const result1 = saltedHashSubstringScrubber('foo|00:00:00:00:00:00|bar', {
+      regex: '00:00:00:00:00:00',
+      initializationVector,
+    })
+
+    const result2 = saltedHashSubstringScrubber('bee|00:00:00:00:00:00|boo', {
+      regex: '00:00:00:00:00:00',
+      initializationVector,
+    })
+
+    expect(result1?.substring(4, 64)).toBe(result2?.substring(4, 64))
+  })
+
+  test('should scrub substring using regex', () => {
+    const result = saltedHashSubstringScrubber('foo|00:00:00:00:00:00|bar', {
+      regex:
+        '[0-9a-zA-Z]{2}:[0-9a-zA-Z]{2}:[0-9a-zA-Z]{2}:[0-9a-zA-Z]{2}:[0-9a-zA-Z]{2}:[0-9a-zA-Z]{2}',
+      initializationVector,
+    })
+
+    expect(result).toMatch(/foo\|.{64}\|bar/)
+    expect(result).not.toContain('00:00:00:00:00:00')
+  })
+
+  test('should scrub multiple occurrences', () => {
+    const result = saltedHashSubstringScrubber('foo|max|bar|max|boo', {
+      regex: 'max',
+      initializationVector,
+    })
+
+    expect(result).not.toContain('max')
+  })
+
+  test('should throw when the salt is missing', () => {
+    expect(() => saltedHashSubstringScrubber('foo|max|bar', { regex: 'max' } as any)).toThrow(
+      'Initialization vector is missing',
+    )
+  })
+
+  test('should throw when the regex or substring is missing', () => {
+    expect(() =>
+      saltedHashSubstringScrubber('foo|max|bar', {
+        initializationVector,
+      } as any),
+    ).toThrow('Substring or regex is missing')
+  })
+})
+
+const scrubberNames = _stringMapEntries(defaultScrubbers).map(([k]) => k)
+test.each(scrubberNames)('the %s should have its SQL scrubber counterpart', scrubberName => {
+  console.log(scrubberName, defaultScrubbersSQL[scrubberName])
+  expect(defaultScrubbersSQL[scrubberName]).toBeDefined()
+})
+
+const sqlScrubberNames = _stringMapEntries(defaultScrubbersSQL).map(([k]) => k)
+test.each(sqlScrubberNames)('the %s should have its scrubber counterpart', scrubberName => {
+  expect(defaultScrubbers[scrubberName]).toBeDefined()
+})

src/scrubbers.ts

@@ -462,6 +462,42 @@ export const bcryptStringScrubberSQL: BcryptStringScrubberSQLFn = params => {
           END`
 }
 
+export type SaltedHashSubstringScrubberFn = ScrubberFn<
+  string | undefined,
+  SaltedHashSubstringScrubberParams
+>
+
+export type SaltedHashSubstringScrubberSQLFn = ScrubberSQLFn<SaltedHashSubstringScrubberParams>
+
+export interface SaltedHashSubstringScrubberParams {
+  initializationVector: string
+  regex: string
+}
+
+export const saltedHashSubstringScrubber: SaltedHashSubstringScrubberFn = (value, params) => {
+  _assert(params?.initializationVector, 'Initialization vector is missing')
+  _assert(params?.regex, 'Substring or regex is missing')
+
+  if (!value) return value
+
+  const regex = new RegExp(params.regex, 'g')
+
+  return value.replace(regex, substring =>
+    crypto.createHash('sha256').update(substring).update(params.initializationVector).digest('hex'),
+  )
+}
+
+export const saltedHashSubstringScrubberSQL: SaltedHashSubstringScrubberSQLFn = params => {
+  _assert(params?.initializationVector, 'Initialization vector is missing')
+  _assert(params?.regex, 'Substring or regex is missing')
+
+  const substringToReplace = `COALESCE(REGEXP_SUBSTR(${sqlValueToReplace}, '${params.regex}'), '')`
+  const hashedValue = `SHA2(${substringToReplace} || '${params.initializationVector}', 256)`
+  const replacedValue = `REGEXP_REPLACE(${sqlValueToReplace}, '${params.regex}', ${hashedValue})`
+
+  return replacedValue
+}
+
 function nthChar(str: string, character: string, n: number): number | undefined {
   let count = 0
   let i = 0
@@ -489,6 +525,7 @@ export const defaultScrubbers: ScrubbersMap = {
   saltedHashScrubber,
   saltedHashEmailScrubber,
   bcryptStringScrubber,
+  saltedHashSubstringScrubber,
 }
 
 export const defaultScrubbersSQL: ScrubbersSQLMap = {
@@ -504,4 +541,5 @@ export const defaultScrubbersSQL: ScrubbersSQLMap = {
   saltedHashScrubber: saltedHashScrubberSQL,
   saltedHashEmailScrubber: saltedHashEmailScrubberSQL,
   bcryptStringScrubber: bcryptStringScrubberSQL,
+  saltedHashSubstringScrubber: saltedHashSubstringScrubberSQL,
 }