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authorAndre Przywara <andre.przywara@linaro.org>2013-05-09 00:28:06 +0200
committerGleb Natapov <gleb@redhat.com>2013-06-03 10:58:56 +0300
commite8180dcaa8470ceca21109f143876fdcd9fe050a (patch)
treee5c4f6dc1e1b0fc3aa34e76a15ccefbdd86ac983 /arch
parented829857b36bc0155d85b661ab227df57ac898f3 (diff)
downloadvexpress-lsk-e8180dcaa8470ceca21109f143876fdcd9fe050a.tar.gz
ARM: KVM: prevent NULL pointer dereferences with KVM VCPU ioctl
Some ARM KVM VCPU ioctls require the vCPU to be properly initialized with the KVM_ARM_VCPU_INIT ioctl before being used with further requests. KVM_RUN checks whether this initialization has been done, but other ioctls do not. Namely KVM_GET_REG_LIST will dereference an array with index -1 without initialization and thus leads to a kernel oops. Fix this by adding checks before executing the ioctl handlers. [ Removed superflous comment from static function - Christoffer ] Changes from v1: * moved check into a static function with a meaningful name Signed-off-by: Andre Przywara <andre.przywara@linaro.org> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/kvm/arm.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 37d216d814c..ef1703b9587 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -492,6 +492,11 @@ static void vcpu_pause(struct kvm_vcpu *vcpu)
wait_event_interruptible(*wq, !vcpu->arch.pause);
}
+static int kvm_vcpu_initialized(struct kvm_vcpu *vcpu)
+{
+ return vcpu->arch.target >= 0;
+}
+
/**
* kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code
* @vcpu: The VCPU pointer
@@ -508,8 +513,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
int ret;
sigset_t sigsaved;
- /* Make sure they initialize the vcpu with KVM_ARM_VCPU_INIT */
- if (unlikely(vcpu->arch.target < 0))
+ if (unlikely(!kvm_vcpu_initialized(vcpu)))
return -ENOEXEC;
ret = kvm_vcpu_first_run_init(vcpu);
@@ -710,6 +714,10 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
case KVM_SET_ONE_REG:
case KVM_GET_ONE_REG: {
struct kvm_one_reg reg;
+
+ if (unlikely(!kvm_vcpu_initialized(vcpu)))
+ return -ENOEXEC;
+
if (copy_from_user(&reg, argp, sizeof(reg)))
return -EFAULT;
if (ioctl == KVM_SET_ONE_REG)
@@ -722,6 +730,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
struct kvm_reg_list reg_list;
unsigned n;
+ if (unlikely(!kvm_vcpu_initialized(vcpu)))
+ return -ENOEXEC;
+
if (copy_from_user(&reg_list, user_list, sizeof(reg_list)))
return -EFAULT;
n = reg_list.n;