diff options
Diffstat (limited to 'KVM-x86-Improve-thread-safety-in-pit.patch')
| -rw-r--r-- | KVM-x86-Improve-thread-safety-in-pit.patch | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/KVM-x86-Improve-thread-safety-in-pit.patch b/KVM-x86-Improve-thread-safety-in-pit.patch new file mode 100644 index 000000000..e6ba59924 --- /dev/null +++ b/KVM-x86-Improve-thread-safety-in-pit.patch @@ -0,0 +1,36 @@ +From: Andy Honig <ahonig@google.com> +Date: Fri, 24 Oct 2014 17:07:14 +0200 +Subject: [PATCH] KVM: x86: Improve thread safety in pit + +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. + +Cc: stable@vger.kernel.org +Signed-off-by: Andrew Honig <ahonig@google.com> +Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> +--- + arch/x86/kvm/i8254.c | 2 ++ + 1 file changed, 2 insertions(+) + +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) +-- +1.9.3 + |