[PATCH RESEND] kvm: Fix nonsense handling of compat ioctl

From: Alan Cox
Date: Mon Aug 20 2012 - 10:26:08 EST


From: Alan Cox <alan@xxxxxxxxxxxxxxx>

KVM_SET_SIGNAL_MASK passed a NULL argument leaves the on stack signal
sets uninitialized. It then passes them through to
kvm_vcpu_ioctl_set_sigmask.

We should be passing a NULL in this case not translated garbage.

Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
---

virt/kvm/kvm_main.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a2e85af..e47a7ca 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1975,9 +1975,10 @@ static long kvm_vcpu_compat_ioctl(struct file *filp,
if (copy_from_user(&csigset, sigmask_arg->sigset,
sizeof csigset))
goto out;
- }
- sigset_from_compat(&sigset, &csigset);
- r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset);
+ sigset_from_compat(&sigset, &csigset);
+ r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset);
+ } else
+ kvm_vcpu_ioctl_set_sigmask(vcpu, NULL);
break;
}
default:

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