From patchwork Thu Apr 18 09:16:21 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 237533 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 887902C01EA for ; Thu, 18 Apr 2013 19:18:15 +1000 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1USkym-0003HS-Gd; Thu, 18 Apr 2013 09:18:08 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1USkya-0002wJ-I6 for kernel-team@lists.ubuntu.com; Thu, 18 Apr 2013 09:17:56 +0000 Received: from bl20-140-10.dsl.telepac.pt ([2.81.140.10] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1USkya-0002Cl-BP; Thu, 18 Apr 2013 09:17:56 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 36/72] KVM: Fix bounds checking in ioapic indirect register reads (CVE-2013-1798) Date: Thu, 18 Apr 2013 10:16:21 +0100 Message-Id: <1366276617-3553-37-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1366276617-3553-1-git-send-email-luis.henriques@canonical.com> References: <1366276617-3553-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Cc: Andrew Honig , Marcelo Tosatti X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.5.7.11 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Honig commit a2c118bfab8bc6b8bb213abfc35201e441693d55 upstream. If the guest specifies a IOAPIC_REG_SELECT with an invalid value and follows that with a read of the IOAPIC_REG_WINDOW KVM does not properly validate that request. ioapic_read_indirect contains an ASSERT(redir_index < IOAPIC_NUM_PINS), but the ASSERT has no effect in non-debug builds. In recent kernels this allows a guest to cause a kernel oops by reading invalid memory. In older kernels (pre-3.3) this allows a guest to read from large ranges of host memory. Tested: tested against apic unit tests. Signed-off-by: Andrew Honig Signed-off-by: Marcelo Tosatti Signed-off-by: Luis Henriques --- virt/kvm/ioapic.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c index 26fd54d..fdb1faf 100644 --- a/virt/kvm/ioapic.c +++ b/virt/kvm/ioapic.c @@ -73,9 +73,12 @@ static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic, u32 redir_index = (ioapic->ioregsel - 0x10) >> 1; u64 redir_content; - ASSERT(redir_index < IOAPIC_NUM_PINS); + if (redir_index < IOAPIC_NUM_PINS) + redir_content = + ioapic->redirtbl[redir_index].bits; + else + redir_content = ~0ULL; - redir_content = ioapic->redirtbl[redir_index].bits; result = (ioapic->ioregsel & 0x1) ? (redir_content >> 32) & 0xffffffff : redir_content & 0xffffffff;