A recently disclosed vulnerability (CVE-2024-27042) in the Linux kernel could potentially lead to out-of-bounds access. This vulnerability was discovered within the 'drm/amdgpu' subsystem, specifically in the 'amdgpu_discovery_reg_base_init()' function. This article will provide an in-depth explanation of the vulnerability, along with a code snippet demonstrating the fix, and additional references for a comprehensive understanding of the issue.

Exploit Details

The vulnerability resides in the way the array 'adev->vcn.vcn_config' is accessed in the function 'amdgpu_discovery_reg_base_init()'. The issue stems from accessing the array before checking if the index 'adev->vcn.num_vcn_inst' is within the bounds of the array. This could potentially lead to an out-of-bounds access vulnerability, which, depending on the circumstances, could result in information leakage, crashes, or other undesirable consequences.

Code Snippet

The fix for this vulnerability involves rearranging the code to ensure that the bounds check of 'adev->vcn.num_vcn_inst' is performed before the array access. The following code snippet demonstrates the corrected version of 'amdgpu_discovery_reg_base_init()' function:

void amdgpu_discovery_reg_base_init(struct amdgpu_device *adev)
{
    /* ... */

    /* Bounds check */
    if (adev->vcn.num_vcn_inst < AMDGPU_MAX_VCN_INST)
    {
        /* Array access */
        adev->vcn.reg_bases[adev->vcn.num_vcn_inst].base = offset;
    }

    /* ... */
}

With this fix in place, the potential out-of-bounds access vulnerability is mitigated.

1. Linux Kernel Mailing List (LKML) - Patch Submission
2. Linux Kernel Git Repository - Commit

Conclusion

CVE-2024-27042 highlights the importance of carefully reviewing code to prevent potential out-of-bounds access vulnerabilities. By addressing this issue, the Linux kernel maintains its commitment to providing a secure, stable, and reliable operating environment. Ensure that your systems are up to date to incorporate this and other security fixes.

Timeline

Published on: 05/01/2024 13:15:49 UTC
Last modified on: 05/29/2024 05:27:31 UTC