[PATCH 3.2 086/102] KVM: x86: Improve thread safety in pit
3.2.64-rc1 review patch. If anyone has any objections, please let me know. -- From: Andy Honig 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 Signed-off-by: Paolo Bonzini [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- arch/x86/kvm/i8254.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -264,8 +264,10 @@ void __kvm_migrate_pit_timer(struct kvm_ return; timer = >pit_state.pit_timer.timer; + mutex_lock(>pit_state.lock); if (hrtimer_cancel(timer)) hrtimer_start_expires(timer, HRTIMER_MODE_ABS); + mutex_unlock(>pit_state.lock); } static void destroy_pit_timer(struct kvm_pit *pit) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 3.2 086/102] KVM: x86: Improve thread safety in pit
3.2.64-rc1 review patch. If anyone has any objections, please let me know. -- From: Andy Honig aho...@google.com 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 aho...@google.com Signed-off-by: Paolo Bonzini pbonz...@redhat.com [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings b...@decadent.org.uk --- arch/x86/kvm/i8254.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -264,8 +264,10 @@ void __kvm_migrate_pit_timer(struct kvm_ return; timer = pit-pit_state.pit_timer.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) -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
