From patchwork Thu Jan 11 02:03:08 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 10156633 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B6713605BA for ; Thu, 11 Jan 2018 02:14:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A245F2874C for ; Thu, 11 Jan 2018 02:14:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 946AF2874F; Thu, 11 Jan 2018 02:14:33 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 321702874C for ; Thu, 11 Jan 2018 02:14:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754206AbeAKCOS (ORCPT ); Wed, 10 Jan 2018 21:14:18 -0500 Received: from mail-pg0-f67.google.com ([74.125.83.67]:42188 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753769AbeAKCJm (ORCPT ); Wed, 10 Jan 2018 21:09:42 -0500 Received: by mail-pg0-f67.google.com with SMTP id q67so1620464pga.9 for ; Wed, 10 Jan 2018 18:09:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=8qTxpXzy0LmGyvde25ZLpEMcEHuJnukJthDsJQWjpv8=; b=Swj7DWQ9+Bjg3NKPmzHMeIIlF4nGP4RGdcoLr+phpY5Z2YnsOM4QW1TFxS0TXs+RpW Y9YwGCF6iPDop+5bA47csryV/JngJcNwzzLoP14tWs+X+7H2PxdwfuYTQqANvzYfvHGS 5+/LS39i6w+Wva2woVmm++zehPkGw9/xSfQ+M= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=8qTxpXzy0LmGyvde25ZLpEMcEHuJnukJthDsJQWjpv8=; b=ej77V8fvZm+vOOAS9qBbHXi32Z+fPD0Q+DfD3n2w3ZhYX6KCtmXnPAkvFAyMKQgO6X pMkIyWMh6zk/ZfwwXEesckle7QmF1TaEdAtsyzU6fM/8Iv52mwud4vI5VHBDJjBwv7z6 7JL8sdo9HP98lD29G/dvc4DtnpFQkEzQNO3jTFLGB0LVVaFMjir6lUZb16JT9De74DHX uSUO6JZ424y3aXDwpaCVINgNGPy7iY9ubBk7JN5THpokGgags+pl675bIXba8+SV4a7A RcKaokydUx24d9wQh7oVQcceq0jJEQbjdFQmL7klPdygIJ7JOiqUtT2qsGkoIPrLWB2j Amaw== X-Gm-Message-State: AKGB3mJ7edufYYI4Nk5Uq/IkoFzxZ1ogb4hptqxaowtwrCqBaYWeqwUT IpOnJs5EAqpiA8EUC2o+NFtUow== X-Google-Smtp-Source: ACJfBovxHB5zdPhAkBxNZFEx8m9EZprTNXvCllA9bjLjpbUqXbAyLoNHNEltj2/Ze9qQkC0nYCPUdA== X-Received: by 10.159.252.75 with SMTP id t11mr16608295plz.324.1515636582148; Wed, 10 Jan 2018 18:09:42 -0800 (PST) Received: from www.outflux.net (173-164-112-133-Oregon.hfc.comcastbusiness.net. [173.164.112.133]) by smtp.gmail.com with ESMTPSA id y3sm33218063pfe.75.2018.01.10.18.09.36 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 10 Jan 2018 18:09:38 -0800 (PST) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , Paolo Bonzini , kernel-hardening@lists.openwall.com, =?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 36/38] kvm: x86: fix KVM_XEN_HVM_CONFIG ioctl Date: Wed, 10 Jan 2018 18:03:08 -0800 Message-Id: <1515636190-24061-37-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 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Paolo Bonzini 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 Cc: Radim Krčmář Signed-off-by: Paolo Bonzini Signed-off-by: Kees Cook --- arch/x86/kvm/x86.c | 7 ++++--- 1 file 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 @@ long kvm_arch_vm_ioctl(struct file *filp, 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; }