efistub/tpm: Use ACPI reclaim memory for event log to avoid corruption
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- Linux Linux
Version range not reported
- Linux Linux
4.16
References 7
git.kernel.org
- stable/c/f76b69ab9cf04358266e3cea5748c0c2791fbb08
- stable/c/11690d7e76842f29b60fbb5b35bc97d206ea0e83
- stable/c/5b22c038fb2757c652642933de5664da471f8cb7
- stable/c/19fd2f2c5fb36b61506d3208474bfd8fdf1cada3
- stable/c/38d9b07d99b789efb6d8dda21f1aaad636c38993
- stable/c/2e6871a632a99d9b9e2ce3a7847acabe99e5a26e
- stable/c/77d48d39e99170b528e4f2e9fc5d1d64cdedd386