Add a new option to limit DH key size in tls connect #1831

shigeki · 2015-05-29T07:26:49Z

This is the fix of logjam attack for a TLS client. It disable connecting to the TLS server with less than DH key size specified by a new option of minDHkeylen. The default is 1024 bits.

And it also introduces a new public API of TLSSocket.getEphemeralKeyInfo() to show the information of an ephemeral key type, name and length of TLS connection. I think it it good for users to know them. We should prepare future vulnerabilities not only DH but also ECDH.
Unfortunately openssl provided SSL_get_server_tmp_key() on only client so that this API returns an empty object on the server.

The last one is my home work from @bnoordhuis to output warning of setDHParams to console.trace().

Here is a list of logjam fix in openssl, Firefox and Chrome. I think iojs is also better to set minimum key length like this.

OpenSSL sets minimum key size 768 bits. iojs will follow this limit after upgrading forthcoming 1.0.2b even if minDHkeylen get less than this.
https://www.openssl.org/blog/blog/2015/05/20/logjam-freak-upcoming-changes/
Firefox(NSS) does it to 1023 bits. (surprisingly there were 1023 bits key certs in the past)
https://bugzilla.mozilla.org/show_bug.cgi?id=1138554
Chrome(BoringSSL) does it to 1024 bits.
https://boringssl-review.googlesource.com/4813

R= @bnoordhuis @indutny

indutny · 2015-05-29T08:09:32Z

Are you sure that we are actually vulnerable to the logjam attack? I always thought that we are not doing False Start, so it should not be possible to perform MiTM attack in this case.

shigeki · 2015-05-29T08:20:48Z

False Start is the worst case to decrypt DATA in offline.
But the paper of https://weakdh.org/imperfect-forward-secrecy.pdf says

we can keep browser connections alive by sending TLS warning alerts

According the paper, 512 bit DH key can be solved about 90 secs for the server with built-in prime such as apache. The current TLS timeout of iojs is 120 secs which is longer than that.

indutny · 2015-05-29T08:23:08Z

@shigeki but this is not logjam anymore, right? I just don't want to say that we was vulnerable to it in the first place, especially if we wasn't.

shigeki · 2015-05-29T08:28:34Z

If the wording of logjam only covers export DH cipher, that is right. I did not care about that. I've just changed this PR title to remove the word of logjam. There is no word of logjam in the commit message.

indutny · 2015-05-29T08:33:30Z

doc/api/tls.markdown

@@ -347,6 +347,11 @@ Creates a new client connection to the given `port` and `host` (old API) or

  - `session`: A `Buffer` instance, containing TLS session.

+  - `minDHkeylen`: Minimum key length of an ephemeral DH parameter to


A camel case (minDHKeyLen)? Or even minDHSize

I take minDHSize as it is shorter and more legible.

indutny · 2015-05-29T08:39:23Z

A couple of nits, otherwise looking great! Good job, @shigeki !

shigeki · 2015-05-30T04:15:05Z

@bnoordhuis @indutny Thanks for reviewing. According to your comments, I updated them. PTAL.

bnoordhuis · 2015-05-30T11:52:53Z

doc/api/tls.markdown

+connection. It returns an empty object when the key exchange is not
+ephemeral. As it is only supported on a client socket, it returns null
+if this is called on a server socket. The type of 'DH' and 'ECDH' are
+supported. The name property is only available in 'ECDH'.


Femto-nit: maybe reword this to:

The supported types are 'DH' and 'ECDH'. The `name` property is only available with 'ECDH'.

bnoordhuis · 2015-05-30T11:56:29Z

LGTM apart from a couple of nits. Can you rebase and run the CI before landing this? Thanks.

jasnell · 2015-10-16T00:07:46Z

@shigeki @bnoordhuis @indutny ... ping

shigeki · 2015-10-16T00:30:44Z

Sorry for my late response. This is a security enhancement of DH as the same way of Chrome/Firefox. It is not so much threat at the usual use but https://freedom-to-tinker.com/blog/haldermanheninger/how-is-nsa-breaking-so-much-crypto/ says that

Breaking a second 1024-bit prime would allow passive eavesdropping on connections to nearly 20% of the top million HTTPS websites. In other words, a one-time investment in massive computation would make it possible to eavesdrop on trillions of encrypted connections.

so that I think it is worth to have this in order to protect against the nation level attack.
The current patch is revised after the last LGTM and I'm not sure that whether I can land it or not without a new review.

indutny · 2015-10-16T00:34:24Z

This should be semver-major. It will definitely break code that was connecting to 1024-bit DH servers. Otherwise LGTM

shigeki · 2015-10-16T00:38:12Z

@indutny Thanks. I agree it. I've changed label. I rebase this, make tests again and land it after 5.0 start.

Fishrock123 · 2015-10-16T00:43:50Z

Note: semver-major will have to land before 5.0 or else be delayed until 6.0

shigeki · 2015-10-16T00:48:36Z

@Fishrock123 Thanks. The current master is already 5.0.0-pre so can I land this now?

shigeki · 2015-10-16T01:27:06Z

CI testing https://ci.nodejs.org/job/node-test-pull-request/519/

shigeki · 2015-10-16T02:20:33Z

CI show the following 7 test failures but they are not related to this PR. Otherwise are green.
@Fishrock123 @rvagg Could you give me a timing to land semver-major?

ubuntu1404-32
not ok 42 test-child-process-fork-net2.js
vs2013,win2008r2
not ok 11 test-child-process-fork-regr-Segfault in node::StreamBase::GetFD #2847.js
vs2015,win2012r2
not ok 223 test-http-pipeline-flood.js
ppcle-ubuntu1404
not ok 904 test-debug-args.js
ppcbe-fedora20
not ok 45 test-child-process-fork-regr-Segfault in node::StreamBase::GetFD #2847.js
not ok 712 test-tick-processor.js
not ok 904 test-debug-args.js

Fishrock123 · 2015-10-16T02:35:59Z

@shigeki v5.0 is set to cut probably next week, and semver-major's have been landing on master. If this PR is green as usual it can land on master at any time, but it will only make it into v5 if it lands soon. :)

(This also assumes this has had enough TSC review, which I think it has.)

Returns an object representing a type, name and size of an ephemeral key exchange in a client connection. Currently only DHE and ECHE are supported. This api only works on on a client connection. When it is called on a server connection, null is returned. When its key exchange is not ephemeral, an empty object is returned. PR-URL: #1831 Reviewed-By: indutny - Fedor Indutny <[email protected]> Reviewed-By: bnoordhuis - Ben Noordhuis <[email protected]>

Add a new option to specifiy a minimum size of an ephemeral DH parameter to accept a tls connection. Default is 1024 bit. PR-URL: #1831 Reviewed-By: indutny - Fedor Indutny <[email protected]> Reviewed-By: bnoordhuis - Ben Noordhuis <[email protected]>

To make it easy to figure out where the warning comes from. Also fix style and variable name that was made in #1739. PR-URL: #1831 Reviewed-By: indutny - Fedor Indutny <[email protected]> Reviewed-By: bnoordhuis - Ben Noordhuis <[email protected]>

shigeki · 2015-10-16T02:43:10Z

@Fishrock123 Thanks.
Landed in 6d92eba, f72e178 and 0140e1b to the current master.

Notable changes: * buffer: (Breaking) Removed both 'raw' and 'raws' encoding types from Buffer, these have been deprecated for a long time (Sakthipriyan Vairamani) nodejs#2859. * console: (Breaking) Values reported by console.time() now have 3 decimals of accuracy added (Michaël Zasso) nodejs#3166. * fs: - fs.readFile*(), fs.writeFile*(), and fs.appendFile*() now also accept a file descriptor as their first argument (Johannes Wüller) nodejs#3163. - (Breaking) In fs.readFile(), if an encoding is specified and the internal toString() fails the error is no longer thrown but is passed to the callback (Evan Lucas) nodejs#3485. - (Breaking) In fs.read() (using the fs.read(fd, length, position, encoding, callback) form), if the internal toString() fails the error is no longer thrown but is passed to the callback (Evan Lucas) nodejs#3503. * http: - Fixed a bug where pipelined http requests would stall (Fedor Indutny) nodejs#3342. - (Breaking) When parsing HTTP, don't add duplicates of the following headers: Retry-After, ETag, Last-Modified, Server, Age, Expires. This is in addition to the following headers which already block duplicates: Content-Type, Content-Length, User-Agent, Referer, Host, Authorization, Proxy-Authorization, If-Modified-Since, If-Unmodified-Since, From, Location, Max-Forwards (James M Snell) nodejs#3090. - (Breaking) The callback argument to OutgoingMessage#setTimeout() must be a function or a TypeError is thrown (James M Snell) nodejs#3090. - (Breaking) HTTP methods and header names must now conform to the RFC 2616 "token" rule, a list of allowed characters that excludes control characters and a number of separator characters. Specifically, methods and header names must now match /^[a-zA-Z0-9_!#$%&'*+.^`|~-]+$/ or a TypeError will be thrown (James M Snell) nodejs#2526. * node: - (Breaking) Deprecated the _linklist module (Rich Trott) nodejs#3078. - (Breaking) Removed require.paths and require.registerExtension(), both had been previously set to throw Error when accessed (Sakthipriyan Vairamani) nodejs#2922. * npm: Upgraded to version 3.3.6 from 2.14.7, see https://github.com/npm/npm/releases/tag/v3.3.6 for more details. This is a major version bump for npm and it has seen a significant amount of change. Please see the original npm v3.0.0 release notes for a list of major changes (Rebecca Turner) nodejs#3310. * src: (Breaking) Bumped NODE_MODULE_VERSION to 47 from 46, this is necessary due to the V8 upgrade. Native add-ons will need to be recompiled (Rod Vagg) nodejs#3400. * timers: Attempt to reuse the timer handle for setTimeout().unref(). This fixes a long-standing known issue where unrefed timers would perviously hold beforeExit open (Fedor Indutny) nodejs#3407. * tls: - Added ALPN Support (Shigeki Ohtsu) nodejs#2564. - TLS options can now be passed in an object to createSecurePair() (Коренберг Марк) nodejs#2441. - (Breaking) The default minimum DH key size for tls.connect() is now 1024 bits and a warning is shown when DH key size is less than 2048 bits. This a security consideration to prevent "logjam" attacks. A new minDHSize TLS option can be used to override the default. (Shigeki Ohtsu) nodejs#1831. * util: - (Breaking) util.p() was deprecated for years, and has now been removed (Wyatt Preul) nodejs#3432. - (Breaking) util.inherits() can now work with ES6 classes. This is considered a breaking change because of potential subtle side-effects caused by a change from directly reassigning the prototype of the constructor using `ctor.prototype = Object.create(superCtor.prototype, { constructor: { ... } })` to using `Object.setPrototypeOf(ctor.prototype, superCtor.prototype)` (Michaël Zasso) nodejs#3455. * v8: (Breaking) Upgraded to 4.6.85.25 from 4.5.103.35 (Ali Ijaz Sheikh) nodejs#3351. - Implements the spread operator, see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator for further information. - Implements new.target, see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/new.target for further information. * zlib: Decompression now throws on truncated input (e.g. unexpected end of file) (Yuval Brik) nodejs#2595. PR-URL: nodejs#3466

Notable changes: * buffer: (Breaking) Removed both 'raw' and 'raws' encoding types from Buffer, these have been deprecated for a long time (Sakthipriyan Vairamani) #2859. * console: (Breaking) Values reported by console.time() now have 3 decimals of accuracy added (Michaël Zasso) #3166. * fs: - fs.readFile*(), fs.writeFile*(), and fs.appendFile*() now also accept a file descriptor as their first argument (Johannes Wüller) #3163. - (Breaking) In fs.readFile(), if an encoding is specified and the internal toString() fails the error is no longer thrown but is passed to the callback (Evan Lucas) #3485. - (Breaking) In fs.read() (using the fs.read(fd, length, position, encoding, callback) form), if the internal toString() fails the error is no longer thrown but is passed to the callback (Evan Lucas) #3503. * http: - Fixed a bug where pipelined http requests would stall (Fedor Indutny) #3342. - (Breaking) When parsing HTTP, don't add duplicates of the following headers: Retry-After, ETag, Last-Modified, Server, Age, Expires. This is in addition to the following headers which already block duplicates: Content-Type, Content-Length, User-Agent, Referer, Host, Authorization, Proxy-Authorization, If-Modified-Since, If-Unmodified-Since, From, Location, Max-Forwards (James M Snell) #3090. - (Breaking) The callback argument to OutgoingMessage#setTimeout() must be a function or a TypeError is thrown (James M Snell) #3090. - (Breaking) HTTP methods and header names must now conform to the RFC 2616 "token" rule, a list of allowed characters that excludes control characters and a number of separator characters. Specifically, methods and header names must now match /^[a-zA-Z0-9_!#$%&'*+.^`|~-]+$/ or a TypeError will be thrown (James M Snell) #2526. * node: - (Breaking) Deprecated the _linklist module (Rich Trott) #3078. - (Breaking) Removed require.paths and require.registerExtension(), both had been previously set to throw Error when accessed (Sakthipriyan Vairamani) #2922. * npm: Upgraded to version 3.3.6 from 2.14.7, see https://github.com/npm/npm/releases/tag/v3.3.6 for more details. This is a major version bump for npm and it has seen a significant amount of change. Please see the original npm v3.0.0 release notes for a list of major changes (Rebecca Turner) #3310. * src: (Breaking) Bumped NODE_MODULE_VERSION to 47 from 46, this is necessary due to the V8 upgrade. Native add-ons will need to be recompiled (Rod Vagg) #3400. * timers: Attempt to reuse the timer handle for setTimeout().unref(). This fixes a long-standing known issue where unrefed timers would perviously hold beforeExit open (Fedor Indutny) #3407. * tls: - Added ALPN Support (Shigeki Ohtsu) #2564. - TLS options can now be passed in an object to createSecurePair() (Коренберг Марк) #2441. - (Breaking) The default minimum DH key size for tls.connect() is now 1024 bits and a warning is shown when DH key size is less than 2048 bits. This a security consideration to prevent "logjam" attacks. A new minDHSize TLS option can be used to override the default. (Shigeki Ohtsu) #1831. * util: - (Breaking) util.p() was deprecated for years, and has now been removed (Wyatt Preul) #3432. - (Breaking) util.inherits() can now work with ES6 classes. This is considered a breaking change because of potential subtle side-effects caused by a change from directly reassigning the prototype of the constructor using `ctor.prototype = Object.create(superCtor.prototype, { constructor: { ... } })` to using `Object.setPrototypeOf(ctor.prototype, superCtor.prototype)` (Michaël Zasso) #3455. * v8: (Breaking) Upgraded to 4.6.85.25 from 4.5.103.35 (Ali Ijaz Sheikh) #3351. - Implements the spread operator, see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator for further information. - Implements new.target, see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/new.target for further information. * zlib: Decompression now throws on truncated input (e.g. unexpected end of file) (Yuval Brik) #2595. PR-URL: #3466

Fishrock123 · 2015-10-30T13:51:21Z

Tagging also as minor since one commit is just additive.

MylesBorins · 2015-11-16T23:39:41Z

Just want to verify that f72e178 will not be landing in lts

jasnell · 2015-11-17T00:00:05Z

@thealphanerd ... this one is a special case, a variation on this will land in v4.x, v0.12 and v0.10 as part of a security fix that landed in master but not in the branches.

MylesBorins · 2015-12-15T00:12:46Z

@jasnell has the security fix landed yet? I could not find any of these commits in v4.x-staging

shigeki added crypto Issues and PRs related to the crypto subsystem. tls Issues and PRs related to the tls subsystem. semver-minor PRs that contain new features and should be released in the next minor version. labels May 29, 2015

shigeki changed the title ~~Fix logjam attack for tls client~~ Add a new option to limit DH key size in tls connect against logjam attack May 29, 2015

shigeki changed the title ~~Add a new option to limit DH key size in tls connect against logjam attack~~ Add a new option to limit DH key size in tls connect May 29, 2015

indutny reviewed May 29, 2015
View reviewed changes

shigeki force-pushed the fix_LogjamAttack_client branch from 484262e to dd8a2a2 Compare May 30, 2015 04:13

bnoordhuis reviewed May 30, 2015
View reviewed changes

shigeki force-pushed the fix_LogjamAttack_client branch 3 times, most recently from 8b16dfd to e4f02bd Compare June 1, 2015 16:37

shigeki added semver-major PRs that contain breaking changes and should be released in the next major version. and removed semver-minor PRs that contain new features and should be released in the next minor version. labels Oct 16, 2015

shigeki closed this Oct 16, 2015

rvagg mentioned this pull request Oct 21, 2015

Release proposal: v5.0.0 #3466

Merged

shigeki mentioned this pull request Oct 21, 2015

tls: make server not use DHE in less than 1024 bits nodejs/Release#49

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Fishrock123 added the semver-minor PRs that contain new features and should be released in the next minor version. label Oct 30, 2015

MylesBorins mentioned this pull request Nov 16, 2015

test: more regression tests for minDHSize option #3629

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MylesBorins mentioned this pull request Nov 17, 2015

v4.2.2+1 commit candidates nodejs/Release#57

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rvagg mentioned this pull request Oct 31, 2016

crypto: initial LibreSSL support (WIP) #9376

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Add a new option to limit DH key size in tls connect #1831

Add a new option to limit DH key size in tls connect #1831

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		@@ -347,6 +347,11 @@ Creates a new client connection to the given `port` and `host` (old API) or

		- `session`: A `Buffer` instance, containing TLS session.

		- `minDHkeylen`: Minimum key length of an ephemeral DH parameter to

Add a new option to limit DH key size in tls connect #1831

Add a new option to limit DH key size in tls connect #1831

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