CVE-2024-49858 Information

Description

In the Linux kernel the following vulnerability has been resolved:

efistub/tpm: Use ACPI reclaim memory for event log to avoid corruption

The TPM event log table is a Linux specific construct where the data produced by the GetEventLog() boot service is cached in memory and passed on to the OS using an EFI configuration table.

The use of EFI_LOADER_DATA here results in the region being left unreserved in the E820 memory map constructed by the EFI stub and this is the memory description that is passed on to the incoming kernel by kexec which is therefore unaware that the region should be reserved.

Even though the utility of the TPM2 event log after a kexec is questionable any corruption might send the parsing code off into the weeds and crash the kernel. So let’s use EFI_ACPI_RECLAIM_MEMORY instead which is always treated as reserved by the E820 conversion logic.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Reference

https://git.kernel.org/stable/c/f76b69ab9cf04358266e3cea5748c0c2791fbb08 https://git.kernel.org/stable/c/11690d7e76842f29b60fbb5b35bc97d206ea0e83 https://git.kernel.org/stable/c/5b22c038fb2757c652642933de5664da471f8cb7 https://git.kernel.org/stable/c/19fd2f2c5fb36b61506d3208474bfd8fdf1cada3 https://git.kernel.org/stable/c/38d9b07d99b789efb6d8dda21f1aaad636c38993 https://git.kernel.org/stable/c/2e6871a632a99d9b9e2ce3a7847acabe99e5a26e https://git.kernel.org/stable/c/77d48d39e99170b528e4f2e9fc5d1d64cdedd386

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.5