Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422822AbbFEOFt (ORCPT ); Fri, 5 Jun 2015 10:05:49 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:60000 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754841AbbFEOAG (ORCPT ); Fri, 5 Jun 2015 10:00:06 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Rusty Russell , Linus Torvalds , Luis Henriques Subject: [PATCH 3.16.y-ckt 096/110] lguest: fix out-by-one error in address checking. Date: Fri, 5 Jun 2015 14:58:19 +0100 Message-Id: <1433512713-22984-97-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1433512713-22984-1-git-send-email-luis.henriques@canonical.com> References: <1433512713-22984-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1459 Lines: 38 3.16.7-ckt13 -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: Luis Henriques --- 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 0bf1e4edf04d..19da22249bd8 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); } /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/