1 files changed, 52 insertions, 0 deletions
diff --git a/src/crypto/internal/boring/fipstls/tls.go b/src/crypto/internal/boring/fipstls/tls.go
new file mode 100644
index 0000000..3bf1471
--- /dev/null
+++ b/src/crypto/internal/boring/fipstls/tls.go
@@ -0,0 +1,52 @@
+// Copyright 2017 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 fipstls allows control over whether crypto/tls requires FIPS-approved settings.
+// This package only exists with GOEXPERIMENT=boringcrypto, but the effects are independent
+// of the use of BoringCrypto.
+package fipstls
+
+import "sync/atomic"
+
+var required atomic.Bool
+
+// Force forces crypto/tls to restrict TLS configurations to FIPS-approved settings.
+// By design, this call is impossible to undo (except in tests).
+//
+// Note that this call has an effect even in programs using
+// standard crypto (that is, even when Enabled = false).
+func Force() {
+	required.Store(true)
+}
+
+// Abandon allows non-FIPS-approved settings.
+// If called from a non-test binary, it panics.
+func Abandon() {
+	// Note: Not using boring.UnreachableExceptTests because we want
+	// this test to happen even when boring.Enabled = false.
+	name := runtime_arg0()
+	// Allow _test for Go command, .test for Bazel,
+	// NaClMain for NaCl (where all binaries run as NaClMain),
+	// and empty string for Windows (where runtime_arg0 can't easily find the name).
+	// Since this is an internal package, testing that this isn't used on the
+	// other operating systems should suffice to catch any mistakes.
+	if !hasSuffix(name, "_test") && !hasSuffix(name, ".test") && name != "NaClMain" && name != "" {
+		panic("fipstls: invalid use of Abandon in " + name)
+	}
+	required.Store(false)
+}
+
+// provided by runtime
+func runtime_arg0() string
+
+func hasSuffix(s, t string) bool {
+	return len(s) > len(t) && s[len(s)-len(t):] == t
+}
+
+// Required reports whether FIPS-approved settings are required.
+func Required() bool {
+	return required.Load()
+}