From a9e38c3e01ad242fe2a625354cf065c34b01e3aa Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Fri, 23 Oct 2009 09:37:00 +0200 Subject: [PATCH] KVM: x86: Catch potential overrun in MCE setup 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 Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9b9695322f567..8a93fa894ba65 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1692,7 +1692,7 @@ 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; -- 2.39.5