Handle static variable secret flag (#2045)

Signed-off-by: Christian Mesh <christianmesh1@gmail.com>

internal/command/e2etest/testdata/encryption-flow/required.tf.disabled

@@ -1,8 +1,18 @@
+variable "passphrase" {
+  type = string
+  default = "26281afb-83f1-47ec-9b2d-2aebf6417167"
+  sensitive = true
+}
+
+locals {
+  key_length = sensitive(32)
+}
+
 terraform {
   encryption {
     key_provider "pbkdf2" "basic" {
-      passphrase    = "26281afb-83f1-47ec-9b2d-2aebf6417167"
-      key_length    = 32
+      passphrase    = var.passphrase
+      key_length    = local.key_length
       iterations    = 200000
       hash_function = "sha512"
       salt_length   = 12

internal/configs/backend.go

@@ -13,6 +13,7 @@ import (
 	"github.com/opentofu/opentofu/internal/addrs"
 	"github.com/opentofu/opentofu/internal/configs/configschema"
 	"github.com/opentofu/opentofu/internal/lang"
+	"github.com/opentofu/opentofu/internal/lang/marks"
 	"github.com/zclconf/go-cty/cty"
 )
 
@@ -62,6 +63,15 @@ func (b *Backend) Hash(schema *configschema.Block) (int, hcl.Diagnostics) {
 		val = cty.UnknownVal(schema.ImpliedType())
 	}
 
+	if marks.Contains(val, marks.Sensitive) {
+		return -1, diags.Append(&hcl.Diagnostic{
+			Severity: hcl.DiagError,
+			Summary:  "Backend config contains sensitive values",
+			Detail:   "The backend configuration is stored in .terraform/terraform.tfstate as well as plan files. It is recommended to instead supply sensitive credentials via backend specific environment variables",
+			Subject:  b.DeclRange.Ptr(),
+		})
+	}
+
 	toHash := cty.TupleVal([]cty.Value{
 		cty.StringVal(b.Type),
 		val,

internal/configs/static_evaluator.go

@@ -6,11 +6,14 @@
 package configs
 
 import (
+	"fmt"
+
 	"github.com/hashicorp/hcl/v2"
 	"github.com/hashicorp/hcl/v2/gohcl"
 	"github.com/hashicorp/hcl/v2/hcldec"
 	"github.com/opentofu/opentofu/internal/addrs"
 	"github.com/opentofu/opentofu/internal/lang"
+	"github.com/opentofu/opentofu/internal/lang/marks"
 	"github.com/zclconf/go-cty/cty"
 )
 
@@ -90,21 +93,21 @@ func (s StaticEvaluator) Evaluate(expr hcl.Expression, ident StaticIdentifier) (
 }
 
 func (s StaticEvaluator) DecodeExpression(expr hcl.Expression, ident StaticIdentifier, val any) hcl.Diagnostics {
-	var diags hcl.Diagnostics
-
-	refs, refsDiags := lang.ReferencesInExpr(addrs.ParseRef, expr)
-	diags = append(diags, refsDiags.ToHCL()...)
+	srcVal, diags := s.Evaluate(expr, ident)
 	if diags.HasErrors() {
 		return diags
 	}
 
-	ctx, ctxDiags := s.scope(ident).EvalContext(refs)
-	diags = append(diags, ctxDiags.ToHCL()...)
-	if diags.HasErrors() {
-		return diags
+	if marks.Contains(srcVal, marks.Sensitive) {
+		return diags.Append(&hcl.Diagnostic{
+			Severity: hcl.DiagError,
+			Summary:  "Sensitive value not allowed",
+			Detail:   fmt.Sprintf("Sensitive values, or values derived from sensitive values, cannot be used as %s.", ident.String()),
+			Subject:  expr.Range().Ptr(),
+		})
 	}
 
-	return gohcl.DecodeExpression(expr, ctx, val)
+	return diags.Extend(gohcl.DecodeValue(srcVal, expr.StartRange(), expr.Range(), val))
 }
 
 func (s StaticEvaluator) DecodeBlock(body hcl.Body, spec hcldec.Spec, ident StaticIdentifier) (cty.Value, hcl.Diagnostics) {

internal/configs/static_evaluator_test.go

@@ -321,8 +321,11 @@ func TestStaticEvaluator_DecodeExpression(t *testing.T) {
 	}{{
 		expr: `"static"`,
 	}, {
-		expr:  `count`,
-		diags: []string{`eval.tf:1,1-6: Invalid reference; The "count" object cannot be accessed directly. Instead, access one of its attributes.`},
+		expr: `count`,
+		diags: []string{
+			`eval.tf:1,1-6: Invalid reference; The "count" object cannot be accessed directly. Instead, access one of its attributes.`,
+			`:0,0-0: Dynamic value in static context; Unable to use count. in static context, which is required by local.test`,
+		},
 	}, {
 		expr:  `module.foo.bar`,
 		diags: []string{`eval.tf:1,1-15: Module output not supported in static context; Unable to use module.foo.bar in static context, which is required by local.test`},
@@ -372,8 +375,28 @@ terraform {
 	}
 }`,
 		diags: []string{`eval.tf:4,11-25: Module output not supported in static context; Unable to use module.foo.bar in static context, which is required by backend.badeval`},
+	}, {
+		ident: "sensitive",
+		body: `
+locals {
+	sens = sensitive("magic")
+}
+terraform {
+	backend "sensitive" {
+		thing = local.sens
+	}
+}`,
+		diags: []string{`eval.tf:6,2-21: Backend config contains sensitive values; The backend configuration is stored in .terraform/terraform.tfstate as well as plan files. It is recommended to instead supply sensitive credentials via backend specific environment variables`},
 	}}
 
+	schema := &configschema.Block{
+		Attributes: map[string]*configschema.Attribute{
+			"thing": &configschema.Attribute{
+				Type: cty.String,
+			},
+		},
+	}
+
 	for _, tc := range cases {
 		t.Run(tc.ident, func(t *testing.T) {
 			parser := testParser(map[string]string{"eval.tf": tc.body})
@@ -383,13 +406,14 @@ terraform {
 			}
 
 			mod, _ := NewModule([]*File{file}, nil, RootModuleCallForTesting(), "dir", SelectiveLoadAll)
-			_, diags := mod.Backend.Decode(&configschema.Block{
-				Attributes: map[string]*configschema.Attribute{
-					"thing": &configschema.Attribute{
-						Type: cty.String,
-					},
-				},
-			})
+
+			_, diags := mod.Backend.Hash(schema)
+			if diags.HasErrors() {
+				assertExactDiagnostics(t, diags, tc.diags)
+				return
+			}
+
+			_, diags = mod.Backend.Decode(schema)
 
 			assertExactDiagnostics(t, diags, tc.diags)
 		})

internal/configs/static_scope.go

@@ -16,6 +16,7 @@ import (
 	"github.com/opentofu/opentofu/internal/addrs"
 	"github.com/opentofu/opentofu/internal/didyoumean"
 	"github.com/opentofu/opentofu/internal/lang"
+	"github.com/opentofu/opentofu/internal/lang/marks"
 	"github.com/opentofu/opentofu/internal/tfdiags"
 )
 
@@ -256,6 +257,9 @@ func (s staticScopeData) GetInputVariable(ident addrs.InputVariable, rng tfdiags
 	}
 
 	val, valDiags := s.eval.call.vars(variable)
+	if variable.Sensitive {
+		val = val.Mark(marks.Sensitive)
+	}
 	return val, s.enhanceDiagnostics(id, diags.Append(valDiags))
 }
 

internal/configs/testdata/error-files/module-sensitive.tf

@@ -0,0 +1,5 @@
+
+module "test" {
+  source  = sensitive("hostname/namespace/name/system") # ERROR: Sensitive value not allowed
+  version = sensitive("1.0.0") # ERROR: Invalid version constraint
+}

internal/configs/version_constraint.go

@@ -10,6 +10,7 @@ import (
 
 	version "github.com/hashicorp/go-version"
 	"github.com/hashicorp/hcl/v2"
+	"github.com/opentofu/opentofu/internal/lang/marks"
 	"github.com/zclconf/go-cty/cty"
 	"github.com/zclconf/go-cty/cty/convert"
 )
@@ -37,6 +38,15 @@ func decodeVersionConstraintValue(attr *hcl.Attribute, val cty.Value) (VersionCo
 		DeclRange: attr.Range,
 	}
 
+	if val.HasMark(marks.Sensitive) {
+		return ret, diags.Append(&hcl.Diagnostic{
+			Severity: hcl.DiagError,
+			Summary:  "Invalid version constraint",
+			Detail:   fmt.Sprintf("Sensitive values, or values derived from sensitive values, cannot be used as %s arguments.", attr.Name),
+			Subject:  attr.Expr.Range().Ptr(),
+		})
+	}
+
 	var err error
 	val, err = convert.Convert(val, cty.String)
 	if err != nil {

internal/encryption/keyprovider.go

@@ -14,6 +14,7 @@ import (
 	"github.com/opentofu/opentofu/internal/configs"
 	"github.com/opentofu/opentofu/internal/encryption/config"
 	"github.com/opentofu/opentofu/internal/lang"
+	"github.com/opentofu/opentofu/internal/lang/marks"
 
 	"github.com/hashicorp/hcl/v2"
 	"github.com/hashicorp/hcl/v2/gohcl"
@@ -187,6 +188,14 @@ func (e *targetBuilder) setupKeyProvider(cfg config.KeyProviderConfig, stack []c
 		return diags
 	}
 
+	// gohcl does not handle marks, we need to remove the sensitive marks from any input variables
+	// We assume that the entire configuration in the encryption block should be treated as sensitive
+	for key, sv := range evalCtx.Variables {
+		if marks.Contains(sv, marks.Sensitive) {
+			evalCtx.Variables[key], _ = sv.UnmarkDeep()
+		}
+	}
+
 	// Initialize the Key Provider
 	decodeDiags := gohcl.DecodeBody(cfg.Body, evalCtx, keyProviderConfig)
 	diags = append(diags, decodeDiags...)