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| author | Andre Przywara <andre.przywara@linaro.org> | 2013-05-09 00:28:06 +0200 |
|---|---|---|
| committer | Gleb Natapov <gleb@redhat.com> | 2013-06-03 09:58:56 +0200 |
| commit | e8180dcaa8470ceca21109f143876fdcd9fe050a (patch) | |
| tree | e5c4f6dc1e1b0fc3aa34e76a15ccefbdd86ac983 /arch | |
| parent | mips/kvm: Use ENOIOCTLCMD to indicate unimplemented ioctls. (diff) | |
| download | linux-e8180dcaa8470ceca21109f143876fdcd9fe050a.tar.xz linux-e8180dcaa8470ceca21109f143876fdcd9fe050a.zip | |
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.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 37d216d814cd..ef1703b9587b 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(®, 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(®_list, user_list, sizeof(reg_list))) return -EFAULT; n = reg_list.n; |