From 78e546c824fa8f96d323b7edd6f5cad5b74af057 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 1 Jun 2016 14:09:20 +0200 Subject: [PATCH] KVM: fail KVM_SET_VCPU_EVENTS with invalid exception number MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This cannot be returned by KVM_GET_VCPU_EVENTS, so it is okay to return EINVAL. It causes a WARN from exception_type: WARNING: CPU: 3 PID: 16732 at arch/x86/kvm/x86.c:345 exception_type+0x49/0x50 [kvm]() CPU: 3 PID: 16732 Comm: a.out Tainted: G W 4.4.6-300.fc23.x86_64 #1 Hardware name: LENOVO 2325F51/2325F51, BIOS G2ET32WW (1.12 ) 05/30/2012 0000000000000286 000000006308a48b ffff8800bec7fcf8 ffffffff813b542e 0000000000000000 ffffffffa0966496 ffff8800bec7fd30 ffffffff810a40f2 ffff8800552a8000 0000000000000000 00000000002c267c 0000000000000001 Call Trace: [] dump_stack+0x63/0x85 [] warn_slowpath_common+0x82/0xc0 [] warn_slowpath_null+0x1a/0x20 [] exception_type+0x49/0x50 [kvm] [] kvm_arch_vcpu_ioctl_run+0x10a2/0x14e0 [kvm] [] kvm_vcpu_ioctl+0x33d/0x620 [kvm] [] do_vfs_ioctl+0x298/0x480 [] SyS_ioctl+0x79/0x90 [] entry_SYSCALL_64_fastpath+0x12/0x71 ---[ end trace b1a0391266848f50 ]--- Testcase (beautified/reduced from syzkaller output): #include #include #include #include #include #include #include long r[31]; int main() { memset(r, -1, sizeof(r)); r[2] = open("/dev/kvm", O_RDONLY); r[3] = ioctl(r[2], KVM_CREATE_VM, 0); r[7] = ioctl(r[3], KVM_CREATE_VCPU, 0); struct kvm_vcpu_events ve = { .exception.injected = 1, .exception.nr = 0xd4 }; r[27] = ioctl(r[7], KVM_SET_VCPU_EVENTS, &ve); r[30] = ioctl(r[7], KVM_RUN, 0); return 0; } Reported-by: Dmitry Vyukov Signed-off-by: Paolo Bonzini Signed-off-by: Radim Krčmář --- arch/x86/kvm/x86.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 990929b..d9db2a4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2973,6 +2973,10 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu, | KVM_VCPUEVENT_VALID_SMM)) return -EINVAL; + if (events->exception.injected && + (events->exception.nr > 31 || events->exception.nr == NMI_VECTOR)) + return -EINVAL; + process_nmi(vcpu); vcpu->arch.exception.pending = events->exception.injected; vcpu->arch.exception.nr = events->exception.nr; -- 2.7.4