From: Carsten Otte <cotte@de.ibm.com>
Date: Tue, 18 Oct 2011 10:27:12 +0000 (+0200)
Subject: KVM: s390: check cpu_id prior to using it
X-Git-Tag: v2.6.32.47~36
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=4796d51e7cedb82b44e9e2375b48ef846de47b08;p=karo-tx-linux.git

KVM: s390: check cpu_id prior to using it

commit 4d47555a80495657161a7e71ec3014ff2021e450 upstream.

We use the cpu id provided by userspace as array index here. Thus we
clearly need to check it first. Ooops.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 75fbf199d71e..693dee728ce4 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -308,11 +308,17 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
 				      unsigned int id)
 {
-	struct kvm_vcpu *vcpu = kzalloc(sizeof(struct kvm_vcpu), GFP_KERNEL);
-	int rc = -ENOMEM;
+	struct kvm_vcpu *vcpu;
+	int rc = -EINVAL;
+
+	if (id >= KVM_MAX_VCPUS)
+		goto out;
+
+	rc = -ENOMEM;
 
+	vcpu = kzalloc(sizeof(struct kvm_vcpu), GFP_KERNEL);
 	if (!vcpu)
-		goto out_nomem;
+		goto out;
 
 	vcpu->arch.sie_block = (struct kvm_s390_sie_block *)
 					get_zeroed_page(GFP_KERNEL);
@@ -347,7 +353,7 @@ out_free_sie_block:
 	free_page((unsigned long)(vcpu->arch.sie_block));
 out_free_cpu:
 	kfree(vcpu);
-out_nomem:
+out:
 	return ERR_PTR(rc);
 }