releases/3.1.1/kvm-s390-check-cpu_id-prior-to-using-it.patch

   1 From 4d47555a80495657161a7e71ec3014ff2021e450 Mon Sep 17 00:00:00 2001
   2 From: Carsten Otte <cotte@de.ibm.com>
   3 Date: Tue, 18 Oct 2011 12:27:12 +0200
   4 Subject: KVM: s390: check cpu_id prior to using it
   5
   6 From: Carsten Otte <cotte@de.ibm.com>
   7
   8 commit 4d47555a80495657161a7e71ec3014ff2021e450 upstream.
   9
  10 We use the cpu id provided by userspace as array index here. Thus we
  11 clearly need to check it first. Ooops.
  12
  13 Signed-off-by: Carsten Otte <cotte@de.ibm.com>
  14 Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
  15 Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
  16 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  17
  18 ---
  19  arch/s390/kvm/kvm-s390.c |   14 ++++++++++----
  20  1 file changed, 10 insertions(+), 4 deletions(-)
  21
  22 --- a/arch/s390/kvm/kvm-s390.c
  23 +++ b/arch/s390/kvm/kvm-s390.c
  24 @@ -312,11 +312,17 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu
  25  struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
  26                                       unsigned int id)
  27  {
  28 -       struct kvm_vcpu *vcpu = kzalloc(sizeof(struct kvm_vcpu), GFP_KERNEL);
  29 -       int rc = -ENOMEM;
  30 +       struct kvm_vcpu *vcpu;
  31 +       int rc = -EINVAL;
  32
  33 +       if (id >= KVM_MAX_VCPUS)
  34 +               goto out;
  35 +
  36 +       rc = -ENOMEM;
  37 +
  38 +       vcpu = kzalloc(sizeof(struct kvm_vcpu), GFP_KERNEL);
  39         if (!vcpu)
  40 -               goto out_nomem;
  41 +               goto out;
  42
  43         vcpu->arch.sie_block = (struct kvm_s390_sie_block *)
  44                                         get_zeroed_page(GFP_KERNEL);
  45 @@ -352,7 +358,7 @@ out_free_sie_block:
  46         free_page((unsigned long)(vcpu->arch.sie_block));
  47  out_free_cpu:
  48         kfree(vcpu);
  49 -out_nomem:
  50 +out:
  51         return ERR_PTR(rc);
  52  }
  53