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: 10156571 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 15EBE605BA for ; Thu, 11 Jan 2018 02:11:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F3F742874B for ; Thu, 11 Jan 2018 02:11:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E520B2874F; Thu, 11 Jan 2018 02:11:37 +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=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 075C62874B for ; Thu, 11 Jan 2018 02:11:36 +0000 (UTC) Received: (qmail 29745 invoked by uid 550); 11 Jan 2018 02:09:59 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 28592 invoked from network); 11 Jan 2018 02:09:53 -0000 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=iApn5Sc/E7UABNmax2BJ2L0QWD8dtyyiRss4Nzpe65m/WwAwFRU8DJy9ZNQ3JzNje/ tsIowxB4E8YaDGS+vsWRsHiZAWhNia++74OnUzVyfe/z5wqhfyLUwi40pHYNu6z+JaUK mMEvMiNPTxTDYDqS8trhNYUAVdgMQuZ0LMCkTmsbaq0zOAYfWo+AP+U/IrUv3qyqVsQS bhcgmipb8l++uzZHWHGdVVltf5Mp1F1H9ZEjxRTVMgM1d73nYpmldor7NKlyC5ibMFb/ EZRxhe+pIGTV+b04wMj/Ss2VhD2ExOW8vyRK7sYe2KyqQCzKqu5Rkeqalx5DLDDTKTyj HCQQ== X-Gm-Message-State: AKGB3mK2Of1Iiw8TwKiYjouKZpMAygPKJn+kVU1Qp/c54WlAUQLeaOZb OcuBLKAgWvumsejwfuq+EOEnzg== 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) 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 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 Subject: [kernel-hardening] [PATCH 36/38] kvm: x86: fix KVM_XEN_HVM_CONFIG ioctl 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; }