| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2022-48765: KVM: LAPIC: Also cancel preemption timer during SET_LAPIC |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| KVM: LAPIC: Also cancel preemption timer during SET_LAPIC |
| |
| The below warning is splatting during guest reboot. |
| |
| ------------[ cut here ]------------ |
| WARNING: CPU: 0 PID: 1931 at arch/x86/kvm/x86.c:10322 kvm_arch_vcpu_ioctl_run+0x874/0x880 [kvm] |
| CPU: 0 PID: 1931 Comm: qemu-system-x86 Tainted: G I 5.17.0-rc1+ #5 |
| RIP: 0010:kvm_arch_vcpu_ioctl_run+0x874/0x880 [kvm] |
| Call Trace: |
| <TASK> |
| kvm_vcpu_ioctl+0x279/0x710 [kvm] |
| __x64_sys_ioctl+0x83/0xb0 |
| do_syscall_64+0x3b/0xc0 |
| entry_SYSCALL_64_after_hwframe+0x44/0xae |
| RIP: 0033:0x7fd39797350b |
| |
| This can be triggered by not exposing tsc-deadline mode and doing a reboot in |
| the guest. The lapic_shutdown() function which is called in sys_reboot path |
| will not disarm the flying timer, it just masks LVTT. lapic_shutdown() clears |
| APIC state w/ LVT_MASKED and timer-mode bit is 0, this can trigger timer-mode |
| switch between tsc-deadline and oneshot/periodic, which can result in preemption |
| timer be cancelled in apic_update_lvtt(). However, We can't depend on this when |
| not exposing tsc-deadline mode and oneshot/periodic modes emulated by preemption |
| timer. Qemu will synchronise states around reset, let's cancel preemption timer |
| under KVM_SET_LAPIC. |
| |
| The Linux kernel CVE team has assigned CVE-2022-48765 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 5.15.19 with commit 54b3439c8e70e0bcfea59aeef9dd98908cbbf655 |
| Fixed in 5.16.5 with commit ce55f63f6cea4cab8ae9212f73285648a5baa30d |
| Fixed in 5.17 with commit 35fe7cfbab2e81f1afb23fc4212210b1de6d9633 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2022-48765 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| arch/x86/kvm/lapic.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/54b3439c8e70e0bcfea59aeef9dd98908cbbf655 |
| https://git.kernel.org/stable/c/ce55f63f6cea4cab8ae9212f73285648a5baa30d |
| https://git.kernel.org/stable/c/35fe7cfbab2e81f1afb23fc4212210b1de6d9633 |
