CVE-2024-47727: x86/tdx: Fix "in-kernel MMIO" check
In the Linux kernel, the following vulnerability has been resolved:
x86/tdx: Fix "in-kernel MMIO" check
TDX only supports kernel-initiated MMIO operations. The handlemmio() function checks if the #VE exception occurred in the kernel and rejects the operation if it did not.
However, userspace can deceive the kernel into performing MMIO on its behalf. For example, if userspace can point a syscall to an MMIO address, syscall does getuser() or putuser() on it, triggering MMIO #VE. The kernel will treat the #VE as in-kernel MMIO.
Ensure that the target MMIO address is within the kernel before decoding instruction.
Other sources
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— Launchpad
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.223-1Fixed in 5.10.234-1Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.22-1Fixed in 6.12.25-1 - Upgrade
Upgrade
debian/linux-6.1to a version that resolves this vulnerability.Fixed in 6.1.129-1~deb11u1 - Upgrade
Upgrade
Linux kernel (x86/tdx)to a version that resolves this vulnerability.Patch x86/tdx: Fix "in-kernel MMIO" check - Configuration
Update the TDX MMIO handling logic (handle_mmio()) to check whether the #VE exception occurred in-kernel, and reject the MMIO operation if it did not; do not treat user-triggered #VE as in-kernel MMIO.
Linux kernel TDX (handle_mmio) in-kernel MMIO check for #VE = Reject MMIO operation unless #VE occurred in the kernel
Event History
Frequently Asked Questions
What is the severity of CVE-2024-47727?
CVE-2024-47727 is classified as a high severity vulnerability that affects the Linux kernel.
How do I fix CVE-2024-47727?
To mitigate CVE-2024-47727, users should update to the latest stable version of the Linux kernel that includes the fix.
Who is affected by CVE-2024-47727?
CVE-2024-47727 affects users running specific versions of the Linux kernel between 5.19 and 6.11.
What are the potential impacts of CVE-2024-47727?
Exploitation of CVE-2024-47727 could lead to unauthorized access and control over system resources in kernel-initiated MMIO operations.
When was CVE-2024-47727 discovered?
CVE-2024-47727 was identified and documented as a vulnerability in the Linux kernel prior to its resolution in recent updates.