KVM: SEV: Compute the correct max length of the in-GHCB scratch area
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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
- Fix
- Fixed in 6.12.93, 6.18.35, 7.0.12
- 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: total
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Compute the correct max length of the in-GHCB scratch area When setting the length of the GHCB scratch area, and the area is in the GHCB shared buffer, set the effective length of the scratch area to the max possible size given the start of the guest-provided pointer, and the end of the shared buffer. The code was "fine" when first introduced, as KVM doesn't consult the length of the buffer when emulating MMIO, because the passed in @len always specifies the max size required. But for PSC requests, the incoming @len is just the minimum length (to process the header), and KVM needs to know the full size of the scratch area to avoid buffer overflows (spoiler alert). Opportunistically rename @len => @min_len to better reflect its role.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Linux Linux
From 9b54e248d2644be71cb394eb85f31ad99e023a05 · fixed in 6ca9400d36005ffdca25f80186bea781c7e1dc4c; From 9b54e248d2644be71cb394eb85f31ad99e023a05 · fixed in 9f0a9e780f02c02d025a190f1885e1d1d73b87bd; From 9b54e248d2644be71cb394eb85f31ad99e023a05 · fixed in 6644565527c4c5f507088b1c9ddf72de47790b68; From 9b54e248d2644be71cb394eb85f31ad99e023a05 · fixed in 5867d7e202e09f037cefe77f7af4413c7c0fa088
- Linux Linux
6.11
- KernelLinux
From 6.11.0 · fixed in 6.12.93; From 6.13.0 · fixed in 6.18.35; From 6.19.0 · fixed in 7.0.12