crypto/internal/fips140: add Supported

Move the logic duplicated in multiple places to a central function.

Change-Id: I6a6a4656469c91dd62b0be716ec8367358f4a3e1
Reviewed-on: https://go-review.googlesource.com/c/go/+/639336
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Filippo Valsorda <filippo@golang.org>
Reviewed-by: Daniel McCarney <daniel@binaryparadox.net>
Reviewed-by: Roland Shoemaker <roland@golang.org>

diff --git a/src/cmd/dist/test.go b/src/cmd/dist/test.go
index 06bd01bc5bb9954cc382b518913b81f9e7b69cd1..bfed14c9152a260814d5a6e9f486638527059c11 100644 (file)
--- a/src/cmd/dist/test.go
+++ b/src/cmd/dist/test.go
@@ -1797,6 +1797,8 @@ func isEnvSet(evar string) bool {
 }
 
 func (t *tester) fipsSupported() bool {
+       // Keep this in sync with [crypto/internal/fips140.Supported].
+
        // Use GOFIPS140 or GOEXPERIMENT=boringcrypto, but not both.
        if strings.Contains(goexperiment, "boringcrypto") {
                return false

diff --git a/src/crypto/internal/fips140/check/asan.go b/src/crypto/internal/fips140/asan.go
similarity index 92%
rename from src/crypto/internal/fips140/check/asan.go
rename to src/crypto/internal/fips140/asan.go
index 2c78348354834465b2363796588ac028018548f0..af8f24df8117d21951765885b70dee694837a299 100644 (file)
--- a/src/crypto/internal/fips140/check/asan.go
+++ b/src/crypto/internal/fips140/asan.go
@@ -4,6 +4,6 @@
 
 //go:build asan
 
-package check
+package fips140
 
 const asanEnabled = true

diff --git a/src/crypto/internal/fips140/boring.go b/src/crypto/internal/fips140/boring.go
new file mode 100644 (file)
index 0000000..d627bc6
--- /dev/null
+++ b/src/crypto/internal/fips140/boring.go
@@ -0,0 +1,10 @@
+// Copyright 2024 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.
+
+// Keep in sync with notboring.go and crypto/internal/boring/boring.go.
+//go:build boringcrypto && linux && (amd64 || arm64) && !android && !msan && cgo
+
+package fips140
+
+const boringEnabled = true

diff --git a/src/crypto/internal/fips140/check/check.go b/src/crypto/internal/fips140/check/check.go
index cf33a1efbee0ceb90984669a7d239450fd3de265..9d2e5d5cf6db68d0de6fb04c6cda45a3e5c99096 100644 (file)
--- a/src/crypto/internal/fips140/check/check.go
+++ b/src/crypto/internal/fips140/check/check.go
@@ -19,7 +19,6 @@ import (
        "crypto/internal/fips140deps/byteorder"
        "crypto/internal/fips140deps/godebug"
        "io"
-       "runtime"
        "unsafe"
 )
 
@@ -27,19 +26,6 @@ import (
 // true when [fips140.Enabled] is true, or init would have panicked.
 var Verified bool
 
-// Supported reports whether the current GOOS/GOARCH is Supported at all.
-func Supported() bool {
-       // See cmd/internal/obj/fips.go's EnableFIPS for commentary.
-       switch {
-       case runtime.GOARCH == "wasm",
-               runtime.GOOS == "windows" && runtime.GOARCH == "386",
-               runtime.GOOS == "windows" && runtime.GOARCH == "arm",
-               runtime.GOOS == "aix":
-               return false
-       }
-       return true
-}
-
 // Linkinfo holds the go:fipsinfo symbol prepared by the linker.
 // See cmd/link/internal/ld/fips.go for details.
 //
@@ -70,19 +56,8 @@ func init() {
                return
        }
 
-       if asanEnabled {
-               // ASAN disapproves of reading swaths of global memory below.
-               // One option would be to expose runtime.asanunpoison through
-               // crypto/internal/fips140deps and then call it to unpoison the range
-               // before reading it, but it is unclear whether that would then cause
-               // false negatives. For now, FIPS+ASAN doesn't need to work.
-               // If this is made to work, also re-enable the test in check_test.go
-               // and in cmd/dist/test.go.
-               panic("fips140: cannot verify in asan mode")
-       }
-
-       if !Supported() {
-               panic("fips140: unavailable on " + runtime.GOOS + "-" + runtime.GOARCH)
+       if err := fips140.Supported(); err != nil {
+               panic("fips140: " + err.Error())
        }
 
        if Linkinfo.Magic[0] != 0xff || string(Linkinfo.Magic[1:]) != fipsMagic || Linkinfo.Sum == zeroSum {

diff --git a/src/crypto/internal/fips140/fips140.go b/src/crypto/internal/fips140/fips140.go
index 55b5dd43ce95396d78481876371ff6d685589d79..cf015db644738f4cfd60764cbb33644a80539440 100644 (file)
--- a/src/crypto/internal/fips140/fips140.go
+++ b/src/crypto/internal/fips140/fips140.go
@@ -4,7 +4,11 @@
 
 package fips140
 
-import "crypto/internal/fips140deps/godebug"
+import (
+       "crypto/internal/fips140deps/godebug"
+       "errors"
+       "runtime"
+)
 
 var Enabled bool
 
@@ -24,6 +28,35 @@ func init() {
        }
 }
 
+// Supported returns an error if FIPS 140-3 mode can't be enabled.
+func Supported() error {
+       // Keep this in sync with fipsSupported in cmd/dist/test.go.
+
+       // ASAN disapproves of reading swaths of global memory in fips140/check.
+       // One option would be to expose runtime.asanunpoison through
+       // crypto/internal/fips140deps and then call it to unpoison the range
+       // before reading it, but it is unclear whether that would then cause
+       // false negatives. For now, FIPS+ASAN doesn't need to work.
+       if asanEnabled {
+               return errors.New("FIPS 140-3 mode is incompatible with ASAN")
+       }
+
+       // See EnableFIPS in cmd/internal/obj/fips.go for commentary.
+       switch {
+       case runtime.GOARCH == "wasm",
+               runtime.GOOS == "windows" && runtime.GOARCH == "386",
+               runtime.GOOS == "windows" && runtime.GOARCH == "arm",
+               runtime.GOOS == "aix":
+               return errors.New("FIPS 140-3 mode is not supported on " + runtime.GOOS + "-" + runtime.GOARCH)
+       }
+
+       if boringEnabled {
+               return errors.New("FIPS 140-3 mode is incompatible with GOEXPERIMENT=boringcrypto")
+       }
+
+       return nil
+}
+
 func Name() string {
        return "Go Cryptographic Module"
 }

diff --git a/src/crypto/internal/fips140/check/noasan.go b/src/crypto/internal/fips140/notasan.go
similarity index 92%
rename from src/crypto/internal/fips140/check/noasan.go
rename to src/crypto/internal/fips140/notasan.go
index 876d726f9890960a8c7adf0d83a9d569edfff2b7..639d419ef9c7b1dade48e1fbe0a1c3e704553ff9 100644 (file)
--- a/src/crypto/internal/fips140/check/noasan.go
+++ b/src/crypto/internal/fips140/notasan.go
@@ -4,6 +4,6 @@
 
 //go:build !asan
 
-package check
+package fips140
 
 const asanEnabled = false

diff --git a/src/crypto/internal/fips140/notboring.go b/src/crypto/internal/fips140/notboring.go
new file mode 100644 (file)
index 0000000..681521c
--- /dev/null
+++ b/src/crypto/internal/fips140/notboring.go
@@ -0,0 +1,9 @@
+// Copyright 2024 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 && linux && (amd64 || arm64) && !android && !msan && cgo)
+
+package fips140
+
+const boringEnabled = false

diff --git a/src/crypto/internal/fips140test/check_test.go b/src/crypto/internal/fips140test/check_test.go
index cf42dbfa7823f9cb6d9dda5183c3846bfda8e8bc..6b0cd3f39e1695cfaefc964a6102e1fe07c34118 100644 (file)
--- a/src/crypto/internal/fips140test/check_test.go
+++ b/src/crypto/internal/fips140test/check_test.go
@@ -5,16 +5,14 @@
 package fipstest
 
 import (
-       "crypto/internal/boring"
+       "crypto/internal/fips140"
        . "crypto/internal/fips140/check"
        "crypto/internal/fips140/check/checktest"
        "fmt"
        "internal/abi"
-       "internal/asan"
        "internal/godebug"
        "internal/testenv"
        "os"
-       "runtime"
        "testing"
        "unicode"
        "unsafe"
@@ -23,10 +21,6 @@ import (
 const enableFIPSTest = true
 
 func TestFIPSCheckVerify(t *testing.T) {
-       if boring.Enabled {
-               t.Skip("not testing fips140 with boringcrypto enabled")
-       }
-
        if Verified {
                t.Logf("verified")
                return
@@ -40,12 +34,8 @@ func TestFIPSCheckVerify(t *testing.T) {
                return
        }
 
-       if !Supported() {
-               t.Skipf("skipping on %s-%s", runtime.GOOS, runtime.GOARCH)
-       }
-       if asan.Enabled {
-               // Verification panics with asan; don't bother.
-               t.Skipf("skipping with -asan")
+       if err := fips140.Supported(); err != nil {
+               t.Skipf("skipping: %v", err)
        }
 
        cmd := testenv.Command(t, os.Args[0], "-test.v", "-test.run=TestFIPSCheck")
@@ -62,8 +52,8 @@ func TestFIPSCheckInfo(t *testing.T) {
                return
        }
 
-       if !Supported() {
-               t.Skipf("skipping on %s-%s", runtime.GOOS, runtime.GOARCH)
+       if err := fips140.Supported(); err != nil {
+               t.Skipf("skipping: %v", err)
        }
 
        // Check that the checktest symbols are initialized properly.