CVE-2022-49219

In the Linux kernel, the following vulnerability has been resolved:

vfio/pci: fix memory leak during D3hot to D0 transition

If vfio_pci_core_device::needs_pm_restore is set (PCI device does not have No_Soft_Reset bit set in its PMCSR config register), then the current PCI state will be saved locally in vfio_pci_core_device::pm_save during D0->D3hot transition and same will be restored back during D3hot->D0 transition. For saving the PCI state locally, pci_store_saved_state() is being used and the pci_load_and_free_saved_state() will free the allocated memory.

But for reset related IOCTLs, vfio driver calls PCI reset-related APIs which will internally change the PCI power state back to D0. So, when the guest resumes, then it will get the current state as D0 and it will skip the call to vfio_pci_set_power_state() for changing the power state to D0 explicitly. In this case, the memory pointed by pm_save will never be freed. In a malicious sequence, the state changing to D3hot followed by VFIO_DEVICE_RESET/VFIO_DEVICE_PCI_HOT_RESET can be run in a loop and it can cause an OOM situation.

This patch frees the earlier allocated memory first before overwriting pm_save to prevent the mentioned memory leak.

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/26ddd196e9eb264da8e1bdc4df8a94d62581c8b5
• https://git.kernel.org/stable/c/4319f17fb8264ba39352b611dfa913a4d8c1d1a0
• https://git.kernel.org/stable/c/c8a1f8bd586ee31020614b8d48b702ece3e2ae44
• https://git.kernel.org/stable/c/da426ad86027b849b877d4628b277ffbbd2f5325
• https://git.kernel.org/stable/c/eadf88ecf6ac7d6a9f47a76c6055d9a1987a8991
• https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html