crypto: add Hash.prototype.copy() method by bnoordhuis · Pull Request #29910 · nodejs/node · GitHub

Make it possible to clone the internal state of a Hash object
into a new Hash object, i.e., to fork the state of the object.

Fixes: #29903

CI: https://ci.nodejs.org/job/node-test-pull-request/25935/

Author of #29903 here. I wasn't able to help with implementation of this feature as I don't know C/C++. But if anything I can do here on docs or testing, or anything involving JS, please shout. Really appreciate this being added to Node.

Could be good to add to end of hash.digest() docs:

Use hash.copy() first if you wish to continue to add data to the hash after hash.digest().

https://nodejs.org/api/stream.html#stream_new_stream_transform_options doesn't have an outputLength option!

It looks like the options are "whatever crypto.createHash() accepts", and that the crypto.createHash docs are wrong, https://nodejs.org/api/crypto.html#crypto_crypto_createhash_algorithm_options, and got copied here.

You could fix the createHash docs, but that's unrelated to this feature, perhaps just change the docs here to link to them and say "same options as over there", so when the createHash docs get fixed this will be fixed, too.

Personally, I don't think it's too confusing but I can split it off into a separate issue if you like.

Could this suffer from problems similar to #28245 depending on OpenSSL internals, since we don't always set state[kFinalized]?

Could this suffer from problems similar to #28245 depending on OpenSSL internals, since we don't always set state[kFinalized]?

Interesting question. I don't believe it actually hurts to copy a finalized hash object, it's just pointless (and that's why I added the guard.)

Make it possible to clone the internal state of a Hash object into a new Hash object, i.e., to fork the state of the object. Fixes: nodejs#29903

Example added to the documentation.

Use hash.copy() first if you wish to continue to add data to the hash after hash.digest().

I didn't use that because it can be construed as meaning that copy() after digest() should work when it doesn't.

Food for thought: we could also make digest() omnipotent by cloning the hash object internally. I.e., this would work:

const hash = crypto.createHash('sha256');
const one = hash.update('one').digest();
const two = hash.update('two').digest();

The downside is that it imposes a (possibly small) performance penalty on single-use hash objects.

@bnoordhuis Only problem with that is that some people feel that the hash object should be reusable in that its internal state is reset after a call to .digest() (#25857). Personally, that doesn't make sense to me, but it could cause confusion it seems.

It's not so hard to call .copy() explicitly I think, and some people will blanche at even a small performance cost.

I don't think it is a good idea to implicitely reset the internal state of the object in .digest(), it will only lead to bugs and problems.

.copy() behaves differently than what you are describing, it does not reset the state, instead, it allows to obtain a second Hash object with the same internal state.

CI: https://ci.nodejs.org/job/node-test-pull-request/26057/

@tniessen Ah sorry I wasn't clear. I understand this is not what .copy() does. What I was trying to say is that there are seemingly two different behaviors that people might expect if you are allowed to call .digest() more than once on a hash.

With this code:

const hash = crypto.createHash('md5');
hash.update('abc');
hash.digest('hex');

hash.update('def');
const res = hash.digest('hex');

res could be expected to be either:

Hash of "abcdef" (rolling hash)
Hash of "def" (1st call to .digest() reset hash)

My expectation would be (1), but it seems from #25857 that some people would expect (2). Personally I think there's little merit to the arguments made by the OP in that issue. But since there are seemingly different opinions, it could lead to confusion and bugs as you say.

So I was trying to say: probably it's safer to keep behavior of .digest() as it is, to avoid any ambiguity.

Hope that make more sense.

CI: https://ci.nodejs.org/job/node-test-pull-request/26060/ ✔️

Landed in 9f203f9

Make it possible to clone the internal state of a Hash object into a new Hash object, i.e., to fork the state of the object. Fixes: #29903 PR-URL: #29910 Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Sam Roberts <vieuxtech@gmail.com> Reviewed-By: Tobias Nießen <tniessen@tnie.de> Reviewed-By: David Carlier <devnexen@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com>

Fantastic. Thanks very much @bnoordhuis for implementing this and everyone else for reviewing.

Can I ask: Is this likely to get into a Node 12.x release before it goes LTS?

Can I ask: Is this likely to get into a Node 12.x release before it goes LTS?

Probably not before it goes LTS but probably the next release after that one. /ping @nodejs/releasers in case I'm wrong about that.

Ah OK great. My mistake - I was confusing the Active and Maintenance phases in terms of when new features can be added, so was wrongly thinking this might not land in an LTS release line until 14.x.

@overlookmotel Thanks for the clarification, I absolutely agree. Resetting the state in .digest() (or silently copying the state) will only lead to confusion.

It seems the YAML processing is broken for this doc section. IIRC, we usually use this structure with PR URL field only in history entries.

This fixes YAML that gets incorrectly processed by our tooling. Refs: nodejs#29910 (comment) PR-URL: nodejs#30016 Reviewed-By: Richard Lau <riclau@uk.ibm.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

Make it possible to clone the internal state of a Hash object into a new Hash object, i.e., to fork the state of the object. Fixes: #29903 PR-URL: #29910 Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Sam Roberts <vieuxtech@gmail.com> Reviewed-By: Tobias Nießen <tniessen@tnie.de> Reviewed-By: David Carlier <devnexen@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com>

This fixes YAML that gets incorrectly processed by our tooling. Refs: #29910 (comment) PR-URL: #30016 Reviewed-By: Richard Lau <riclau@uk.ibm.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

Notable changes: * cli: * Added a new flag (`--trace-uncaught`) that makes Node.js print the stack trace at the time of throwing uncaught exceptions, rather than at the creation of the `Error` object, if there is any. This is disabled by default because it affects GC behavior. #30025 * crypto * Added `Hash.prototype.copy()` method. It returns a new `Hash` object with its internal state cloned from the original one. #29910 * dgram * Added source-specific multicast support. This adds methods to Datagram sockets to support RFC 4607 (https://tools.ietf.org/html/rfc4607) for IPv4 and IPv6. #15735 * fs * Added a `bufferSize` option to `fs.opendir()`. It allows to control the number of entries that are buffered internally when reading from the directory. #30114 * meta * Added Chengzhong Wu (https://github.com/legendecas) to collaborators. #30115 PR-URL: #30262

@bnoordhuis Hi. I wondered if there were any plans to backport this to Node 12?

NB This is not a demand, but a question. No is an acceptable answer!

@overlookmotel It will likely be included in one of the next 12.x releases :)

@tniessen Thank you! Can't wait to get my hands on it...

Make it possible to clone the internal state of a Hash object into a new Hash object, i.e., to fork the state of the object. Fixes: #29903 PR-URL: #29910 Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Sam Roberts <vieuxtech@gmail.com> Reviewed-By: Tobias Nießen <tniessen@tnie.de> Reviewed-By: David Carlier <devnexen@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com>

This fixes YAML that gets incorrectly processed by our tooling. Refs: #29910 (comment) PR-URL: #30016 Reviewed-By: Richard Lau <riclau@uk.ibm.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

Make it possible to clone the internal state of a Hash object into a new Hash object, i.e., to fork the state of the object. Fixes: #29903 PR-URL: #29910 Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Sam Roberts <vieuxtech@gmail.com> Reviewed-By: Tobias Nießen <tniessen@tnie.de> Reviewed-By: David Carlier <devnexen@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com>

This fixes YAML that gets incorrectly processed by our tooling. Refs: #29910 (comment) PR-URL: #30016 Reviewed-By: Richard Lau <riclau@uk.ibm.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

Notable changes: New assert APIs The `assert` module now provides experimental `assert.match()` and `assert.doesNotMatch()` methods. They will validate that the first argument is a string and matches (or does not match) the provided regular expression This is an experimental feature. Ruben Bridgewater [#30929](#30929). Advanced serialization for IPC The `child_process` and `cluster` modules now support a `serialization` option to change the serialization mechanism used for IPC. The option can have one of two values: * `'json'` (default): `JSON.stringify()` and `JSON.parse()` are used. This is how message serialization was done before. * `'advanced'`: The serialization API of the `v8` module is used. It is based on the HTML structured clone algorithm. and is able to serialize more built-in JavaScript object types, such as `BigInt`, `Map`, `Set` etc. as well as circular data structures. Anna Henningsen [#30162](#30162). CLI flags The new `--trace-exit` CLI flag makes Node.js print a stack trace whenever the Node.js environment is exited proactively (i.e. by invoking the `process.exit()` function or pressing Ctrl+C). legendecas [#30516](#30516). ___ The new `--trace-uncaught` CLI flag makes Node.js print a stack trace at the time of throwing uncaught exceptions, rather than at the creation of the `Error` object, if there is any. This option is not enabled by default because it may affect garbage collection behavior negatively. Anna Henningsen [#30025](#30025). ___ The `--disallow-code-generation-from-strings` V8 CLI flag is now whitelisted in the `NODE_OPTIONS` environment variable. Shelley Vohr [#30094](#30094). New crypto APIs For DSA and ECDSA, a new signature encoding is now supported in addition to the existing one (DER). The `verify` and `sign` methods accept a `dsaEncoding` option, which can have one of two values: * `'der'` (default): DER-encoded ASN.1 signature structure encoding `(r, s)`. * `'ieee-p1363'`: Signature format `r || s` as proposed in IEEE-P1363. Tobias Nießen [#29292](#29292). ___ A new method was added to `Hash`: `Hash.prototype.copy`. It makes it possible to clone the internal state of a `Hash` object into a new `Hash` object, allowing to compute the digest between updates. Ben Noordhuis [#29910](#29910). Dependency updates libuv was updated to 1.34.0. This includes fixes to `uv_fs_copyfile()` and `uv_interface_addresses()` and adds two new functions: `uv_sleep()` and `uv_fs_mkstemp()`. Colin Ihrig [#30783](#30783). ___ V8 was updated to 7.8.279.23. This includes performance improvements to object destructuring, RegExp match failures and WebAssembly startup time. The official release notes are available at https://v8.dev/blog/v8-release-78. Michaël Zasso [#30109](#30109). New EventEmitter APIs The new `EventEmitter.on` static method allows to async iterate over events. Matteo Collina [#27994](#27994). ___ It is now possible to monitor `'error'` events on an `EventEmitter` without consuming the emitted error by installing a listener using the symbol `EventEmitter.errorMonitor`. Gerhard Stoebich [#30932](#30932). ___ Using `async` functions with event handlers is problematic, because it can lead to an unhandled rejection in case of a thrown exception. The experimental `captureRejections` option in the `EventEmitter` constructor or the global setting change this behavior, installing a `.then(undefined, handler)` handler on the `Promise`. This handler routes the exception asynchronously to the `Symbol.for('nodejs.rejection')` method if there is one, or to the `'error'` event handler if there is none. Setting `EventEmitter.captureRejections = true` will change the default for all new instances of `EventEmitter`. This is an experimental feature. Matteo Collina [#27867](#27867). Performance Hooks are no longer experimental The `perf_hooks` module is now considered a stable API. legendecas [#31101](#31101). Introduction of experimental WebAssembly System Interface (WASI) support A new core module, `wasi`, is introduced to provide an implementation of the [WebAssembly System Interface](https://wasi.dev/) specification. WASI gives sandboxed WebAssembly applications access to the underlying operating system via a collection of POSIX-like functions. This is an experimental feature. Colin Ihrig [#30258](#30258). PR-URL: #31691

Thank you very much for backporting this to Node 12. Great stuff!

nodejs-github-bot added c++ Issues and PRs that require attention from people who are familiar with C++. lib / src Issues and PRs related to general changes in the lib or src directory. labels Oct 9, 2019

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Calculating rolling hashes #29903

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bnoordhuis added 2 commits October 15, 2019 12:16

crypto: add Hash.prototype.copy() method

bb039ef

Make it possible to clone the internal state of a Hash object into a new Hash object, i.e., to fork the state of the object. Fixes: nodejs#29903

fixup! add example

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bnoordhuis force-pushed the fix29903 branch from 939ad26 to 0291c30 Compare October 15, 2019 10:23

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doc: make YAML matter consistent in crypto.md #30016

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v13.1.0 release proposal #30262

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v12.16.0 proposal #31691

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