From patchwork Mon May 28 09:59:56 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 10431345 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 820DA602CB for ; Mon, 28 May 2018 10:53:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 692522895B for ; Mon, 28 May 2018 10:53:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5D6BB28C10; Mon, 28 May 2018 10:53:55 +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=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED 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 5FC532895B for ; Mon, 28 May 2018 10:53:53 +0000 (UTC) Received: (qmail 16064 invoked by uid 550); 28 May 2018 10:53:45 -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 Delivered-To: moderator for kernel-hardening@lists.openwall.com Received: (qmail 10023 invoked from network); 28 May 2018 10:15:06 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1527502494; bh=gnVyPjMYzKOVyXp2yZ3gIgdTgwpLV5XDOur452kJVWU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xinsf/IsMEkcyi1HBH7cllyrBxRNVQoF0Lntnw8n5xUQRjcqRA1UdEe9tLVPW+5au HaWCCttcMeEmCdj3SfiqHY93n6hrVTD21Fr2XFCyA9O/arWjN7AR+4dM7XNDDKSREG Y6Cf/ETSVnlpsyO4u55KAZ9Po047jDXH1Zgtr/pg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, kernel-hardening@lists.openwall.com, Kees Cook , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Paolo Bonzini , Sasha Levin Subject: [PATCH 4.4 022/268] kvm: x86: fix KVM_XEN_HVM_CONFIG ioctl Date: Mon, 28 May 2018 11:59:56 +0200 Message-Id: <20180528100204.614345592@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180528100202.045206534@linuxfoundation.org> References: <20180528100202.045206534@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 X-Virus-Scanned: ClamAV using ClamSMTP 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Bonzini [ 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 Cc: Radim Krčmář Signed-off-by: Paolo Bonzini Signed-off-by: Kees Cook Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/x86.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3973,13 +3973,14 @@ 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; }