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>
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>
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>
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>
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>
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>
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>
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>
Since this changes the offered curves in the ClientHello, all the test
data needs to be updated too.
Change-Id: I227934711104349c0f0eab11d854e5a2adcbc363
Reviewed-on: https://go-review.googlesource.com/30825
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
X25519 (RFC 7748) is now commonly used for key agreement in TLS
connections, as specified in
https://tools.ietf.org/html/draft-ietf-tls-curve25519-01.
This change adds support for that in crypto/tls, but does not enabled it
by default so that there's less test noise. A future change will enable
it by default and will update all the test data at the same time.
Change-Id: I91802ecd776d73aae5c65bcb653d12e23c413ed4
Reviewed-on: https://go-review.googlesource.com/30824
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Since there's no aspect of key logging that OpenSSL can check for us,
the tests for it might as well just connect to another goroutine as this
is lower-maintainance.
Change-Id: I746d1dbad1b4bbfc8ef6ccf136ee4824dbda021e
Reviewed-on: https://go-review.googlesource.com/30089
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Joonas Kuorilehto <joneskoo@derbian.fi>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Concurrent use of tls.Config is allowed, and may lead to
KeyLogWriter being written to concurrently. Without a mutex
to protect it, corrupted output may occur. A mutex is added
for correctness.
The mutex is made global to save size of the config struct as
KeyLogWriter is rarely enabled.
Related to #13057.
Change-Id: I5ee55b6d8b43a191ec21f06e2aaae5002a71daef
Reviewed-on: https://go-review.googlesource.com/29016
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
In Go 1.0, the Config struct consisted only of exported fields.
In Go 1.1, it started to grow private, uncopyable fields (sync.Once,
sync.Mutex, etc).
Ever since, people have been writing their own private Config.Clone
methods, or risking it and doing a language-level shallow copy and
copying the unexported sync variables.
Clean this up and export the Config.clone method as Config.Clone.
This matches the convention of Template.Clone from text/template and
html/template at least.
Fixes#15771
Updates #16228 (needs update in x/net/http2 before fixed)
Updates #16492 (not sure whether @agl wants to do more)
Change-Id: I48c2825d4fef55a75d2f99640a7079c56fce39ca
Reviewed-on: https://go-review.googlesource.com/28075
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
Add support for writing TLS client random and master secret
in NSS key log format.
https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/Key_Log_Format
Normally this is enabled by a developer debugging TLS based
applications, especially HTTP/2, by setting the KeyLogWriter
to an open file. The keys negotiated in handshake are then
logged and can be used to decrypt TLS sessions e.g. in Wireshark.
Applications may choose to add support similar to NSS where this
is enabled by environment variable, but no such mechanism is
built in to Go. Instead each application must explicitly enable.
Fixes#13057.
Change-Id: If6edd2d58999903e8390b1674ba4257ecc747ae1
Reviewed-on: https://go-review.googlesource.com/27434
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
If SetSessionTicketKeys was called on a fresh tls.Config, the configured
keys would be overridden with a random key by serverInit.
Fixes#15421.
Change-Id: I5d6cc81fc3e5de4dfa15eb614d102fb886150d1b
Reviewed-on: https://go-review.googlesource.com/27317
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This fixes some 40 warnings from go vet.
Fixes#16134.
Change-Id: Ib9fcba275fe692f027a2a07b581c8cf503b11087
Reviewed-on: https://go-review.googlesource.com/24287
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
This change adds Config.Renegotiation which controls whether a TLS
client will accept renegotiation requests from a server. This is used,
for example, by some web servers that wish to “add” a client certificate
to an HTTPS connection.
This is disabled by default because it significantly complicates the
state machine.
Originally, handshakeMutex was taken before locking either Conn.in or
Conn.out. However, if renegotiation is permitted then a handshake may
be triggered during a Read() call. If Conn.in were unlocked before
taking handshakeMutex then a concurrent Read() call could see an
intermediate state and trigger an error. Thus handshakeMutex is now
locked after Conn.in and the handshake functions assume that Conn.in is
locked for the duration of the handshake.
Additionally, handshakeMutex used to protect Conn.out also. With the
possibility of renegotiation that's no longer viable and so
writeRecordLocked has been split off.
Fixes#5742.
Change-Id: I935914db1f185d507ff39bba8274c148d756a1c8
Reviewed-on: https://go-review.googlesource.com/22475
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Error strings in this package were all over the place: some were
prefixed with “tls:”, some with “crypto/tls:” and some didn't have a
prefix.
This change makes everything use the prefix “tls:”.
Change-Id: Ie8b073c897764b691140412ecd6613da8c4e33a2
Reviewed-on: https://go-review.googlesource.com/21893
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Standardize on space between "RFC" and number. Additionally change
the couple "a RFC" instances to "an RFC."
Fixes#15258
Change-Id: I2b17ecd06be07dfbb4207c690f52a59ea9b04808
Reviewed-on: https://go-review.googlesource.com/21902
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This change removes a lot of dead code. Some of the code has never been
used, not even when it was first commited. The rest shouldn't have
survived refactors.
This change doesn't remove unused routines helpful for debugging, nor
does it remove code that's used in commented out blocks of code that are
only unused temporarily. Furthermore, unused constants weren't removed
when they were part of a set of constants from specifications.
One noteworthy omission from this CL are about 1000 lines of unused code
in cmd/fix, 700 lines of which are the typechecker, which hasn't been
used ever since the pre-Go 1 fixes have been removed. I wasn't sure if
this code should stick around for future uses of cmd/fix or be culled as
well.
Change-Id: Ib714bc7e487edc11ad23ba1c3222d1fd02e4a549
Reviewed-on: https://go-review.googlesource.com/20926
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently, if a client of crypto/tls (e.g., net/http, http2) calls
tls.Conn.Write with a 33KB buffer, that ends up writing three TLS
records: 16KB, 16KB, and 1KB. Slow clients (such as 2G phones) must
download the first 16KB record before they can decrypt the first byte.
To improve latency, it's better to send smaller TLS records. However,
sending smaller records adds overhead (more overhead bytes and more
crypto calls), which slightly hurts throughput.
A simple heuristic, implemented in this change, is to send small
records for new connections, then boost to large records after the
first 1MB has been written on the connection.
Fixes#14376
Change-Id: Ice0f6279325be6775aa55351809f88e07dd700cd
Reviewed-on: https://go-review.googlesource.com/19591
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tom Bergan <tombergan@google.com>
Reviewed-by: Adam Langley <agl@golang.org>
(This relands commit a4dcc692011bf1ceca9b1a363fd83f3e59e399ee.)
https://tools.ietf.org/html/rfc6066#section-3 states:
“Literal IPv4 and IPv6 addresses are not permitted in "HostName".”
However, if an IP literal was set as Config.ServerName (which could
happen as easily as calling Dial with an IP address) then the code would
send the IP literal as the SNI value.
This change filters out IP literals, as recognised by net.ParseIP, from
being sent as the SNI value.
Fixes#13111.
Change-Id: I6e544a78a01388f8fe98150589d073b917087f75
Reviewed-on: https://go-review.googlesource.com/16776
Run-TryBot: Adam Langley <agl@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
https://tools.ietf.org/html/rfc6066#section-3 states:
“Literal IPv4 and IPv6 addresses are not permitted in "HostName".”
However, if an IP literal was set as Config.ServerName (which could
happen as easily as calling Dial with an IP address) then the code would
send the IP literal as the SNI value.
This change filters out IP literals, as recognised by net.ParseIP, from
being sent as the SNI value.
Fixes#13111.
Change-Id: Ie9ec7acc767ae172b48c9c6dd8d84fa27b1cf0de
Reviewed-on: https://go-review.googlesource.com/16742
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
In Go 1.5, Config.Certificates is no longer required if
Config.GetCertificate has been set. This change updated four comments to
reflect that.
Change-Id: Id72cc22fc79e931b2d645a7c3960c3241042762c
Reviewed-on: https://go-review.googlesource.com/13800
Reviewed-by: Adam Langley <agl@golang.org>
Strengthening VerifyHostname exposed the fact that for resumed
connections, ConnectionState().VerifiedChains was not being saved
and restored during the ClientSessionCache operations.
Do that.
This change just saves the verified chains in the client's session
cache. It does not re-verify the certificates when resuming a
connection.
There are arguments both ways about this: we want fast, light-weight
resumption connections (thus suggesting that we shouldn't verify) but
it could also be a little surprising that, if the verification config
is changed, that would be ignored if the same session cache is used.
On the server side we do re-verify client-auth certificates, but the
situation is a little different there. The client session cache is an
object in memory that's reset each time the process restarts. But the
server's session cache is a conceptual object, held by the clients, so
can persist across server restarts. Thus the chance of a change in
verification config being surprisingly ignored is much higher in the
server case.
Fixes#12024.
Change-Id: I3081029623322ce3d9f4f3819659fdd9a381db16
Reviewed-on: https://go-review.googlesource.com/13164
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
This is the second in a two-part change. See https://golang.org/cl/9415
for details of the overall change.
This change updates the supported signature algorithms to include
SHA-384 and updates all the testdata/ files accordingly. Even some of
the testdata/ files named “TLS1.0” and “TLS1.1” have been updated
because they have TLS 1.2 ClientHello's even though the server picks a
lower version.
Fixes#9757.
Change-Id: Ia76de2b548d3b39cd4aa3f71132b0da7c917debd
Reviewed-on: https://go-review.googlesource.com/9472
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Prior to TLS 1.2, the handshake had a pleasing property that one could
incrementally hash it and, from that, get the needed hashes for both
the CertificateVerify and Finished messages.
TLS 1.2 introduced negotiation for the signature and hash and it became
possible for the handshake hash to be, say, SHA-384, but for the
CertificateVerify to sign the handshake with SHA-1. The problem is that
one doesn't know in advance which hashes will be needed and thus the
handshake needs to be buffered.
Go ignored this, always kept a single handshake hash, and any signatures
over the handshake had to use that hash.
However, there are a set of servers that inspect the client's offered
signature hash functions and will abort the handshake if one of the
server's certificates is signed with a hash function outside of that
set. https://robertsspaceindustries.com/ is an example of such a server.
Clearly not a lot of thought happened when that server code was written,
but its out there and we have to deal with it.
This change decouples the handshake hash from the CertificateVerify
hash. This lays the groundwork for advertising support for SHA-384 but
doesn't actually make that change in the interests of reviewability.
Updating the advertised hash functions will cause changes in many of the
testdata/ files and some errors might get lost in the noise. This change
only needs to update four testdata/ files: one because a SHA-384-based
handshake is now being signed with SHA-256 and the others because the
TLS 1.2 CertificateRequest message now includes SHA-1.
This change also has the effect of adding support for
client-certificates in SSLv3 servers. However, SSLv3 is now disabled by
default so this should be moot.
It would be possible to avoid much of this change and just support
SHA-384 for the ServerKeyExchange as the SKX only signs over the nonces
and SKX params (a design mistake in TLS). However, that would leave Go
in the odd situation where it advertised support for SHA-384, but would
only use the handshake hash when signing client certificates. I fear
that'll just cause problems in the future.
Much of this code was written by davidben@ for the purposes of testing
BoringSSL.
Partly addresses #9757
Change-Id: I5137a472b6076812af387a5a69fc62c7373cd485
Reviewed-on: https://go-review.googlesource.com/9415
Run-TryBot: Adam Langley <agl@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
This change causes the GetCertificate callback to be called if
Certificates is empty. Previously this configuration would result in an
error.
This allows people to have servers that depend entirely on dynamic
certificate selection, even when the client doesn't send SNI.
Fixes#9208.
Change-Id: I2f5a5551215958b88b154c64a114590300dfc461
Reviewed-on: https://go-review.googlesource.com/8792
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
The OCSP response is currently only exposed via a method on Conn,
which makes it inaccessible when using wrappers like net/http. The
ConnectionState structure is typically available even when using
wrappers and contains many of the other handshake details, so this
change exposes the stapled OCSP response in that structure.
Change-Id: If8dab49292566912c615d816321b4353e711f71f
Reviewed-on: https://go-review.googlesource.com/9361
Reviewed-by: Adam Langley <agl@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
This change adds a new method to tls.Config, SetSessionTicketKeys, that
changes the key used to encrypt session tickets while the server is
running. Additional keys may be provided that will be used to maintain
continuity while rotating keys. If a ticket encrypted with an old key is
provided by the client, the server will resume the session and provide
the client with a ticket encrypted using the new key.
Fixes#9994
Change-Id: Idbc16b10ff39616109a51ed39a6fa208faad5b4e
Reviewed-on: https://go-review.googlesource.com/9072
Reviewed-by: Jonathan Rudenberg <jonathan@titanous.com>
Reviewed-by: Adam Langley <agl@golang.org>
This change adds support for serving and receiving Signed Certificate
Timestamps as described in RFC 6962.
The server is now capable of serving SCTs listed in the Certificate
structure. The client now asks for SCTs and, if any are received,
they are exposed in the ConnectionState structure.
Fixes#10201
Change-Id: Ib3adae98cb4f173bc85cec04d2bdd3aa0fec70bb
Reviewed-on: https://go-review.googlesource.com/8988
Reviewed-by: Adam Langley <agl@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
Reviewed-by: Jonathan Rudenberg <jonathan@titanous.com>
This is a follow on to 28f33b4a which removes one of the boolean flags
and adds a test for the key-driven cipher selection.
Change-Id: If2a400de807eb19110352912a9f467491cc8986c
Reviewed-on: https://go-review.googlesource.com/8428
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
Reviewed-by: Jacob Haven <jacob@cloudflare.com>
This change replaces all direct ECDSA/RSA sign and decrypt operations
with calls through the crypto.Signer and crypto.Decrypter interfaces.
This is a follow-up to https://go-review.googlesource.com/#/c/3900/
which added crypto.Decrypter and implemented it for RSA.
Change-Id: Ie0f3928448b285f329efcd3a93ca3fd5e3b3e42d
Reviewed-on: https://go-review.googlesource.com/7804
Reviewed-by: Adam Langley <agl@golang.org>
Commit 604fa4d5 made TLS 1.0 the default minimum version. This commit
amends a comment to reflect that.
This is where the default is used in the absence of an explicit version
being set:
edadffa2f3/src/crypto/tls/common.go (L391-L393)
Change-Id: I8f1117ecdddc85bb1cc76a6834026505a380b793
Reviewed-on: https://go-review.googlesource.com/5525
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
Commit f1d669aee9 added support for
AES_256_GCM_SHA384 cipher suites as specified in RFC5289. However, it
did not take the arbitrary hash function into account in the TLS client
handshake when using client certificates.
The hashForClientCertificate method always returned SHA256 as its
hashing function, even if it actually used a different one to calculate
its digest. Setting up the connection would eventually fail with the
error "tls: failed to sign handshake with client certificate:
crypto/rsa: input must be hashed message".
Included is an additional test for this specific situation that uses the
SHA384 hash.
Fixes#9808
Change-Id: Iccbf4ab225633471ef897907c208ad31f92855a3
Reviewed-on: https://go-review.googlesource.com/7040
Reviewed-by: Adam Langley <agl@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
SSLv3 (the old minimum) is still supported and can be enabled via the
tls.Config, but this change increases the default minimum version to TLS
1.0. This is now common practice in light of the POODLE[1] attack
against SSLv3's CBC padding format.
[1] https://www.imperialviolet.org/2014/10/14/poodle.htmlFixes#9364.
Change-Id: Ibae6666ee038ceee0cb18c339c393155928c6510
Reviewed-on: https://go-review.googlesource.com/1791
Reviewed-by: Minux Ma <minux@golang.org>
Signer is an interface to support opaque private keys.
These keys typically result from being kept in special hardware
(i.e. a TPM) although sometimes operating systems provide a
similar interface using process isolation for security rather
than hardware boundaries.
This changes provides interfaces for representing them and
alters crypto/tls so that client certificates can use
opaque keys.
LGTM=bradfitz
R=bradfitz
CC=golang-codereviews, jdeprez
https://golang.org/cl/114680043
Artyom Pervukhin
Adam Langley
Mike Danese
Максим Федосеев
Daniel Martí
Anmol Sethi
Filippo Valsorda
Joshua Boelter
Joonas Kuorilehto
Brad Fitzpatrick
Ian Lance Taylor
Dan Peterson
Dominik Honnef
Tom Bergan
Russ Cox
Jonathan Rudenberg
Jacob H. Haven
Matt Bostock
Joël Stemmer
Andres Erbsen
Percy Wegmann