mitigations.md

Mitigation Strategies Analysis for emilk/egui

Mitigation Strategy: Strict Text Input Filtering and Sanitization (within egui)

Mitigation Strategy: Strict Text Input Filtering and Sanitization (within egui)

• Description:

  1. Identify egui Input Fields: Locate all instances within your egui code where user input is accepted. This primarily involves TextEdit widgets, but also includes any custom input handling you've implemented.
  2. Define Allowed Character Sets: For each egui input field, determine the precise set of acceptable characters. A username field might allow alphanumerics and underscores; a numeric field would only allow digits.
  3. Implement Filtering Within egui: Inside the egui frame rendering loop (where the input widget is used), add code to filter the input string before it's used for anything (display, storage, processing). This can be done:
     • Character-by-character: Iterate through the input string and reject any character not in the allowed set.
     • Regular Expressions: Use regular expressions to enforce more complex input patterns.
     • Combination: Use a combination of both techniques for optimal validation.
  4. Enforce Length Limits (using egui features): Utilize egui's built-in features to set maximum lengths for text input fields. This often involves the TextEdit::desired_width property, but you might need additional custom logic to truncate input if it exceeds the limit.
  5. Escape/Encode Output Before egui Display: Before displaying any user-provided data back to the user within egui, escape or encode it appropriately. Since egui doesn't provide built-in escaping, you must do this manually. For web contexts, use a robust HTML escaping function (e.g., from a library like html-escape in Rust). For other contexts, use the appropriate escaping mechanism for that output format.

• Threats Mitigated:

  • Cross-Site Scripting (XSS) (High Severity): Prevents malicious JavaScript from being injected through egui input fields and executed. The output escaping step is critical here.
  • Code Injection (High Severity): If (and you should avoid this) user input is used to construct code, filtering within egui prevents malicious code injection.
  • Buffer Overflow (Medium to High Severity): egui's length limits, combined with your own checks, help prevent buffer overflows.
  • Denial of Service (DoS) (Medium Severity): Length limits and filtering within egui prevent extremely large inputs that could cause performance issues.
  • Data Corruption (Medium Severity): Prevents invalid data from being processed by the egui portion of your application.

• Impact:

  • XSS: Significantly reduces XSS risk within the egui context. Proper escaping is essential.
  • Code Injection: Significantly reduces risk, provided user input is not used to generate code.
  • Buffer Overflow: Reduces risk, especially when combined with secure memory management.
  • DoS: Reduces risk of certain DoS attacks targeting egui input.
  • Data Corruption: Reduces risk of egui-related data corruption.

• Currently Implemented:

  • Basic length limits on most TextEdit widgets in src/ui/input_forms.rs.
  • HTML escaping when displaying user names in src/ui/user_profile.rs before passing to egui.

• Missing Implementation:

  • Character-level filtering is missing for several egui input fields: "search" (src/ui/search_bar.rs) and "comment" (src/ui/comment_section.rs).
  • Regular expression validation is not used anywhere within the egui code.
  • Output escaping is inconsistent. Missing in src/ui/message_display.rs before displaying user messages with egui.

Mitigation Strategy: Secure State Management (within egui)

Mitigation Strategy: Secure State Management (within egui)

• Description:

  1. Identify Mutable egui State: Analyze your egui code to identify all variables and data structures that are modified during the egui rendering loop or between frames.
  2. Minimize egui Mutability: Refactor your egui code to use immutable data structures whenever possible. Instead of modifying a Vec in place within the egui loop, create a new Vec with the changes.
  3. Isolate egui State: Encapsulate egui-related state within specific egui components or modules. Avoid using global variables that are accessible from within the egui rendering loop.
  4. Clear Sensitive egui Data: If sensitive data (passwords, tokens) is temporarily stored within egui's state (e.g., during input in a TextEdit), explicitly overwrite that data in memory with zeros or random characters immediately after it's no longer needed, within the same frame. Don't rely on garbage collection. Use a secure memory wiping function if available.
  5. Validate egui::data: If you use egui::data to store data that persists between frames, validate and sanitize that data every time it is loaded and used within the egui rendering loop, especially if it originates from user input.

• Threats Mitigated:

  • Data Tampering (Medium to High Severity): Reduces the risk of attackers modifying egui-related application state.
  • Information Disclosure (Medium to High Severity): Clearing sensitive data prevents leaks from egui's temporary memory.
  • Logic Errors (Variable Severity): Minimizing mutable state within egui improves code clarity and reduces vulnerability risks.

• Impact:

  • Data Tampering: Reduces the attack surface for tampering with egui-managed data.
  • Information Disclosure: Significantly reduces risk of sensitive data leaks from egui's in-memory state.
  • Logic Errors: Improves egui code maintainability and reduces vulnerability introduction.

• Currently Implemented:

  • Some use of immutable data structures in src/data/models.rs, but this is not directly within the egui rendering logic.
  • Sensitive data (passwords) are cleared after use in the egui login form (src/ui/login_form.rs).

• Missing Implementation:

  • Significant mutable state is still used within src/ui/main_window.rs for handling user interactions and data updates within the egui loop. This needs refactoring.
  • egui::data is used in src/app_state.rs, but the data is not validated within the egui loop when it's loaded and used.
  • No secure memory wiping function is used; only simple overwriting.

Mitigation Strategy: Secure Rendering and Output Handling (within egui)

Mitigation Strategy: Secure Rendering and Output Handling (within egui)

• Description:

  1. Avoid Dynamic egui Code Generation: Never use user input to dynamically construct egui code or UI elements. Do not use functions like eval() or string interpolation to create egui widgets based on user-provided data. This is a fundamental security principle.
  2. Sanitize HTML Before egui Rendering (if used): If you utilize egui's limited HTML rendering capabilities (e.g., for rich text), you must use a dedicated HTML sanitization library (like ammonia in Rust) to sanitize any user-provided input that might be included in the HTML. Do this before passing the string to egui.
  3. Contextual Output Encoding Before egui: Always encode or escape output based on the context where it is displayed before passing it to egui for rendering. Use HTML escaping for web contexts, and appropriate encoding for other output formats.

• Threats Mitigated:

  • Cross-Site Scripting (XSS) (High Severity): HTML sanitization and output encoding before passing data to egui are critical.
  • Code Injection (High Severity): Avoiding dynamic egui code generation eliminates this risk within the egui context.

• Impact:

  • XSS: Sanitization and encoding drastically reduce XSS risk related to egui's rendering.
  • Code Injection: Eliminates the risk if dynamic egui code generation is avoided.

• Currently Implemented:

  • Dynamic egui code generation is not used.

• Missing Implementation:

  • HTML sanitization is not implemented. Any user input displayed as rich text within egui should be sanitized before being passed to egui. This is missing in src/ui/rich_text_display.rs.
  • Contextual output encoding is not consistently used before data is given to egui.

Mitigation Strategy: Robust Error Handling (within egui)

Mitigation Strategy: Robust Error Handling (within egui)

• Description:

  1. Avoid Exposing Internal egui Errors: Never display raw error messages, stack traces, or internal egui implementation details directly to the user from within your egui code.
  2. Use Generic Error Messages (within egui): If an error occurs within your egui logic, display a user-friendly, generic error message using egui widgets. The message should not reveal sensitive information.
  3. Handle All egui Errors: Use Result types (or the appropriate error handling mechanism for your language) to handle all potential errors that could occur within your egui code. Don't let errors propagate unhandled.
  4. Fail Gracefully within egui: Ensure that your egui code handles errors gracefully and doesn't cause the entire UI to crash or become unresponsive. Provide fallback UI elements or states where appropriate.

• Threats Mitigated:

  • Information Disclosure (Medium Severity): Prevents attackers from gaining information about egui's internal workings or your application's structure.
  • Denial of Service (DoS) (Medium Severity): Graceful error handling within egui prevents UI crashes.

• Impact:

  • Information Disclosure: Reduces risk of information leakage through egui-generated error messages.
  • DoS: Improves egui UI resilience to errors.

• Currently Implemented:

  • Most egui code uses Result types.
  • Generic error messages are displayed to the user in some egui contexts.

• Missing Implementation:

  • Some error handling paths within the egui code still expose internal error messages (this needs auditing).
  • Fallback UI elements are not consistently implemented for error conditions within egui.