This is a note to let you know that I've just added the patch titled
KVM: x86: nSVM: harden svm_free_nested against freeing vmcb02 while still in use
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-nsvm-harden-svm_free_nested-against-freeing-vmcb02-while-still-in-use.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 16ae56d7e0528559bf8dc9070e3bfd8ba3de80df Mon Sep 17 00:00:00 2001
From: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Date: Thu, 3 Nov 2022 16:13:44 +0200
Subject: KVM: x86: nSVM: harden svm_free_nested against freeing vmcb02 while still in use
From: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
commit 16ae56d7e0528559bf8dc9070e3bfd8ba3de80df upstream.
Make sure that KVM uses vmcb01 before freeing nested state, and warn if
that is not the case.
This is a minimal fix for CVE-2022-3344 making the kernel print a warning
instead of a kernel panic.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Message-Id: <20221103141351.50662-3-mlevitsk@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/svm/nested.c | 3 +++
1 file changed, 3 insertions(+)
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1143,6 +1143,9 @@ void svm_free_nested(struct vcpu_svm *sv
if (!svm->nested.initialized)
return;
+ if (WARN_ON_ONCE(svm->vmcb != svm->vmcb01.ptr))
+ svm_switch_vmcb(svm, &svm->vmcb01);
+
svm_vcpu_free_msrpm(svm->nested.msrpm);
svm->nested.msrpm = NULL;
Patches currently in stable-queue which might be from mlevitsk@xxxxxxxxxx are
queue-6.0/kvm-x86-nsvm-harden-svm_free_nested-against-freeing-vmcb02-while-still-in-use.patch
queue-6.0/kvm-x86-forcibly-leave-nested-mode-on-vcpu-reset.patch
queue-6.0/kvm-x86-nsvm-leave-nested-mode-on-vcpu-free.patch
queue-6.0/kvm-x86-add-kvm_leave_nested.patch
queue-6.0/kvm-x86-remove-exit_int_info-warning-in-svm_handle_exit.patch
