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CVE-2024-40953

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

Description (CNA)

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 (CNA)

Vendor / productVersions
Linux / Linuxaffected 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 before 11a772d5376aa6d3e2e69b5b5c585f79b60c0e17; affected 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 before 4c141136a28421b78f34969b25a4fa32e06e2180; affected 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 before 71fbc3af3dacb26c3aa2f30bb3ab05c44d082c84; affected 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 before 82bd728a06e55f5b5f93d10ce67f4fe7e689853a; affected 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 before 92c77807d938145c7c3350c944ef9f39d7f6017c; affected 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 before a937ef951bba72f48d2402451419d725d70dba20; affected 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 before 95c8dd79f3a14df96b3820b35b8399bd91b2be60; affected 217ece6129f2d3b4fdd18d9e79be9e43d8d14a42 before 49f683b41f28918df3e51ddc0d928cb2e934ccdb
Linux / Linuxaffected 2.6.39; unaffected 0 before 2.6.39; unaffected 4.19.323 through 4.19.*; unaffected 5.4.285 through 5.4.*; unaffected 5.10.228 through 5.10.*; unaffected 5.15.169 through 5.15.*; unaffected 6.1.96 through 6.1.*; unaffected 6.6.36 through 6.6.*; unaffected 6.9.7 through 6.9.*; unaffected 6.10 through *

CWE

No CWE identifiers supplied.

References

ADP enrichment

CVE

No English description supplied.

CISA-ADP

No English description supplied.

No references supplied.