diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2017-10-26 15:45:47 +0200 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2018-01-15 12:08:07 -0800 |
| commit | 51776043afa415435c7e4636204fbe4f7edc4501 (patch) | |
| tree | 7b3364b6df0e880aa682ec710a69b11953e4ad79 /arch/x86/kvm/x86.c | |
| parent | 46515736f8687c5dbde5637ca2f2678055c9c0f7 (diff) | |
| download | lwn-51776043afa415435c7e4636204fbe4f7edc4501.tar.gz lwn-51776043afa415435c7e4636204fbe4f7edc4501.zip | |
kvm: x86: fix KVM_XEN_HVM_CONFIG ioctl
This ioctl is obsolete (it was used by Xenner as far as I know) but
still let's not break it gratuitously... Its handler is copying
directly into struct kvm. Go through a bounce buffer instead, with
the added benefit that we can actually do something useful with the
flags argument---the previous code was exiting with -EINVAL but still
doing the copy.
This technically is a userspace ABI breakage, but since no one should be
using the ioctl, it's a good occasion to see if someone actually
complains.
Cc: kernel-hardening@lists.openwall.com
Cc: Kees Cook <keescook@chromium.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index eee8e7faf1af..6c16461e3a86 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4238,13 +4238,14 @@ set_identity_unlock: mutex_unlock(&kvm->lock); break; case KVM_XEN_HVM_CONFIG: { + struct kvm_xen_hvm_config xhc; r = -EFAULT; - if (copy_from_user(&kvm->arch.xen_hvm_config, argp, - sizeof(struct kvm_xen_hvm_config))) + if (copy_from_user(&xhc, argp, sizeof(xhc))) goto out; r = -EINVAL; - if (kvm->arch.xen_hvm_config.flags) + if (xhc.flags) goto out; + memcpy(&kvm->arch.xen_hvm_config, &xhc, sizeof(xhc)); r = 0; break; } |