KVM: nVMX: Don't emulate instructions in guest mode (CVE-2020-2732)

debian/changelog

@@ -1,3 +1,9 @@
+linux (4.19.98-1+deb10u1) UNRELEASED; urgency=medium
+
+  * [x86] KVM: nVMX: Don't emulate instructions in guest mode (CVE-2020-2732)
+
+ -- Salvatore Bonaccorso <carnil@debian.org>  Sun, 26 Apr 2020 20:32:58 +0200
+
 linux (4.19.98-1) buster; urgency=medium
 
   * New upstream stable update:

debian/patches/bugfix/x86/KVM-nVMX-Don-t-emulate-instructions-in-guest-mode.patch

@@ -0,0 +1,35 @@
+From: Paolo Bonzini <pbonzini@redhat.com>
+Date: Tue, 4 Feb 2020 15:26:29 -0800
+Subject: KVM: nVMX: Don't emulate instructions in guest mode
+Origin: https://git.kernel.org/linus/07721feee46b4b248402133228235318199b05ec
+Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2020-2732
+
+vmx_check_intercept is not yet fully implemented. To avoid emulating
+instructions disallowed by the L1 hypervisor, refuse to emulate
+instructions by default.
+
+Cc: stable@vger.kernel.org
+[Made commit, added commit msg - Oliver]
+Signed-off-by: Oliver Upton <oupton@google.com>
+Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+[Salvatore Bonaccorso: Backport to 4.19: Adjust filename to arch/x86/kvm/vmx.c]
+---
+ arch/x86/kvm/vmx/vmx.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
+index dcca514ffd42..5801a86f9c24 100644
+--- a/arch/x86/kvm/vmx.c
++++ b/arch/x86/kvm/vmx.c
+@@ -7164,7 +7164,7 @@ static int vmx_check_intercept(struct kvm_vcpu *vcpu,
+ 	}
+ 
+ 	/* TODO: check more intercepts... */
+-	return X86EMUL_CONTINUE;
++	return X86EMUL_UNHANDLEABLE;
+ }
+ 
+ #ifdef CONFIG_X86_64
+-- 
+2.26.2
+

debian/patches/series

@@ -304,6 +304,7 @@ debian/ntfs-mark-it-as-broken.patch
 bugfix/all/libertas-fix-two-buffer-overflows-at-parsing-bss-descriptor.patch
 bugfix/all/wimax-i2400-fix-memory-leak.patch
 bugfix/all/wimax-i2400-fix-memory-leak-in-i2400m_op_rfkill_sw_toggle.patch
+bugfix/x86/KVM-nVMX-Don-t-emulate-instructions-in-guest-mode.patch
 
 # Backported change to provide boot-time entropy
 bugfix/all/random-try-to-actively-add-entropy-rather-than-passi.patch