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CVE PROGRAM SOURCE RECORD7.9 High

CVE-2024-40953

KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin()

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin() Use {READ,WRITE}_ONCE() to access kvm->last_boosted_vcpu to ensure the loads and stores are atomic. In the extremely unlikely scenario the compiler tears the stores, it's theoretically possible for KVM to attempt to get a vCPU using an out-of-bounds index, e.g. if the write is split into multiple 8-bit stores, and is paired with a 32-bit load on a VM with 257 vCPUs: CPU0 CPU1 last_boosted_vcpu = 0xff; (last_boosted_vcpu = 0x100) last_boosted_vcpu[15:8] = 0x01; i = (last_boosted_vcpu = 0x1ff) last_boosted_vcpu[7:0] = 0x00; vcpu = kvm->vcpu_array[0x1ff]; As detected by KCSAN: BUG: KCSAN: data-race in kvm_vcpu_on_spin [kvm] / kvm_vcpu_on_spin [kvm] write to 0xffffc90025a92344 of 4 bytes by task 4340 on cpu 16: kvm_vcpu_on_spin (arch/x86/kvm/../../../virt/kvm/kvm_main.c:4112) kvm handle_pause (arch/x86/kvm/vmx/vmx.c:5929) kvm_intel vmx_handle_exit (arch/x86/kvm/vmx/vmx.c:? arch/x86/kvm/vmx/vmx.c:6606) kvm_intel vcpu_run (arch/x86/kvm/x86.c:11107 arch/x86/kvm/x86.c:11211) kvm kvm_arch_vcpu_ioctl_run (arch/x86/kvm/x86.c:?) kvm kvm_vcpu_ioctl (arch/x86/kvm/../../../virt/kvm/kvm_main.c:?) kvm __se_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:904 fs/ioctl.c:890) __x64_sys_ioctl (fs/ioctl.c:890) x64_sys_call (arch/x86/entry/syscall_64.c:33) do_syscall_64 (arch/x86/entry/common.c:?) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) read to 0xffffc90025a92344 of 4 bytes by task 4342 on cpu 4: kvm_vcpu_on_spin (arch/x86/kvm/../../../virt/kvm/kvm_main.c:4069) kvm handle_pause (arch/x86/kvm/vmx/vmx.c:5929) kvm_intel vmx_handle_exit (arch/x86/kvm/vmx/vmx.c:? arch/x86/kvm/vmx/vmx.c:6606) kvm_intel vcpu_run (arch/x86/kvm/x86.c:11107 arch/x86/kvm/x86.c:11211) kvm kvm_arch_vcpu_ioctl_run (arch/x86/kvm/x86.c:?) kvm kvm_vcpu_ioctl (arch/x86/kvm/../../../virt/kvm/kvm_main.c:?) kvm __se_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:904 fs/ioctl.c:890) __x64_sys_ioctl (fs/ioctl.c:890) x64_sys_call (arch/x86/entry/syscall_64.c:33) do_syscall_64 (arch/x86/entry/common.c:?) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) value changed: 0x00000012 -> 0x00000000

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 to < 11a772d5376aa6d3e2e69b5b5c585f79b60c0e17affected
  • 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 to < 4c141136a28421b78f34969b25a4fa32e06e2180affected
  • 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 to < 71fbc3af3dacb26c3aa2f30bb3ab05c44d082c84affected
  • 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 to < 82bd728a06e55f5b5f93d10ce67f4fe7e689853aaffected
  • 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 to < 92c77807d938145c7c3350c944ef9f39d7f6017caffected
  • 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 to < a937ef951bba72f48d2402451419d725d70dba20affected
  • 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 to < 95c8dd79f3a14df96b3820b35b8399bd91b2be60affected
  • 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 to < 49f683b41f28918df3e51ddc0d928cb2e934ccdbaffected

Linux Linux

Default version status: affected

  • 2.6.39affected
  • 0 to < 2.6.39unaffected
  • 4.19.323 to ≤ 4.19.*unaffected
  • 5.4.285 to ≤ 5.4.*unaffected
  • 5.10.228 to ≤ 5.10.*unaffected
  • 5.15.169 to ≤ 5.15.*unaffected
  • 6.1.96 to ≤ 6.1.*unaffected
  • 6.6.36 to ≤ 6.6.*unaffected
  • 6.9.7 to ≤ 6.9.*unaffected
  • 6.10 to ≤ *unaffected

References