feat: add max download size validation for media files

- settings.go: add WhatsappSettingMaxDownloadSize for file size
  validation (500MB)
- utils.go: check file size before writing media to disk, returning
  an error if it exceeds the max limit

src/config/settings.go

@@ -19,13 +19,14 @@ var (
 
 	DBName = "whatsapp.db"
 
-	WhatsappAutoReplyMessage    string
-	WhatsappWebhook             string
-	WhatsappWebhookSecret             = "secret"
-	WhatsappLogLevel                  = "ERROR"
-	WhatsappSettingMaxFileSize  int64 = 50000000  // 50MB
-	WhatsappSettingMaxVideoSize int64 = 100000000 // 100MB
-	WhatsappTypeUser                  = "@s.whatsapp.net"
-	WhatsappTypeGroup                 = "@g.us"
-	WhatsappAccountValidation         = true
+	WhatsappAutoReplyMessage       string
+	WhatsappWebhook                string
+	WhatsappWebhookSecret                = "secret"
+	WhatsappLogLevel                     = "ERROR"
+	WhatsappSettingMaxFileSize     int64 = 50000000  // 50MB
+	WhatsappSettingMaxVideoSize    int64 = 100000000 // 100MB
+	WhatsappSettingMaxDownloadSize int64 = 500000000 // 500MB
+	WhatsappTypeUser                     = "@s.whatsapp.net"
+	WhatsappTypeGroup                    = "@g.us"
+	WhatsappAccountValidation            = true
 )

src/pkg/whatsapp/utils.go

@@ -34,6 +34,12 @@ func ExtractMedia(storageLocation string, mediaFile whatsmeow.DownloadableMessag
 		return extractedMedia, err
 	}
 
+	// Validate file size before writing to disk
+	maxFileSize := config.WhatsappSettingMaxDownloadSize
+	if int64(len(data)) > maxFileSize {
+		return extractedMedia, fmt.Errorf("file size exceeds the maximum limit of %d bytes", maxFileSize)
+	}
+
 	switch media := mediaFile.(type) {
 	case *waE2E.ImageMessage:
 		extractedMedia.MimeType = media.GetMimetype()