From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935588AbbGHPzl (ORCPT ); Wed, 8 Jul 2015 11:55:41 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:47837 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753491AbbGHPlA (ORCPT ); Wed, 8 Jul 2015 11:41:00 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Rusty Russell , Linus Torvalds , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 13/56] lguest: fix out-by-one error in address checking. Date: Wed, 8 Jul 2015 08:39:54 -0700 Message-Id: <1436370037-25874-14-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1436370037-25874-1-git-send-email-kamal@canonical.com> References: <1436370037-25874-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11-ckt23 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Rusty Russell commit 83a35114d0e4583e6b0ca39502e68b6a92e2910c upstream. This bug has been there since day 1; addresses in the top guest physical page weren't considered valid. You could map that page (the check in check_gpte() is correct), but if a guest tried to put a pagetable there we'd check that address manually when walking it, and kill the guest. Signed-off-by: Rusty Russell Signed-off-by: Linus Torvalds Signed-off-by: Kamal Mostafa --- drivers/lguest/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c index 0bf1e4e..19da222 100644 --- a/drivers/lguest/core.c +++ b/drivers/lguest/core.c @@ -176,7 +176,7 @@ static void unmap_switcher(void) bool lguest_address_ok(const struct lguest *lg, unsigned long addr, unsigned long len) { - return (addr+len) / PAGE_SIZE < lg->pfn_limit && (addr+len >= addr); + return addr+len <= lg->pfn_limit * PAGE_SIZE && (addr+len >= addr); } /* -- 1.9.1