* [PATCH] KVM: x86: Catch potential overrun in MCE setup
@ 2009-10-23 7:37 Jan Kiszka
2009-10-23 17:54 ` Marcelo Tosatti
0 siblings, 1 reply; 2+ messages in thread
From: Jan Kiszka @ 2009-10-23 7:37 UTC (permalink / raw)
To: Avi Kivity, Marcelo Tosatti; +Cc: kvm-devel
We only allocate memory for 32 MCE banks (KVM_MAX_MCE_BANKS) but we
allow user space to fill up to 255 on setup (mcg_cap & 0xff), corrupting
kernel memory. Catch these overflows.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
arch/x86/kvm/x86.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c1e9094..e2fb5e0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1720,7 +1720,7 @@ static int kvm_vcpu_ioctl_x86_setup_mce(struct kvm_vcpu *vcpu,
unsigned bank_num = mcg_cap & 0xff, bank;
r = -EINVAL;
- if (!bank_num)
+ if (!bank_num || bank_num >= KVM_MAX_MCE_BANKS)
goto out;
if (mcg_cap & ~(KVM_MCE_CAP_SUPPORTED | 0xff | 0xff0000))
goto out;
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] KVM: x86: Catch potential overrun in MCE setup
2009-10-23 7:37 [PATCH] KVM: x86: Catch potential overrun in MCE setup Jan Kiszka
@ 2009-10-23 17:54 ` Marcelo Tosatti
0 siblings, 0 replies; 2+ messages in thread
From: Marcelo Tosatti @ 2009-10-23 17:54 UTC (permalink / raw)
To: Jan Kiszka; +Cc: Avi Kivity, kvm-devel
On Fri, Oct 23, 2009 at 09:37:00AM +0200, Jan Kiszka wrote:
> We only allocate memory for 32 MCE banks (KVM_MAX_MCE_BANKS) but we
> allow user space to fill up to 255 on setup (mcg_cap & 0xff), corrupting
> kernel memory. Catch these overflows.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Applied, thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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