51 lines
1.8 KiB
Diff
51 lines
1.8 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
|
|
From: Paolo Bonzini <pbonzini@redhat.com>
|
|
Date: Mon, 25 Feb 2019 11:48:07 +0000
|
|
Subject: [PATCH] KVM: x86: work around leak of uninitialized stack contents
|
|
(CVE-2019-7222)
|
|
|
|
Bugzilla: 1671930
|
|
|
|
Emulation of certain instructions (VMXON, VMCLEAR, VMPTRLD, VMWRITE with
|
|
memory operand, INVEPT, INVVPID) can incorrectly inject a page fault
|
|
when passed an operand that points to an MMIO address. The page fault
|
|
will use uninitialized kernel stack memory as the CR2 and error code.
|
|
|
|
The right behavior would be to abort the VM with a KVM_EXIT_INTERNAL_ERROR
|
|
exit to userspace; however, it is not an easy fix, so for now just
|
|
ensure that the error code and CR2 are zero.
|
|
|
|
Embargoed until Feb 7th 2019.
|
|
|
|
Reported-by: Felix Wilhelm <fwilhelm@google.com>
|
|
Cc: stable@kernel.org
|
|
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
|
|
CVE-2019-7222
|
|
|
|
(cherry picked from commit 353c0956a618a07ba4bbe7ad00ff29fe70e8412a)
|
|
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
|
|
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
|
|
---
|
|
arch/x86/kvm/x86.c | 7 +++++++
|
|
1 file changed, 7 insertions(+)
|
|
|
|
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
|
|
index b3df576413cd..13804929adce 100644
|
|
--- a/arch/x86/kvm/x86.c
|
|
+++ b/arch/x86/kvm/x86.c
|
|
@@ -4632,6 +4632,13 @@ int kvm_read_guest_virt(struct kvm_vcpu *vcpu,
|
|
{
|
|
u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
|
|
|
|
+ /*
|
|
+ * FIXME: this should call handle_emulation_failure if X86EMUL_IO_NEEDED
|
|
+ * is returned, but our callers are not ready for that and they blindly
|
|
+ * call kvm_inject_page_fault. Ensure that they at least do not leak
|
|
+ * uninitialized kernel stack memory into cr2 and error code.
|
|
+ */
|
|
+ memset(exception, 0, sizeof(*exception));
|
|
return kvm_read_guest_virt_helper(addr, val, bytes, vcpu, access,
|
|
exception);
|
|
}
|