x86/efistub: Use 1:1 file:memory mapping for PE/COFF .compat section
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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: x86/efistub: Use 1:1 file:memory mapping for PE/COFF .compat section The .compat section is a dummy PE section that contains the address of the 32-bit entrypoint of the 64-bit kernel image if it is bootable from 32-bit firmware (i.e., CONFIG_EFI_MIXED=y) This section is only 8 bytes in size and is only referenced from the loader, and so it is placed at the end of the memory view of the image, to avoid the need for padding it to 4k, which is required for sections appearing in the middle of the image. Unfortunately, this violates the PE/COFF spec, and even if most EFI loaders will work correctly (including the Tianocore reference implementation), PE loaders do exist that reject such images, on the basis that both the file and memory views of the file contents should be described by the section headers in a monotonically increasing manner without leaving any gaps. So reorganize the sections to avoid this issue. This results in a slight padding overhead (< 4k) which can be avoided if desired by disabling CONFIG_EFI_MIXED (which is only needed in rare cases these days)
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
6.7