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Normalize salt, iv, uuid params of .toV3() before encrypting #95

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Aug 28, 2019
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1 change: 1 addition & 0 deletions .npmrc
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
package-lock = false
1 change: 0 additions & 1 deletion .travis.yml
Original file line number Diff line number Diff line change
@@ -1,6 +1,5 @@
language: node_js
node_js:
- "6"
- "8"
- "10"
addons:
Expand Down
3 changes: 3 additions & 0 deletions package.json
Original file line number Diff line number Diff line change
Expand Up @@ -60,8 +60,11 @@
"@types/bn.js": "^4.11.5",
"@types/mocha": "^5.2.7",
"@types/node": "^12.0.10",
"@types/lodash.zip": "^4.2.6",
"coveralls": "^3.0.0",
"ethers": "^4.0.33",
"husky": "^2.1.0",
"lodash.zip": "^4.2.0",
"mocha": "^5.2.0",
"nyc": "^14.1.1",
"prettier": "^1.15.3",
Expand Down
126 changes: 104 additions & 22 deletions src/index.ts
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,19 @@ const uuidv4 = require('uuid/v4')
// parameters for the toV3() method

interface V3Params {
kdf: string
cipher: string
salt: string | Buffer
iv: string | Buffer
uuid: string | Buffer
dklen: number
c: number
n: number
r: number
p: number
}

interface V3ParamsStrict {
kdf: string
cipher: string
salt: Buffer
Expand All @@ -21,8 +34,43 @@ interface V3Params {
p: number
}

function mergeToV3ParamsWithDefaults(params?: Partial<V3Params>): V3Params {
const v3Defaults: V3Params = {
function validateHexString(paramName: string, str: string, length?: number) {
if (str.toLowerCase().startsWith('0x')) {
str = str.slice(2)
}
if (!str && !length) {
return str
}
if ((length as number) % 2) {
throw new Error(`Invalid length argument, must be an even number`)
}
if (typeof length === 'number' && str.length !== length) {
throw new Error(`Invalid ${paramName}, string must be ${length} hex characters`)
}
if (!/^([0-9a-f]{2})+$/i.test(str)) {
const howMany = typeof length === 'number' ? length : 'empty or a non-zero even number of'
throw new Error(`Invalid ${paramName}, string must be ${howMany} hex characters`)
}
return str
}

function validateBuffer(paramName: string, buff: Buffer, length?: number) {
if (!Buffer.isBuffer(buff)) {
const howManyHex =
typeof length === 'number' ? `${length * 2}` : 'empty or a non-zero even number of'
const howManyBytes = typeof length === 'number' ? ` (${length} bytes)` : ''
throw new Error(
`Invalid ${paramName}, must be a string (${howManyHex} hex characters) or buffer${howManyBytes}`,
)
}
if (typeof length === 'number' && buff.length !== length) {
throw new Error(`Invalid ${paramName}, buffer must be ${length} bytes`)
}
return buff
}

function mergeToV3ParamsWithDefaults(params?: Partial<V3Params>): V3ParamsStrict {
const v3Defaults: V3ParamsStrict = {
cipher: 'aes-128-ctr',
kdf: 'scrypt',
salt: randomBytes(32),
Expand All @@ -38,17 +86,30 @@ function mergeToV3ParamsWithDefaults(params?: Partial<V3Params>): V3Params {
if (!params) {
return v3Defaults
}

if (typeof params.salt === 'string') {
params.salt = Buffer.from(validateHexString('salt', params.salt), 'hex')
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I just noticed that in ethereumjs-util we pad the string to even length, so that if implicitly e.g. a 0x01 byte was converted to 0x1, it would be covered:

https://github.com/ethereumjs/ethereumjs-util/blob/3b1085059194b02354177d334f89cd82a5187883/src/bytes.ts#L76

Not sure whether that applies here.

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It's a possibility, for sure, though I wonder if it would end up masking legit user errors more than providing shorthand/convenience.

}
if (typeof params.iv === 'string') {
params.iv = Buffer.from(validateHexString('iv', params.iv, 32), 'hex')
}
if (typeof params.uuid === 'string') {
params.uuid = Buffer.from(validateHexString('uuid', params.uuid, 32), 'hex')
}

if (params.salt) {
validateBuffer('salt', params.salt)
}
if (params.iv) {
validateBuffer('iv', params.iv, 16)
}
if (params.uuid) {
validateBuffer('uuid', params.uuid, 16)
}

return {
cipher: params.cipher || 'aes-128-ctr',
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This can be simplified as: return { ...params, ...v3Defaults }

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Done, but it needed to be: return { ...v3Defaults, ...(params as V3ParamsStrict) } in order for caller supplied params to replace the defaults.

kdf: params.kdf || 'scrypt',
salt: params.salt || randomBytes(32),
iv: params.iv || randomBytes(16),
uuid: params.uuid || randomBytes(16),
dklen: params.dklen || 32,
c: params.c || 262144,
n: params.n || 262144,
r: params.r || 8,
p: params.p || 1,
...v3Defaults,
...(params as V3ParamsStrict),
}
}

Expand All @@ -60,6 +121,14 @@ const enum KDFFunctions {
}

interface ScryptKDFParams {
dklen: number
n: number
p: number
r: number
salt: Buffer
}

interface ScryptKDFParamsOut {
dklen: number
n: number
p: number
Expand All @@ -68,27 +137,35 @@ interface ScryptKDFParams {
}

interface PBKDFParams {
c: number
dklen: number
prf: string
salt: Buffer
}

interface PBKDFParamsOut {
c: number
dklen: number
prf: string
salt: string
}

type KDFParams = ScryptKDFParams | PBKDFParams
type KDFParamsOut = ScryptKDFParamsOut | PBKDFParamsOut

function kdfParamsForPBKDF(opts: V3Params): PBKDFParams {
function kdfParamsForPBKDF(opts: V3ParamsStrict): PBKDFParams {
return {
dklen: opts.dklen,
salt: opts.salt.toString('hex'),
salt: opts.salt,
c: opts.c,
prf: 'hmac-sha256',
}
}

function kdfParamsForScrypt(opts: V3Params): ScryptKDFParams {
function kdfParamsForScrypt(opts: V3ParamsStrict): ScryptKDFParams {
return {
dklen: opts.dklen,
salt: opts.salt.toString('hex'),
salt: opts.salt,
n: opts.n,
r: opts.r,
p: opts.p,
Expand Down Expand Up @@ -130,7 +207,7 @@ interface V3Keystore {
}
ciphertext: string
kdf: string
kdfparams: KDFParams
kdfparams: KDFParamsOut
mac: string
}
id: string
Expand Down Expand Up @@ -361,6 +438,7 @@ export default class Wallet {

// public instance methods

// tslint:disable-next-line
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Why is it necessary to ignore tslint errors here and in getPublicKey()?

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@michaelsbradleyjr michaelsbradleyjr Aug 20, 2019

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Without disabling those lines for tslint I get the following when doing npm run tslint:

ERROR: /Users/michael/repos/ethereumjs-wallet/src/index.ts:439:10 - Refactor this getter so that it actually refers to the property 'privateKey'
ERROR: /Users/michael/repos/ethereumjs-wallet/src/index.ts:448:10 - Refactor this getter so that it actually refers to the property 'publicKey'

I felt that refactoring that code from the TS rewrite was beyond the scope of this PR, especially since the README documents those get... methods as part of the API. So I chose to stop the linter from failing on those lines.

public getPrivateKey(): Buffer {
return this.privKey
}
Expand All @@ -369,6 +447,7 @@ export default class Wallet {
return ethUtil.bufferToHex(this.privKey)
}

// tslint:disable-next-line
public getPublicKey(): Buffer {
return this.pubKey
}
Expand All @@ -394,16 +473,16 @@ export default class Wallet {
throw new Error('This is a public key only wallet')
}

const v3Params: V3Params = mergeToV3ParamsWithDefaults(opts)
const v3Params: V3ParamsStrict = mergeToV3ParamsWithDefaults(opts)

let kdfParams: PBKDFParams | ScryptKDFParams
let kdfParams: KDFParams
let derivedKey: Buffer
switch (v3Params.kdf) {
case KDFFunctions.PBKDF:
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I couldn't comment on the code below, but now that KDFParams.salt is a buffer and not converted to string, kdfparams.salt could be passed to pbkdf2Sync and scryptsy instead of v3Params.

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Nice catch, I've made the change.

kdfParams = kdfParamsForPBKDF(v3Params)
derivedKey = crypto.pbkdf2Sync(
Buffer.from(password),
v3Params.salt,
kdfParams.salt,
kdfParams.c,
kdfParams.dklen,
'sha256',
Expand All @@ -414,7 +493,7 @@ export default class Wallet {
// FIXME: support progress reporting callback
derivedKey = scryptsy(
Buffer.from(password),
v3Params.salt,
kdfParams.salt,
kdfParams.n,
kdfParams.r,
kdfParams.p,
Expand Down Expand Up @@ -449,7 +528,10 @@ export default class Wallet {
cipherparams: { iv: v3Params.iv.toString('hex') },
cipher: v3Params.cipher,
kdf: v3Params.kdf,
kdfparams: kdfParams,
kdfparams: {
...kdfParams,
salt: kdfParams.salt.toString('hex'),
},
mac: mac.toString('hex'),
},
}
Expand Down
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