kvm: x86: fix KVM_XEN_HVM_CONFIG ioctl
authorPaolo Bonzini <pbonzini@redhat.com>
Thu, 26 Oct 2017 13:45:47 +0000 (15:45 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 26 Apr 2018 09:02:03 +0000 (11:02 +0200)
commit8e40eae185f85426d9d6d667f2e55aa721b84e0d
tree50f1d764a504d80f4a1cb3d83aae088851689788
parent3f3017fa1540cf5eb6bd6af1f76f76a831c99652
kvm: x86: fix KVM_XEN_HVM_CONFIG ioctl

[ Upstream commit 51776043afa415435c7e4636204fbe4f7edc4501 ]

This ioctl is obsolete (it was used by Xenner as far as I know) but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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/kvm/x86.c