Fixing Index.js In React-native-sensitive-info

Fixing Index.js and getSupportedSecurityLevels in react-native-sensitive-info

Hey there! 👋 I recently encountered an issue with react-native-sensitive-info version 5.6.1 while working on a project, and I wanted to share the solution. This is about fixing index.js file broken and getSupportedSecurityLevels returning hardcoded values.

The Problem: Broken index.js and Hardcoded Values

I'm a big fan of this project, and I use react-native-sensitive-info to securely store sensitive data in my React Native applications. I used patch-package to patch react-native-sensitive-info@5.6.1 for the project I'm working on, as the index.js file seemed to be broken. **Specifically, the getSupportedSecurityLevels function was returning hardcoded values instead of dynamically checking for device capabilities.** This meant that the app wasn't accurately reflecting the security features available on the user's device. This is a problem because if the function always returns the same hardcoded values, the app may not be able to use the available security features, or it may report incorrect information about the security level.

Here's a snippet of the problematic code:

return {
    secureEnclave: true,
    strongBox: true,
    biometry: false,
    deviceCredential: true,
    iCloudSync: false
}

As you can see, this code always returns the same object, regardless of the device's actual capabilities. This is not ideal as it doesn't take into account whether the device actually supports features like biometry or secure enclave. **The correct behavior should involve checking the device's hardware and software to determine which security levels are supported and then returning an object that accurately reflects these capabilities.** This is crucial for ensuring that the app behaves correctly on different devices and that sensitive information is protected using the most appropriate security features.

The Solution: A Quick Patch

Thankfully, the fix was relatively straightforward. I used patch-package to apply the necessary changes. Here's the diff that resolved the issue:

diff --git a/node_modules/react-native-sensitive-info/lib/module/index.js b/node_modules/react-native-sensitive-info/lib/module/index.js
index 3502753..9bc9478 100644
--- a/node_modules/react-native-sensitive-info/lib/module/index.js
+++ b/node_modules/react-native-sensitive-info/lib/module/index.js
@@ -491,29 +453,28 @@
  * ```
  */
 export async function getSupportedSecurityLevels() {
-  return {
-    secureEnclave: true,
-    strongBox: true,
-    biometry: false,
-    deviceCredential: true,
-    iCloudSync: false
-  };
+  const nativeModule = getNativeModule();
+  try {
+    if (nativeModule?.getSupportedSecurityLevels) {
+      return await nativeModule.getSupportedSecurityLevels();
+    }
+
+    return {
+      biometry: false,
+      deviceCredential: false,
+      secureEnclave: false,
+      strongBox: false,
+      iCloudSync: false,
+    };
+  } catch (error) {
+    return {
+      biometry: false,
+      deviceCredential: false,
+      secureEnclave: false,
+      strongBox: false,
+      iCloudSync: false,
+    };
+  }
 }

The key change here is that the getSupportedSecurityLevels function now attempts to call a native module to determine the supported levels. If the native module is available and provides the implementation, it will be used. If not, the function defaults to returning an object with all security features set to false. This ensures that the app doesn't crash if the native module is unavailable or if there's an issue with the native implementation.

Why This Matters: Security and Device Compatibility

This fix is crucial for a couple of reasons:

1. Enhanced Security: By correctly identifying supported security levels, the app can leverage the device's hardware-backed security features (like Secure Enclave or StrongBox) when available. This provides a much stronger layer of protection for sensitive information than relying on software-based solutions.
2. Device Compatibility: The original hardcoded values could lead to incorrect behavior on different devices. For instance, if a device doesn't support biometry, the app shouldn't try to use it. This fix ensures that the app adapts to the device's capabilities, providing a consistent and secure experience across all supported platforms.

How to Apply the Patch

Applying this patch using patch-package is pretty simple:

1. Make sure you have patch-package installed in your project: npm install patch-package --save-dev or yarn add patch-package --dev.
2. Save the diff provided above as a patch file (e.g., react-native-sensitive-info+5.6.1.patch). You can do this by copying the diff and saving it to a file, or by using the patch-package command to create a patch directly.
3. Run patch-package react-native-sensitive-info in your project's root directory. This will apply the patch to your node_modules and create a patches directory with the patch file.
4. Commit the patch file (patches/react-native-sensitive-info+5.6.1.patch) to your version control system so that the fix is applied to all team members' environments.

Further Improvements and Considerations

While this patch addresses the immediate issue, there are a few things to consider for future improvements:

• Error Handling: The getSupportedSecurityLevels function could benefit from more robust error handling. If the native module fails to provide the supported levels, the app should handle this gracefully (e.g., by logging an error or falling back to a default security level).
• Platform-Specific Implementations: Depending on the platform (iOS, Android, etc.), the native module might have different ways of determining the supported security levels. Ensuring that the native module correctly handles these platform-specific differences is crucial for accurate results.
• Testing: Thorough testing on a variety of devices and operating system versions is essential to ensure that the app correctly identifies and utilizes the available security features.

Conclusion

This was a minor issue with a significant impact on security and device compatibility. By applying this patch, you can ensure that react-native-sensitive-info correctly identifies the supported security levels on each device, enabling your app to protect sensitive data more effectively. Remember that keeping your dependencies up-to-date and regularly reviewing your security practices are essential for building secure applications. I hope this helps anyone facing the same problem! Don't hesitate to reach out if you have any questions or need further assistance.

For more information on react-native-sensitive-info, check out the official GitHub repository here.`

And for patch-package, you can visit its GitHub page here.