cbcvebase.
CVE-2022-48763
published 2024-06-20

CVE-2022-48763: In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Forcibly leave nested virt when SMM state is toggled Forcibly leave nested…

PriorityP420medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.22%
12.5th percentile
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Forcibly leave nested virt when SMM state is toggled Forcibly leave nested virtualization operation if userspace toggles SMM state via KVM_SET_VCPU_EVENTS or KVM_SYNC_X86_EVENTS. If userspace forces the vCPU out of SMM while it's post-VMXON and then injects an SMI, vmx_enter_smm() will overwrite vmx->nested.smm.vmxon and end up with both vmxon=false and smm.vmxon=false, but all other nVMX state allocated. Don't attempt to gracefully handle the transition as (a) most transitions are nonsencial, e.g. forcing SMM while L2 is running, (b) there isn't sufficient information to handle all transitions, e.g. SVM wants access to the SMRAM save state, and (c) KVM_SET_VCPU_EVENTS must precede KVM_SET_NESTED_STATE during state restore as the latter disallows putting the vCPU into L2 if SMM is active, and disallows tagging the vCPU as being post-VMXON in SMM if SMM is not active. Abuse of KVM_SET_VCPU_EVENTS manifests as a WARN and memory leak in nVMX due to failure to free vmcs01's shadow VMCS, but the bug goes far beyond just a memory leak, e.g. toggling SMM on while L2 is active puts the vCPU in an architecturally impossible state. WARNING: CPU: 0 PID: 3606 at free_loaded_vmcs arch/x86/kvm/vmx/vmx.c:2665 [inline] WARNING: CPU: 0 PID: 3606 at free_loaded_vmcs+0x158/0x1a0 arch/x86/kvm/vmx/vmx.c:2656 Modules linked in: CPU: 1 PID: 3606 Comm: syz-executor725 Not tainted 5.17.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:free_loaded_vmcs arch/x86/kvm/vmx/vmx.c:2665 [inline] RIP: 0010:free_loaded_vmcs+0x158/0x1a0 arch/x86/kvm/vmx/vmx.c:2656 Code: 0b eb b3 e8 8f 4d 9f 00 e9 f7 fe ff ff 48 89 df e8 92 4d 9f 00 Call Trace: kvm_arch_vcpu_destroy+0x72/0x2f0 arch/x86/kvm/x86.c:11123 kvm_vcpu_destroy arch/x86/kvm/../../../virt/kvm/kvm_main.c:441 [inline] kvm_destroy_vcpus+0x11f/0x290 arch/x86/kvm/../../../virt/kvm/kvm_main.c:460 kvm_f

Affected

14 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 5.16.7-1 (bookworm)linux 5.16.7-1 (bookworm)
linuxlinux——
linuxlinux>= 72e9cbdb43384ceacc49e2fb6b8c8fb7c5988778 < 080dbe7e9b86a0392d8dffc00d9971792afc121f080dbe7e9b86a0392d8dffc00d9971792afc121f
linuxlinux>= 72e9cbdb43384ceacc49e2fb6b8c8fb7c5988778 < e302786233e6bc512986d007c96458ccf5ca21c7e302786233e6bc512986d007c96458ccf5ca21c7
linuxlinux>= 72e9cbdb43384ceacc49e2fb6b8c8fb7c5988778 < b4c0d89c92e957ecccce12e66b63875d0cc7af7eb4c0d89c92e957ecccce12e66b63875d0cc7af7e
linuxlinux>= 72e9cbdb43384ceacc49e2fb6b8c8fb7c5988778 < f7e570780efc5cec9b2ed1e0472a7da14e864fdbf7e570780efc5cec9b2ed1e0472a7da14e864fdb
linuxlinux_kernel< 5.10.975.10.97
linuxlinux_kernel——
linuxlinux_kernel>= 0 < 5.10.103-15.10.103-1
linuxlinux_kernel>= 0 < 5.16.7-15.16.7-1
linuxlinux_kernel>= 0 < 5.16.7-15.16.7-1
linuxlinux_kernel>= 0 < 5.16.7-15.16.7-1
linuxlinux_kernel>= 5.11 < 5.15.195.15.19
linuxlinux_kernel>= 5.16 < 5.16.55.16.5

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5MEDIUM
vendor_redhat5.5MEDIUM
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