Mount tune options (#5809)

* Refactor mount tune to support upsert options values and unset options.

* Do not allow unsetting options map

* add secret tune version regression test

* Only accept valid options version

* s/meVersion/optVersion/

command/secrets_tune_test.go

@@ -70,6 +70,80 @@ func TestSecretsTuneCommand_Run(t *testing.T) {
 		}
 	})
 
+	t.Run("protect_downgrade", func(t *testing.T) {
+		t.Parallel()
+		client, closer := testVaultServer(t)
+		defer closer()
+
+		ui, cmd := testSecretsTuneCommand(t)
+		cmd.client = client
+
+		// Mount
+		if err := client.Sys().Mount("kv", &api.MountInput{
+			Type: "kv",
+			Options: map[string]string{
+				"version": "2",
+			},
+		}); err != nil {
+			t.Fatal(err)
+		}
+
+		// confirm default max_versions
+		mounts, err := client.Sys().ListMounts()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		mountInfo, ok := mounts["kv/"]
+		if !ok {
+			t.Fatalf("expected mount to exist")
+		}
+		if exp := "kv"; mountInfo.Type != exp {
+			t.Errorf("expected %q to be %q", mountInfo.Type, exp)
+		}
+		if exp := "2"; mountInfo.Options["version"] != exp {
+			t.Errorf("expected %q to be %q", mountInfo.Options["version"], exp)
+		}
+
+		if exp := ""; mountInfo.Options["max_versions"] != exp {
+			t.Errorf("expected %s to be empty", mountInfo.Options["max_versions"])
+		}
+
+		// omitting the version should not cause a downgrade
+		code := cmd.Run([]string{
+			"-options", "max_versions=2",
+			"kv/",
+		})
+		if exp := 0; code != exp {
+			t.Errorf("expected %d to be %d", code, exp)
+		}
+
+		expected := "Success! Tuned the secrets engine at: kv/"
+		combined := ui.OutputWriter.String() + ui.ErrorWriter.String()
+		if !strings.Contains(combined, expected) {
+			t.Errorf("expected %q to contain %q", combined, expected)
+		}
+
+		mounts, err = client.Sys().ListMounts()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		mountInfo, ok = mounts["kv/"]
+		if !ok {
+			t.Fatalf("expected mount to exist")
+		}
+		if exp := "2"; mountInfo.Options["version"] != exp {
+			t.Errorf("expected %q to be %q", mountInfo.Options["version"], exp)
+		}
+		if exp := "kv"; mountInfo.Type != exp {
+			t.Errorf("expected %q to be %q", mountInfo.Type, exp)
+		}
+		if exp := "2"; mountInfo.Options["max_versions"] != exp {
+			t.Errorf("expected %s to be %s", mountInfo.Options["max_versions"], exp)
+		}
+	})
+
 	t.Run("integration", func(t *testing.T) {
 		t.Run("flags_all", func(t *testing.T) {
 			t.Parallel()

http/sys_mount_test.go

@@ -712,7 +712,7 @@ func TestSysTuneMount_Options(t *testing.T) {
 		t.Fatalf("bad:\nExpected: %#v\nActual:%#v", expected, actual)
 	}
 
-	// Unset the mount tune value
+	// Check that we're not allowed to unset the options map once that's set
 	resp = testHttpPost(t, token, addr+"/v1/sys/mounts/foo/tune", map[string]interface{}{
 		"options": map[string]string{},
 	})

vault/logical_system.go

@@ -1218,14 +1218,14 @@ func (b *SystemBackend) handleTuneWriteCommon(ctx context.Context, path string,
 	if optionsRaw, ok := data.GetOk("options"); ok {
 		options = optionsRaw.(map[string]string)
 	}
+
 	if len(options) > 0 {
 		b.Core.logger.Info("mount tuning of options", "path", path, "options", options)
+		newOptions := make(map[string]string)
+		var kvUpgraded bool
 
-		var changed bool
-		var numBuiltIn int
+		// The version options should only apply to the KV mount, check that first
 		if v, ok := options["version"]; ok {
-			changed = true
-			numBuiltIn++
 			// Special case to make sure we can not disable versioning once it's
 			// enabled. If the vkv backend suports downgrading this can be removed.
 			meVersion, err := parseutil.ParseInt(mountEntry.Options["version"])
@@ -1236,38 +1236,59 @@ func (b *SystemBackend) handleTuneWriteCommon(ctx context.Context, path string,
 			if err != nil {
 				return handleError(errwrap.Wrapf("unable to parse options: {{err}}", err))
 			}
+
+			// Only accept valid versions
+			switch optVersion {
+			case 1:
+			case 2:
+			default:
+				return logical.ErrorResponse(fmt.Sprintf("invalid version provided: %d", optVersion)), logical.ErrInvalidRequest
+			}
+
 			if meVersion > optVersion {
+				// Return early if version option asks for a downgrade
 				return logical.ErrorResponse(fmt.Sprintf("cannot downgrade mount from version %d", meVersion)), logical.ErrInvalidRequest
 			}
 			if meVersion < optVersion {
+				kvUpgraded = true
 				resp = &logical.Response{}
 				resp.AddWarning(fmt.Sprintf("Upgrading mount from version %d to version %d. This mount will be unavailable for a brief period and will resume service shortly.", meVersion, optVersion))
 			}
 		}
-		if options != nil {
-			// For anything we don't recognize and provide special handling,
-			// always write
-			if len(options) > numBuiltIn {
-				changed = true
+
+		// Upsert options value to a copy of the existing mountEntry's options
+		for k, v := range mountEntry.Options {
+			newOptions[k] = v
+		}
+		for k, v := range options {
+			// If the value of the provided option is empty, delete the key We
+			// special-case the version value here to guard against KV downgrades, but
+			// this piece could potentially be refactored in the future to be non-KV
+			// specific.
+			if len(v) == 0 && k != "version" {
+				delete(newOptions, k)
+			} else {
+				newOptions[k] = v
 			}
 		}
 
-		if changed {
-			oldVal := mountEntry.Options
-			mountEntry.Options = options
-			// Update the mount table
-			switch {
-			case strings.HasPrefix(path, "auth/"):
-				err = b.Core.persistAuth(ctx, b.Core.auth, &mountEntry.Local)
-			default:
-				err = b.Core.persistMounts(ctx, b.Core.mounts, &mountEntry.Local)
-			}
-			if err != nil {
-				mountEntry.Options = oldVal
-				return handleError(err)
-			}
+		// Update the mount table
+		oldVal := mountEntry.Options
+		mountEntry.Options = newOptions
+		switch {
+		case strings.HasPrefix(path, "auth/"):
+			err = b.Core.persistAuth(ctx, b.Core.auth, &mountEntry.Local)
+		default:
+			err = b.Core.persistMounts(ctx, b.Core.mounts, &mountEntry.Local)
+		}
+		if err != nil {
+			mountEntry.Options = oldVal
+			return handleError(err)
+		}
 
-			// Reload the backend to kick off the upgrade process.
+		// Reload the backend to kick off the upgrade process. It should only apply to KV backend so we
+		// trigger based on the version logic above.
+		if kvUpgraded {
 			b.Core.reloadBackendCommon(ctx, mountEntry, strings.HasPrefix(path, credentialRoutePrefix))
 		}
 	}