I opted for adding a separate TLS13CipherSuites field to the Config
because library users that did not set Config.MaxVersion are
supposed to get TLS 1.3 support automatically, like it has been for
HTTP/2, but having set CipherSuites would effectively disable it.

Updates #9671

Change-Id: I26a2776b68374d6f5ee45629da09f9494fe723ad

Updates #9671

Change-Id: Ia1b06ae518a4b2821a584a420d99859a2666c8f0

Opening the 1.3 dances with the record layer because it has been the
most stable through the drafts, has the least dependencies, and has been
tricky in my experience.

Note that the record layer version check is entirely removed according
to https://tools.ietf.org/html/draft-ietf-tls-tls13-18#appendix-C.2.

A test that happened to hit that check (but was not made to test for it)
has changed to the next error in the stack.

There are no 1.3 tests at the moment, and I suspect they will all have to
wait for the patch cycle to reach interoperability.

Using > / <= VersionTLS13 for all conditionals to transparently support
draft versions and hypotetical future versions.

See https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-5.

Updates #9671

Change-Id: I97f0a59439728f194a1c50b48cff041469a0f00b

Updates #20164.

Change-Id: Ib900095e7885f25cd779750674a712c770603ca8
Reviewed-on: https://go-review.googlesource.com/42137
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Users (like myself) may be tempted to think the higher-numbered curve
is somehow better or more secure, but P256 is currently the best
ECDSA implementation, due to its better support in TLS clients, and a
constant time implementation.

For example, sites that present a certificate signed with P521
currently fail to load in Chrome stable, and the error on the Go side
says simply "remote error: tls: illegal parameter".

Fixes #19901.

Change-Id: Ia5e689e7027ec423624627420e33029c56f0bd82
Reviewed-on: https://go-review.googlesource.com/40211
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Using GetClientCertificate with the http client is currently completely
broken because inside the transport we clone the tls.Config and pass it
off to the tls.Client. Since tls.Config.Clone() does not pass forward
the GetClientCertificate field, GetClientCertificate is ignored in this
context.

Fixes #19264

Change-Id: Ie214f9f0039ac7c3a2dab8ffd14d30668bdb4c71
Signed-off-by: Mike Danese <mikedanese@google.com>
Reviewed-on: https://go-review.googlesource.com/37541
Reviewed-by: Filippo Valsorda <hi@filippo.io>
Reviewed-by: Adam Langley <agl@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

An io.Reader does not guarantee that it will read in the entire buffer.
To ensure that property, io.ReadFull should be used instead.

Change-Id: I0b863135ab9abc40e813f9dac07bfb2a76199950
Reviewed-on: https://go-review.googlesource.com/37403
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

There's no need to hold the handshake lock across this call and it can
lead to deadlocks if the net.Conn calls back into the tls.Conn.

Fixes #18426.

Change-Id: Ib1b2813cce385949d970f8ad2e52cfbd1390e624
Reviewed-on: https://go-review.googlesource.com/36561
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Link in the description of TLSUnique field of ConnectionState struct
leads to an article that is no longer available, so this commit
replaces it with link to a copy of the very same article on another
site.

Fixes #18842.

Change-Id: I8f8d298c4774dc0fbbad5042db0684bb3220aee8
Reviewed-on: https://go-review.googlesource.com/36052
Reviewed-by: Filippo Valsorda <hi@filippo.io>
Reviewed-by: Adam Langley <agl@golang.org>

This change clarifies that only ticket-based resumption is supported by
crypto/tls. It's not clear where to document this for a server,
although perhaps it's obvious there because there's nowhere to plug in
the storage that would be needed by SessionID-based resumption.

Fixes #18607

Change-Id: Iaaed53e8d8f2f45c2f24c0683052df4be6340922
Reviewed-on: https://go-review.googlesource.com/36560
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Ib47e295e8646b769c30fd81e5c7f20f964df163e
Reviewed-on: https://go-review.googlesource.com/36335
Reviewed-by: Filippo Valsorda <hi@filippo.io>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

SNI values may not include a trailing dot according to
https://tools.ietf.org/html/rfc6066#section-3. Although crypto/tls
handled this correctly as a client, it didn't reject this as a server.

This change makes sending an SNI value with a trailing dot a fatal
error.

Updates #18114.

Change-Id: Ib7897ab40e98d4a7a4646ff8469a55233621f631
Reviewed-on: https://go-review.googlesource.com/33904
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

ConnectionState.NegotiatedProtocol's documentation implies that it will
always be from Config.NextProtos. This commit clarifies that there is no
guarantee.

This commit also adds a note to
ConnectionState.NegotiatedProtocolIsMutual, making it clear that it is
client side only.

Fixes #18841

Change-Id: Icd028af8042f31e45575f1080c5e9bd3012e03d7
Reviewed-on: https://go-review.googlesource.com/35917
Reviewed-by: Filippo Valsorda <hi@filippo.io>
Reviewed-by: Adam Langley <agl@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

As is, they were fully vulnerable to the Lucky13 attack. The SHA1
variants implement limited countermeasures (see f28cf8346c4) but the
SHA256 ones are apparently used rarely enough (see 8741504888b) that
it's not worth the extra code.

Instead, disable them by default and update the warning.

Updates #13385
Updates #15487

Change-Id: I45b8b716001e2fa0811b17e25be76e2512e5abb2
Reviewed-on: https://go-review.googlesource.com/35290
Reviewed-by: Adam Langley <alangley@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Matt Layher <mdlayher@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Id0044c45c23c12ee0bca362a9cdd25369ed7776c
Reviewed-on: https://go-review.googlesource.com/34533
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Some countermeasures were implemented in https://golang.org/cl/18130

Updates #13385

Change-Id: I723e1e3be0fa6d13767b65b145d90c89e92b2774
Reviewed-on: https://go-review.googlesource.com/33665
Reviewed-by: Adam Langley <agl@golang.org>

The SignedCertificateTimestampList[1] specifies that both the list and
each element must not be empty. Checking that the list is not empty was
handled in [2] and this change checks that the SCTs themselves are not
zero-length.

[1] https://tools.ietf.org/html/rfc6962#section-3.3
[2] https://golang.org/cl/33265

Change-Id: Iabaae7a15f6d111eb079e5086e0bd2005fae9e48
Reviewed-on: https://go-review.googlesource.com/33355
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

When the CT extension is enabled but no SCTs are present, the existing
code calls "continue" which causes resizing the data byte slice to be
skipped. In fact, such extensions should be rejected.

Fixes #17958

Change-Id: Iad12da10d1ea72d04ae2e1012c28bb2636f06bcd
Reviewed-on: https://go-review.googlesource.com/33265
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

For #13057.

Change-Id: Idbc50d5b08e055a23ab7cc9eb62dbc47b65b1815
Reviewed-on: https://go-review.googlesource.com/29050
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #17900.

Change-Id: I42cda6ac9cf48ed739d3a015a90b3cb15edf8ddf
Reviewed-on: https://go-review.googlesource.com/33243
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The tree is inconsistent about single l vs double l in those
words in documentation, test messages, and one error value text.

	$ git grep -E '[Mm]arshall(|s|er|ers|ed|ing)' | wc -l
	      42
	$ git grep -E '[Mm]arshal(|s|er|ers|ed|ing)' | wc -l
	    1694

Make it consistently a single l, per earlier decisions. This means
contributors won't be confused by misleading precedence, and it helps
consistency.

Change the spelling in one error value text in newRawAttributes of
crypto/x509 package to be consistent.

This change was generated with:

	perl -i -npe 's,([Mm]arshal)l(|s|er|ers|ed|ing),$1$2,' $(git grep -l -E '[Mm]arshall' | grep -v AUTHORS | grep -v CONTRIBUTORS)

Updates #12431.
Follows https://golang.org/cl/14150.

Change-Id: I85d28a2d7692862ccb02d6a09f5d18538b6049a2
Reviewed-on: https://go-review.googlesource.com/33017
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fix spelling of "original" and "occurred" in new gofmt docs. The same
misspelling of "occurred" was also present in crypto/tls, I fixed it there as
well.

Change-Id: I67b4f1c09bd1a2eb1844207d5514f08a9f525ff9
Reviewed-on: https://go-review.googlesource.com/33138
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

CL 32871 updated the default cipher suites to use AES-GCM in
preference to ChaCha20-Poly1305 on platforms which have hardware
implementations of AES-GCM. This change makes BenchmarkThroughput
use the default cipher suites instead of the test cipher suites to
ensure that the recommended (fastest) algorithms are used.

Updates #17779.

Change-Id: Ib551223e4a00b5ea197d4d73748e1fdd8a47c32d
Reviewed-on: https://go-review.googlesource.com/32838
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>

Support for ChaCha20-Poly1305 ciphers was recently added to crypto/tls.
These ciphers are preferable in software, but they cannot beat hardware
support for AES-GCM, if present.

This change moves detection for hardware AES-GCM support into
cipher/internal/cipherhw so that it can be used from crypto/tls. Then,
when AES-GCM hardware is present, the AES-GCM cipher suites are
prioritised by default in crypto/tls. (Some servers, such as Google,
respect the client's preference between AES-GCM and ChaCha20-Poly1305.)

Fixes #17779.

Change-Id: I50de2be486f0b0b8052c4628d3e3205a1d54a646
Reviewed-on: https://go-review.googlesource.com/32871
Run-TryBot: Adam Langley <agl@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

I used the slowtests.go tool as described in
https://golang.org/cl/32684 on packages that stood out.

go test -short std drops from ~56 to ~52 seconds.

This isn't a huge win, but it was mostly an exercise.

Updates #17751

Change-Id: I9f3402e36a038d71e662d06ce2c1d52f6c4b674d
Reviewed-on: https://go-review.googlesource.com/32751
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Currently, the selection of a client certificate done internally based
on the limitations given by the server's request and the certifcates in
the Config. This means that it's not possible for an application to
control that selection based on details of the request.

This change adds a callback, GetClientCertificate, that is called by a
Client during the handshake and which allows applications to select the
best certificate at that time.

(Based on https://golang.org/cl/25570/ by Bernd Fix.)

Fixes #16626.

Change-Id: Ia4cea03235d2aa3c9fd49c99c227593c8e86ddd9
Reviewed-on: https://go-review.googlesource.com/32115
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The SignatureAndHashAlgorithm from TLS 1.2[1] is being changed to
SignatureScheme in TLS 1.3[2]. (The actual values are compatible
however.)

Since we expect to support TLS 1.3 in the future, we're already using
the name and style of SignatureScheme in the recently augmented
ClientHelloInfo. As this is public API, it seems that SignatureScheme
should have its own type and exported values, which is implemented in
this change.

[1] https://tools.ietf.org/html/rfc5246#section-7.4.1.4.1
[2] https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.3

Change-Id: I0482755d02bb9a04eaf075c012696103eb806645
Reviewed-on: https://go-review.googlesource.com/32119
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The CloseWrite method sends a close_notify alert record to the other
side of the connection. This record indicates that the sender has
finished sending on the connection. Unlike the Close method, the sender
may still read from the connection until it recieves a close_notify
record (or the underlying connection is closed). This is analogous to a
TCP half-close.

This is a rework of CL 25159 with fixes for the unstable test.

Updates #8579

Change-Id: I47608d2f82a88baff07a90fd64c280ed16a60d5e
Reviewed-on: https://go-review.googlesource.com/31318
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #17430

Change-Id: Ia1c25363d64e3091455ce00644438715aff30a0d
Reviewed-on: https://go-review.googlesource.com/31391
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Filippo Valsorda <hi@filippo.io>

While we're here, use test[%d] in place of #%d.

Change-Id: Ie30afcab9673e78d3ea7ca80f5e662fbea897488
Reviewed-on: https://go-review.googlesource.com/31936
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

VerifyPeerCertificate returns an error if the peer should not be
trusted. It will be called after the initial handshake and before
any other verification checks on the cert or chain are performed.
This provides the callee an opportunity to augment the certificate
verification.

If VerifyPeerCertificate is not nil and returns an error,
then the handshake will fail.

Fixes #16363

Change-Id: I6a22f199f0e81b6f5d5f37c54d85ab878216bb22
Reviewed-on: https://go-review.googlesource.com/26654
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I22f0f3e792052762499f632571155768b4052bc9
Reviewed-on: https://go-review.googlesource.com/31759
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Now that we have the Clone method on tls.Config, net/http doesn't need
any custom functions to do that any more.

Change-Id: Ib60707d37f1a7f9a7d7723045f83e59eceffd026
Reviewed-on: https://go-review.googlesource.com/31595
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This change enables the ChaCha20-Poly1305 cipher suites by default. This
changes the default ClientHello and thus requires updating all the
tests.

Change-Id: I6683a2647caaff4a11f9e932babb6f07912cad94
Reviewed-on: https://go-review.googlesource.com/30958
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

GetConfigForClient allows the tls.Config to be updated on a per-client
basis.

Fixes #16066.
Fixes #15707.
Fixes #15699.

Change-Id: I2c675a443d557f969441226729f98502b38901ea
Reviewed-on: https://go-review.googlesource.com/30790
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>