Linux Kernel Register Corruption via Uninitialized Cregs

Executive Summary

This vulnerability in the Linux kernel involves register corruption due to uninitialized cregs on error. The functions compat_riscv_gpr_set() and compat_restore_sigcontext() call cregs_to_regs() even when user_regset_copyin() or __copy_from_user() fails. Since cregs is an uninitialized stack variable, failure leads to uninitialized stack data corrupting the target task's pt_regs or signal-returning task's register state, potentially leaking kernel stack contents.

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Detection Guidance

This vulnerability is specific to the Linux kernel's RISC-V implementation and requires kernel-level inspection. Detection involves checking kernel logs for errors related to register corruption or failed user copy operations in RISC-V compatibility layers. Use commands like dmesg | grep -i riscv or journalctl -k | grep -i riscv to search for relevant errors.

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Impact Analysis

This vulnerability could allow an attacker to corrupt kernel registers, leading to system instability, crashes, or unauthorized access. It may also leak sensitive kernel memory contents, posing a security risk by exposing internal data.

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Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it pertains to kernel-level register corruption in the Linux riscv architecture. Compliance impacts would depend on system-specific implementations and data exposure risks, which are not detailed in the provided CVE information.

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Mitigation Strategies

Apply the latest kernel update provided by your Linux distribution to patch this vulnerability. If immediate patching is not possible, consider disabling RISC-V compatibility features if unused. Monitor kernel logs for signs of exploitation or corruption.

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