From 3a33d030daaa7c507e1c12d5adcf828248429593 Mon Sep 17 00:00:00 2001 From: Tom Roeder Date: Thu, 24 Jan 2019 13:48:20 -0800 Subject: kvm: x86/vmx: Use kzalloc for cached_vmcs12 This changes the allocation of cached_vmcs12 to use kzalloc instead of kmalloc. This removes the information leak found by Syzkaller (see Reported-by) in this case and prevents similar leaks from happening based on cached_vmcs12. It also changes vmx_get_nested_state to copy out the full 4k VMCS12_SIZE in copy_to_user rather than only the size of the struct. Tested: rebuilt against head, booted, and ran the syszkaller repro https://syzkaller.appspot.com/text?tag=ReproC&x=174efca3400000 without observing any problems. Reported-by: syzbot+ded1696f6b50b615b630@syzkaller.appspotmail.com Fixes: 8fcc4b5923af5de58b80b53a069453b135693304 Cc: stable@vger.kernel.org Signed-off-by: Tom Roeder Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'arch/x86/kvm/vmx/nested.c') diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 2616bd2c7f2c..ce8153923854 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -4140,11 +4140,11 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu) if (r < 0) goto out_vmcs02; - vmx->nested.cached_vmcs12 = kmalloc(VMCS12_SIZE, GFP_KERNEL); + vmx->nested.cached_vmcs12 = kzalloc(VMCS12_SIZE, GFP_KERNEL); if (!vmx->nested.cached_vmcs12) goto out_cached_vmcs12; - vmx->nested.cached_shadow_vmcs12 = kmalloc(VMCS12_SIZE, GFP_KERNEL); + vmx->nested.cached_shadow_vmcs12 = kzalloc(VMCS12_SIZE, GFP_KERNEL); if (!vmx->nested.cached_shadow_vmcs12) goto out_cached_shadow_vmcs12; @@ -5263,13 +5263,17 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu, copy_shadow_to_vmcs12(vmx); } - if (copy_to_user(user_kvm_nested_state->data, vmcs12, sizeof(*vmcs12))) + /* + * Copy over the full allocated size of vmcs12 rather than just the size + * of the struct. + */ + if (copy_to_user(user_kvm_nested_state->data, vmcs12, VMCS12_SIZE)) return -EFAULT; if (nested_cpu_has_shadow_vmcs(vmcs12) && vmcs12->vmcs_link_pointer != -1ull) { if (copy_to_user(user_kvm_nested_state->data + VMCS12_SIZE, - get_shadow_vmcs12(vcpu), sizeof(*vmcs12))) + get_shadow_vmcs12(vcpu), VMCS12_SIZE)) return -EFAULT; } -- cgit v1.2.3 From 8997f657001d1ac5042d368a936987c87251c5ec Mon Sep 17 00:00:00 2001 From: Yi Wang Date: Mon, 21 Jan 2019 15:27:05 +0800 Subject: kvm: vmx: fix some -Wmissing-prototypes warnings MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We get some warnings when building kernel with W=1: arch/x86/kvm/vmx/vmx.c:426:5: warning: no previous prototype for ‘kvm_fill_hv_flush_list_func’ [-Wmissing-prototypes] arch/x86/kvm/vmx/nested.c:58:6: warning: no previous prototype for ‘init_vmcs_shadow_fields’ [-Wmissing-prototypes] Make them static to fix this. Signed-off-by: Yi Wang Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kvm/vmx/nested.c') diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index ce8153923854..8ff20523661b 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -55,7 +55,7 @@ static u16 shadow_read_write_fields[] = { static int max_shadow_read_write_fields = ARRAY_SIZE(shadow_read_write_fields); -void init_vmcs_shadow_fields(void) +static void init_vmcs_shadow_fields(void) { int i, j; -- cgit v1.2.3 From ecec76885bcfe3294685dc363fd1273df0d5d65f Mon Sep 17 00:00:00 2001 From: Peter Shier Date: Thu, 11 Oct 2018 11:46:46 -0700 Subject: KVM: nVMX: unconditionally cancel preemption timer in free_nested (CVE-2019-7221) Bugzilla: 1671904 There are multiple code paths where an hrtimer may have been started to emulate an L1 VMX preemption timer that can result in a call to free_nested without an intervening L2 exit where the hrtimer is normally cancelled. Unconditionally cancel in free_nested to cover all cases. Embargoed until Feb 7th 2019. Signed-off-by: Peter Shier Reported-by: Jim Mattson Reviewed-by: Jim Mattson Reported-by: Felix Wilhelm Cc: stable@kernel.org Message-Id: <20181011184646.154065-1-pshier@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/x86/kvm/vmx/nested.c') diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 8ff20523661b..d8ea4ebd79e7 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -211,6 +211,7 @@ static void free_nested(struct kvm_vcpu *vcpu) if (!vmx->nested.vmxon && !vmx->nested.smm.vmxon) return; + hrtimer_cancel(&vmx->nested.preemption_timer); vmx->nested.vmxon = false; vmx->nested.smm.vmxon = false; free_vpid(vmx->nested.vpid02); -- cgit v1.2.3