Random Number Generator Zero Value Handling in Linux Kernel

Executive Summary

This vulnerability involves the Linux kernel's cryptographic random number generator (qcom-rng). The issue is that the generator was not allowing zero as a valid random number output. Since zero is a valid random number, excluding it makes the output distinguishable from true randomness, weakening cryptographic operations.

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Detection Guidance

This vulnerability is specific to the Linux kernel's crypto subsystem (qcom-rng). Detection requires checking kernel version and configuration. Use 'uname -r' to check kernel version and 'modinfo qcom-rng' to verify if the affected module is loaded. If the module is present and kernel version matches affected releases, the system is potentially vulnerable.

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Impact Analysis

This vulnerability could impact cryptographic operations that rely on the Linux kernel's random number generator. If an attacker can distinguish the output from random, it may weaken encryption, authentication, or other security mechanisms using this generator.

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Compliance Impact

This vulnerability does not directly affect compliance with standards like GDPR or HIPAA as it relates to the Linux kernel's random number generation functionality. The issue is about ensuring zero is allowed as a valid random number output, which does not introduce a security or privacy risk that would impact regulatory compliance.

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Mitigation Strategies

Update the Linux kernel to the latest patched version. If using a distribution kernel, apply vendor security updates immediately. For custom kernels, recompile with the fix for the qcom-rng module. Disable the qcom-rng module if not required using 'rmmod qcom-rng' or blacklisting it.

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