From a9e38c3e01ad242fe2a625354cf065c34b01e3aa Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Fri, 23 Oct 2009 09:37:00 +0200 Subject: [PATCH 1/2] 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 9b9695322f5..8a93fa894ba 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; From abb3911965c1bd8eea305f64d4840a314259d96d Mon Sep 17 00:00:00 2001 From: Gleb Natapov Date: Sun, 25 Oct 2009 17:42:02 +0200 Subject: [PATCH 2/2] KVM: get_tss_base_addr() should return a gpa_t If TSS we are switching to resides in high memory task switch will fail since address will be truncated. Windows2k3 does this sometimes when running with more then 4G Cc: stable@kernel.org Signed-off-by: Gleb Natapov Signed-off-by: Avi Kivity --- 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 8a93fa894ba..ae07d261527 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4051,7 +4051,7 @@ static int save_guest_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, return kvm_write_guest_virt(dtable.base + index*8, seg_desc, sizeof(*seg_desc), vcpu); } -static u32 get_tss_base_addr(struct kvm_vcpu *vcpu, +static gpa_t get_tss_base_addr(struct kvm_vcpu *vcpu, struct desc_struct *seg_desc) { u32 base_addr = get_desc_base(seg_desc);