How to Avoid the Null Trap in Privilege Mode Drivers TL;DR: Using null pointers in critical code can crash your system Problems Memory access violation
Unpredictable behavior
Null Pointer Dereference
Unexpected program termination
System instability
No healing/recovery strategy
Security Risk Solutions Avoid using NULLs
Use address sanitizers
Make controlled releases to mission-critical software
Create better rollback strategies instead of BSOD
Use Smart Pointers: Manage memory automatically and avoid null pointers with smart pointers
Create self-healing software.
Apply defensive programming
Improve your QA tests before deploying to production. Context When you use nulls in a privileged driver, you risk causing serious issues. Privilege mode drivers run with high permissions, and if you use a null pointer, the system might try to access an invalid memory address. For example, trying to read from address 0x9c (156) or using 0x0 as a special value can lead to critical errors. You can't just abort the program in privileged mode, so you must handle these cases carefully. In privileged drivers, null pointer usage poses significant risks. You can mitigate these risks using modern C++ features like std::optional. This problem caused one of the worst software blackouts in 2024. Sample Code Wrong // This case is not exactly what happened with Crowdstrike
// It is here for illustration purposes
void* get_data() {
  if (data_available) {
    return data_ptr;  // This could be null!
  } else {
    // Uh oh, what if data_ptr is null here?
    return NULL;  
    // Using Null to indicate no data
    // knowing Null is schizophrenic
  }
}

int process_data(void* data) {
  if (data != NULL) { 
    // Maybe a null check, but not guaranteed!
    // Accessing data... (crash if data is Null)
    return *data;
  }
  // No check? Silent failure or unexpected behavior.
  return -1;
} Right // You should ideally replace the null with a polymorphic call
// You can see the technique in related articles

std::unique_ptr<int> get_data() { 
  if (data_available) {
    return std::make_unique<int>(data_value);
  } else {
    return nullptr;  // Explicitly return nullptr
  }
}

int process_data(const std::unique_ptr<int>& data) {
  if (data) { // Check for valid pointer
    return *data;
  } else {
    // Handle no data case (e.g., return default value)
    return 0;
  }
} Important Notes About this Code Smell Detection [x]Semi-Automatic You can detect this smell by checking for null pointer usage in critical parts of your code. Look for functions that process pointers and see if they handle null pointers safely. Human code reviews are good for checking this kind of problem. Tags Null Level [x]Advanced /AI Generation AI generators can sometimes produce this smell, especially if they generate code without context about the environment where the code will run. AI generators are fed with code with NULL usage even though his creator told us to avoid it altogether. AI Detection AI tools can detect this smell with specific instructions. AI can be trained to identify code patterns. Teaching it the nuances of privileged driver development and null safety best practices might require more advanced techniques. Use static analysis tools to flag null pointer dereferences. Conclusion Voyager 1's software has been running for more than 50 years. It was designed to be robust, reliable, and redundant which is sadly uncommon in some immature systems in 2024. Avoid using null pointers in privileged mode drivers. I have written a book on clean code and a whole chapter #15 on how to avoid NULL and all the consequences it carries. Hopefully, Crowdstrike engineers will read it! Related Code Smells Code Smell 12 - Null Code Smell 126 - Fake Null Object Code Smell 208 - Null Island Further Reading https://hackernoon.com/null-the-billion-dollar-mistake-8t5z32d6?embedable=true https://github.com/google/sanitizers/wiki/AddressSanitizer?embedable=true https://x.com/perpetualmaniac/status/1814376668095754753?embedable=true Disclaimer: Code Smells are my opinion. I couldn't resist the temptation to put in a null reference, simply because it was so easy to implement. This has led to innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last forty years. Tony Hoare https://hackernoon.com/400-thought-provoking-software-engineering-quotes?embedable=true This article is part of the CodeSmell Series on HackerNoon. https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-i-xqz3evd?embedable=true How to Avoid the Null Trap in Privilege Mode Drivers TL;DR: Using null pointers in critical code can crash your system TL;DR: Using null pointers in critical code can crash your system Problems Memory access violation Unpredictable behavior Null Pointer Dereference Unexpected program termination System instability No healing/recovery strategy Security Risk Memory access violation Unpredictable behavior Null Pointer Dereference Unexpected program termination System instability No healing/recovery strategy Security Risk Solutions Avoid using NULLs Use address sanitizers Make controlled releases to mission-critical software Create better rollback strategies instead of BSOD Use Smart Pointers: Manage memory automatically and avoid null pointers with smart pointers Create self-healing software. Apply defensive programming Improve your QA tests before deploying to production. Avoid using NULLs NULLs Use address sanitizers address sanitizers Make controlled releases to mission-critical software Create better rollback strategies instead of BSOD BSOD Use Smart Pointers: Manage memory automatically and avoid null pointers with smart pointers Create self-healing software. Apply defensive programming Improve your QA tests before deploying to production. Context When you use nulls in a privileged driver, you risk causing serious issues. Privilege mode drivers run with high permissions, and if you use a null pointer, the system might try to access an invalid memory address. For example, trying to read from address 0x9c (156) or using 0x0 as a special value can lead to critical errors. You can't just abort the program in privileged mode, so you must handle these cases carefully. In privileged drivers, null pointer usage poses significant risks. You can mitigate these risks using modern C++ features like std::optional . std::optional This problem caused one of the worst software blackouts in 2024. This problem Sample Code Wrong // This case is not exactly what happened with Crowdstrike
// It is here for illustration purposes
void* get_data() {
  if (data_available) {
    return data_ptr;  // This could be null!
  } else {
    // Uh oh, what if data_ptr is null here?
    return NULL;  
    // Using Null to indicate no data
    // knowing Null is schizophrenic
  }
}

int process_data(void* data) {
  if (data != NULL) { 
    // Maybe a null check, but not guaranteed!
    // Accessing data... (crash if data is Null)
    return *data;
  }
  // No check? Silent failure or unexpected behavior.
  return -1;
} // This case is not exactly what happened with Crowdstrike
// It is here for illustration purposes
void* get_data() {
  if (data_available) {
    return data_ptr;  // This could be null!
  } else {
    // Uh oh, what if data_ptr is null here?
    return NULL;  
    // Using Null to indicate no data
    // knowing Null is schizophrenic
  }
}

int process_data(void* data) {
  if (data != NULL) { 
    // Maybe a null check, but not guaranteed!
    // Accessing data... (crash if data is Null)
    return *data;
  }
  // No check? Silent failure or unexpected behavior.
  return -1;
} Right // You should ideally replace the null with a polymorphic call
// You can see the technique in related articles

std::unique_ptr<int> get_data() { 
  if (data_available) {
    return std::make_unique<int>(data_value);
  } else {
    return nullptr;  // Explicitly return nullptr
  }
}

int process_data(const std::unique_ptr<int>& data) {
  if (data) { // Check for valid pointer
    return *data;
  } else {
    // Handle no data case (e.g., return default value)
    return 0;
  }
} // You should ideally replace the null with a polymorphic call
// You can see the technique in related articles

std::unique_ptr<int> get_data() { 
  if (data_available) {
    return std::make_unique<int>(data_value);
  } else {
    return nullptr;  // Explicitly return nullptr
  }
}

int process_data(const std::unique_ptr<int>& data) {
  if (data) { // Check for valid pointer
    return *data;
  } else {
    // Handle no data case (e.g., return default value)
    return 0;
  }
} Important Notes About this Code Smell Detection [x]Semi-Automatic [x] Semi-Automatic [x] You can detect this smell by checking for null pointer usage in critical parts of your code. Look for functions that process pointers and see if they handle null pointers safely. Human code reviews are good for checking this kind of problem. Tags Null Null Level [x]Advanced [x] Advanced [x] /AI Generation AI generators can sometimes produce this smell, especially if they generate code without context about the environment where the code will run. AI generators are fed with code with NULL usage even though his creator told us to avoid it altogether. his creator told us AI Detection AI tools can detect this smell with specific instructions. AI can be trained to identify code patterns. Teaching it the nuances of privileged driver development and null safety best practices might require more advanced techniques. Use static analysis tools to flag null pointer dereferences. Conclusion Voyager 1's software has been running for more than 50 years. It was designed to be robust, reliable, and redundant which is sadly uncommon in some immature systems in 2024. Avoid using null pointers in privileged mode drivers. I have written a book on clean code and a whole chapter #15 on how to avoid NULL and all the consequences it carries. clean code #15 Hopefully, Crowdstrike engineers will read it! Related Code Smells Code Smell 12 - Null Code Smell 12 - Null Code Smell 126 - Fake Null Object Code Smell 126 - Fake Null Object Code Smell 208 - Null Island Code Smell 208 - Null Island Further Reading https://hackernoon.com/null-the-billion-dollar-mistake-8t5z32d6?embedable=true https://hackernoon.com/null-the-billion-dollar-mistake-8t5z32d6?embedable=true https://github.com/google/sanitizers/wiki/AddressSanitizer?embedable=true https://github.com/google/sanitizers/wiki/AddressSanitizer?embedable=true https://x.com/perpetualmaniac/status/1814376668095754753?embedable=true https://x.com/perpetualmaniac/status/1814376668095754753?embedable=true Disclaimer: Code Smells are my opinion. Disclaimer: Code Smells are my opinion. Disclaimer: Code Smells are my opinion . opinion I couldn't resist the temptation to put in a null reference, simply because it was so easy to implement. This has led to innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last forty years. I couldn't resist the temptation to put in a null reference, simply because it was so easy to implement. This has led to innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last forty years. Tony Hoare Tony Hoare https://hackernoon.com/400-thought-provoking-software-engineering-quotes?embedable=true https://hackernoon.com/400-thought-provoking-software-engineering-quotes?embedable=true This article is part of the CodeSmell Series on HackerNoon. This article is part of the CodeSmell Series on HackerNoon. https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-i-xqz3evd?embedable=true https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-i-xqz3evd?embedable=true

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