CVE-2024-44948

Summary

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

x86/mtrr: Check if fixed MTRRs exist before saving them

MTRRs have an obsolete fixed variant for fine grained caching control of the 640K-1MB region that uses separate MSRs. This fixed variant has a separate capability bit in the MTRR capability MSR.

So far all x86 CPUs which support MTRR have this separate bit set, so it went unnoticed that mtrr_save_state() does not check the capability bit before accessing the fixed MTRR MSRs.

Though on a CPU that does not support the fixed MTRR capability this results in a #GP. The #GP itself is harmless because the RDMSR fault is handled gracefully, but results in a WARN_ON().

Add the missing capability check to prevent this.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux2b1f6278d77c1f2f669346fc2bb48012b5e9495a < 34f36e6ee5bd7eff8b2adcd9fcaef369f752d82eaffected
LinuxLinux2b1f6278d77c1f2f669346fc2bb48012b5e9495a < 06c1de44d378ec5439db17bf476507d68589bfe9affected
LinuxLinux2b1f6278d77c1f2f669346fc2bb48012b5e9495a < 450b6b22acdaac67a18eaf5ed498421ffcf10051affected
LinuxLinux2b1f6278d77c1f2f669346fc2bb48012b5e9495a < ca7d00c5656d1791e28369919e3e10febe9c3b16affected
LinuxLinux2b1f6278d77c1f2f669346fc2bb48012b5e9495a < 8aa79dfb216b865e96ff890bc4ea71650f9bc8d7affected
LinuxLinux2b1f6278d77c1f2f669346fc2bb48012b5e9495a < 8a90d3fc7c24608548d3a750671f9dac21d1a462affected
LinuxLinux2b1f6278d77c1f2f669346fc2bb48012b5e9495a < 388f1c954019f253a8383f7eb733f38d541e10b6affected
LinuxLinux2b1f6278d77c1f2f669346fc2bb48012b5e9495a < 919f18f961c03d6694aa726c514184f2311a4614affected
LinuxLinux2.6.22affected
LinuxLinux0 < 2.6.22unaffected
LinuxLinux4.19.320 <= 4.19.*unaffected
LinuxLinux5.4.282 <= 5.4.*unaffected
LinuxLinux5.10.224 <= 5.10.*unaffected
LinuxLinux5.15.165 <= 5.15.*unaffected
LinuxLinux6.1.105 <= 6.1.*unaffected
LinuxLinux6.6.46 <= 6.6.*unaffected
LinuxLinux6.10.5 <= 6.10.*unaffected
LinuxLinux6.11 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

Additional References

References