extension_install_dialog.md

Extension Install Dialog

This document analyzes the security of the Chromium extension install dialog, specifically the ExtensionInstallDialogView class in chrome/browser/ui/views/extensions/extension_install_dialog_view.cc.

Component Focus

chrome/browser/ui/views/extensions/extension_install_dialog_view.cc and chrome/browser/ui/views/extensions/extension_install_dialog_view.h.

Potential Logic Flaws

• The dialog's asynchronous initialization and use of timers (enable_install_timer_, install_result_timer_) could introduce race conditions.
• The justification text field (justification_field_) could be vulnerable to injection attacks if not properly sanitized.
• The dialog's focus handling, especially when interacting with the webstore link or the grant permissions checkbox, could be a source of vulnerabilities.
• The dialog handles extension uninstallation events (OnExtensionUninstalled), which could be a source of vulnerabilities if not handled correctly.
• The dialog handles data from the ExtensionInstallPrompt, which could be a source of vulnerabilities if not properly validated.
• The dialog's UI elements could be manipulated by a malicious actor if not properly protected.

Further Analysis and Potential Issues

• The ExtensionInstallDialogView class manages the extension install dialog. This class should be carefully analyzed for potential vulnerabilities, such as improper initialization or resource leaks.
• The enable_install_timer_ and the install_result_timer_ should be reviewed for potential race conditions.
• The ContentsChanged method and the justification_field_ member should be reviewed for potential injection vulnerabilities.
• The OnExtensionUninstalled method should be reviewed for potential vulnerabilities related to extension uninstallation.
• The interaction between the dialog and the ExtensionInstallPrompt should be reviewed for potential vulnerabilities related to data handling.
• The dialog's UI elements should be reviewed for potential manipulation vulnerabilities.
• The RatingsView and RatingStar classes should be reviewed for potential accessibility issues.
• The TitleLabelWrapper class should be reviewed for potential layout issues.
• The CustomScrollableView class should be reviewed for potential issues related to scrolling and resizing.
• The ExtensionJustificationView class should be reviewed for potential vulnerabilities related to text input and length validation.

Code Analysis

• Timer Usage: The enable_install_timer_ is used to delay the enabling of the install button. This timer should be reviewed for potential race conditions or unexpected behavior if the dialog is closed or modified before the timer fires.

  void ExtensionInstallDialogView::VisibilityChanged(views::View* starting_from,
                                                     bool is_visible) {
    if (is_visible && !install_result_timer_) {
      install_result_timer_ = base::ElapsedTimer();
  
      if (!install_button_enabled_) {
        enable_install_timer_.Start(
            FROM_HERE, base::Milliseconds(g_install_delay_in_ms),
            base::BindOnce(&ExtensionInstallDialogView::EnableInstallButton,
                           base::Unretained(this)));
      }
    }
  }

• Justification Text Field: The ContentsChanged method is used to update the length label and the state of the OK button. This method should be reviewed for potential injection vulnerabilities and for proper handling of different input types.

  void ExtensionInstallDialogView::ContentsChanged(
      views::Textfield* sender,
      const std::u16string& new_contents) {
    DCHECK(justification_view_);
  
    justification_view_->UpdateLengthLabel();
  
    bool is_justification_length_within_limit =
        justification_view_->IsJustificationLengthWithinLimit();
    if (request_button_enabled_ != is_justification_length_within_limit) {
      request_button_enabled_ = is_justification_length_within_limit;
      DialogModelChanged();
    }
  }

• Extension Uninstallation: The OnExtensionUninstalled method is used to close the dialog if the extension is uninstalled. This method should be reviewed to ensure that it handles uninstallation events correctly and doesn't introduce any vulnerabilities.

  void ExtensionInstallDialogView::OnExtensionUninstalled(
      content::BrowserContext* browser_context,
      const extensions::Extension* extension,
      extensions::UninstallReason reason) {
    CHECK(extension);
    CHECK(prompt_);
    CHECK(prompt_->extension());
    if (extension->id() != prompt_->extension()->id())
      return;
    CloseDialog();
  }

• Data Handling: The dialog receives data from the ExtensionInstallPrompt object. This data should be validated and sanitized to prevent any potential vulnerabilities.

Areas Requiring Further Investigation

• How are the dialog's UI elements protected from manipulation?
• How does the dialog handle errors during the installation process?
• What are the security implications of a malicious extension manipulating the dialog?
• How does the dialog interact with the extension system?
• What are the security implications of the dialog's access to extension data?
• How does the dialog handle different types of prompts (e.g., install, update, permissions)?
• How does the dialog handle different types of extensions (e.g., apps, themes, extensions)?
• How does the dialog handle different types of permissions?