Harden scheme request body parsing

pkg/display/scheme.go

@@ -2,6 +2,7 @@ package display
 
 import (
 	"context"
+	"fmt"
 	"html"
 	"net/url"
 	"sort"
@@ -16,6 +17,8 @@ import (
 
 type SchemeHandler func(context.Context, string, url.Values) core.Result
 
+const maxSchemeRequestBodyBytes = 1 << 20
+
 type assetMiddlewareHandler struct {
 	next    application.Handler
 	service *Service
@@ -365,6 +368,16 @@ func (s *Service) ResolveSchemeRequest(ctx context.Context, rawURL, method strin
 	if strings.TrimSpace(rawURL) == "" {
 		return core.Result{Value: coreerr.E("display.ResolveScheme", "scheme URL is required", nil), OK: false}
 	}
+	if len(body) > maxSchemeRequestBodyBytes {
+		return core.Result{
+			Value: coreerr.E(
+				"display.ResolveScheme",
+				fmt.Sprintf("request body exceeds %d bytes", maxSchemeRequestBodyBytes),
+				nil,
+			),
+			OK: false,
+		}
+	}
 	parsed, err := url.Parse(rawURL)
 	if err != nil {
 		return core.Result{Value: err, OK: false}

pkg/display/scheme_test.go

@@ -3,6 +3,7 @@ package display
 import (
 	"context"
 	"net/url"
+	"strings"
 	"testing"
 
 	core "dappco.re/go/core"
@@ -155,6 +156,38 @@ func TestScheme_ResolveScheme_Bad(t *testing.T) {
 	require.False(t, noHandlerResult.OK)
 }
 
+func TestScheme_ResolveSchemeRequest_BodyQuery_Good(t *testing.T) {
+	svc, _ := newTestDisplayService(t)
+	svc.registerDefaultSchemes()
+
+	result := svc.ResolveSchemeRequest(
+		context.Background(),
+		"core://store",
+		"POST",
+		map[string][]string{"Content-Type": {"application/x-www-form-urlencoded"}},
+		[]byte("q=theme"),
+	)
+	require.True(t, result.OK)
+	payload := result.Value.(map[string]any)
+	assert.Equal(t, "store", payload["route"])
+	assert.Contains(t, payload["body"].(string), "Search the in-memory storage scopes")
+}
+
+func TestScheme_ResolveSchemeRequest_BodyQuery_Bad(t *testing.T) {
+	svc, _ := newTestDisplayService(t)
+	svc.registerDefaultSchemes()
+
+	result := svc.ResolveSchemeRequest(
+		context.Background(),
+		"core://store",
+		"POST",
+		nil,
+		[]byte(strings.Repeat("a", maxSchemeRequestBodyBytes+1)),
+	)
+	require.False(t, result.OK)
+	assert.Contains(t, result.Value.(error).Error(), "request body exceeds")
+}
+
 func TestScheme_ResolveScheme_Ugly(t *testing.T) {
 	svc, _ := newTestDisplayService(t)
 	svc.registerDefaultSchemes()