diff options
| author | Andy Honig <ahonig@google.com> | 2014-08-27 14:42:54 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-14 10:10:28 -0800 |
| commit | 9ed3340ff2253a769253e559d8d0f240047a3757 (patch) | |
| tree | 94d8f8ec8fa411f7d96dd0a60e77c999b1cb4a77 /arch | |
| parent | b1bc00a31682b0e2dc1f536d76dfd36bcae3fa14 (diff) | |
KVM: x86: Improve thread safety in pit
commit 2febc839133280d5a5e8e1179c94ea674489dae2 upstream.
There's a race condition in the PIT emulation code in KVM. In
__kvm_migrate_pit_timer the pit_timer object is accessed without
synchronization. If the race condition occurs at the wrong time this
can crash the host kernel.
This fixes CVE-2014-3611.
Signed-off-by: Andrew Honig <ahonig@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/i8254.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 518d86471b76..298781d4cfb4 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -262,8 +262,10 @@ void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu) return; timer = &pit->pit_state.timer; + mutex_lock(&pit->pit_state.lock); if (hrtimer_cancel(timer)) hrtimer_start_expires(timer, HRTIMER_MODE_ABS); + mutex_unlock(&pit->pit_state.lock); } static void destroy_pit_timer(struct kvm_pit *pit) |