From 8bbdac7c18f64f00e48b5c7d00bd7bc81f1d1da8 Mon Sep 17 00:00:00 2001
From: melsonic <work.melsonic@gmail.com>
Date: Wed, 16 Apr 2025 00:22:55 +0530
Subject: [PATCH] feat: validate gradient color stops

---
 d2renderers/d2svg/d2svg.go | 33 ++++++++++++++++++++++++---------
 lib/color/gradient.go      | 21 ++++++++++++++-------
 2 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/d2renderers/d2svg/d2svg.go b/d2renderers/d2svg/d2svg.go
index 089eaae4b..07faa9464 100644
--- a/d2renderers/d2svg/d2svg.go
+++ b/d2renderers/d2svg/d2svg.go
@@ -1069,9 +1069,10 @@ func renderDoubleOval(tl *geo.Point, width, height float64, fill, fillStroke, st
 	return renderOval(tl, width, height, fill, fillStroke, stroke, style, inlineTheme) + renderOval(innerTL, width-10, height-10, fill, "", stroke, style, inlineTheme)
 }
 
-func defineGradients(writer io.Writer, cssGradient string) {
-	gradient, _ := color.ParseGradient(cssGradient)
+func defineGradients(writer io.Writer, cssGradient string) error {
+	gradient, err := color.ParseGradient(cssGradient)
 	fmt.Fprint(writer, fmt.Sprintf(`<defs>%s</defs>`, color.GradientToSVG(gradient)))
+	return err
 }
 
 func defineShadowFilter(writer io.Writer) {
@@ -2278,28 +2279,42 @@ func Render(diagram *d2target.Diagram, opts *RenderOpts) ([]byte, error) {
 	}
 
 	if color.IsGradient(diagram.Root.Fill) {
-		defineGradients(buf, diagram.Root.Fill)
+		if err := defineGradients(buf, diagram.Root.Fill); err != nil {
+			return nil, err
+		}
 	}
 	if color.IsGradient(diagram.Root.Stroke) {
-		defineGradients(buf, diagram.Root.Stroke)
+		if err := defineGradients(buf, diagram.Root.Stroke); err != nil {
+			return nil, err
+		}
 	}
 	for _, s := range diagram.Shapes {
 		if color.IsGradient(s.Fill) {
-			defineGradients(buf, s.Fill)
+			if err := defineGradients(buf, s.Fill); err != nil {
+				return nil, err
+			}
 		}
 		if color.IsGradient(s.Stroke) {
-			defineGradients(buf, s.Stroke)
+			if err := defineGradients(buf, s.Stroke); err != nil {
+				return nil, err
+			}
 		}
 		if color.IsGradient(s.Color) {
-			defineGradients(buf, s.Color)
+			if err := defineGradients(buf, s.Color); err != nil {
+				return nil, err
+			}
 		}
 	}
 	for _, c := range diagram.Connections {
 		if color.IsGradient(c.Stroke) {
-			defineGradients(buf, c.Stroke)
+			if err := defineGradients(buf, c.Stroke); err != nil {
+				return nil, err
+			}
 		}
 		if color.IsGradient(c.Fill) {
-			defineGradients(buf, c.Fill)
+			if err := defineGradients(buf, c.Fill); err != nil {
+				return nil, err
+			}
 		}
 	}
 
diff --git a/lib/color/gradient.go b/lib/color/gradient.go
index 29f29acc3..5abda25e5 100644
--- a/lib/color/gradient.go
+++ b/lib/color/gradient.go
@@ -9,6 +9,8 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
+
+	"github.com/mazznoer/csscolorparser"
 )
 
 type Gradient struct {
@@ -46,23 +48,26 @@ func ParseGradient(cssGradient string) (Gradient, error) {
 	}
 
 	firstParam := strings.TrimSpace(paramList[0])
-
+	var err error
 	if gradient.Type == "linear" && (strings.HasSuffix(firstParam, "deg") || strings.HasPrefix(firstParam, "to ")) {
 		gradient.Direction = firstParam
 		colorStops := paramList[1:]
 		if len(colorStops) == 0 {
 			return Gradient{}, errors.New("no color stops in gradient")
 		}
-		gradient.ColorStops = parseColorStops(colorStops)
+		gradient.ColorStops, err = parseColorStops(colorStops)
 	} else if gradient.Type == "radial" && (firstParam == "circle" || firstParam == "ellipse") {
 		gradient.Direction = firstParam
 		colorStops := paramList[1:]
 		if len(colorStops) == 0 {
 			return Gradient{}, errors.New("no color stops in gradient")
 		}
-		gradient.ColorStops = parseColorStops(colorStops)
+		gradient.ColorStops, err = parseColorStops(colorStops)
 	} else {
-		gradient.ColorStops = parseColorStops(paramList)
+		gradient.ColorStops, err = parseColorStops(paramList)
+	}
+	if err != nil {
+		return Gradient{}, err
 	}
 	gradient.ID = UniqueGradientID(cssGradient)
 
@@ -97,12 +102,14 @@ func splitParams(params string) []string {
 	return parts
 }
 
-func parseColorStops(params []string) []ColorStop {
+func parseColorStops(params []string) ([]ColorStop, error) {
 	var colorStops []ColorStop
 	for _, p := range params {
 		p = strings.TrimSpace(p)
 		parts := strings.Fields(p)
-
+		if _, err := csscolorparser.Parse(parts[0]); err != nil {
+			return nil, fmt.Errorf("%s is not a valid color format", parts[0])
+		}
 		switch len(parts) {
 		case 1:
 			colorStops = append(colorStops, ColorStop{Color: parts[0]})
@@ -112,7 +119,7 @@ func parseColorStops(params []string) []ColorStop {
 			continue
 		}
 	}
-	return colorStops
+	return colorStops, nil
 }
 
 func GradientToSVG(gradient Gradient) string {