Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754405AbeAKCTj (ORCPT + 1 other); Wed, 10 Jan 2018 21:19:39 -0500 Received: from mail-pf0-f194.google.com ([209.85.192.194]:38942 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753373AbeAKCTf (ORCPT ); Wed, 10 Jan 2018 21:19:35 -0500 X-Google-Smtp-Source: ACJfBosY3jfUbaE/EQIyBkHfxLjutv6k5hqHGCcjebynQV0LlqniiUPjjtu2D8Q26ZCW08IAuw+Qww== From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , Paolo Bonzini , kernel-hardening@lists.openwall.com, Christian Borntraeger , Christoffer Dall , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Linus Torvalds , David Windsor , Alexander Viro , Andrew Morton , Andy Lutomirski , Christoph Hellwig , Christoph Lameter , "David S. Miller" , Laura Abbott , Mark Rutland , "Martin K. Petersen" , Christian Borntraeger , Christoffer Dall , Dave Kleikamp , Jan Kara , Luis de Bethencourt , Marc Zyngier , Rik van Riel , Matthew Garrett , linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, netdev@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 35/38] kvm: whitelist struct kvm_vcpu_arch Date: Wed, 10 Jan 2018 18:03:07 -0800 Message-Id: <1515636190-24061-36-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1515636190-24061-1-git-send-email-keescook@chromium.org> References: <1515636190-24061-1-git-send-email-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: Paolo Bonzini On x86, ARM and s390, struct kvm_vcpu_arch has a usercopy region that is read and written by the KVM_GET/SET_CPUID2 ioctls (x86) or KVM_GET/SET_ONE_REG (ARM/s390). Without whitelisting the area, KVM is completely broken on those architectures with usercopy hardening enabled. For now, allow writing to the entire struct on all architectures. The KVM tree will not refine this to an architecture-specific subset of struct kvm_vcpu_arch. Cc: kernel-hardening@lists.openwall.com Cc: Kees Cook Cc: Christian Borntraeger Cc: Christoffer Dall Cc: Radim Krčmář Signed-off-by: Paolo Bonzini Acked-by: Christoffer Dall Acked-by: Marc Zyngier Acked-by: Christian Borntraeger Signed-off-by: Kees Cook --- virt/kvm/kvm_main.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index c422c10cd1dd..96689967f5c3 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -4029,8 +4029,12 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align, /* A kmem cache lets us meet the alignment requirements of fx_save. */ if (!vcpu_align) vcpu_align = __alignof__(struct kvm_vcpu); - kvm_vcpu_cache = kmem_cache_create("kvm_vcpu", vcpu_size, vcpu_align, - SLAB_ACCOUNT, NULL); + kvm_vcpu_cache = + kmem_cache_create_usercopy("kvm_vcpu", vcpu_size, vcpu_align, + SLAB_ACCOUNT, + offsetof(struct kvm_vcpu, arch), + sizeof_field(struct kvm_vcpu, arch), + NULL); if (!kvm_vcpu_cache) { r = -ENOMEM; goto out_free_3; -- 2.7.4