* [PATCH MANUALSEL 4.19] KVM: Don't null dereference ops->destroy
@ 2022-06-14 2:12 Sasha Levin
0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2022-06-14 2:12 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Alexey Kardashevskiy, Paolo Bonzini, Sasha Levin, kvm
From: Alexey Kardashevskiy <aik@ozlabs.ru>
[ Upstream commit e8bc2427018826e02add7b0ed0fc625a60390ae5 ]
A KVM device cleanup happens in either of two callbacks:
1) destroy() which is called when the VM is being destroyed;
2) release() which is called when a device fd is closed.
Most KVM devices use 1) but Book3s's interrupt controller KVM devices
(XICS, XIVE, XIVE-native) use 2) as they need to close and reopen during
the machine execution. The error handling in kvm_ioctl_create_device()
assumes destroy() is always defined which leads to NULL dereference as
discovered by Syzkaller.
This adds a checks for destroy!=NULL and adds a missing release().
This is not changing kvm_destroy_devices() as devices with defined
release() should have been removed from the KVM devices list by then.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
virt/kvm/kvm_main.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3d45ce134227..d3a2eb8ee04e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3193,8 +3193,11 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
kvm_put_kvm(kvm);
mutex_lock(&kvm->lock);
list_del(&dev->vm_node);
+ if (ops->release)
+ ops->release(dev);
mutex_unlock(&kvm->lock);
- ops->destroy(dev);
+ if (ops->destroy)
+ ops->destroy(dev);
return ret;
}
--
2.35.1
^ permalink raw reply related [flat|nested] only message in thread
only message in thread, other threads:[~2022-06-14 2:35 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-06-14 2:12 [PATCH MANUALSEL 4.19] KVM: Don't null dereference ops->destroy Sasha Levin
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).