diff options
Diffstat (limited to 'arch/powerpc/kvm/book3s_64_vio.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_64_vio.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 9a3f2646ecc7..3c17977ffea6 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -599,6 +599,24 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu, ret = kvmppc_tce_validate(stt, tce); if (ret != H_SUCCESS) goto unlock_exit; + } + + for (i = 0; i < npages; ++i) { + /* + * This looks unsafe, because we validate, then regrab + * the TCE from userspace which could have been changed by + * another thread. + * + * But it actually is safe, because the relevant checks will be + * re-executed in the following code. If userspace tries to + * change this dodgily it will result in a messier failure mode + * but won't threaten the host. + */ + if (get_user(tce, tces + i)) { + ret = H_TOO_HARD; + goto unlock_exit; + } + tce = be64_to_cpu(tce); if (kvmppc_gpa_to_ua(vcpu->kvm, tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), |