crypto: fix webcrypto derive(Bits|Key) resolve values and docs #38148
Conversation
nodejs-github-bot
added
crypto
This comment has been minimized.
This comment has been minimized.
panva
added
doc
| @@ -122,7 +122,7 @@ async function pbkdf2DeriveBits(algorithm, baseKey, length) { | |||
| return new Promise((resolve, reject) => { | |||
| pbkdf2(raw, salt, iterations, byteLength, hash, (err, result) => { | |||
| if (err) return reject(err); | |||
| resolve(result); | |||
| resolve(result.buffer); | |||
There was a problem hiding this comment.
Technically, pbkdf2 is only required to give us a Buffer, which does not necessarily have the same byte length as the backing ArrayBuffer:
> Buffer.from([1, 2, 3]).buffer.byteLength
8192
> crypto.randomFillSync(Buffer.allocUnsafe(1024)).buffer.byteLength
8192
That's one of many reasons why WebCrypto doesn't align well with Node.js. However, we know that the implementation of PBKDF2 always returns a Buffer that has the same byteLength as the backing ArrayBuffer. And, hopefully, tests will catch it if that ever changes.
There was a problem hiding this comment.
Yes, i've checked that they do. Alternatively we can do new Uint8Array(result).buffer
> const foo = Buffer.from('foo')
> foo.buffer.byteLength
8192
> new Uint8Array(foo).buffer
ArrayBuffer { [Uint8Contents]: <66 6f 6f>, byteLength: 3 }
There was a problem hiding this comment.
I think these would be places where adding assertions about matching lengths and byteOffsets might make sense :)
There was a problem hiding this comment.
Alternatively we can do
new Uint8Array(result).buffer
That would create an unnecessary copy of sensitive data (the result of PBKDF2 is considered secret). And yes, I realize that arguing about memory safety is moot in JavaScript :)
panva
added
the
author ready
fixes #38115 PR-URL: #38148 Reviewed-By: Tobias Nießen <[email protected]> Reviewed-By: James M Snell <[email protected]>
|
Landed in 896dc39 |
fixes #38115 PR-URL: #38148 Reviewed-By: Tobias Nießen <[email protected]> Reviewed-By: James M Snell <[email protected]>
Couple of issues discovered in #38115 addressed by this PR
PBKDF2deriveBits resolve value typeNODE-SCRYPTderiveBits resolve value typesubtle.deriveKeyresolve value type### Deriving bits and keysexample does not work withderiveBitsad resolve value types see SubtleCrypto interface definition.