[dev.boringcrypto] all: add boringcrypto build tags

A plain make.bash in this tree will produce a working,
standard Go toolchain, not a BoringCrypto-enabled one.

The BoringCrypto-enabled one will be created with:

	GOEXPERIMENT=boringcrypto ./make.bash

For #51940.

Change-Id: Ia9102ed993242eb1cb7f9b93eca97e81986a27b3
Reviewed-on: https://go-review.googlesource.com/c/go/+/395881
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

37 files changed, 153 insertions, 43 deletions

diff --git a/api/go1.16.txt b/api/go1.16.txt
index d9fb7e3884..ce015fd6fb 100644
--- a/api/go1.16.txt
+++ b/api/go1.16.txt
@@ -1,6 +1,5 @@
 pkg archive/zip, method (*ReadCloser) Open(string) (fs.File, error)
 pkg archive/zip, method (*Reader) Open(string) (fs.File, error)
-pkg crypto/boring, func Enabled() bool
 pkg crypto/x509, method (SystemRootsError) Unwrap() error
 pkg debug/elf, const DT_ADDRRNGHI = 1879047935
 pkg debug/elf, const DT_ADDRRNGHI DynTag
diff --git a/misc/boring/release.sh b/misc/boring/release.sh
index 6ab440c91b..6e72a56192 100755
--- a/misc/boring/release.sh
+++ b/misc/boring/release.sh
@@ -18,7 +18,7 @@ git fetch
 git worktree add --track -b "$BRANCH" "$WORKTREE" origin/dev.boringcrypto
 
 cd "$WORKTREE/src"
-./make.bash
+GOEXPERIMENT=boringcrypto ./make.bash
 
 cd ../misc/boring
 for branch in "$@"; do
diff --git a/misc/cgo/testshared/shared_test.go b/misc/cgo/testshared/shared_test.go
index b78083bc80..616630979c 100644
--- a/misc/cgo/testshared/shared_test.go
+++ b/misc/cgo/testshared/shared_test.go
@@ -57,7 +57,7 @@ func runWithEnv(t *testing.T, msg string, env []string, args ...string) {
 func goCmd(t *testing.T, args ...string) string {
 	newargs := []string{args[0]}
 	if *testX && args[0] != "env" {
-		newargs = append(newargs, "-x")
+		newargs = append(newargs, "-x", "-ldflags=-v")
 	}
 	newargs = append(newargs, args[1:]...)
 	c := exec.Command("go", newargs...)
diff --git a/src/cmd/api/goapi_boring_test.go b/src/cmd/api/goapi_boring_test.go
new file mode 100644
index 0000000000..f0e3575637
--- /dev/null
+++ b/src/cmd/api/goapi_boring_test.go
@@ -0,0 +1,17 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build boringcrypto
+
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+func init() {
+	fmt.Printf("SKIP with boringcrypto enabled\n")
+	os.Exit(0)
+}
diff --git a/src/cmd/go/go_boring_test.go b/src/cmd/go/go_boring_test.go
index 0000497f06..ed0fbf3d53 100644
--- a/src/cmd/go/go_boring_test.go
+++ b/src/cmd/go/go_boring_test.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build boringcrypto
+
 package main_test
 
 import "testing"
diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index 5103e55e00..680f509ec5 100644
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -1060,6 +1060,7 @@ var hostobj []Hostobj
 // Others trigger external mode.
 var internalpkg = []string{
 	"crypto/internal/boring",
+	"crypto/internal/boring/syso",
 	"crypto/x509",
 	"net",
 	"os/user",
diff --git a/src/crypto/boring/boring.go b/src/crypto/boring/boring.go
index 19e2a0876f..097c37e343 100644
--- a/src/crypto/boring/boring.go
+++ b/src/crypto/boring/boring.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build boringcrypto
+
 // Package boring exposes functions that are only available when building with
 // Go+BoringCrypto. This package is available on all targets as long as the
 // Go+BoringCrypto toolchain is used. Use the Enabled function to determine
diff --git a/src/crypto/boring/boring_test.go b/src/crypto/boring/boring_test.go
index ace50de0c2..9e8fd353b7 100644
--- a/src/crypto/boring/boring_test.go
+++ b/src/crypto/boring/boring_test.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build boringcrypto
+
 package boring_test
 
 import (
diff --git a/src/crypto/boring/notboring_test.go b/src/crypto/boring/notboring_test.go
index e69a3a93fd..ffe18e9109 100644
--- a/src/crypto/boring/notboring_test.go
+++ b/src/crypto/boring/notboring_test.go
@@ -2,13 +2,13 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !boringcrypto
-// +build !boringcrypto
+//go:build (goexperiment.boringcrypto && !boringcrypto) || (!goexperiment.boringcrypto && boringcrypto)
+// +build goexperiment.boringcrypto,!boringcrypto !goexperiment.boringcrypto,boringcrypto
 
 package boring_test
 
 import "testing"
 
 func TestNotBoring(t *testing.T) {
-	t.Error("a file tagged !boringcrypto should not build under Go+BoringCrypto")
+	t.Error("goexperiment.boringcrypto and boringcrypto should be equivalent build tags")
 }
diff --git a/src/crypto/ecdsa/boring.go b/src/crypto/ecdsa/boring.go
index fa15ecb850..d7de5c96e5 100644
--- a/src/crypto/ecdsa/boring.go
+++ b/src/crypto/ecdsa/boring.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build boringcrypto
+
 package ecdsa
 
 import (
diff --git a/src/crypto/ecdsa/notboring.go b/src/crypto/ecdsa/notboring.go
new file mode 100644
index 0000000000..039bd82ed2
--- /dev/null
+++ b/src/crypto/ecdsa/notboring.go
@@ -0,0 +1,16 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !boringcrypto
+
+package ecdsa
+
+import "crypto/internal/boring"
+
+func boringPublicKey(*PublicKey) (*boring.PublicKeyECDSA, error) {
+	panic("boringcrypto: not available")
+}
+func boringPrivateKey(*PrivateKey) (*boring.PrivateKeyECDSA, error) {
+	panic("boringcrypto: not available")
+}
diff --git a/src/crypto/internal/boring/Dockerfile b/src/crypto/internal/boring/Dockerfile
index dab7c85f7c..5bd7438f69 100644
--- a/src/crypto/internal/boring/Dockerfile
+++ b/src/crypto/internal/boring/Dockerfile
@@ -8,8 +8,8 @@
 #
 #   $ podman build -t goboring:140sp3678 .
 #   $ podman run -it --name goboring-140sp3678 goboring:140sp3678
-#   $ podman cp goboring-140sp3678:/boring/godriver/goboringcrypto_linux_amd64.syso .
-#   $ sha256sum goboringcrypto_linux_amd64.syso # compare to docker output
+#   $ podman cp goboring-140sp3678:/boring/godriver/goboringcrypto_linux_amd64.syso syso
+#   $ sha256sum syso/goboringcrypto_linux_amd64.syso # compare to docker output
 #
 # The podman commands may need to run under sudo to work around a subuid/subgid bug.
 
diff --git a/src/crypto/internal/boring/LICENSE b/src/crypto/internal/boring/LICENSE
index fc103a79d4..38990bdb77 100644
--- a/src/crypto/internal/boring/LICENSE
+++ b/src/crypto/internal/boring/LICENSE
@@ -1,6 +1,8 @@
 The Go source code and supporting files in this directory
 are covered by the usual Go license (see ../../../../LICENSE).
 
+When building with GOEXPERIMENT=boringcrypto, the following applies.
+
 The goboringcrypto_linux_amd64.syso object file is built
 from BoringSSL source code by build/build.sh and is covered
 by the BoringSSL license reproduced below and also at
@@ -40,7 +42,7 @@ record keeping.)
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer. 
+ *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
@@ -95,21 +97,21 @@ record keeping.)
  * This package is an SSL implementation written
  * by Eric Young (eay@cryptsoft.com).
  * The implementation was written so as to conform with Netscapes SSL.
- * 
+ *
  * This library is free for commercial and non-commercial use as long as
  * the following conditions are aheared to.  The following conditions
  * apply to all code found in this distribution, be it the RC4, RSA,
  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  * included with this distribution is covered by the same copyright terms
  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
- * 
+ *
  * Copyright remains Eric Young's, and as such any Copyright notices in
  * the code are not to be removed.
  * If this package is used in a product, Eric Young should be given attribution
  * as the author of the parts of the library used.
  * This can be in the form of a textual message at program startup or
  * in documentation (online or textual) provided with the package.
- * 
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
@@ -124,10 +126,10 @@ record keeping.)
  *     Eric Young (eay@cryptsoft.com)"
  *    The word 'cryptographic' can be left out if the rouines from the library
  *    being used are not cryptographic related :-).
- * 4. If you include any Windows specific code (or a derivative thereof) from 
+ * 4. If you include any Windows specific code (or a derivative thereof) from
  *    the apps directory (application code) you must include an acknowledgement:
  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
- * 
+ *
  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
@@ -139,7 +141,7 @@ record keeping.)
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
- * 
+ *
  * The licence and distribution terms for any publically available version or
  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  * copied and put under another distribution licence
diff --git a/src/crypto/internal/boring/aes.go b/src/crypto/internal/boring/aes.go
index b5d360151c..515b60bb8a 100644
--- a/src/crypto/internal/boring/aes.go
+++ b/src/crypto/internal/boring/aes.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux && amd64 && !android && !cmd_go_bootstrap && !msan
-// +build linux,amd64,!android,!cmd_go_bootstrap,!msan
+//go:build boringcrypto && linux && amd64 && !android && !cmd_go_bootstrap && !msan
+// +build boringcrypto,linux,amd64,!android,!cmd_go_bootstrap,!msan
 
 package boring
 
diff --git a/src/crypto/internal/boring/boring.go b/src/crypto/internal/boring/boring.go
index b8804ceb68..29e0baa131 100644
--- a/src/crypto/internal/boring/boring.go
+++ b/src/crypto/internal/boring/boring.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux && amd64 && !android && !cmd_go_bootstrap && !msan
-// +build linux,amd64,!android,!cmd_go_bootstrap,!msan
+//go:build boringcrypto && linux && amd64 && !android && !cmd_go_bootstrap && !msan
+// +build boringcrypto,linux,amd64,!android,!cmd_go_bootstrap,!msan
 
 package boring
 
@@ -16,6 +16,7 @@ package boring
 import "C"
 import (
 	"crypto/internal/boring/sig"
+	_ "crypto/internal/boring/syso"
 	"math/big"
 )
 
diff --git a/src/crypto/internal/boring/ecdsa.go b/src/crypto/internal/boring/ecdsa.go
index b9c68a97af..20612e6a2c 100644
--- a/src/crypto/internal/boring/ecdsa.go
+++ b/src/crypto/internal/boring/ecdsa.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux && amd64 && !android && !cmd_go_bootstrap && !msan
-// +build linux,amd64,!android,!cmd_go_bootstrap,!msan
+//go:build boringcrypto && linux && amd64 && !android && !cmd_go_bootstrap && !msan
+// +build boringcrypto,linux,amd64,!android,!cmd_go_bootstrap,!msan
 
 package boring
 
diff --git a/src/crypto/internal/boring/fipstls/dummy.s b/src/crypto/internal/boring/fipstls/stub.s
index 53bb7d9430..f2e5a503ea 100644
--- a/src/crypto/internal/boring/fipstls/dummy.s
+++ b/src/crypto/internal/boring/fipstls/stub.s
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build boringcrypto
+
 // runtime_arg0 is declared in tls.go without a body.
 // It's provided by package runtime,
 // but the go command doesn't know that.
diff --git a/src/crypto/internal/boring/fipstls/tls.go b/src/crypto/internal/boring/fipstls/tls.go
index 4127533fbd..701700e4e3 100644
--- a/src/crypto/internal/boring/fipstls/tls.go
+++ b/src/crypto/internal/boring/fipstls/tls.go
@@ -2,8 +2,11 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build boringcrypto
+
 // Package fipstls allows control over whether crypto/tls requires FIPS-approved settings.
-// This package's effects are independent of the use of the BoringCrypto implementation.
+// This package only exists with GOEXPERIMENT=boringcrypto, but the effects are independent
+// of the use of BoringCrypto.
 package fipstls
 
 import "sync/atomic"
diff --git a/src/crypto/internal/boring/hmac.go b/src/crypto/internal/boring/hmac.go
index be0670c05a..c36fe6b26c 100644
--- a/src/crypto/internal/boring/hmac.go
+++ b/src/crypto/internal/boring/hmac.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux && amd64 && !android && !cmd_go_bootstrap && !msan
-// +build linux,amd64,!android,!cmd_go_bootstrap,!msan
+//go:build boringcrypto && linux && amd64 && !android && !cmd_go_bootstrap && !msan
+// +build boringcrypto,linux,amd64,!android,!cmd_go_bootstrap,!msan
 
 package boring
 
diff --git a/src/crypto/internal/boring/notboring.go b/src/crypto/internal/boring/notboring.go
index 2e2414c73b..be1dd4b8fc 100644
--- a/src/crypto/internal/boring/notboring.go
+++ b/src/crypto/internal/boring/notboring.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !linux || !amd64 || !cgo || android || cmd_go_bootstrap || msan
-// +build !linux !amd64 !cgo android cmd_go_bootstrap msan
+//go:build !boringcrypto || !linux || !amd64 || !cgo || android || cmd_go_bootstrap || msan
+// +build !boringcrypto !linux !amd64 !cgo android cmd_go_bootstrap msan
 
 package boring
 
diff --git a/src/crypto/internal/boring/rand.go b/src/crypto/internal/boring/rand.go
index 57937eb3c8..d2e432e7b7 100644
--- a/src/crypto/internal/boring/rand.go
+++ b/src/crypto/internal/boring/rand.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux && amd64 && !android && !cmd_go_bootstrap && !msan
-// +build linux,amd64,!android,!cmd_go_bootstrap,!msan
+//go:build boringcrypto && linux && amd64 && !android && !cmd_go_bootstrap && !msan
+// +build boringcrypto,linux,amd64,!android,!cmd_go_bootstrap,!msan
 
 package boring
 
diff --git a/src/crypto/internal/boring/rsa.go b/src/crypto/internal/boring/rsa.go
index 327dfa0309..642287709e 100644
--- a/src/crypto/internal/boring/rsa.go
+++ b/src/crypto/internal/boring/rsa.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux && amd64 && !android && !cmd_go_bootstrap && !msan
-// +build linux,amd64,!android,!cmd_go_bootstrap,!msan
+//go:build boringcrypto && linux && amd64 && !android && !cmd_go_bootstrap && !msan
+// +build boringcrypto,linux,amd64,!android,!cmd_go_bootstrap,!msan
 
 package boring
 
diff --git a/src/crypto/internal/boring/sha.go b/src/crypto/internal/boring/sha.go
index 4672119df1..ba0cc29034 100644
--- a/src/crypto/internal/boring/sha.go
+++ b/src/crypto/internal/boring/sha.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux && amd64 && !android && !cmd_go_bootstrap && !msan
-// +build linux,amd64,!android,!cmd_go_bootstrap,!msan
+//go:build boringcrypto && linux && amd64 && !android && !cmd_go_bootstrap && !msan
+// +build boringcrypto,linux,amd64,!android,!cmd_go_bootstrap,!msan
 
 package boring
 
diff --git a/src/crypto/internal/boring/goboringcrypto_linux_amd64.syso b/src/crypto/internal/boring/syso/goboringcrypto_linux_amd64.syso
index 2459dd7804..2459dd7804 100644
--- a/src/crypto/internal/boring/goboringcrypto_linux_amd64.syso
+++ b/src/crypto/internal/boring/syso/goboringcrypto_linux_amd64.syso
diff --git a/src/crypto/internal/boring/syso/syso.go b/src/crypto/internal/boring/syso/syso.go
new file mode 100644
index 0000000000..b3387545e6
--- /dev/null
+++ b/src/crypto/internal/boring/syso/syso.go
@@ -0,0 +1,9 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build boringcrypto
+
+// This package only exists with GOEXPERIMENT=boringcrypto.
+// It provides the actual syso file.
+package syso
diff --git a/src/crypto/rsa/boring.go b/src/crypto/rsa/boring.go
index 0f362a2f16..49a195f0f4 100644
--- a/src/crypto/rsa/boring.go
+++ b/src/crypto/rsa/boring.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build boringcrypto
+
 package rsa
 
 import (
diff --git a/src/crypto/rsa/boring_test.go b/src/crypto/rsa/boring_test.go
index 11dcdf88fd..1373da9937 100644
--- a/src/crypto/rsa/boring_test.go
+++ b/src/crypto/rsa/boring_test.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build boringcrypto
+
 // Note: Can run these tests against the non-BoringCrypto
 // version of the code by using "CGO_ENABLED=0 go test".
 
diff --git a/src/crypto/rsa/notboring.go b/src/crypto/rsa/notboring.go
new file mode 100644
index 0000000000..2abc043640
--- /dev/null
+++ b/src/crypto/rsa/notboring.go
@@ -0,0 +1,16 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !boringcrypto
+
+package rsa
+
+import "crypto/internal/boring"
+
+func boringPublicKey(*PublicKey) (*boring.PublicKeyRSA, error) {
+	panic("boringcrypto: not available")
+}
+func boringPrivateKey(*PrivateKey) (*boring.PrivateKeyRSA, error) {
+	panic("boringcrypto: not available")
+}
diff --git a/src/crypto/tls/boring.go b/src/crypto/tls/boring.go
index dabc67423d..c40d4a0e48 100644
--- a/src/crypto/tls/boring.go
+++ b/src/crypto/tls/boring.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build boringcrypto
+
 package tls
 
 import (
@@ -124,5 +126,3 @@ func supportedSignatureAlgorithms() []SignatureScheme {
 	}
 	return fipsSupportedSignatureAlgorithms
 }
-
-var testingOnlyForceClientHelloSignatureAlgorithms []SignatureScheme
diff --git a/src/crypto/tls/boring_test.go b/src/crypto/tls/boring_test.go
index 8dd477a021..12a7d937cb 100644
--- a/src/crypto/tls/boring_test.go
+++ b/src/crypto/tls/boring_test.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build boringcrypto
+
 package tls
 
 import (
diff --git a/src/crypto/tls/fipsonly/fipsonly.go b/src/crypto/tls/fipsonly/fipsonly.go
index 85b3532d26..e5e47835e2 100644
--- a/src/crypto/tls/fipsonly/fipsonly.go
+++ b/src/crypto/tls/fipsonly/fipsonly.go
@@ -2,13 +2,15 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build boringcrypto
+
 // Package fipsonly restricts all TLS configuration to FIPS-approved settings.
 //
 // The effect is triggered by importing the package anywhere in a program, as in:
 //
 //	import _ "crypto/tls/fipsonly"
 //
-// This package only exists in the dev.boringcrypto branch of Go.
+// This package only exists when using Go compiled with GOEXPERIMENT=boringcrypto.
 package fipsonly
 
 // This functionality is provided as a side effect of an import to make
diff --git a/src/crypto/tls/fipsonly/fipsonly_test.go b/src/crypto/tls/fipsonly/fipsonly_test.go
index facd24807d..f8485dc3ca 100644
--- a/src/crypto/tls/fipsonly/fipsonly_test.go
+++ b/src/crypto/tls/fipsonly/fipsonly_test.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build boringcrypto
+
 package fipsonly
 
 import (
diff --git a/src/crypto/tls/handshake_client.go b/src/crypto/tls/handshake_client.go
index 7bf0f84417..de19b7ede5 100644
--- a/src/crypto/tls/handshake_client.go
+++ b/src/crypto/tls/handshake_client.go
@@ -34,6 +34,8 @@ type clientHandshakeState struct {
 	session      *ClientSessionState
 }
 
+var testingOnlyForceClientHelloSignatureAlgorithms []SignatureScheme
+
 func (c *Conn) makeClientHello() (*clientHelloMsg, ecdheParameters, error) {
 	config := c.config
 	if len(config.ServerName) == 0 && !config.InsecureSkipVerify {
@@ -859,13 +861,14 @@ func (c *Conn) verifyServerCertificate(certificates [][]byte) error {
 
 	if !c.config.InsecureSkipVerify {
 		opts := x509.VerifyOptions{
-			IsBoring: isBoringCertificate,
-
 			Roots:         c.config.RootCAs,
 			CurrentTime:   c.config.time(),
 			DNSName:       c.config.ServerName,
 			Intermediates: x509.NewCertPool(),
 		}
+		if needFIPS() {
+			opts.IsBoring = isBoringCertificate
+		}
 		for _, cert := range certs[1:] {
 			opts.Intermediates.AddCert(cert)
 		}
diff --git a/src/crypto/tls/handshake_server.go b/src/crypto/tls/handshake_server.go
index 5db605681e..2d71d0869a 100644
--- a/src/crypto/tls/handshake_server.go
+++ b/src/crypto/tls/handshake_server.go
@@ -812,13 +812,14 @@ func (c *Conn) processCertsFromClient(certificate Certificate) error {
 
 	if c.config.ClientAuth >= VerifyClientCertIfGiven && len(certs) > 0 {
 		opts := x509.VerifyOptions{
-			IsBoring: isBoringCertificate,
-
 			Roots:         c.config.ClientCAs,
 			CurrentTime:   c.config.time(),
 			Intermediates: x509.NewCertPool(),
 			KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
 		}
+		if needFIPS() {
+			opts.IsBoring = isBoringCertificate
+		}
 
 		for _, cert := range certs[1:] {
 			opts.Intermediates.AddCert(cert)
diff --git a/src/crypto/tls/notboring.go b/src/crypto/tls/notboring.go
new file mode 100644
index 0000000000..d79ea21a0b
--- /dev/null
+++ b/src/crypto/tls/notboring.go
@@ -0,0 +1,23 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !boringcrypto
+
+package tls
+
+import "crypto/x509"
+
+func needFIPS() bool { return false }
+
+func supportedSignatureAlgorithms() []SignatureScheme {
+	return defaultSupportedSignatureAlgorithms
+}
+
+func fipsMinVersion(c *Config) uint16              { panic("fipsMinVersion") }
+func fipsMaxVersion(c *Config) uint16              { panic("fipsMaxVersion") }
+func fipsCurvePreferences(c *Config) []CurveID     { panic("fipsCurvePreferences") }
+func fipsCipherSuites(c *Config) []uint16          { panic("fipsCipherSuites") }
+func isBoringCertificate(c *x509.Certificate) bool { panic("isBoringCertificate") }
+
+var fipsSupportedSignatureAlgorithms []SignatureScheme
diff --git a/src/go/build/build.go b/src/go/build/build.go
index f40b486635..b373feab33 100644
--- a/src/go/build/build.go
+++ b/src/go/build/build.go
@@ -1907,9 +1907,8 @@ func (ctxt *Context) matchTag(name string, allTags map[string]bool) bool {
 	if name == "unix" && unixOS[ctxt.GOOS] {
 		return true
 	}
-	// Let applications know that the Go+BoringCrypto toolchain is in use.
 	if name == "boringcrypto" {
-		return true
+		name = "goexperiment.boringcrypto" // boringcrypto is an old name for goexperiment.boringcrypto
 	}
 
 	// other tags
diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go
index 651257a357..d955081869 100644
--- a/src/go/build/deps_test.go
+++ b/src/go/build/deps_test.go
@@ -397,12 +397,12 @@ var depsRules = `
 	NET, log
 	< net/mail;
 
-	NONE < crypto/internal/boring/sig;
+	NONE < crypto/internal/boring/sig, crypto/internal/boring/syso;
 	sync/atomic < crypto/internal/boring/fipstls;
 
 	encoding/binary, golang.org/x/sys/cpu, hash,
 	FMT, math/big, embed,
-	CGO, crypto/internal/boring/sig, crypto/internal/boring/fipstls
+	CGO, crypto/internal/boring/sig, crypto/internal/boring/fipstls, crypto/internal/boring/syso
 	< crypto
 	< crypto/subtle
 	< crypto/internal/subtle